[Intel-gfx] [PATCH 07/11] drm/helper: add Displayport multi-stream helper (v0.5)

[Todd Previte]

This patch is a monster, but that's to be expected with MST, I suppose. 
:) It has some formatting issues (lines over 80 characters in length) 
but that can be cleaned up later (as far as I'm concerned). Otherwise I 
don't see anything glaring here, so...

Reviewed-by: Todd Previte <tprevite at gmail.com>

> Dave Airlie <mailto:airlied at gmail.com>
> Tuesday, May 20, 2014 7:55 PM
> From: Dave Airlie <airlied at redhat.com>
>
> This is the initial import of the helper for displayport multistream.
>
> It consists of a topology manager, init/destroy/set mst state
>
> It supports DP 1.2 MST sideband msg protocol handler - via hpd irqs
>
> connector detect and edid retrieval interface.
>
> It supports i2c device over DP 1.2 sideband msg protocol (EDID reads only)
>
> bandwidth manager API via vcpi allocation and payload updating,
> along with a helper to check the ACT status.
>
> Objects:
> MST topology manager - one per toplevel MST capable GPU port - not 
> sure if this should be higher level again
> MST branch unit - one instance per plugged branching unit - one at top 
> of hierarchy - others hanging from ports
> MST port - one port per port reported by branching units, can have MST 
> units hanging from them as well.
>
> Changes since initial posting:
> a) add a mutex responsbile for the queues, it locks the sideband and 
> msg slots, and msgs to transmit state
> b) add worker to handle connection state change events, for MST device 
> chaining and hotplug
> c) add a payload spinlock
> d) add path sideband msg support
> e) fixup enum path resources transmit
> f) reduce max dpcd msg to 16, as per DP1.2 spec.
> g) separate tx queue kicking from irq processing and move irq acking 
> back to drivers.
>
> Changes since v0.2:
> a) reorganise code,
> b) drop ACT forcing code
> c) add connector naming interface using path property
> d) add topology dumper helper
> e) proper reference counting and lookup for ports and mstbs.
> f) move tx kicking into a workq
> g) add aux locking - this should be redone
> h) split teardown into two parts
> i) start working on documentation on interface.
>
> Changes since v0.3:
> a) vc payload locking and tracking fixes
> b) add hotplug callback into driver - replaces crazy return 1 scheme
> c) txmsg + mst branch device refcount fixes
> d) don't bail on mst shutdown if device is gone
> e) change irq handler to take all 4 bytes of SINK_COUNT + ESI vectors
> f) make DP payload updates timeout longer - observed on docking 
> station redock
> g) add more info to debugfs dumper
>
> Changes since v0.4:
> a) suspend/resume support
> b) more debugging in debugfs
>
> TODO:
> misc features
>
> Signed-off-by: Dave Airlie <airlied at redhat.com>
> ---
> Documentation/DocBook/drm.tmpl | 6 +
> drivers/gpu/drm/Makefile | 2 +-
> drivers/gpu/drm/drm_dp_mst_topology.c | 2739 
> +++++++++++++++++++++++++++++++++
> include/drm/drm_dp_mst_helper.h | 507 ++++++
> 4 files changed, 3253 insertions(+), 1 deletion(-)
> create mode 100644 drivers/gpu/drm/drm_dp_mst_topology.c
> create mode 100644 include/drm/drm_dp_mst_helper.h
>
> diff --git a/Documentation/DocBook/drm.tmpl 
> b/Documentation/DocBook/drm.tmpl
> index 83dd0b0..1883976 100644
> --- a/Documentation/DocBook/drm.tmpl
> +++ b/Documentation/DocBook/drm.tmpl
> @@ -2296,6 +2296,12 @@ void intel_crt_init(struct drm_device *dev)
> !Edrivers/gpu/drm/drm_dp_helper.c
> </sect2>
> <sect2>
> + <title>Display Port MST Helper Functions Reference</title>
> +!Pdrivers/gpu/drm/drm_dp_mst_topology.c dp mst helper
> +!Iinclude/drm/drm_dp_mst_helper.h
> +!Edrivers/gpu/drm/drm_dp_mst_topology.c
> + </sect2>
> + <sect2>
> <title>EDID Helper Functions Reference</title>
> !Edrivers/gpu/drm/drm_edid.c
> </sect2>
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index 48e38ba..712b73e 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -23,7 +23,7 @@ drm-$(CONFIG_DRM_PANEL) += drm_panel.o
>
> drm-usb-y := drm_usb.o
>
> -drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o
> +drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o 
> drm_probe_helper.o drm_dp_mst_topology.o
> drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
> drm_kms_helper-$(CONFIG_DRM_KMS_FB_HELPER) += drm_fb_helper.o
> drm_kms_helper-$(CONFIG_DRM_KMS_CMA_HELPER) += drm_fb_cma_helper.o
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c 
> b/drivers/gpu/drm/drm_dp_mst_topology.c
> new file mode 100644
> index 0000000..ebd9292
> --- /dev/null
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -0,0 +1,2739 @@
> +/*
> + * Copyright © 2014 Red Hat
> + *
> + * Permission to use, copy, modify, distribute, and sell this 
> software and its
> + * documentation for any purpose is hereby granted without fee, 
> provided that
> + * the above copyright notice appear in all copies and that both that 
> copyright
> + * notice and this permission notice appear in supporting 
> documentation, and
> + * that the name of the copyright holders not be used in advertising or
> + * publicity pertaining to distribution of the software without specific,
> + * written prior permission. The copyright holders make no 
> representations
> + * about the suitability of this software for any purpose. It is 
> provided "as
> + * is" without express or implied warranty.
> + *
> + * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS 
> SOFTWARE,
> + * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
> + * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, 
> INDIRECT OR
> + * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 
> LOSS OF USE,
> + * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
> + * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 
> PERFORMANCE
> + * OF THIS SOFTWARE.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/delay.h>
> +#include <linux/init.h>
> +#include <linux/errno.h>
> +#include <linux/sched.h>
> +#include <linux/i2c.h>
> +#include <drm/drm_dp_mst_helper.h>
> +#include <drm/drmP.h>
> +
> +#include <drm/drm_fixed.h>
> +
> +/**
> + * DOC: dp mst helper
> + *
> + * These functions contain parts of the DisplayPort 1.2a MultiStream 
> Transport
> + * protocol. The helpers contain a topology manager and bandwidth 
> manager.
> + * The helpers encapsulate the sending and received of sideband msgs.
> + */
> +static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
> + char *buf);
> +static int test_calc_pbn_mode(void);
> +
> +static void drm_dp_put_port(struct drm_dp_mst_port *port);
> +
> +static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
> + int id,
> + struct drm_dp_payload *payload);
> +
> +static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_mst_port *port,
> + int offset, int size, u8 *bytes);
> +
> +static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_mst_branch *mstb);
> +static int drm_dp_send_enum_path_resources(struct 
> drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_mst_branch *mstb,
> + struct drm_dp_mst_port *port);
> +static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
> + u8 *guid);
> +
> +static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux);
> +static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_aux *aux);
> +static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
> +/* sideband msg handling */
> +static u8 drm_dp_msg_header_crc4(const uint8_t *data, size_t num_nibbles)
> +{
> + u8 bitmask = 0x80;
> + u8 bitshift = 7;
> + u8 array_index = 0;
> + int number_of_bits = num_nibbles * 4;
> + u8 remainder = 0;
> +
> + while (number_of_bits != 0) {
> + number_of_bits--;
> + remainder <<= 1;
> + remainder |= (data[array_index] & bitmask) >> bitshift;
> + bitmask >>= 1;
> + bitshift--;
> + if (bitmask == 0) {
> + bitmask = 0x80;
> + bitshift = 7;
> + array_index++;
> + }
> + if ((remainder & 0x10) == 0x10)
> + remainder ^= 0x13;
> + }
> +
> + number_of_bits = 4;
> + while (number_of_bits != 0) {
> + number_of_bits--;
> + remainder <<= 1;
> + if ((remainder & 0x10) != 0)
> + remainder ^= 0x13;
> + }
> +
> + return remainder;
> +}
> +
> +static u8 drm_dp_msg_data_crc4(const uint8_t *data, u8 number_of_bytes)
> +{
> + u8 bitmask = 0x80;
> + u8 bitshift = 7;
> + u8 array_index = 0;
> + int number_of_bits = number_of_bytes * 8;
> + u16 remainder = 0;
> +
> + while (number_of_bits != 0) {
> + number_of_bits--;
> + remainder <<= 1;
> + remainder |= (data[array_index] & bitmask) >> bitshift;
> + bitmask >>= 1;
> + bitshift--;
> + if (bitmask == 0) {
> + bitmask = 0x80;
> + bitshift = 7;
> + array_index++;
> + }
> + if ((remainder & 0x100) == 0x100)
> + remainder ^= 0xd5;
> + }
> +
> + number_of_bits = 8;
> + while (number_of_bits != 0) {
> + number_of_bits--;
> + remainder <<= 1;
> + if ((remainder & 0x100) != 0)
>
> + remainder ^= 0xd5;
> + }
> +
> + return remainder & 0xff;
> +}
> +static inline u8 drm_dp_calc_sb_hdr_size(struct 
> drm_dp_sideband_msg_hdr *hdr)
> +{
> + u8 size = 3;
> + size += (hdr->lct / 2);
> + return size;
> +}
> +
> +static void drm_dp_encode_sideband_msg_hdr(struct 
> drm_dp_sideband_msg_hdr *hdr,
> + u8 *buf, int *len)
> +{
> + int idx = 0;
> + int i;
> + u8 crc4;
> + buf[idx++] = ((hdr->lct & 0xf) << 4) | (hdr->lcr & 0xf);
> + for (i = 0; i < (hdr->lct / 2); i++)
> + buf[idx++] = hdr->rad[i];
> + buf[idx++] = (hdr->broadcast << 7) | (hdr->path_msg << 6) |
> + (hdr->msg_len & 0x3f);
> + buf[idx++] = (hdr->somt << 7) | (hdr->eomt << 6) | (hdr->seqno << 4);
> +
> + crc4 = drm_dp_msg_header_crc4(buf, (idx * 2) - 1);
> + buf[idx - 1] |= (crc4 & 0xf);
> +
> + *len = idx;
> +}
> +
> +static bool drm_dp_decode_sideband_msg_hdr(struct 
> drm_dp_sideband_msg_hdr *hdr,
> + u8 *buf, int buflen, u8 *hdrlen)
> +{
> + u8 crc4;
> + u8 len;
> + int i;
> + u8 idx;
> + if (buf[0] == 0)
> + return false;
> + len = 3;
> + len += ((buf[0] & 0xf0) >> 4) / 2;
> + if (len > buflen)
> + return false;
> + crc4 = drm_dp_msg_header_crc4(buf, (len * 2) - 1);
> +
> + if ((crc4 & 0xf) != (buf[len - 1] & 0xf)) {
> + DRM_DEBUG_KMS("crc4 mismatch 0x%x 0x%x\n", crc4, buf[len - 1]);
> + return false;
> + }
> +
> + hdr->lct = (buf[0] & 0xf0) >> 4;
> + hdr->lcr = (buf[0] & 0xf);
> + idx = 1;
> + for (i = 0; i < (hdr->lct / 2); i++)
> + hdr->rad[i] = buf[idx++];
> + hdr->broadcast = (buf[idx] >> 7) & 0x1;
> + hdr->path_msg = (buf[idx] >> 6) & 0x1;
> + hdr->msg_len = buf[idx] & 0x3f;
> + idx++;
> + hdr->somt = (buf[idx] >> 7) & 0x1;
> + hdr->eomt = (buf[idx] >> 6) & 0x1;
> + hdr->seqno = (buf[idx] >> 4) & 0x1;
> + idx++;
> + *hdrlen = idx;
> + return true;
> +}
> +
> +static void drm_dp_encode_sideband_req(struct 
> drm_dp_sideband_msg_req_body *req,
> + struct drm_dp_sideband_msg_tx *raw)
> +{
> + int idx = 0;
> + int i;
> + u8 *buf = raw->msg;
> + buf[idx++] = req->req_type & 0x7f;
> +
> + switch (req->req_type) {
> + case DP_ENUM_PATH_RESOURCES:
> + buf[idx] = (req->u.port_num.port_number & 0xf) << 4;
> + idx++;
> + break;
> + case DP_ALLOCATE_PAYLOAD:
> + buf[idx] = (req->u.allocate_payload.port_number & 0xf) << 4 |
> + (req->u.allocate_payload.number_sdp_streams & 0xf);
> + idx++;
> + buf[idx] = (req->u.allocate_payload.vcpi & 0x7f);
> + idx++;
> + buf[idx] = (req->u.allocate_payload.pbn >> 8);
> + idx++;
> + buf[idx] = (req->u.allocate_payload.pbn & 0xff);
> + idx++;
> + for (i = 0; i < req->u.allocate_payload.number_sdp_streams / 2; i++) {
> + buf[idx] = ((req->u.allocate_payload.sdp_stream_sink[i * 2] & 0xf) 
> << 4) |
> + (req->u.allocate_payload.sdp_stream_sink[i * 2 + 1] & 0xf);
> + idx++;
> + }
> + if (req->u.allocate_payload.number_sdp_streams & 1) {
> + i = req->u.allocate_payload.number_sdp_streams - 1;
> + buf[idx] = (req->u.allocate_payload.sdp_stream_sink[i] & 0xf) << 4;
> + idx++;
> + }
> + break;
> + case DP_QUERY_PAYLOAD:
> + buf[idx] = (req->u.query_payload.port_number & 0xf) << 4;
> + idx++;
> + buf[idx] = (req->u.query_payload.vcpi & 0x7f);
> + idx++;
> + break;
> + case DP_REMOTE_DPCD_READ:
> + buf[idx] = (req->u.dpcd_read.port_number & 0xf) << 4;
> + buf[idx] |= ((req->u.dpcd_read.dpcd_address & 0xf0000) >> 16) & 0xf;
> + idx++;
> + buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff00) >> 8;
> + idx++;
> + buf[idx] = (req->u.dpcd_read.dpcd_address & 0xff);
> + idx++;
> + buf[idx] = (req->u.dpcd_read.num_bytes);
> + idx++;
> + break;
> +
> + case DP_REMOTE_DPCD_WRITE:
> + buf[idx] = (req->u.dpcd_write.port_number & 0xf) << 4;
> + buf[idx] |= ((req->u.dpcd_write.dpcd_address & 0xf0000) >> 16) & 0xf;
> + idx++;
> + buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff00) >> 8;
> + idx++;
> + buf[idx] = (req->u.dpcd_write.dpcd_address & 0xff);
> + idx++;
> + buf[idx] = (req->u.dpcd_write.num_bytes);
> + idx++;
> + memcpy(&buf[idx], req->u.dpcd_write.bytes, req->u.dpcd_write.num_bytes);
> + idx += req->u.dpcd_write.num_bytes;
> + break;
> + case DP_REMOTE_I2C_READ:
> + buf[idx] = (req->u.i2c_read.port_number & 0xf) << 4;
> + buf[idx] |= (req->u.i2c_read.num_transactions & 0x3);
> + idx++;
> + for (i = 0; i < (req->u.i2c_read.num_transactions & 0x3); i++) {
> + buf[idx] = req->u.i2c_read.transactions[i].i2c_dev_id & 0x7f;
>
> + idx++;
> + buf[idx] = req->u.i2c_read.transactions[i].num_bytes;
> + idx++;
> + memcpy(&buf[idx], req->u.i2c_read.transactions[i].bytes, 
> req->u.i2c_read.transactions[i].num_bytes);
> + idx += req->u.i2c_read.transactions[i].num_bytes;
> +
> + buf[idx] = (req->u.i2c_read.transactions[i].no_stop_bit & 0x1) << 5;
> + buf[idx] |= (req->u.i2c_read.transactions[i].i2c_transaction_delay & 
> 0xf);
> + idx++;
> + }
> + buf[idx] = (req->u.i2c_read.read_i2c_device_id) & 0x7f;
> + idx++;
> + buf[idx] = (req->u.i2c_read.num_bytes_read);
> + idx++;
> + break;
> +
> + case DP_REMOTE_I2C_WRITE:
> + buf[idx] = (req->u.i2c_write.port_number & 0xf) << 4;
> + idx++;
> + buf[idx] = (req->u.i2c_write.write_i2c_device_id) & 0x7f;
> + idx++;
> + buf[idx] = (req->u.i2c_write.num_bytes);
> + idx++;
> + memcpy(&buf[idx], req->u.i2c_write.bytes, req->u.i2c_write.num_bytes);
> + idx += req->u.i2c_write.num_bytes;
> + break;
> + }
> + raw->cur_len = idx;
> +}
> +
> +static void drm_dp_crc_sideband_chunk_req(u8 *msg, u8 len)
> +{
> + u8 crc4;
> + crc4 = drm_dp_msg_data_crc4(msg, len);
> + msg[len] = crc4;
> +}
> +
> +static void drm_dp_encode_sideband_reply(struct 
> drm_dp_sideband_msg_reply_body *rep,
> + struct drm_dp_sideband_msg_tx *raw)
> +{
> + int idx = 0;
> + u8 *buf = raw->msg;
> +
> + buf[idx++] = (rep->reply_type & 0x1) << 7 | (rep->req_type & 0x7f);
> +
> + raw->cur_len = idx;
> +}
> +
> +/* this adds a chunk of msg to the builder to get the final msg */
> +static bool drm_dp_sideband_msg_build(struct drm_dp_sideband_msg_rx *msg,
> + u8 *replybuf, u8 replybuflen, bool hdr)
> +{
> + int ret;
> + u8 crc4;
> +
> + if (hdr) {
> + u8 hdrlen;
> + struct drm_dp_sideband_msg_hdr recv_hdr;
> + ret = drm_dp_decode_sideband_msg_hdr(&recv_hdr, replybuf, 
> replybuflen, &hdrlen);
> + if (ret == false) {
> + print_hex_dump(KERN_DEBUG, "failed hdr", DUMP_PREFIX_NONE, 16, 1, 
> replybuf, replybuflen, false);
> + return false;
> + }
> +
> + /* get length contained in this portion */
> + msg->curchunk_len = recv_hdr.msg_len;
> + msg->curchunk_hdrlen = hdrlen;
> +
> + /* we have already gotten an somt - don't bother parsing */
> + if (recv_hdr.somt && msg->have_somt)
> + return false;
> +
> + if (recv_hdr.somt) {
> + memcpy(&msg->initial_hdr, &recv_hdr, sizeof(struct 
> drm_dp_sideband_msg_hdr));
> + msg->have_somt = true;
> + }
> + if (recv_hdr.eomt)
> + msg->have_eomt = true;
> +
> + /* copy the bytes for the remainder of this header chunk */
> + msg->curchunk_idx = min(msg->curchunk_len, (u8)(replybuflen - hdrlen));
> + memcpy(&msg->chunk[0], replybuf + hdrlen, msg->curchunk_idx);
> + } else {
> + memcpy(&msg->chunk[msg->curchunk_idx], replybuf, replybuflen);
> + msg->curchunk_idx += replybuflen;
> + }
> +
> + if (msg->curchunk_idx >= msg->curchunk_len) {
> + /* do CRC */
> + crc4 = drm_dp_msg_data_crc4(msg->chunk, msg->curchunk_len - 1);
> + /* copy chunk into bigger msg */
> + memcpy(&msg->msg[msg->curlen], msg->chunk, msg->curchunk_len - 1);
> + msg->curlen += msg->curchunk_len - 1;
> + }
> + return true;
> +}
> +
> +static bool drm_dp_sideband_parse_link_address(struct 
> drm_dp_sideband_msg_rx *raw,
> + struct drm_dp_sideband_msg_reply_body *repmsg)
> +{
> + int idx = 1;
> + int i;
> + memcpy(repmsg->u.link_addr.guid, &raw->msg[idx], 16);
> + idx += 16;
> + repmsg->u.link_addr.nports = raw->msg[idx] & 0xf;
> + idx++;
> + if (idx > raw->curlen)
> + goto fail_len;
> + for (i = 0; i < repmsg->u.link_addr.nports; i++) {
> + if (raw->msg[idx] & 0x80)
> + repmsg->u.link_addr.ports[i].input_port = 1;
> +
> + repmsg->u.link_addr.ports[i].peer_device_type = (raw->msg[idx] >> 4) 
> & 0x7;
> + repmsg->u.link_addr.ports[i].port_number = (raw->msg[idx] & 0xf);
> +
> + idx++;
> + if (idx > raw->curlen)
> + goto fail_len;
> + repmsg->u.link_addr.ports[i].mcs = (raw->msg[idx] >> 7) & 0x1;
> + repmsg->u.link_addr.ports[i].ddps = (raw->msg[idx] >> 6) & 0x1;
> + if (repmsg->u.link_addr.ports[i].input_port == 0)
> + repmsg->u.link_addr.ports[i].legacy_device_plug_status = 
> (raw->msg[idx] >> 5) & 0x1;
> + idx++;
> + if (idx > raw->curlen)
> + goto fail_len;
> + if (repmsg->u.link_addr.ports[i].input_port == 0) {
> + repmsg->u.link_addr.ports[i].dpcd_revision = (raw->msg[idx]);
> + idx++;
> + if (idx > raw->curlen)
> + goto fail_len;
> + memcpy(repmsg->u.link_addr.ports[i].peer_guid, &raw->msg[idx], 16);
> + idx += 16;
> + if (idx > raw->curlen)
> + goto fail_len;
> + repmsg->u.link_addr.ports[i].num_sdp_streams = (raw->msg[idx] >> 4) 
> & 0xf;
> + repmsg->u.link_addr.ports[i].num_sdp_stream_sinks = (raw->msg[idx] & 
> 0xf);
> + idx++;
> +
> + }
> + if (idx > raw->curlen)
> + goto fail_len;
> + }
> +
> + return true;
> +fail_len:
> + DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, 
> raw->curlen);
> + return false;
> +}
> +
> +static bool drm_dp_sideband_parse_remote_dpcd_read(struct 
> drm_dp_sideband_msg_rx *raw,
> + struct drm_dp_sideband_msg_reply_body *repmsg)
> +{
> + int idx = 1;
> + repmsg->u.remote_dpcd_read_ack.port_number = raw->msg[idx] & 0xf;
> + idx++;
> + if (idx > raw->curlen)
> + goto fail_len;
> + repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx];
> + if (idx > raw->curlen)
> + goto fail_len;
> +
> + memcpy(repmsg->u.remote_dpcd_read_ack.bytes, &raw->msg[idx], 
> repmsg->u.remote_dpcd_read_ack.num_bytes);
> + return true;
> +fail_len:
> + DRM_DEBUG_KMS("link address reply parse length fail %d %d\n", idx, 
> raw->curlen);
> + return false;
> +}
> +
> +static bool drm_dp_sideband_parse_remote_dpcd_write(struct 
> drm_dp_sideband_msg_rx *raw,
> + struct drm_dp_sideband_msg_reply_body *repmsg)
> +{
> + int idx = 1;
> + repmsg->u.remote_dpcd_write_ack.port_number = raw->msg[idx] & 0xf;
> + idx++;
> + if (idx > raw->curlen)
> + goto fail_len;
> + return true;
> +fail_len:
> + DRM_DEBUG_KMS("parse length fail %d %d\n", idx, raw->curlen);
> + return false;
> +}
> +
> +static bool drm_dp_sideband_parse_remote_i2c_read_ack(struct 
> drm_dp_sideband_msg_rx *raw,
> + struct drm_dp_sideband_msg_reply_body *repmsg)
> +{
> + int idx = 1;
> +
> + repmsg->u.remote_i2c_read_ack.port_number = (raw->msg[idx] & 0xf);
> + idx++;
> + if (idx > raw->curlen)
> + goto fail_len;
> + repmsg->u.remote_i2c_read_ack.num_bytes = raw->msg[idx];
> + idx++;
> + /* TODO check */
> + memcpy(repmsg->u.remote_i2c_read_ack.bytes, &raw->msg[idx], 
> repmsg->u.remote_i2c_read_ack.num_bytes);
> + return true;
> +fail_len:
> + DRM_DEBUG_KMS("remote i2c reply parse length fail %d %d\n", idx, 
> raw->curlen);
> + return false;
> +}
> +
> +static bool drm_dp_sideband_parse_enum_path_resources_ack(struct 
> drm_dp_sideband_msg_rx *raw,
> + struct drm_dp_sideband_msg_reply_body *repmsg)
> +{
> + int idx = 1;
> + repmsg->u.path_resources.port_number = (raw->msg[idx] >> 4) & 0xf;
> + idx++;
> + if (idx > raw->curlen)
> + goto fail_len;
> + repmsg->u.path_resources.full_payload_bw_number = (raw->msg[idx] << 
> 8) | (raw->msg[idx+1]);
> + idx += 2;
> + if (idx > raw->curlen)
> + goto fail_len;
> + repmsg->u.path_resources.avail_payload_bw_number = (raw->msg[idx] << 
> 8) | (raw->msg[idx+1]);
> + idx += 2;
> + if (idx > raw->curlen)
> + goto fail_len;
> + return true;
> +fail_len:
> + DRM_DEBUG_KMS("enum resource parse length fail %d %d\n", idx, 
> raw->curlen);
> + return false;
> +}
> +
> +static bool drm_dp_sideband_parse_allocate_payload_ack(struct 
> drm_dp_sideband_msg_rx *raw,
> + struct drm_dp_sideband_msg_reply_body *repmsg)
> +{
> + int idx = 1;
> + repmsg->u.allocate_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
> + idx++;
> + if (idx > raw->curlen)
> + goto fail_len;
> + repmsg->u.allocate_payload.vcpi = raw->msg[idx];
> + idx++;
> + if (idx > raw->curlen)
> + goto fail_len;
> + repmsg->u.allocate_payload.allocated_pbn = (raw->msg[idx] << 8) | 
> (raw->msg[idx+1]);
> + idx += 2;
> + if (idx > raw->curlen)
> + goto fail_len;
> + return true;
> +fail_len:
> + DRM_DEBUG_KMS("allocate payload parse length fail %d %d\n", idx, 
> raw->curlen);
> + return false;
> +}
> +
> +static bool drm_dp_sideband_parse_query_payload_ack(struct 
> drm_dp_sideband_msg_rx *raw,
> + struct drm_dp_sideband_msg_reply_body *repmsg)
> +{
> + int idx = 1;
> + repmsg->u.query_payload.port_number = (raw->msg[idx] >> 4) & 0xf;
> + idx++;
> + if (idx > raw->curlen)
> + goto fail_len;
> + repmsg->u.query_payload.allocated_pbn = (raw->msg[idx] << 8) | 
> (raw->msg[idx + 1]);
> + idx += 2;
> + if (idx > raw->curlen)
> + goto fail_len;
> + return true;
> +fail_len:
> + DRM_DEBUG_KMS("query payload parse length fail %d %d\n", idx, 
> raw->curlen);
> + return false;
> +}
> +
> +static bool drm_dp_sideband_parse_reply(struct drm_dp_sideband_msg_rx 
> *raw,
> + struct drm_dp_sideband_msg_reply_body *msg)
> +{
> + memset(msg, 0, sizeof(*msg));
> + msg->reply_type = (raw->msg[0] & 0x80) >> 7;
> + msg->req_type = (raw->msg[0] & 0x7f);
> +
> + if (msg->reply_type) {
> + memcpy(msg->u.nak.guid, &raw->msg[1], 16);
> + msg->u.nak.reason = raw->msg[17];
> + msg->u.nak.nak_data = raw->msg[18];
> + return false;
> + }
> +
> + switch (msg->req_type) {
> + case DP_LINK_ADDRESS:
> + return drm_dp_sideband_parse_link_address(raw, msg);
> + case DP_QUERY_PAYLOAD:
> + return drm_dp_sideband_parse_query_payload_ack(raw, msg);
> + case DP_REMOTE_DPCD_READ:
> + return drm_dp_sideband_parse_remote_dpcd_read(raw, msg);
> + case DP_REMOTE_DPCD_WRITE:
> + return drm_dp_sideband_parse_remote_dpcd_write(raw, msg);
> + case DP_REMOTE_I2C_READ:
> + return drm_dp_sideband_parse_remote_i2c_read_ack(raw, msg);
> + case DP_ENUM_PATH_RESOURCES:
> + return drm_dp_sideband_parse_enum_path_resources_ack(raw, msg);
> + case DP_ALLOCATE_PAYLOAD:
> + return drm_dp_sideband_parse_allocate_payload_ack(raw, msg);
> + default:
> + DRM_ERROR("Got unknown reply 0x%02x\n", msg->req_type);
> + return false;
> + }
> +}
> +
> +static bool drm_dp_sideband_parse_connection_status_notify(struct 
> drm_dp_sideband_msg_rx *raw,
> + struct drm_dp_sideband_msg_req_body *msg)
> +{
> + int idx = 1;
> +
> + msg->u.conn_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
> + idx++;
> + if (idx > raw->curlen)
> + goto fail_len;
> +
> + memcpy(msg->u.conn_stat.guid, &raw->msg[idx], 16);
> + idx += 16;
> + if (idx > raw->curlen)
> + goto fail_len;
> +
> + msg->u.conn_stat.legacy_device_plug_status = (raw->msg[idx] >> 6) & 0x1;
> + msg->u.conn_stat.displayport_device_plug_status = (raw->msg[idx] >> 
> 5) & 0x1;
> + msg->u.conn_stat.message_capability_status = (raw->msg[idx] >> 4) & 0x1;
> + msg->u.conn_stat.input_port = (raw->msg[idx] >> 3) & 0x1;
> + msg->u.conn_stat.peer_device_type = (raw->msg[idx] & 0x7);
> + idx++;
> + return true;
> +fail_len:
> + DRM_DEBUG_KMS("connection status reply parse length fail %d %d\n", 
> idx, raw->curlen);
> + return false;
> +}
> +
> +static bool drm_dp_sideband_parse_resource_status_notify(struct 
> drm_dp_sideband_msg_rx *raw,
> + struct drm_dp_sideband_msg_req_body *msg)
> +{
> + int idx = 1;
> +
> + msg->u.resource_stat.port_number = (raw->msg[idx] & 0xf0) >> 4;
> + idx++;
> + if (idx > raw->curlen)
> + goto fail_len;
> +
> + memcpy(msg->u.resource_stat.guid, &raw->msg[idx], 16);
> + idx += 16;
> + if (idx > raw->curlen)
> + goto fail_len;
> +
> + msg->u.resource_stat.available_pbn = (raw->msg[idx] << 8) | 
> (raw->msg[idx + 1]);
> + idx++;
> + return true;
> +fail_len:
> + DRM_DEBUG_KMS("resource status reply parse length fail %d %d\n", 
> idx, raw->curlen);
> + return false;
> +}
> +
> +static bool drm_dp_sideband_parse_req(struct drm_dp_sideband_msg_rx *raw,
> + struct drm_dp_sideband_msg_req_body *msg)
> +{
> + memset(msg, 0, sizeof(*msg));
> + msg->req_type = (raw->msg[0] & 0x7f);
> +
> + switch (msg->req_type) {
> + case DP_CONNECTION_STATUS_NOTIFY:
> + return drm_dp_sideband_parse_connection_status_notify(raw, msg);
> + case DP_RESOURCE_STATUS_NOTIFY:
> + return drm_dp_sideband_parse_resource_status_notify(raw, msg);
> + default:
> + DRM_ERROR("Got unknown request 0x%02x\n", msg->req_type);
> + return false;
> + }
> +}
> +
> +static int build_dpcd_write(struct drm_dp_sideband_msg_tx *msg, u8 
> port_num, u32 offset, u8 num_bytes, u8 *bytes)
> +{
> + struct drm_dp_sideband_msg_req_body req;
> +
> + req.req_type = DP_REMOTE_DPCD_WRITE;
> + req.u.dpcd_write.port_number = port_num;
> + req.u.dpcd_write.dpcd_address = offset;
> + req.u.dpcd_write.num_bytes = num_bytes;
> + memcpy(req.u.dpcd_write.bytes, bytes, num_bytes);
> + drm_dp_encode_sideband_req(&req, msg);
> +
> + return 0;
> +}
> +
> +static int build_link_address(struct drm_dp_sideband_msg_tx *msg)
> +{
> + struct drm_dp_sideband_msg_req_body req;
> +
> + req.req_type = DP_LINK_ADDRESS;
> + drm_dp_encode_sideband_req(&req, msg);
> + return 0;
> +}
> +
> +static int build_enum_path_resources(struct drm_dp_sideband_msg_tx 
> *msg, int port_num)
> +{
> + struct drm_dp_sideband_msg_req_body req;
> +
> + req.req_type = DP_ENUM_PATH_RESOURCES;
> + req.u.port_num.port_number = port_num;
> + drm_dp_encode_sideband_req(&req, msg);
>
> + msg->path_msg = true;
> + return 0;
> +}
> +
> +static int build_allocate_payload(struct drm_dp_sideband_msg_tx *msg, 
> int port_num,
> + u8 vcpi, uint16_t pbn)
> +{
> + struct drm_dp_sideband_msg_req_body req;
> + memset(&req, 0, sizeof(req));
> + req.req_type = DP_ALLOCATE_PAYLOAD;
> + req.u.allocate_payload.port_number = port_num;
> + req.u.allocate_payload.vcpi = vcpi;
> + req.u.allocate_payload.pbn = pbn;
> + drm_dp_encode_sideband_req(&req, msg);
> + msg->path_msg = true;
> + return 0;
> +}
> +
> +static int drm_dp_mst_assign_payload_id(struct 
> drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_vcpi *vcpi)
> +{
> + int ret;
> +
> + mutex_lock(&mgr->payload_lock);
> + ret = find_first_zero_bit(&mgr->payload_mask, mgr->max_payloads + 1);
> + if (ret > mgr->max_payloads) {
> + ret = -EINVAL;
> + DRM_DEBUG_KMS("out of payload ids %d\n", ret);
> + goto out_unlock;
> + }
> +
> + set_bit(ret, &mgr->payload_mask);
> + vcpi->vcpi = ret;
> + mgr->proposed_vcpis[ret - 1] = vcpi;
> +out_unlock:
> + mutex_unlock(&mgr->payload_lock);
> + return ret;
> +}
> +
> +static void drm_dp_mst_put_payload_id(struct drm_dp_mst_topology_mgr 
> *mgr,
> + int id)
> +{
> + if (id == 0)
> + return;
> +
> + mutex_lock(&mgr->payload_lock);
> + DRM_DEBUG_KMS("putting payload %d\n", id);
> + clear_bit(id, &mgr->payload_mask);
> + mgr->proposed_vcpis[id - 1] = NULL;
> + mutex_unlock(&mgr->payload_lock);
> +}
> +
> +static bool check_txmsg_state(struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_sideband_msg_tx *txmsg)
> +{
> + bool ret;
> + mutex_lock(&mgr->qlock);
> + ret = (txmsg->state == DRM_DP_SIDEBAND_TX_RX ||
> + txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT);
> + mutex_unlock(&mgr->qlock);
> + return ret;
> +}
> +
> +static int drm_dp_mst_wait_tx_reply(struct drm_dp_mst_branch *mstb,
> + struct drm_dp_sideband_msg_tx *txmsg)
> +{
> + struct drm_dp_mst_topology_mgr *mgr = mstb->mgr;
> + int ret;
> +
> + ret = wait_event_timeout(mgr->tx_waitq,
> + check_txmsg_state(mgr, txmsg),
> + (4 * HZ));
> + mutex_lock(&mstb->mgr->qlock);
> + if (ret > 0) {
> + if (txmsg->state == DRM_DP_SIDEBAND_TX_TIMEOUT) {
> + ret = -EIO;
> + goto out;
> + }
> + } else {
> + DRM_DEBUG_KMS("timedout msg send %p %d %d\n", txmsg, txmsg->state, 
> txmsg->seqno);
> +
> + /* dump some state */
> + ret = -EIO;
> +
> + /* remove from q */
> + if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED ||
> + txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND) {
> + list_del(&txmsg->next);
> + }
> +
> + if (txmsg->state == DRM_DP_SIDEBAND_TX_START_SEND ||
> + txmsg->state == DRM_DP_SIDEBAND_TX_SENT) {
> + mstb->tx_slots[txmsg->seqno] = NULL;
> + }
> + }
> +out:
> + mutex_unlock(&mgr->qlock);
> +
> + return ret;
> +}
> +
> +static struct drm_dp_mst_branch *drm_dp_add_mst_branch_device(u8 lct, 
> u8 *rad)
> +{
> + struct drm_dp_mst_branch *mstb;
> +
> + mstb = kzalloc(sizeof(*mstb), GFP_KERNEL);
> + if (!mstb)
> + return NULL;
> +
> + mstb->lct = lct;
> + if (lct > 1)
> + memcpy(mstb->rad, rad, lct / 2);
> + INIT_LIST_HEAD(&mstb->ports);
> + kref_init(&mstb->kref);
> + return mstb;
> +}
> +
> +static void drm_dp_destroy_mst_branch_device(struct kref *kref)
> +{
> + struct drm_dp_mst_branch *mstb = container_of(kref, struct 
> drm_dp_mst_branch, kref);
> + struct drm_dp_mst_port *port, *tmp;
> + bool wake_tx = false;
> +
> + cancel_work_sync(&mstb->mgr->work);
> +
> + /*
> + * destroy all ports - don't need lock
> + * as there are no more references to the mst branch
> + * device at this point.
> + */
> + list_for_each_entry_safe(port, tmp, &mstb->ports, next) {
> + list_del(&port->next);
> + drm_dp_put_port(port);
> + }
> +
> + /* drop any tx slots msg */
> + mutex_lock(&mstb->mgr->qlock);
> + if (mstb->tx_slots[0]) {
> + mstb->tx_slots[0]->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
> + mstb->tx_slots[0] = NULL;
> + wake_tx = true;
> + }
> + if (mstb->tx_slots[1]) {
> + mstb->tx_slots[1]->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
> + mstb->tx_slots[1] = NULL;
> + wake_tx = true;
> + }
> + mutex_unlock(&mstb->mgr->qlock);
> +
> + if (wake_tx)
> + wake_up(&mstb->mgr->tx_waitq);
> + kfree(mstb);
> +}
> +
> +static void drm_dp_put_mst_branch_device(struct drm_dp_mst_branch *mstb)
> +{
> + kref_put(&mstb->kref, drm_dp_destroy_mst_branch_device);
> +}
> +
> +
> +static void drm_dp_port_teardown_pdt(struct drm_dp_mst_port *port, 
> int old_pdt)
> +{
> + switch (old_pdt) {
> + case DP_PEER_DEVICE_DP_LEGACY_CONV:
> + case DP_PEER_DEVICE_SST_SINK:
> + /* remove i2c over sideband */
> + drm_dp_mst_unregister_i2c_bus(&port->aux);
> + break;
> + case DP_PEER_DEVICE_MST_BRANCHING:
> + drm_dp_put_mst_branch_device(port->mstb);
> + port->mstb = NULL;
> + break;
> + }
> +}
> +
> +static void drm_dp_destroy_port(struct kref *kref)
> +{
> + struct drm_dp_mst_port *port = container_of(kref, struct 
> drm_dp_mst_port, kref);
> + struct drm_dp_mst_topology_mgr *mgr = port->mgr;
> + if (!port->input) {
> + port->vcpi.num_slots = 0;
> + if (port->connector)
> + (*port->mgr->cbs->destroy_connector)(mgr, port->connector);
> + drm_dp_port_teardown_pdt(port, port->pdt);
> +
> + if (!port->input && port->vcpi.vcpi > 0)
> + drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
> + }
> + kfree(port);
> +}
> +
> +static void drm_dp_put_port(struct drm_dp_mst_port *port)
> +{
> + kref_put(&port->kref, drm_dp_destroy_port);
> +}
> +
> +static struct drm_dp_mst_branch 
> *drm_dp_mst_get_validated_mstb_ref_locked(struct drm_dp_mst_branch 
> *mstb, struct drm_dp_mst_branch *to_find)
> +{
> + struct drm_dp_mst_port *port;
> + struct drm_dp_mst_branch *rmstb;
> + if (to_find == mstb) {
> + kref_get(&mstb->kref);
> + return mstb;
> + }
> + list_for_each_entry(port, &mstb->ports, next) {
> + if (port->mstb) {
> + rmstb = drm_dp_mst_get_validated_mstb_ref_locked(port->mstb, to_find);
> + if (rmstb)
> + return rmstb;
> + }
> + }
> + return NULL;
> +}
> +
> +static struct drm_dp_mst_branch *drm_dp_get_validated_mstb_ref(struct 
> drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_branch *mstb)
> +{
> + struct drm_dp_mst_branch *rmstb = NULL;
> + mutex_lock(&mgr->lock);
> + if (mgr->mst_primary)
> + rmstb = drm_dp_mst_get_validated_mstb_ref_locked(mgr->mst_primary, 
> mstb);
> + mutex_unlock(&mgr->lock);
> + return rmstb;
> +}
> +
> +static struct drm_dp_mst_port *drm_dp_mst_get_port_ref_locked(struct 
> drm_dp_mst_branch *mstb, struct drm_dp_mst_port *to_find)
> +{
> + struct drm_dp_mst_port *port, *mport;
> +
> + list_for_each_entry(port, &mstb->ports, next) {
> + if (port == to_find) {
> + kref_get(&port->kref);
> + return port;
> + }
> + if (port->mstb) {
> + mport = drm_dp_mst_get_port_ref_locked(port->mstb, to_find);
> + if (mport)
> + return mport;
> + }
> + }
> + return NULL;
> +}
> +
> +static struct drm_dp_mst_port *drm_dp_get_validated_port_ref(struct 
> drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
> +{
> + struct drm_dp_mst_port *rport = NULL;
> + mutex_lock(&mgr->lock);
> + if (mgr->mst_primary)
> + rport = drm_dp_mst_get_port_ref_locked(mgr->mst_primary, port);
> + mutex_unlock(&mgr->lock);
> + return rport;
> +}
> +
> +static struct drm_dp_mst_port *drm_dp_get_port(struct 
> drm_dp_mst_branch *mstb, u8 port_num)
> +{
> + struct drm_dp_mst_port *port;
> +
> + list_for_each_entry(port, &mstb->ports, next) {
> + if (port->port_num == port_num) {
> + kref_get(&port->kref);
> + return port;
> + }
> + }
> +
> + return NULL;
> +}
> +
> +/*
> + * calculate a new RAD for this MST branch device
> + * if parent has an LCT of 2 then it has 1 nibble of RAD,
> + * if parent has an LCT of 3 then it has 2 nibbles of RAD,
> + */
> +static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port,
> + u8 *rad)
> +{
> + int lct = port->parent->lct;
> + int shift = 4;
> + int idx = lct / 2;
> + if (lct > 1) {
> + memcpy(rad, port->parent->rad, idx);
> + shift = (lct % 2) ? 4 : 0;
> + } else
> + rad[0] = 0;
> +
> + rad[idx] |= port->port_num << shift;
> + return lct + 1;
> +}
> +
> +/*
> + * return sends link address for new mstb
> + */
> +static bool drm_dp_port_setup_pdt(struct drm_dp_mst_port *port)
> +{
> + int ret;
> + u8 rad[6], lct;
> + bool send_link = false;
> + switch (port->pdt) {
> + case DP_PEER_DEVICE_DP_LEGACY_CONV:
> + case DP_PEER_DEVICE_SST_SINK:
> + /* add i2c over sideband */
> + ret = drm_dp_mst_register_i2c_bus(&port->aux);
> + break;
> + case DP_PEER_DEVICE_MST_BRANCHING:
> + lct = drm_dp_calculate_rad(port, rad);
> +
> + port->mstb = drm_dp_add_mst_branch_device(lct, rad);
> + port->mstb->mgr = port->mgr;
> + port->mstb->port_parent = port;
> +
> + send_link = true;
> + break;
> + }
> + return send_link;
> +}
> +
> +static void drm_dp_check_port_guid(struct drm_dp_mst_branch *mstb,
> + struct drm_dp_mst_port *port)
> +{
> + int ret;
> + if (port->dpcd_rev >= 0x12) {
> + port->guid_valid = drm_dp_validate_guid(mstb->mgr, port->guid);
> + if (!port->guid_valid) {
> + ret = drm_dp_send_dpcd_write(mstb->mgr,
> + port,
> + DP_GUID,
> + 16, port->guid);
> + port->guid_valid = true;
> + }
> + }
> +}
> +
> +static void build_mst_prop_path(struct drm_dp_mst_port *port,
> + struct drm_dp_mst_branch *mstb,
> + char *proppath)
> +{
> + int i;
> + char temp[8];
> + snprintf(proppath, 255, "mst:%d", mstb->mgr->conn_base_id);
> + for (i = 0; i < (mstb->lct - 1); i++) {
> + int shift = (i % 2) ? 0 : 4;
> + int port_num = mstb->rad[i / 2] >> shift;
> + snprintf(temp, 8, "-%d", port_num);
> + strncat(proppath, temp, 255);
> + }
> + snprintf(temp, 8, "-%d", port->port_num);
> + strncat(proppath, temp, 255);
> +}
> +
> +static void drm_dp_add_port(struct drm_dp_mst_branch *mstb,
> + struct device *dev,
> + struct drm_dp_link_addr_reply_port *port_msg)
> +{
> + struct drm_dp_mst_port *port;
> + bool ret;
> + bool created = false;
> + int old_pdt = 0;
> + int old_ddps = 0;
> + port = drm_dp_get_port(mstb, port_msg->port_number);
> + if (!port) {
> + port = kzalloc(sizeof(*port), GFP_KERNEL);
> + if (!port)
> + return;
> + kref_init(&port->kref);
> + port->parent = mstb;
> + port->port_num = port_msg->port_number;
> + port->mgr = mstb->mgr;
> + port->aux.name = "DPMST";
> + port->aux.dev = dev;
> + created = true;
> + } else {
> + old_pdt = port->pdt;
> + old_ddps = port->ddps;
> + }
> +
> + port->pdt = port_msg->peer_device_type;
> + port->input = port_msg->input_port;
> + port->mcs = port_msg->mcs;
> + port->ddps = port_msg->ddps;
> + port->ldps = port_msg->legacy_device_plug_status;
> + port->dpcd_rev = port_msg->dpcd_revision;
> +
> + memcpy(port->guid, port_msg->peer_guid, 16);
> +
> + /* manage mstb port lists with mgr lock - take a reference
> + for this list */
> + if (created) {
> + mutex_lock(&mstb->mgr->lock);
> + kref_get(&port->kref);
> + list_add(&port->next, &mstb->ports);
> + mutex_unlock(&mstb->mgr->lock);
> + }
> +
> + if (old_ddps != port->ddps) {
> + if (port->ddps) {
> + drm_dp_check_port_guid(mstb, port);
> + if (!port->input)
> + drm_dp_send_enum_path_resources(mstb->mgr, mstb, port);
> + } else {
> + port->guid_valid = false;
> + port->available_pbn = 0;
> + }
> + }
> +
> + if (old_pdt != port->pdt && !port->input) {
> + drm_dp_port_teardown_pdt(port, old_pdt);
> +
> + ret = drm_dp_port_setup_pdt(port);
> + if (ret == true) {
> + drm_dp_send_link_address(mstb->mgr, port->mstb);
> + port->mstb->link_address_sent = true;
> + }
> + }
> +
> + if (created && !port->input) {
> + char proppath[255];
> + build_mst_prop_path(port, mstb, proppath);
> + port->connector = (*mstb->mgr->cbs->add_connector)(mstb->mgr, port, 
> proppath);
> + }
> +
> + /* put reference to this port */
> + drm_dp_put_port(port);
> +}
> +
> +static void drm_dp_update_port(struct drm_dp_mst_branch *mstb,
> + struct drm_dp_connection_status_notify *conn_stat)
> +{
> + struct drm_dp_mst_port *port;
> + int old_pdt;
> + int old_ddps;
> + bool dowork = false;
> + port = drm_dp_get_port(mstb, conn_stat->port_number);
> + if (!port)
> + return;
> +
> + old_ddps = port->ddps;
> + old_pdt = port->pdt;
> + port->pdt = conn_stat->peer_device_type;
> + port->mcs = conn_stat->message_capability_status;
> + port->ldps = conn_stat->legacy_device_plug_status;
> + port->ddps = conn_stat->displayport_device_plug_status;
> +
> + if (old_ddps != port->ddps) {
> + if (port->ddps) {
> + drm_dp_check_port_guid(mstb, port);
> + dowork = true;
> + } else {
> + port->guid_valid = false;
> + port->available_pbn = 0;
> + }
> + }
> + if (old_pdt != port->pdt && !port->input) {
> + drm_dp_port_teardown_pdt(port, old_pdt);
> +
> + if (drm_dp_port_setup_pdt(port))
> + dowork = true;
> + }
> +
> + drm_dp_put_port(port);
> + if (dowork)
> + queue_work(system_long_wq, &mstb->mgr->work);
> +
> +}
> +
> +static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct 
> drm_dp_mst_topology_mgr *mgr,
> + u8 lct, u8 *rad)
> +{
> + struct drm_dp_mst_branch *mstb;
> + struct drm_dp_mst_port *port;
> + int i;
> + /* find the port by iterating down */
> + mstb = mgr->mst_primary;
> +
> + for (i = 0; i < lct - 1; i++) {
> + int shift = (i % 2) ? 0 : 4;
> + int port_num = rad[i / 2] >> shift;
> +
> + list_for_each_entry(port, &mstb->ports, next) {
> + if (port->port_num == port_num) {
> + if (!port->mstb) {
> + DRM_ERROR("failed to lookup MSTB with lct %d, rad %02x\n", lct, rad[0]);
> + return NULL;
> + }
> +
> + mstb = port->mstb;
> + break;
> + }
> + }
> + }
> + kref_get(&mstb->kref);
> + return mstb;
> +}
> +
> +static void drm_dp_check_and_send_link_address(struct 
> drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_mst_branch *mstb)
> +{
> + struct drm_dp_mst_port *port;
> +
> + if (!mstb->link_address_sent) {
> + drm_dp_send_link_address(mgr, mstb);
> + mstb->link_address_sent = true;
> + }
> + list_for_each_entry(port, &mstb->ports, next) {
> + if (port->input)
> + continue;
> +
> + if (!port->ddps)
> + continue;
> +
> + if (!port->available_pbn)
> + drm_dp_send_enum_path_resources(mgr, mstb, port);
> +
> + if (port->mstb)
> + drm_dp_check_and_send_link_address(mgr, port->mstb);
> + }
> +}
> +
> +static void drm_dp_mst_link_probe_work(struct work_struct *work)
> +{
> + struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct 
> drm_dp_mst_topology_mgr, work);
> +
> + drm_dp_check_and_send_link_address(mgr, mgr->mst_primary);
> +
> +}
> +
> +static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr,
> + u8 *guid)
> +{
> + static u8 zero_guid[16];
> +
> + if (!memcmp(guid, zero_guid, 16)) {
> + u64 salt = get_jiffies_64();
> + memcpy(&guid[0], &salt, sizeof(u64));
> + memcpy(&guid[8], &salt, sizeof(u64));
> + return false;
> + }
> + return true;
> +}
> +
> +#if 0
> +static int build_dpcd_read(struct drm_dp_sideband_msg_tx *msg, u8 
> port_num, u32 offset, u8 num_bytes)
> +{
> + struct drm_dp_sideband_msg_req_body req;
> +
> + req.req_type = DP_REMOTE_DPCD_READ;
> + req.u.dpcd_read.port_number = port_num;
> + req.u.dpcd_read.dpcd_address = offset;
> + req.u.dpcd_read.num_bytes = num_bytes;
> + drm_dp_encode_sideband_req(&req, msg);
> +
> + return 0;
> +}
> +#endif
> +
> +static int drm_dp_send_sideband_msg(struct drm_dp_mst_topology_mgr *mgr,
> + bool up, u8 *msg, int len)
> +{
> + int ret;
> + int regbase = up ? DP_SIDEBAND_MSG_UP_REP_BASE : 
> DP_SIDEBAND_MSG_DOWN_REQ_BASE;
> + int tosend, total, offset;
> + int retries = 0;
> +
> +retry:
> + total = len;
> + offset = 0;
> + do {
> + tosend = min3(mgr->max_dpcd_transaction_bytes, 16, total);
> +
> + mutex_lock(&mgr->aux_lock);
> + ret = drm_dp_dpcd_write(mgr->aux, regbase + offset,
> + &msg[offset],
> + tosend);
> + mutex_unlock(&mgr->aux_lock);
> + if (ret != tosend) {
> + if (ret == -EIO && retries < 5) {
> + retries++;
> + goto retry;
> + }
> + DRM_DEBUG_KMS("failed to dpcd write %d %d\n", tosend, ret);
> + WARN(1, "fail\n");
> +
> + return -EIO;
> + }
> + offset += tosend;
> + total -= tosend;
> + } while (total > 0);
> + return 0;
> +}
> +
> +static int set_hdr_from_dst_qlock(struct drm_dp_sideband_msg_hdr *hdr,
> + struct drm_dp_sideband_msg_tx *txmsg)
> +{
> + struct drm_dp_mst_branch *mstb = txmsg->dst;
> +
> + /* both msg slots are full */
> + if (txmsg->seqno == -1) {
> + if (mstb->tx_slots[0] && mstb->tx_slots[1]) {
> + DRM_DEBUG_KMS("%s: failed to find slot\n", __func__);
> + return -EAGAIN;
> + }
> + if (mstb->tx_slots[0] == NULL && mstb->tx_slots[1] == NULL) {
> + txmsg->seqno = mstb->last_seqno;
> + mstb->last_seqno ^= 1;
> + } else if (mstb->tx_slots[0] == NULL)
> + txmsg->seqno = 0;
> + else
> + txmsg->seqno = 1;
> + mstb->tx_slots[txmsg->seqno] = txmsg;
> + }
> + hdr->broadcast = 0;
> + hdr->path_msg = txmsg->path_msg;
> + hdr->lct = mstb->lct;
> + hdr->lcr = mstb->lct - 1;
> + if (mstb->lct > 1)
> + memcpy(hdr->rad, mstb->rad, mstb->lct / 2);
> + hdr->seqno = txmsg->seqno;
> + return 0;
> +}
> +/*
> + * process a single block of the next message in the sideband queue
> + */
> +static int process_single_tx_qlock(struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_sideband_msg_tx *txmsg,
> + bool up)
> +{
> + u8 chunk[48];
> + struct drm_dp_sideband_msg_hdr hdr;
> + int len, space, idx, tosend;
> + int ret;
> +
> + if (txmsg->state == DRM_DP_SIDEBAND_TX_QUEUED) {
> + txmsg->seqno = -1;
> + txmsg->state = DRM_DP_SIDEBAND_TX_START_SEND;
> + }
> +
> + /* make hdr from dst mst - for replies use seqno
> + otherwise assign one */
> + ret = set_hdr_from_dst_qlock(&hdr, txmsg);
> + if (ret < 0)
> + return ret;
> +
> + /* amount left to send in this message */
> + len = txmsg->cur_len - txmsg->cur_offset;
> +
> + /* 48 - sideband msg size - 1 byte for data CRC, x header bytes */
> + space = 48 - 1 - drm_dp_calc_sb_hdr_size(&hdr);
> +
> + tosend = min(len, space);
> + if (len == txmsg->cur_len)
> + hdr.somt = 1;
> + if (space >= len)
> + hdr.eomt = 1;
> +
> +
> + hdr.msg_len = tosend + 1;
> + drm_dp_encode_sideband_msg_hdr(&hdr, chunk, &idx);
> + memcpy(&chunk[idx], &txmsg->msg[txmsg->cur_offset], tosend);
> + /* add crc at end */
> + drm_dp_crc_sideband_chunk_req(&chunk[idx], tosend);
> + idx += tosend + 1;
> +
> + ret = drm_dp_send_sideband_msg(mgr, up, chunk, idx);
> + if (ret) {
> + DRM_DEBUG_KMS("sideband msg failed to send\n");
> + return ret;
> + }
> +
> + txmsg->cur_offset += tosend;
> + if (txmsg->cur_offset == txmsg->cur_len) {
> + txmsg->state = DRM_DP_SIDEBAND_TX_SENT;
> + return 1;
> + }
> + return 0;
> +}
> +
> +/* must be called holding qlock */
> +static void process_single_down_tx_qlock(struct 
> drm_dp_mst_topology_mgr *mgr)
> +{
> + struct drm_dp_sideband_msg_tx *txmsg;
> + int ret;
> +
> + /* construct a chunk from the first msg in the tx_msg queue */
> + if (list_empty(&mgr->tx_msg_downq)) {
> + mgr->tx_down_in_progress = false;
> + return;
> + }
> + mgr->tx_down_in_progress = true;
> +
> + txmsg = list_first_entry(&mgr->tx_msg_downq, struct 
> drm_dp_sideband_msg_tx, next);
> + ret = process_single_tx_qlock(mgr, txmsg, false);
> + if (ret == 1) {
> + /* txmsg is sent it should be in the slots now */
> + list_del(&txmsg->next);
> + } else if (ret) {
> + DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
> + list_del(&txmsg->next);
> + if (txmsg->seqno != -1)
> + txmsg->dst->tx_slots[txmsg->seqno] = NULL;
> + txmsg->state = DRM_DP_SIDEBAND_TX_TIMEOUT;
> + wake_up(&mgr->tx_waitq);
> + }
> + if (list_empty(&mgr->tx_msg_downq)) {
> + mgr->tx_down_in_progress = false;
> + return;
> + }
> +}
> +
> +/* called holding qlock */
> +static void process_single_up_tx_qlock(struct drm_dp_mst_topology_mgr 
> *mgr)
> +{
> + struct drm_dp_sideband_msg_tx *txmsg;
> + int ret;
> +
> + /* construct a chunk from the first msg in the tx_msg queue */
> + if (list_empty(&mgr->tx_msg_upq)) {
> + mgr->tx_up_in_progress = false;
> + return;
> + }
> +
> + txmsg = list_first_entry(&mgr->tx_msg_upq, struct 
> drm_dp_sideband_msg_tx, next);
> + ret = process_single_tx_qlock(mgr, txmsg, true);
> + if (ret == 1) {
> + /* up txmsgs aren't put in slots - so free after we send it */
> + list_del(&txmsg->next);
> + kfree(txmsg);
> + } else if (ret)
> + DRM_DEBUG_KMS("failed to send msg in q %d\n", ret);
> + mgr->tx_up_in_progress = true;
> +}
> +
> +static void drm_dp_queue_down_tx(struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_sideband_msg_tx *txmsg)
> +{
> + mutex_lock(&mgr->qlock);
> + list_add_tail(&txmsg->next, &mgr->tx_msg_downq);
> + if (!mgr->tx_down_in_progress)
> + process_single_down_tx_qlock(mgr);
> + mutex_unlock(&mgr->qlock);
> +}
> +
> +static int drm_dp_send_link_address(struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_mst_branch *mstb)
> +{
> + int len;
> + struct drm_dp_sideband_msg_tx *txmsg;
> + int ret;
> +
> + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
> + if (!txmsg)
> + return -ENOMEM;
> +
> + txmsg->dst = mstb;
> + len = build_link_address(txmsg);
> +
> + drm_dp_queue_down_tx(mgr, txmsg);
> +
> + ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
> + if (ret > 0) {
> + int i;
> +
> + if (txmsg->reply.reply_type == 1)
> + DRM_DEBUG_KMS("link address nak received\n");
> + else {
> + DRM_DEBUG_KMS("link address reply: %d\n", 
> txmsg->reply.u.link_addr.nports);
> + for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) {
> + DRM_DEBUG_KMS("port %d: input %d, pdt: %d, pn: %d, dpcd_rev: %02x, 
> mcs: %d, ddps: %d, ldps %d\n", i,
> + txmsg->reply.u.link_addr.ports[i].input_port,
> + txmsg->reply.u.link_addr.ports[i].peer_device_type,
> + txmsg->reply.u.link_addr.ports[i].port_number,
> + txmsg->reply.u.link_addr.ports[i].dpcd_revision,
> + txmsg->reply.u.link_addr.ports[i].mcs,
> + txmsg->reply.u.link_addr.ports[i].ddps,
> + txmsg->reply.u.link_addr.ports[i].legacy_device_plug_status);
> + }
> + for (i = 0; i < txmsg->reply.u.link_addr.nports; i++) {
> + drm_dp_add_port(mstb, mgr->dev, &txmsg->reply.u.link_addr.ports[i]);
> + }
> + (*mgr->cbs->hotplug)(mgr);
> + }
> + } else
> + DRM_DEBUG_KMS("link address failed %d\n", ret);
> +
> + kfree(txmsg);
> + return 0;
> +}
> +
> +static int drm_dp_send_enum_path_resources(struct 
> drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_mst_branch *mstb,
> + struct drm_dp_mst_port *port)
> +{
> + int len;
> + struct drm_dp_sideband_msg_tx *txmsg;
> + int ret;
> +
> + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
> + if (!txmsg)
> + return -ENOMEM;
> +
> + txmsg->dst = mstb;
> + len = build_enum_path_resources(txmsg, port->port_num);
> +
> + drm_dp_queue_down_tx(mgr, txmsg);
> +
> + ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
> + if (ret > 0) {
> + if (txmsg->reply.reply_type == 1)
> + DRM_DEBUG_KMS("enum path resources nak received\n");
> + else {
> + if (port->port_num != txmsg->reply.u.path_resources.port_number)
> + DRM_ERROR("got incorrect port in response\n");
> + DRM_DEBUG_KMS("enum path resources %d: %d %d\n", 
> txmsg->reply.u.path_resources.port_number, 
> txmsg->reply.u.path_resources.full_payload_bw_number,
> + txmsg->reply.u.path_resources.avail_payload_bw_number);
> + port->available_pbn = 
> txmsg->reply.u.path_resources.avail_payload_bw_number;
> + }
> + }
> +
> + kfree(txmsg);
> + return 0;
> +}
> +
> +int drm_dp_payload_send_msg(struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_mst_port *port,
> + int id,
> + int pbn)
> +{
> + struct drm_dp_sideband_msg_tx *txmsg;
> + struct drm_dp_mst_branch *mstb;
> + int len, ret;
> +
> + mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
> + if (!mstb)
> + return -EINVAL;
> +
> + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
> + if (!txmsg) {
> + ret = -ENOMEM;
> + goto fail_put;
> + }
> +
> + txmsg->dst = mstb;
> + len = build_allocate_payload(txmsg, port->port_num,
> + id,
> + pbn);
> +
> + drm_dp_queue_down_tx(mgr, txmsg);
> +
> + ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
> + if (ret > 0) {
> + if (txmsg->reply.reply_type == 1) {
> + ret = -EINVAL;
> + } else
> + ret = 0;
> + }
> + kfree(txmsg);
> +fail_put:
> + drm_dp_put_mst_branch_device(mstb);
> + return ret;
> +}
> +
> +static int drm_dp_create_payload_step1(struct drm_dp_mst_topology_mgr 
> *mgr,
> + int id,
> + struct drm_dp_payload *payload)
> +{
> + int ret;
> +
> + ret = drm_dp_dpcd_write_payload(mgr, id, payload);
> + if (ret < 0) {
> + payload->payload_state = 0;
> + return ret;
> + }
> + payload->payload_state = DP_PAYLOAD_LOCAL;
> + return 0;
> +}
> +
> +int drm_dp_create_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_mst_port *port,
> + int id,
> + struct drm_dp_payload *payload)
> +{
> + int ret;
> + ret = drm_dp_payload_send_msg(mgr, port, id, port->vcpi.pbn);
> + if (ret < 0)
> + return ret;
> + payload->payload_state = DP_PAYLOAD_REMOTE;
> + return ret;
> +}
> +
> +int drm_dp_destroy_payload_step1(struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_mst_port *port,
> + int id,
> + struct drm_dp_payload *payload)
> +{
> + DRM_DEBUG_KMS("\n");
> + /* its okay for these to fail */
> + if (port) {
> + drm_dp_payload_send_msg(mgr, port, id, 0);
> + }
> +
> + drm_dp_dpcd_write_payload(mgr, id, payload);
> + payload->payload_state = 0;
> + return 0;
> +}
> +
> +int drm_dp_destroy_payload_step2(struct drm_dp_mst_topology_mgr *mgr,
> + int id,
> + struct drm_dp_payload *payload)
> +{
> + payload->payload_state = 0;
> + return 0;
> +}
> +
> +/**
> + * drm_dp_update_payload_part1() - Execute payload update part 1
> + * @mgr: manager to use.
> + *
> + * This iterates over all proposed virtual channels, and tries to
> + * allocate space in the link for them. For 0->slots transitions,
> + * this step just writes the VCPI to the MST device. For slots->0
> + * transitions, this writes the updated VCPIs and removes the
> + * remote VC payloads.
> + *
> + * after calling this the driver should generate ACT and payload
> + * packets.
> + */
> +int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
> +{
> + int i;
> + int cur_slots = 1;
> + struct drm_dp_payload req_payload;
> + struct drm_dp_mst_port *port;
> +
> + mutex_lock(&mgr->payload_lock);
> + for (i = 0; i < mgr->max_payloads; i++) {
> + /* solve the current payloads - compare to the hw ones
> + - update the hw view */
> + req_payload.start_slot = cur_slots;
> + if (mgr->proposed_vcpis[i]) {
> + port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, 
> vcpi);
> + req_payload.num_slots = mgr->proposed_vcpis[i]->num_slots;
> + } else {
> + port = NULL;
> + req_payload.num_slots = 0;
> + }
> + /* work out what is required to happen with this payload */
> + if (mgr->payloads[i].start_slot != req_payload.start_slot ||
> + mgr->payloads[i].num_slots != req_payload.num_slots) {
> +
> + /* need to push an update for this payload */
> + if (req_payload.num_slots) {
> + drm_dp_create_payload_step1(mgr, i + 1, &req_payload);
> + mgr->payloads[i].num_slots = req_payload.num_slots;
> + } else if (mgr->payloads[i].num_slots) {
> + mgr->payloads[i].num_slots = 0;
> + drm_dp_destroy_payload_step1(mgr, port, i + 1, &mgr->payloads[i]);
> + req_payload.payload_state = mgr->payloads[i].payload_state;
> + }
> + mgr->payloads[i].start_slot = req_payload.start_slot;
> + mgr->payloads[i].payload_state = req_payload.payload_state;
> + }
> + cur_slots += req_payload.num_slots;
> + }
> + mutex_unlock(&mgr->payload_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(drm_dp_update_payload_part1);
> +
> +/**
> + * drm_dp_update_payload_part2() - Execute payload update part 2
> + * @mgr: manager to use.
> + *
> + * This iterates over all proposed virtual channels, and tries to
> + * allocate space in the link for them. For 0->slots transitions,
> + * this step writes the remote VC payload commands. For slots->0
> + * this just resets some internal state.
> + */
> +int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
> +{
> + struct drm_dp_mst_port *port;
> + int i;
> + int ret;
> + mutex_lock(&mgr->payload_lock);
> + for (i = 0; i < mgr->max_payloads; i++) {
> +
> + if (!mgr->proposed_vcpis[i])
> + continue;
> +
> + port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, 
> vcpi);
> +
> + DRM_DEBUG_KMS("payload %d %d\n", i, mgr->payloads[i].payload_state);
> + if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
> + ret = drm_dp_create_payload_step2(mgr, port, i + 1, &mgr->payloads[i]);
> + } else if (mgr->payloads[i].payload_state == DP_PAYLOAD_DELETE_LOCAL) {
> + ret = drm_dp_destroy_payload_step2(mgr, i + 1, &mgr->payloads[i]);
> + }
> + if (ret) {
> + mutex_unlock(&mgr->payload_lock);
> + return ret;
> + }
> + }
> + mutex_unlock(&mgr->payload_lock);
> + return 0;
> +}
> +EXPORT_SYMBOL(drm_dp_update_payload_part2);
> +
> +#if 0 /* unused as of yet */
> +static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_mst_port *port,
> + int offset, int size)
> +{
> + int len;
> + struct drm_dp_sideband_msg_tx *txmsg;
> +
> + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
> + if (!txmsg)
> + return -ENOMEM;
> +
> + len = build_dpcd_read(txmsg, port->port_num, 0, 8);
> + txmsg->dst = port->parent;
> +
> + drm_dp_queue_down_tx(mgr, txmsg);
> +
> + return 0;
> +}
> +#endif
> +
> +static int drm_dp_send_dpcd_write(struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_mst_port *port,
> + int offset, int size, u8 *bytes)
> +{
> + int len;
> + int ret;
> + struct drm_dp_sideband_msg_tx *txmsg;
> + struct drm_dp_mst_branch *mstb;
> +
> + mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
> + if (!mstb)
> + return -EINVAL;
> +
> + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
> + if (!txmsg) {
> + ret = -ENOMEM;
> + goto fail_put;
> + }
> +
> + len = build_dpcd_write(txmsg, port->port_num, offset, size, bytes);
> + txmsg->dst = mstb;
> +
> + drm_dp_queue_down_tx(mgr, txmsg);
> +
> + ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
> + if (ret > 0) {
> + if (txmsg->reply.reply_type == 1) {
> + ret = -EINVAL;
> + } else
> + ret = 0;
> + }
> + kfree(txmsg);
> +fail_put:
> + drm_dp_put_mst_branch_device(mstb);
> + return ret;
> +}
> +
> +static int drm_dp_encode_up_ack_reply(struct drm_dp_sideband_msg_tx 
> *msg, u8 req_type)
> +{
> + struct drm_dp_sideband_msg_reply_body reply;
> +
> + reply.reply_type = 1;
> + reply.req_type = req_type;
> + drm_dp_encode_sideband_reply(&reply, msg);
> + return 0;
> +}
> +
> +static int drm_dp_send_up_ack_reply(struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_mst_branch *mstb,
> + int req_type, int seqno, bool broadcast)
> +{
> + struct drm_dp_sideband_msg_tx *txmsg;
> +
> + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
> + if (!txmsg)
> + return -ENOMEM;
> +
> + txmsg->dst = mstb;
> + txmsg->seqno = seqno;
> + drm_dp_encode_up_ack_reply(txmsg, req_type);
> +
> + mutex_lock(&mgr->qlock);
> + list_add_tail(&txmsg->next, &mgr->tx_msg_upq);
> + if (!mgr->tx_up_in_progress) {
> + process_single_up_tx_qlock(mgr);
> + }
> + mutex_unlock(&mgr->qlock);
> + return 0;
> +}
> +
> +static int drm_dp_get_vc_payload_bw(int dp_link_bw, int dp_link_count)
> +{
> + switch (dp_link_bw) {
> + case DP_LINK_BW_1_62:
> + return 3 * dp_link_count;
> + case DP_LINK_BW_2_7:
> + return 5 * dp_link_count;
> + case DP_LINK_BW_5_4:
> + return 10 * dp_link_count;
> + }
> + return 0;
> +}
> +
> +/**
> + * drm_dp_mst_topology_mgr_set_mst() - Set the MST state for a 
> topology manager
> + * @mgr: manager to set state for
> + * @mst_state: true to enable MST on this connector - false to disable.
> + *
> + * This is called by the driver when it detects an MST capable device 
> plugged
> + * into a DP MST capable port, or when a DP MST capable device is 
> unplugged.
> + */
> +int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr 
> *mgr, bool mst_state)
> +{
> + int ret = 0;
> + struct drm_dp_mst_branch *mstb = NULL;
> +
> + mutex_lock(&mgr->lock);
> + if (mst_state == mgr->mst_state)
> + goto out_unlock;
> +
> + mgr->mst_state = mst_state;
> + /* set the device into MST mode */
> + if (mst_state) {
> + WARN_ON(mgr->mst_primary);
> +
> + /* get dpcd info */
> + mutex_lock(&mgr->aux_lock);
> + ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, 
> DP_RECEIVER_CAP_SIZE);
> + mutex_unlock(&mgr->aux_lock);
> + if (ret != DP_RECEIVER_CAP_SIZE) {
> + DRM_DEBUG_KMS("failed to read DPCD\n");
> + goto out_unlock;
> + }
> +
> + mgr->pbn_div = drm_dp_get_vc_payload_bw(mgr->dpcd[1], mgr->dpcd[2] & 
> DP_MAX_LANE_COUNT_MASK);
> + mgr->total_pbn = 2560;
> + mgr->total_slots = DIV_ROUND_UP(mgr->total_pbn, mgr->pbn_div);
> + mgr->avail_slots = mgr->total_slots;
> +
> + /* add initial branch device at LCT 1 */
> + mstb = drm_dp_add_mst_branch_device(1, NULL);
> + if (mstb == NULL) {
> + ret = -ENOMEM;
> + goto out_unlock;
> + }
> + mstb->mgr = mgr;
> +
> + /* give this the main reference */
> + mgr->mst_primary = mstb;
> + kref_get(&mgr->mst_primary->kref);
> +
> + {
> + struct drm_dp_payload reset_pay;
> + reset_pay.start_slot = 0;
> + reset_pay.num_slots = 0x3f;
> + drm_dp_dpcd_write_payload(mgr, 0, &reset_pay);
> + }
> +
> + mutex_lock(&mgr->aux_lock);
> + ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
> + DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC);
> + mutex_unlock(&mgr->aux_lock);
> + if (ret < 0) {
> + goto out_unlock;
> + }
> +
> +
> + /* sort out guid */
> + mutex_lock(&mgr->aux_lock);
> + ret = drm_dp_dpcd_read(mgr->aux, DP_GUID, mgr->guid, 16);
> + mutex_unlock(&mgr->aux_lock);
> + if (ret != 16) {
> + DRM_DEBUG_KMS("failed to read DP GUID %d\n", ret);
> + goto out_unlock;
> + }
> +
> + mgr->guid_valid = drm_dp_validate_guid(mgr, mgr->guid);
> + if (!mgr->guid_valid) {
> + ret = drm_dp_dpcd_write(mgr->aux, DP_GUID, mgr->guid, 16);
> + mgr->guid_valid = true;
> + }
> +
> + queue_work(system_long_wq, &mgr->work);
> +
> + ret = 0;
> + } else {
> + /* disable MST on the device */
> + mstb = mgr->mst_primary;
> + mgr->mst_primary = NULL;
> + /* this can fail if the device is gone */
> + drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL, 0);
> + ret = 0;
> + memset(mgr->payloads, 0, mgr->max_payloads * sizeof(struct 
> drm_dp_payload));
> + mgr->payload_mask = 0;
> + set_bit(0, &mgr->payload_mask);
> + }
> +
> +out_unlock:
> + mutex_unlock(&mgr->lock);
> + if (mstb)
> + drm_dp_put_mst_branch_device(mstb);
> + return ret;
> +
> +}
> +EXPORT_SYMBOL(drm_dp_mst_topology_mgr_set_mst);
> +
> +/**
> + * drm_dp_mst_topology_mgr_suspend() - suspend the MST manager
> + * @mgr: manager to suspend
> + *
> + * This function tells the MST device that we can't handle UP messages
> + * anymore. This should stop it from sending any since we are suspended.
> + */
> +void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr)
> +{
> + mutex_lock(&mgr->lock);
> + mutex_lock(&mgr->aux_lock);
> + drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
> + DP_MST_EN | DP_UPSTREAM_IS_SRC);
> + mutex_unlock(&mgr->aux_lock);
> + mutex_unlock(&mgr->lock);
> +}
> +EXPORT_SYMBOL(drm_dp_mst_topology_mgr_suspend);
> +
> +/**
> + * drm_dp_mst_topology_mgr_resume() - resume the MST manager
> + * @mgr: manager to resume
> + *
> + * This will fetch DPCD and see if the device is still there,
> + * if it is, it will rewrite the MSTM control bits, and return.
> + *
> + * if the device fails this returns -1, and the driver should do
> + * a full MST reprobe, in case we were undocked.
> + */
> +int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr)
> +{
> + int ret = 0;
> +
> + mutex_lock(&mgr->lock);
> +
> + if (mgr->mst_primary) {
> + int sret;
> + mutex_lock(&mgr->aux_lock);
> + sret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, mgr->dpcd, 
> DP_RECEIVER_CAP_SIZE);
> + mutex_unlock(&mgr->aux_lock);
> + if (sret != DP_RECEIVER_CAP_SIZE) {
> + DRM_DEBUG_KMS("dpcd read failed - undocked during suspend?\n");
> + ret = -1;
> + goto out_unlock;
> + }
> +
> + mutex_lock(&mgr->aux_lock);
> + ret = drm_dp_dpcd_writeb(mgr->aux, DP_MSTM_CTRL,
> + DP_MST_EN | DP_UP_REQ_EN | DP_UPSTREAM_IS_SRC);
> + mutex_unlock(&mgr->aux_lock);
> + if (ret < 0) {
> + DRM_DEBUG_KMS("mst write failed - undocked during suspend?\n");
> + ret = -1;
> + goto out_unlock;
> + }
> + ret = 0;
> + } else
> + ret = -1;
> +
> +out_unlock:
> + mutex_unlock(&mgr->lock);
> + return ret;
> +}
> +EXPORT_SYMBOL(drm_dp_mst_topology_mgr_resume);
> +
> +static void drm_dp_get_one_sb_msg(struct drm_dp_mst_topology_mgr 
> *mgr, bool up)
> +{
> + int len;
> + u8 replyblock[32];
> + int replylen, origlen, curreply;
> + int ret;
> + struct drm_dp_sideband_msg_rx *msg;
> + int basereg = up ? DP_SIDEBAND_MSG_UP_REQ_BASE : 
> DP_SIDEBAND_MSG_DOWN_REP_BASE;
> + msg = up ? &mgr->up_req_recv : &mgr->down_rep_recv;
> +
> + len = min(mgr->max_dpcd_transaction_bytes, 16);
> + mutex_lock(&mgr->aux_lock);
> + ret = drm_dp_dpcd_read(mgr->aux, basereg,
> + replyblock, len);
> + mutex_unlock(&mgr->aux_lock);
> + if (ret != len) {
> + DRM_DEBUG_KMS("failed to read DPCD down rep %d %d\n", len, ret);
> + return;
> + }
> + ret = drm_dp_sideband_msg_build(msg, replyblock, len, true);
> + if (!ret) {
> + DRM_DEBUG_KMS("sideband msg build failed %d\n", replyblock[0]);
> + return;
> + }
> + replylen = msg->curchunk_len + msg->curchunk_hdrlen;
> +
> + origlen = replylen;
> + replylen -= len;
> + curreply = len;
> + while (replylen > 0) {
> + len = min3(replylen, mgr->max_dpcd_transaction_bytes, 16);
> + mutex_lock(&mgr->aux_lock);
> + ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply,
> + replyblock, len);
> + mutex_unlock(&mgr->aux_lock);
> + if (ret != len) {
> + DRM_DEBUG_KMS("failed to read a chunk\n");
> + }
> + ret = drm_dp_sideband_msg_build(msg, replyblock, len, false);
> + if (ret == false)
> + DRM_DEBUG_KMS("failed to build sideband msg\n");
> + curreply += len;
> + replylen -= len;
> + }
> +}
> +
> +static int drm_dp_mst_handle_down_rep(struct drm_dp_mst_topology_mgr 
> *mgr)
> +{
> + int ret = 0;
> +
> + drm_dp_get_one_sb_msg(mgr, false);
> +
> + if (mgr->down_rep_recv.have_eomt) {
> + struct drm_dp_sideband_msg_tx *txmsg;
> + struct drm_dp_mst_branch *mstb;
> + int slot = -1;
> + mstb = drm_dp_get_mst_branch_device(mgr,
> + mgr->down_rep_recv.initial_hdr.lct,
> + mgr->down_rep_recv.initial_hdr.rad);
> +
> + if (!mstb) {
> + DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", 
> mgr->down_rep_recv.initial_hdr.lct);
> + memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
> + return 0;
> + }
> +
> + /* find the message */
> + slot = mgr->down_rep_recv.initial_hdr.seqno;
> + mutex_lock(&mgr->qlock);
> + txmsg = mstb->tx_slots[slot];
> + /* remove from slots */
> + mutex_unlock(&mgr->qlock);
> +
> + if (!txmsg) {
> + DRM_DEBUG_KMS("Got MST reply with no msg %p %d %d %02x %02x\n",
> + mstb,
> + mgr->down_rep_recv.initial_hdr.seqno,
> + mgr->down_rep_recv.initial_hdr.lct,
> + mgr->down_rep_recv.initial_hdr.rad[0],
> + mgr->down_rep_recv.msg[0]);
> + drm_dp_put_mst_branch_device(mstb);
> + memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
> + return 0;
> + }
> +
> + drm_dp_sideband_parse_reply(&mgr->down_rep_recv, &txmsg->reply);
> + if (txmsg->reply.reply_type == 1) {
> + DRM_DEBUG_KMS("Got NAK reply: req 0x%02x, reason 0x%02x, nak data 
> 0x%02x\n", txmsg->reply.req_type, txmsg->reply.u.nak.reason, 
> txmsg->reply.u.nak.nak_data);
> + }
> +
> + memset(&mgr->down_rep_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
> + drm_dp_put_mst_branch_device(mstb);
> +
> + mutex_lock(&mgr->qlock);
> + txmsg->state = DRM_DP_SIDEBAND_TX_RX;
> + mstb->tx_slots[slot] = NULL;
> + mutex_unlock(&mgr->qlock);
> +
> + wake_up(&mgr->tx_waitq);
> + }
> + return ret;
> +}
> +
> +static int drm_dp_mst_handle_up_req(struct drm_dp_mst_topology_mgr *mgr)
> +{
> + int ret = 0;
> + drm_dp_get_one_sb_msg(mgr, true);
> +
> + if (mgr->up_req_recv.have_eomt) {
> + struct drm_dp_sideband_msg_req_body msg;
> + struct drm_dp_mst_branch *mstb;
> + bool seqno;
> + mstb = drm_dp_get_mst_branch_device(mgr,
> + mgr->up_req_recv.initial_hdr.lct,
> + mgr->up_req_recv.initial_hdr.rad);
> + if (!mstb) {
> + DRM_DEBUG_KMS("Got MST reply from unknown device %d\n", 
> mgr->up_req_recv.initial_hdr.lct);
> + memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
> + return 0;
> + }
> +
> + seqno = mgr->up_req_recv.initial_hdr.seqno;
> + drm_dp_sideband_parse_req(&mgr->up_req_recv, &msg);
> +
> + if (msg.req_type == DP_CONNECTION_STATUS_NOTIFY) {
> + drm_dp_send_up_ack_reply(mgr, mstb, msg.req_type, seqno, false);
> + drm_dp_update_port(mstb, &msg.u.conn_stat);
> + DRM_DEBUG_KMS("Got CSN: pn: %d ldps:%d ddps: %d mcs: %d ip: %d pdt: 
> %d\n", msg.u.conn_stat.port_number, 
> msg.u.conn_stat.legacy_device_plug_status, 
> msg.u.conn_stat.displayport_device_plug_status, 
> msg.u.conn_stat.message_capability_status, msg.u.conn_stat.input_port, 
> msg.u.conn_stat.peer_device_type);
> + (*mgr->cbs->hotplug)(mgr);
> +
> + } else if (msg.req_type == DP_RESOURCE_STATUS_NOTIFY) {
> + drm_dp_send_up_ack_reply(mgr, mstb, msg.req_type, seqno, false);
> + DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n", 
> msg.u.resource_stat.port_number, msg.u.resource_stat.available_pbn);
> + }
> +
> + drm_dp_put_mst_branch_device(mstb);
> + memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx));
> + }
> + return ret;
> +}
> +
> +/**
> + * drm_dp_mst_hpd_irq() - MST hotplug IRQ notify
> + * @mgr: manager to notify irq for.
> + * @esi: 4 bytes from SINK_COUNT_ESI
> + *
> + * This should be called from the driver when it detects a short IRQ,
> + * along with the value of the DEVICE_SERVICE_IRQ_VECTOR_ESI0. The
> + * topology manager will process the sideband messages received as a 
> result
> + * of this.
> + */
> +int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, 
> bool *handled)
> +{
> + int ret = 0;
> + int sc;
> + *handled = false;
> + sc = esi[0] & 0x3f;
> + if (sc != mgr->sink_count) {
> +
> + if (mgr->mst_primary && mgr->sink_count == 0 && sc) {
> + mgr->mst_primary->link_address_sent = false;
> + queue_work(system_long_wq, &mgr->work);
> + }
> + mgr->sink_count = sc;
> + *handled = true;
> +
> + }
> +
> + if (esi[1] & DP_DOWN_REP_MSG_RDY) {
> + ret = drm_dp_mst_handle_down_rep(mgr);
> + *handled = true;
> + }
> +
> + if (esi[1] & DP_UP_REQ_MSG_RDY) {
> + ret |= drm_dp_mst_handle_up_req(mgr);
> + *handled = true;
> + }
> +
> + drm_dp_mst_kick_tx(mgr);
> + return ret;
> +}
> +EXPORT_SYMBOL(drm_dp_mst_hpd_irq);
> +
> +/**
> + * drm_dp_mst_detect_port() - get connection status for an MST port
> + * @mgr: manager for this port
> + * @port: unverified pointer to a port
> + *
> + * This returns the current connection state for a port. It validates the
> + * port pointer still exists so the caller doesn't require a reference
> + */
> +enum drm_connector_status drm_dp_mst_detect_port(struct 
> drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
> +{
> + enum drm_connector_status status = connector_status_disconnected;
> +
> + /* we need to search for the port in the mgr in case its gone */
> + port = drm_dp_get_validated_port_ref(mgr, port);
> + if (!port)
> + return connector_status_disconnected;
> +
> + if (!port->ddps)
> + goto out;
> +
> + switch (port->pdt) {
> + case DP_PEER_DEVICE_NONE:
> + case DP_PEER_DEVICE_MST_BRANCHING:
> + break;
> +
> + case DP_PEER_DEVICE_SST_SINK:
> + status = connector_status_connected;
> + break;
> + case DP_PEER_DEVICE_DP_LEGACY_CONV:
> + if (port->ldps)
> + status = connector_status_connected;
> + break;
> + }
> +out:
> + drm_dp_put_port(port);
> + return status;
> +}
> +EXPORT_SYMBOL(drm_dp_mst_detect_port);
> +
> +/**
> + * drm_dp_mst_get_edid() - get EDID for an MST port
> + * @connector: toplevel connector to get EDID for
> + * @mgr: manager for this port
> + * @port: unverified pointer to a port.
> + *
> + * This returns an EDID for the port connected to a connector,
> + * It validates the pointer still exists so the caller doesn't require a
> + * reference.
> + */
> +struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, 
> struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
> +{
> + struct edid *edid = NULL;
> +
> + /* we need to search for the port in the mgr in case its gone */
> + port = drm_dp_get_validated_port_ref(mgr, port);
> + if (!port)
> + return NULL;
> +
> + edid = drm_get_edid(connector, &port->aux.ddc);
> + drm_dp_put_port(port);
> + return edid;
> +}
> +EXPORT_SYMBOL(drm_dp_mst_get_edid);
> +
> +/**
> + * drm_dp_find_vcpi_slots() - find slots for this PBN value
> + * @mgr: manager to use
> + * @pbn: payload bandwidth to convert into slots.
> + */
> +int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
> + int pbn)
> +{
> + int num_slots;
> +
> + num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
> +
> + if (num_slots > mgr->avail_slots)
> + return -ENOSPC;
> + return num_slots;
> +}
> +EXPORT_SYMBOL(drm_dp_find_vcpi_slots);
> +
> +static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_vcpi *vcpi, int pbn)
> +{
> + int num_slots;
> + int ret;
> +
> + num_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
> +
> + if (num_slots > mgr->avail_slots)
> + return -ENOSPC;
> +
> + vcpi->pbn = pbn;
> + vcpi->aligned_pbn = num_slots * mgr->pbn_div;
> + vcpi->num_slots = num_slots;
> +
> + ret = drm_dp_mst_assign_payload_id(mgr, vcpi);
> + if (ret < 0)
> + return ret;
> + return 0;
> +}
> +
> +/**
> + * drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
> + * @mgr: manager for this port
> + * @port: port to allocate a virtual channel for.
> + * @pbn: payload bandwidth number to request
> + * @slots: returned number of slots for this PBN.
> + */
> +bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, 
> struct drm_dp_mst_port *port, int pbn, int *slots)
> +{
> + int ret;
> +
> + port = drm_dp_get_validated_port_ref(mgr, port);
> + if (!port)
> + return false;
> +
> + if (port->vcpi.vcpi > 0) {
> + DRM_DEBUG_KMS("payload: vcpi %d already allocated for pbn %d - 
> requested pbn %d\n", port->vcpi.vcpi, port->vcpi.pbn, pbn);
> + if (pbn == port->vcpi.pbn) {
> + *slots = port->vcpi.num_slots;
> + return true;
> + }
> + }
> +
> + ret = drm_dp_init_vcpi(mgr, &port->vcpi, pbn);
> + if (ret) {
> + DRM_DEBUG_KMS("failed to init vcpi %d %d %d\n", DIV_ROUND_UP(pbn, 
> mgr->pbn_div), mgr->avail_slots, ret);
> + goto out;
> + }
> + DRM_DEBUG_KMS("initing vcpi for %d %d\n", pbn, port->vcpi.num_slots);
> + *slots = port->vcpi.num_slots;
> +
> + drm_dp_put_port(port);
> + return true;
> +out:
> + return false;
> +}
> +EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
> +
> +/**
> + * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
> + * @mgr: manager for this port
> + * @port: unverified pointer to a port.
> + *
> + * This just resets the number of slots for the ports VCPI for later 
> programming.
> + */
> +void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, 
> struct drm_dp_mst_port *port)
> +{
> + port = drm_dp_get_validated_port_ref(mgr, port);
> + if (!port)
> + return;
> + port->vcpi.num_slots = 0;
> + drm_dp_put_port(port);
> +}
> +EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
> +
> +/**
> + * drm_dp_mst_deallocate_vcpi() - deallocate a VCPI
> + * @mgr: manager for this port
> + * @port: unverified port to deallocate vcpi for
> + */
> +void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, 
> struct drm_dp_mst_port *port)
> +{
> + port = drm_dp_get_validated_port_ref(mgr, port);
> + if (!port)
> + return;
> +
> + drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
> + port->vcpi.num_slots = 0;
> + port->vcpi.pbn = 0;
> + port->vcpi.aligned_pbn = 0;
> + port->vcpi.vcpi = 0;
> + drm_dp_put_port(port);
> +}
> +EXPORT_SYMBOL(drm_dp_mst_deallocate_vcpi);
> +
> +static int drm_dp_dpcd_write_payload(struct drm_dp_mst_topology_mgr *mgr,
> + int id, struct drm_dp_payload *payload)
> +{
> + u8 payload_alloc[3], status;
> + int ret;
> + int retries = 0;
> +
> + mutex_lock(&mgr->aux_lock);
> + drm_dp_dpcd_writeb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS,
> + DP_PAYLOAD_TABLE_UPDATED);
> + mutex_unlock(&mgr->aux_lock);
> +
> + payload_alloc[0] = id;
> + payload_alloc[1] = payload->start_slot;
> + payload_alloc[2] = payload->num_slots;
> +
> + mutex_lock(&mgr->aux_lock);
> + ret = drm_dp_dpcd_write(mgr->aux, DP_PAYLOAD_ALLOCATE_SET, 
> payload_alloc, 3);
> + mutex_unlock(&mgr->aux_lock);
> + if (ret != 3) {
> + DRM_DEBUG_KMS("failed to write payload allocation %d\n", ret);
> + goto fail;
> + }
> +
> +retry:
> + mutex_lock(&mgr->aux_lock);
> + ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, 
> &status);
> + mutex_unlock(&mgr->aux_lock);
> + if (ret < 0) {
> + DRM_DEBUG_KMS("failed to read payload table status %d\n", ret);
> + goto fail;
> + }
> +
> + if (!(status & DP_PAYLOAD_TABLE_UPDATED)) {
> + retries++;
> + if (retries < 20) {
> + usleep_range(10000, 20000);
> + goto retry;
> + }
> + DRM_DEBUG_KMS("status not set after read payload table status %d\n", 
> status);
> + ret = -EINVAL;
> + goto fail;
> + }
> + ret = 0;
> +fail:
> + return ret;
> +}
> +
> +
> +/**
> + * drm_dp_check_act_status() - Check ACT handled status.
> + * @mgr: manager to use
> + *
> + * Check the payload status bits in the DPCD for ACT handled completion.
> + */
> +int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
> +{
> + u8 status;
> + int ret;
> + int count = 0;
> +
> + do {
> + mutex_lock(&mgr->aux_lock);
> + ret = drm_dp_dpcd_readb(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, 
> &status);
> + mutex_unlock(&mgr->aux_lock);
> +
> + if (ret < 0) {
> + DRM_DEBUG_KMS("failed to read payload table status %d\n", ret);
> + goto fail;
> + }
> +
> + if (status & DP_PAYLOAD_ACT_HANDLED)
> + break;
> + count++;
> + udelay(100);
> +
> + } while (count < 30);
> +
> + if (!(status & DP_PAYLOAD_ACT_HANDLED)) {
> + DRM_DEBUG_KMS("failed to get ACT bit %d after %d retries\n", status, 
> count);
> + ret = -EINVAL;
> + goto fail;
> + }
> + return 0;
> +fail:
> + return ret;
> +}
> +EXPORT_SYMBOL(drm_dp_check_act_status);
> +
> +/**
> + * drm_dp_calc_pbn_mode() - Calculate the PBN for a mode.
> + * @clock: dot clock for the mode
> + * @bpp: bpp for the mode.
> + *
> + * This uses the formula in the spec to calculate the PBN value for a 
> mode.
> + */
> +int drm_dp_calc_pbn_mode(int clock, int bpp)
> +{
> + fixed20_12 pix_bw;
> + fixed20_12 fbpp;
> + fixed20_12 result;
> + fixed20_12 margin, tmp;
> + u32 res;
> +
> + pix_bw.full = dfixed_const(clock);
> + fbpp.full = dfixed_const(bpp);
> + tmp.full = dfixed_const(8);
> + fbpp.full = dfixed_div(fbpp, tmp);
> +
> + result.full = dfixed_mul(pix_bw, fbpp);
> + margin.full = dfixed_const(54);
> + tmp.full = dfixed_const(64);
> + margin.full = dfixed_div(margin, tmp);
> + result.full = dfixed_div(result, margin);
> +
> + margin.full = dfixed_const(1006);
> + tmp.full = dfixed_const(1000);
> + margin.full = dfixed_div(margin, tmp);
> + result.full = dfixed_mul(result, margin);
> +
> + result.full = dfixed_div(result, tmp);
> + result.full = dfixed_ceil(result);
> + res = dfixed_trunc(result);
> + return res;
> +}
> +EXPORT_SYMBOL(drm_dp_calc_pbn_mode);
> +
> +static int test_calc_pbn_mode(void)
> +{
> + int ret;
> + ret = drm_dp_calc_pbn_mode(154000, 30);
> + if (ret != 689)
> + return -EINVAL;
> + ret = drm_dp_calc_pbn_mode(234000, 30);
> + if (ret != 1047)
> + return -EINVAL;
> + return 0;
> +}
> +
> +/* we want to kick the TX after we've ack the up/down IRQs. */
> +static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr)
> +{
> + queue_work(system_long_wq, &mgr->tx_work);
> +}
> +
> +static void drm_dp_mst_dump_mstb(struct seq_file *m,
> + struct drm_dp_mst_branch *mstb)
> +{
> + struct drm_dp_mst_port *port;
> + int tabs = mstb->lct;
> + char prefix[10];
> + int i;
> +
> + for (i = 0; i < tabs; i++)
> + prefix[i] = '\t';
> + prefix[i] = '\0';
> +
> + seq_printf(m, "%smst: %p, %d\n", prefix, mstb, mstb->num_ports);
> + list_for_each_entry(port, &mstb->ports, next) {
> + seq_printf(m, "%sport: %d: ddps: %d ldps: %d, %p, conn: %p\n", 
> prefix, port->port_num, port->ddps, port->ldps, port, port->connector);
> + if (port->mstb)
> + drm_dp_mst_dump_mstb(m, port->mstb);
> + }
> +}
> +
> +static bool dump_dp_payload_table(struct drm_dp_mst_topology_mgr *mgr,
> + char *buf)
> +{
> + int ret;
> + int i;
> + mutex_lock(&mgr->aux_lock);
> + for (i = 0; i < 4; i++) {
> + ret = drm_dp_dpcd_read(mgr->aux, DP_PAYLOAD_TABLE_UPDATE_STATUS + (i 
> * 16), &buf[i * 16], 16);
> + if (ret != 16)
> + break;
> + }
> + mutex_unlock(&mgr->aux_lock);
> + if (i == 4)
> + return true;
> + return false;
> +}
> +
> +/**
> + * drm_dp_mst_dump_topology(): dump topology to seq file.
> + * @m: seq_file to dump output to
> + * @mgr: manager to dump current topology for.
> + *
> + * helper to dump MST topology to a seq file for debugfs.
> + */
> +void drm_dp_mst_dump_topology(struct seq_file *m,
> + struct drm_dp_mst_topology_mgr *mgr)
> +{
> + int i;
> + struct drm_dp_mst_port *port;
> + mutex_lock(&mgr->lock);
> + if (mgr->mst_primary)
> + drm_dp_mst_dump_mstb(m, mgr->mst_primary);
> +
> + /* dump VCPIs */
> + mutex_unlock(&mgr->lock);
> +
> + mutex_lock(&mgr->payload_lock);
> + seq_printf(m, "vcpi: %lx\n", mgr->payload_mask);
> +
> + for (i = 0; i < mgr->max_payloads; i++) {
> + if (mgr->proposed_vcpis[i]) {
> + port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, 
> vcpi);
> + seq_printf(m, "vcpi %d: %d %d %d\n", i, port->port_num, 
> port->vcpi.vcpi, port->vcpi.num_slots);
> + } else
> + seq_printf(m, "vcpi %d:unsed\n", i);
> + }
> + for (i = 0; i < mgr->max_payloads; i++) {
> + seq_printf(m, "payload %d: %d, %d, %d\n",
> + i,
> + mgr->payloads[i].payload_state,
> + mgr->payloads[i].start_slot,
> + mgr->payloads[i].num_slots);
> +
> +
> + }
> + mutex_unlock(&mgr->payload_lock);
> +
> + mutex_lock(&mgr->lock);
> + if (mgr->mst_primary) {
> + u8 buf[64];
> + bool bret;
> + int ret;
> + ret = drm_dp_dpcd_read(mgr->aux, DP_DPCD_REV, buf, 
> DP_RECEIVER_CAP_SIZE);
> + seq_printf(m, "dpcd: ");
> + for (i = 0; i < DP_RECEIVER_CAP_SIZE; i++)
> + seq_printf(m, "%02x ", buf[i]);
> + seq_printf(m, "\n");
> + ret = drm_dp_dpcd_read(mgr->aux, DP_FAUX_CAP, buf, 2);
> + seq_printf(m, "faux/mst: ");
> + for (i = 0; i < 2; i++)
> + seq_printf(m, "%02x ", buf[i]);
> + seq_printf(m, "\n");
> + ret = drm_dp_dpcd_read(mgr->aux, DP_MSTM_CTRL, buf, 1);
> + seq_printf(m, "mst ctrl: ");
> + for (i = 0; i < 1; i++)
> + seq_printf(m, "%02x ", buf[i]);
> + seq_printf(m, "\n");
> +
> + bret = dump_dp_payload_table(mgr, buf);
> + if (bret == true) {
> + seq_printf(m, "payload table: ");
> + for (i = 0; i < 63; i++)
> + seq_printf(m, "%02x ", buf[i]);
> + seq_printf(m, "\n");
> + }
> +
> + }
> +
> + mutex_unlock(&mgr->lock);
> +
> +}
> +EXPORT_SYMBOL(drm_dp_mst_dump_topology);
> +
> +static void drm_dp_tx_work(struct work_struct *work)
> +{
> + struct drm_dp_mst_topology_mgr *mgr = container_of(work, struct 
> drm_dp_mst_topology_mgr, tx_work);
> +
> + mutex_lock(&mgr->qlock);
> + if (mgr->tx_down_in_progress)
> + process_single_down_tx_qlock(mgr);
> + mutex_unlock(&mgr->qlock);
> +}
> +
> +/**
> + * drm_dp_mst_topology_mgr_init - initialise a topology manager
> + * @mgr: manager struct to initialise
> + * @dev: device providing this structure - for i2c addition.
> + * @aux: DP helper aux channel to talk to this device
> + * @max_dpcd_transaction_bytes: hw specific DPCD transaction limit
> + * @max_payloads: maximum number of payloads this GPU can source
> + * @conn_base_id: the connector object ID the MST device is connected to.
> + *
> + * Return 0 for success, or negative error code on failure
> + */
> +int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr,
> + struct device *dev, struct drm_dp_aux *aux,
> + int max_dpcd_transaction_bytes,
> + int max_payloads, int conn_base_id)
> +{
> + mutex_init(&mgr->lock);
> + mutex_init(&mgr->qlock);
> + mutex_init(&mgr->aux_lock);
> + mutex_init(&mgr->payload_lock);
> + INIT_LIST_HEAD(&mgr->tx_msg_upq);
> + INIT_LIST_HEAD(&mgr->tx_msg_downq);
> + INIT_WORK(&mgr->work, drm_dp_mst_link_probe_work);
> + INIT_WORK(&mgr->tx_work, drm_dp_tx_work);
> + init_waitqueue_head(&mgr->tx_waitq);
> + mgr->dev = dev;
> + mgr->aux = aux;
> + mgr->max_dpcd_transaction_bytes = max_dpcd_transaction_bytes;
> + mgr->max_payloads = max_payloads;
> + mgr->conn_base_id = conn_base_id;
> + mgr->payloads = kcalloc(max_payloads, sizeof(struct drm_dp_payload), 
> GFP_KERNEL);
> + if (!mgr->payloads)
> + return -ENOMEM;
> + mgr->proposed_vcpis = kcalloc(max_payloads, sizeof(struct 
> drm_dp_vcpi *), GFP_KERNEL);
> + if (!mgr->proposed_vcpis)
> + return -ENOMEM;
> + set_bit(0, &mgr->payload_mask);
> + test_calc_pbn_mode();
> + return 0;
> +}
> +EXPORT_SYMBOL(drm_dp_mst_topology_mgr_init);
> +
> +/**
> + * drm_dp_mst_topology_mgr_destroy() - destroy topology manager.
> + * @mgr: manager to destroy
> + */
> +void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr)
> +{
> + mutex_lock(&mgr->payload_lock);
> + kfree(mgr->payloads);
> + mgr->payloads = NULL;
> + kfree(mgr->proposed_vcpis);
> + mgr->proposed_vcpis = NULL;
> + mutex_unlock(&mgr->payload_lock);
> + mgr->dev = NULL;
> + mgr->aux = NULL;
> +}
> +EXPORT_SYMBOL(drm_dp_mst_topology_mgr_destroy);
> +
> +/* I2C device */
> +static int drm_dp_mst_i2c_xfer(struct i2c_adapter *adapter, struct 
> i2c_msg *msgs,
> + int num)
> +{
> + struct drm_dp_aux *aux = adapter->algo_data;
> + struct drm_dp_mst_port *port = container_of(aux, struct 
> drm_dp_mst_port, aux);
> + struct drm_dp_mst_branch *mstb;
> + struct drm_dp_mst_topology_mgr *mgr = port->mgr;
> + unsigned int i;
> + bool reading = false;
> + struct drm_dp_sideband_msg_req_body msg;
> + struct drm_dp_sideband_msg_tx *txmsg = NULL;
> + int ret;
> +
> + mstb = drm_dp_get_validated_mstb_ref(mgr, port->parent);
> + if (!mstb)
> + return -EREMOTEIO;
> +
> + /* construct i2c msg */
> + /* see if last msg is a read */
> + if (msgs[num - 1].flags & I2C_M_RD)
> + reading = true;
> +
> + if (!reading) {
> + DRM_DEBUG_KMS("Unsupported I2C transaction for MST device\n");
> + ret = -EIO;
> + goto out;
> + }
> +
> + msg.req_type = DP_REMOTE_I2C_READ;
> + msg.u.i2c_read.num_transactions = num - 1;
> + msg.u.i2c_read.port_number = port->port_num;
> + for (i = 0; i < num - 1; i++) {
> + msg.u.i2c_read.transactions[i].i2c_dev_id = msgs[i].addr;
> + msg.u.i2c_read.transactions[i].num_bytes = msgs[i].len;
> + memcpy(&msg.u.i2c_read.transactions[i].bytes, msgs[i].buf, msgs[i].len);
> + }
> + msg.u.i2c_read.read_i2c_device_id = msgs[num - 1].addr;
> + msg.u.i2c_read.num_bytes_read = msgs[num - 1].len;
> +
> + txmsg = kzalloc(sizeof(*txmsg), GFP_KERNEL);
> + if (!txmsg) {
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> + txmsg->dst = mstb;
> + drm_dp_encode_sideband_req(&msg, txmsg);
> +
> + drm_dp_queue_down_tx(mgr, txmsg);
> +
> + ret = drm_dp_mst_wait_tx_reply(mstb, txmsg);
> + if (ret > 0) {
> +
> + if (txmsg->reply.reply_type == 1) { /* got a NAK back */
> + ret = -EREMOTEIO;
> + goto out;
> + }
> + if (txmsg->reply.u.remote_i2c_read_ack.num_bytes != msgs[num - 1].len) {
> + ret = -EIO;
> + goto out;
> + }
> + memcpy(msgs[num - 1].buf, txmsg->reply.u.remote_i2c_read_ack.bytes, 
> msgs[num - 1].len);
> + ret = num;
> + }
> +out:
> + kfree(txmsg);
> + drm_dp_put_mst_branch_device(mstb);
> + return ret;
> +}
> +
> +static u32 drm_dp_mst_i2c_functionality(struct i2c_adapter *adapter)
> +{
> + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
> + I2C_FUNC_SMBUS_READ_BLOCK_DATA |
> + I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
> + I2C_FUNC_10BIT_ADDR;
> +}
> +
> +static const struct i2c_algorithm drm_dp_mst_i2c_algo = {
> + .functionality = drm_dp_mst_i2c_functionality,
> + .master_xfer = drm_dp_mst_i2c_xfer,
> +};
> +
> +/**
> + * drm_dp_mst_register_i2c_bus() - register an I2C adapter for 
> I2C-over-AUX
> + * @aux: DisplayPort AUX channel
> + *
> + * Returns 0 on success or a negative error code on failure.
> + */
> +static int drm_dp_mst_register_i2c_bus(struct drm_dp_aux *aux)
> +{
> + aux->ddc.algo = &drm_dp_mst_i2c_algo;
> + aux->ddc.algo_data = aux;
> + aux->ddc.retries = 3;
> +
> + aux->ddc.class = I2C_CLASS_DDC;
> + aux->ddc.owner = THIS_MODULE;
> + aux->ddc.dev.parent = aux->dev;
> + aux->ddc.dev.of_node = aux->dev->of_node;
> +
> + strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
> + sizeof(aux->ddc.name));
> +
> + return i2c_add_adapter(&aux->ddc);
> +}
> +
> +/**
> + * drm_dp_mst_unregister_i2c_bus() - unregister an I2C-over-AUX adapter
> + * @aux: DisplayPort AUX channel
> + */
> +static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_aux *aux)
> +{
> + i2c_del_adapter(&aux->ddc);
> +}
> diff --git a/include/drm/drm_dp_mst_helper.h 
> b/include/drm/drm_dp_mst_helper.h
> new file mode 100644
> index 0000000..6626d1b
> --- /dev/null
> +++ b/include/drm/drm_dp_mst_helper.h
> @@ -0,0 +1,507 @@
> +/*
> + * Copyright © 2014 Red Hat.
> + *
> + * Permission to use, copy, modify, distribute, and sell this 
> software and its
> + * documentation for any purpose is hereby granted without fee, 
> provided that
> + * the above copyright notice appear in all copies and that both that 
> copyright
> + * notice and this permission notice appear in supporting 
> documentation, and
> + * that the name of the copyright holders not be used in advertising or
> + * publicity pertaining to distribution of the software without specific,
> + * written prior permission. The copyright holders make no 
> representations
> + * about the suitability of this software for any purpose. It is 
> provided "as
> + * is" without express or implied warranty.
> + *
> + * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS 
> SOFTWARE,
> + * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
> + * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, 
> INDIRECT OR
> + * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 
> LOSS OF USE,
> + * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
> + * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 
> PERFORMANCE
> + * OF THIS SOFTWARE.
> + */
> +#ifndef _DRM_DP_MST_HELPER_H_
> +#define _DRM_DP_MST_HELPER_H_
> +
> +#include <linux/types.h>
> +#include <drm/drm_dp_helper.h>
> +
> +struct drm_dp_mst_branch;
> +
> +/**
> + * struct drm_dp_vcpi - Virtual Channel Payload Identifer
> + * @vcpi: Virtual channel ID.
> + * @pbn: Payload Bandwidth Number for this channel
> + * @aligned_pbn: PBN aligned with slot size
> + * @num_slots: number of slots for this PBN
> + */
> +struct drm_dp_vcpi {
> + int vcpi;
> + int pbn;
> + int aligned_pbn;
> + int num_slots;
> +};
> +
> +/**
> + * struct drm_dp_mst_port - MST port
> + * @kref: reference count for this port.
> + * @guid_valid: for DP 1.2 devices if we have validated the GUID.
> + * @guid: guid for DP 1.2 device on this port.
> + * @port_num: port number
> + * @input: if this port is an input port.
> + * @mcs: message capability status - DP 1.2 spec.
> + * @ddps: DisplayPort Device Plug Status - DP 1.2
> + * @pdt: Peer Device Type
> + * @ldps: Legacy Device Plug Status
> + * @dpcd_rev: DPCD revision of device on this port
> + * @available_pbn: Available bandwidth for this port.
> + * @next: link to next port on this branch device
> + * @mstb: branch device attach below this port
> + * @aux: i2c aux transport to talk to device connected to this port.
> + * @parent: branch device parent of this port
> + * @vcpi: Virtual Channel Payload info for this port.
> + * @connector: DRM connector this port is connected to.
> + * @mgr: topology manager this port lives under.
> + *
> + * This structure represents an MST port endpoint on a device somewhere
> + * in the MST topology.
> + */
> +struct drm_dp_mst_port {
> + struct kref kref;
> +
> + /* if dpcd 1.2 device is on this port - its GUID info */
> + bool guid_valid;
> + u8 guid[16];
> +
> + u8 port_num;
> + bool input;
> + bool mcs;
> + bool ddps;
> + u8 pdt;
> + bool ldps;
> + u8 dpcd_rev;
> + uint16_t available_pbn;
> + struct list_head next;
> + struct drm_dp_mst_branch *mstb; /* pointer to an mstb if this port 
> has one */
> + struct drm_dp_aux aux; /* i2c bus for this port? */
> + struct drm_dp_mst_branch *parent;
> +
> + struct drm_dp_vcpi vcpi;
> + struct drm_connector *connector;
> + struct drm_dp_mst_topology_mgr *mgr;
> +};
> +
> +/**
> + * struct drm_dp_mst_branch - MST branch device.
> + * @kref: reference count for this port.
> + * @rad: Relative Address to talk to this branch device.
> + * @lct: Link count total to talk to this branch device.
> + * @num_ports: number of ports on the branch.
> + * @msg_slots: one bit per transmitted msg slot.
> + * @ports: linked list of ports on this branch.
> + * @port_parent: pointer to the port parent, NULL if toplevel.
> + * @mgr: topology manager for this branch device.
> + * @tx_slots: transmission slots for this device.
> + * @last_seqno: last sequence number used to talk to this.
> + * @link_address_sent: if a link address message has been sent to 
> this device yet.
> + *
> + * This structure represents an MST branch device, there is one
> + * primary branch device at the root, along with any others connected
> + * to downstream ports
> + */
> +struct drm_dp_mst_branch {
> + struct kref kref;
> + u8 rad[8];
> + u8 lct;
> + int num_ports;
> +
> + int msg_slots;
> + struct list_head ports;
> +
> + /* list of tx ops queue for this port */
> + struct drm_dp_mst_port *port_parent;
> + struct drm_dp_mst_topology_mgr *mgr;
> +
> + /* slots are protected by mstb->mgr->qlock */
> + struct drm_dp_sideband_msg_tx *tx_slots[2];
> + int last_seqno;
> + bool link_address_sent;
> +};
> +
> +
> +/* sideband msg header - not bit struct */
> +struct drm_dp_sideband_msg_hdr {
> + u8 lct;
> + u8 lcr;
> + u8 rad[8];
> + bool broadcast;
> + bool path_msg;
> + u8 msg_len;
> + bool somt;
> + bool eomt;
> + bool seqno;
> +};
> +
> +struct drm_dp_nak_reply {
> + u8 guid[16];
> + u8 reason;
> + u8 nak_data;
> +};
> +
> +struct drm_dp_link_address_ack_reply {
> + u8 guid[16];
> + u8 nports;
> + struct drm_dp_link_addr_reply_port {
> + bool input_port;
> + u8 peer_device_type;
> + u8 port_number;
> + bool mcs;
> + bool ddps;
> + bool legacy_device_plug_status;
> + u8 dpcd_revision;
> + u8 peer_guid[16];
> + bool num_sdp_streams;
> + bool num_sdp_stream_sinks;
> + } ports[16];
> +};
> +
> +struct drm_dp_remote_dpcd_read_ack_reply {
> + u8 port_number;
> + u8 num_bytes;
> + u8 bytes[255];
> +};
> +
> +struct drm_dp_remote_dpcd_write_ack_reply {
> + u8 port_number;
> +};
> +
> +struct drm_dp_remote_dpcd_write_nak_reply {
> + u8 port_number;
> + u8 reason;
> + u8 bytes_written_before_failure;
> +};
> +
> +struct drm_dp_remote_i2c_read_ack_reply {
> + u8 port_number;
> + u8 num_bytes;
> + u8 bytes[255];
> +};
> +
> +struct drm_dp_remote_i2c_read_nak_reply {
> + u8 port_number;
> + u8 nak_reason;
> + u8 i2c_nak_transaction;
> +};
> +
> +struct drm_dp_remote_i2c_write_ack_reply {
> + u8 port_number;
> +};
> +
> +
> +struct drm_dp_sideband_msg_rx {
> + u8 chunk[48];
> + u8 msg[256];
> + u8 curchunk_len;
> + u8 curchunk_idx; /* chunk we are parsing now */
> + u8 curchunk_hdrlen;
> + u8 curlen; /* total length of the msg */
> + bool have_somt;
> + bool have_eomt;
> + struct drm_dp_sideband_msg_hdr initial_hdr;
> +};
> +
> +
> +struct drm_dp_allocate_payload {
> + u8 port_number;
> + u8 number_sdp_streams;
> + u8 vcpi;
> + u16 pbn;
> + u8 sdp_stream_sink[8];
> +};
> +
> +struct drm_dp_allocate_payload_ack_reply {
> + u8 port_number;
> + u8 vcpi;
> + u16 allocated_pbn;
> +};
> +
> +struct drm_dp_connection_status_notify {
> + u8 guid[16];
> + u8 port_number;
> + bool legacy_device_plug_status;
> + bool displayport_device_plug_status;
> + bool message_capability_status;
> + bool input_port;
> + u8 peer_device_type;
> +};
> +
> +struct drm_dp_remote_dpcd_read {
> + u8 port_number;
> + u32 dpcd_address;
> + u8 num_bytes;
> +};
> +
> +struct drm_dp_remote_dpcd_write {
> + u8 port_number;
> + u32 dpcd_address;
> + u8 num_bytes;
> + u8 bytes[255];
> +};
> +
> +struct drm_dp_remote_i2c_read {
> + u8 num_transactions;
> + u8 port_number;
> + struct {
> + u8 i2c_dev_id;
> + u8 num_bytes;
> + u8 bytes[255];
> + u8 no_stop_bit;
> + u8 i2c_transaction_delay;
> + } transactions[4];
> + u8 read_i2c_device_id;
> + u8 num_bytes_read;
> +};
> +
> +struct drm_dp_remote_i2c_write {
> + u8 port_number;
> + u8 write_i2c_device_id;
> + u8 num_bytes;
> + u8 bytes[255];
> +};
> +
> +/* this covers ENUM_RESOURCES, POWER_DOWN_PHY, POWER_UP_PHY */
> +struct drm_dp_port_number_req {
> + u8 port_number;
> +};
> +
> +struct drm_dp_enum_path_resources_ack_reply {
> + u8 port_number;
> + u16 full_payload_bw_number;
> + u16 avail_payload_bw_number;
> +};
> +
> +/* covers POWER_DOWN_PHY, POWER_UP_PHY */
> +struct drm_dp_port_number_rep {
> + u8 port_number;
> +};
> +
> +struct drm_dp_query_payload {
> + u8 port_number;
> + u8 vcpi;
> +};
> +
> +struct drm_dp_resource_status_notify {
> + u8 port_number;
> + u8 guid[16];
> + u16 available_pbn;
> +};
> +
> +struct drm_dp_query_payload_ack_reply {
> + u8 port_number;
> + u8 allocated_pbn;
> +};
> +
> +struct drm_dp_sideband_msg_req_body {
> + u8 req_type;
> + union ack_req {
> + struct drm_dp_connection_status_notify conn_stat;
> + struct drm_dp_port_number_req port_num;
> + struct drm_dp_resource_status_notify resource_stat;
> +
> + struct drm_dp_query_payload query_payload;
> + struct drm_dp_allocate_payload allocate_payload;
> +
> + struct drm_dp_remote_dpcd_read dpcd_read;
> + struct drm_dp_remote_dpcd_write dpcd_write;
> +
> + struct drm_dp_remote_i2c_read i2c_read;
> + struct drm_dp_remote_i2c_write i2c_write;
> + } u;
> +};
> +
> +struct drm_dp_sideband_msg_reply_body {
> + u8 reply_type;
> + u8 req_type;
> + union ack_replies {
> + struct drm_dp_nak_reply nak;
> + struct drm_dp_link_address_ack_reply link_addr;
> + struct drm_dp_port_number_rep port_number;
> +
> + struct drm_dp_enum_path_resources_ack_reply path_resources;
> + struct drm_dp_allocate_payload_ack_reply allocate_payload;
> + struct drm_dp_query_payload_ack_reply query_payload;
> +
> + struct drm_dp_remote_dpcd_read_ack_reply remote_dpcd_read_ack;
> + struct drm_dp_remote_dpcd_write_ack_reply remote_dpcd_write_ack;
> + struct drm_dp_remote_dpcd_write_nak_reply remote_dpcd_write_nack;
> +
> + struct drm_dp_remote_i2c_read_ack_reply remote_i2c_read_ack;
> + struct drm_dp_remote_i2c_read_nak_reply remote_i2c_read_nack;
> + struct drm_dp_remote_i2c_write_ack_reply remote_i2c_write_ack;
> + } u;
> +};
> +
> +/* msg is queued to be put into a slot */
> +#define DRM_DP_SIDEBAND_TX_QUEUED 0
> +/* msg has started transmitting on a slot - still on msgq */
> +#define DRM_DP_SIDEBAND_TX_START_SEND 1
> +/* msg has finished transmitting on a slot - removed from msgq only 
> in slot */
> +#define DRM_DP_SIDEBAND_TX_SENT 2
> +/* msg has received a response - removed from slot */
> +#define DRM_DP_SIDEBAND_TX_RX 3
> +#define DRM_DP_SIDEBAND_TX_TIMEOUT 4
> +
> +struct drm_dp_sideband_msg_tx {
> + u8 msg[256];
> + u8 chunk[48];
> + u8 cur_offset;
> + u8 cur_len;
> + struct drm_dp_mst_branch *dst;
> + struct list_head next;
> + int seqno;
> + int state;
> + bool path_msg;
> + struct drm_dp_sideband_msg_reply_body reply;
> +};
> +
> +/* sideband msg handler */
> +struct drm_dp_mst_topology_mgr;
> +struct drm_dp_mst_topology_cbs {
> + /* create a connector for a port */
> + struct drm_connector *(*add_connector)(struct 
> drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, char *path);
> + void (*destroy_connector)(struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_connector *connector);
> + void (*hotplug)(struct drm_dp_mst_topology_mgr *mgr);
> +
> +};
> +
> +#define DP_MAX_PAYLOAD (sizeof(unsigned long) * 8)
> +
> +#define DP_PAYLOAD_LOCAL 1
> +#define DP_PAYLOAD_REMOTE 2
> +#define DP_PAYLOAD_DELETE_LOCAL 3
> +
> +struct drm_dp_payload {
> + int payload_state;
> + int start_slot;
> + int num_slots;
> +};
> +
> +/**
> + * struct drm_dp_mst_topology_mgr - DisplayPort MST manager
> + * @dev: device pointer for adding i2c devices etc.
> + * @cbs: callbacks for connector addition and destruction.
> + * @max_dpcd_transaction_bytes - maximum number of bytes to 
> read/write in one go.
> + * @aux: aux channel for the DP connector.
> + * @max_payloads: maximum number of payloads the GPU can generate.
> + * @conn_base_id: DRM connector ID this mgr is connected to.
> + * @down_rep_recv: msg receiver state for down replies.
> + * @up_req_recv: msg receiver state for up requests.
> + * @lock: protects mst state, primary, guid, dpcd.
> + * @aux_lock: protects aux channel.
> + * @mst_state: if this manager is enabled for an MST capable port.
> + * @mst_primary: pointer to the primary branch device.
> + * @guid_valid: GUID valid for the primary branch device.
> + * @guid: GUID for primary port.
> + * @dpcd: cache of DPCD for primary port.
> + * @pbn_div: PBN to slots divisor.
> + *
> + * This struct represents the toplevel displayport MST topology manager.
> + * There should be one instance of this for every MST capable DP 
> connector
> + * on the GPU.
> + */
> +struct drm_dp_mst_topology_mgr {
> +
> + struct device *dev;
> + struct drm_dp_mst_topology_cbs *cbs;
> + int max_dpcd_transaction_bytes;
> + struct drm_dp_aux *aux; /* auxch for this topology mgr to use */
> + int max_payloads;
> + int conn_base_id;
> +
> + /* only ever accessed from the workqueue - which should be serialised */
> + struct drm_dp_sideband_msg_rx down_rep_recv;
> + struct drm_dp_sideband_msg_rx up_req_recv;
> +
> + /* pointer to info about the initial MST device */
> + struct mutex lock; /* protects mst_state + primary + guid + dpcd */
> +
> + struct mutex aux_lock; /* protect access to the AUX */
> + bool mst_state;
> + struct drm_dp_mst_branch *mst_primary;
> + /* primary MST device GUID */
> + bool guid_valid;
> + u8 guid[16];
> + u8 dpcd[DP_RECEIVER_CAP_SIZE];
> + u8 sink_count;
> + int pbn_div;
> + int total_slots;
> + int avail_slots;
> + int total_pbn;
> +
> + /* messages to be transmitted */
> + /* qlock protects the upq/downq and in_progress,
> + the mstb tx_slots and txmsg->state once they are queued */
> + struct mutex qlock;
> + struct list_head tx_msg_downq;
> + struct list_head tx_msg_upq;
> + bool tx_down_in_progress;
> + bool tx_up_in_progress;
> +
> + /* payload info + lock for it */
> + struct mutex payload_lock;
> + struct drm_dp_vcpi **proposed_vcpis;
> + struct drm_dp_payload *payloads;
> + unsigned long payload_mask;
> +
> + wait_queue_head_t tx_waitq;
> + struct work_struct work;
> +
> + struct work_struct tx_work;
> +};
> +
> +int drm_dp_mst_topology_mgr_init(struct drm_dp_mst_topology_mgr *mgr, 
> struct device *dev, struct drm_dp_aux *aux, int 
> max_dpcd_transaction_bytes, int max_payloads, int conn_base_id);
> +
> +void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr 
> *mgr);
> +
> +
> +int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr 
> *mgr, bool mst_state);
> +
> +
> +int drm_dp_mst_hpd_irq(struct drm_dp_mst_topology_mgr *mgr, u8 *esi, 
> bool *handled);
> +
> +
> +enum drm_connector_status drm_dp_mst_detect_port(struct 
> drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port);
> +
> +struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, 
> struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port);
> +
> +
> +int drm_dp_calc_pbn_mode(int clock, int bpp);
> +
> +
> +bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, 
> struct drm_dp_mst_port *port, int pbn, int *slots);
> +
> +
> +void drm_dp_mst_reset_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, 
> struct drm_dp_mst_port *port);
> +
> +
> +void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
> + struct drm_dp_mst_port *port);
> +
> +
> +int drm_dp_find_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr,
> + int pbn);
> +
> +
> +int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr);
> +
> +
> +int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr);
> +
> +int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr);
> +
> +void drm_dp_mst_dump_topology(struct seq_file *m,
> + struct drm_dp_mst_topology_mgr *mgr);
> +
> +void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr 
> *mgr);
> +int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr);
> +#endif
> Dave Airlie <mailto:airlied at gmail.com>
> Tuesday, May 20, 2014 7:54 PM
> Hey,
>
> So this set is pretty close to what I think we should be merging 
> initially,
>
> Since the last set, it makes fbcon and suspend/resume work a lot better,
>
> I've also fixed a couple of bugs in -intel that make things work a lot
> better.
>
> I've bashed on this a bit using kms-flip from intel-gpu-tools, hacked
> to add 3 monitor support.
>
> It still generates a fair few i915 state checker backtraces, and some
> of them are fairly hard to work out, it might be we should just tone
> down the state checker for encoders/connectors with no actual hw backing
> them.
>
> Dave.
>
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

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