[PATCH 08/13] drm/i915/guc: New CTB based communication
Matthew Brost
matthew.brost at intel.com
Thu Jun 10 04:01:02 UTC 2021
On Mon, Jun 07, 2021 at 07:20:01PM -0700, Daniele Ceraolo Spurio wrote:
>
>
> On 6/7/2021 11:03 AM, Matthew Brost wrote:
> > From: Michal Wajdeczko <michal.wajdeczko at intel.com>
> >
> > Format of the CTB messages has changed:
> > - support for multiple formats
> > - message fence is now part of the header
> > - reuse of unified HXG message formats
> >
> > Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
> > Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> > Cc: Piotr Piórkowski <piotr.piorkowski at intel.com>
> > ---
> > .../gt/uc/abi/guc_communication_ctb_abi.h | 56 +++++
> > drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c | 194 +++++++-----------
> > drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h | 2 +-
> > 3 files changed, 135 insertions(+), 117 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/gt/uc/abi/guc_communication_ctb_abi.h b/drivers/gpu/drm/i915/gt/uc/abi/guc_communication_ctb_abi.h
> > index 127b256a662c..92660726c094 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/abi/guc_communication_ctb_abi.h
> > +++ b/drivers/gpu/drm/i915/gt/uc/abi/guc_communication_ctb_abi.h
> > @@ -60,6 +60,62 @@ struct guc_ct_buffer_desc {
> > } __packed;
> > static_assert(sizeof(struct guc_ct_buffer_desc) == 64);
> > +/**
> > + * DOC: CTB Message
> > + *
> > + * +---+-------+--------------------------------------------------------------+
> > + * | | Bits | Description |
> > + * +===+=======+==============================================================+
> > + * | 0 | 31:16 | **FENCE** - message identifier |
> > + * | +-------+--------------------------------------------------------------+
> > + * | | 15:12 | **FORMAT** - format of the CTB message |
> > + * | | | - _`GUC_CTB_FORMAT_HXG` = 0 - see `CTB HXG Message`_ |
> > + * | +-------+--------------------------------------------------------------+
> > + * | | 11:8 | **RESERVED** |
> > + * | +-------+--------------------------------------------------------------+
> > + * | | 7:0 | **NUM_DWORDS** - length of the CTB message (w/o header) |
> > + * +---+-------+--------------------------------------------------------------+
> > + * | 1 | 31:0 | optional (depends on FORMAT) |
> > + * +---+-------+ |
> > + * |...| | |
> > + * +---+-------+ |
> > + * | n | 31:0 | |
> > + * +---+-------+--------------------------------------------------------------+
> > + */
> > +
> > +#define GUC_CTB_MSG_MIN_LEN 1u
> > +#define GUC_CTB_MSG_MAX_LEN 256u
> > +#define GUC_CTB_MSG_0_FENCE (0xffff << 16)
> > +#define GUC_CTB_MSG_0_FORMAT (0xf << 12)
> > +#define GUC_CTB_FORMAT_HXG 0u
> > +#define GUC_CTB_MSG_0_RESERVED (0xf << 8)
> > +#define GUC_CTB_MSG_0_NUM_DWORDS (0xff << 0)
> > +
> > +/**
> > + * DOC: CTB HXG Message
> > + *
> > + * +---+-------+--------------------------------------------------------------+
> > + * | | Bits | Description |
> > + * +===+=======+==============================================================+
> > + * | 0 | 31:16 | FENCE |
> > + * | +-------+--------------------------------------------------------------+
> > + * | | 15:12 | FORMAT = GUC_CTB_FORMAT_HXG_ |
> > + * | +-------+--------------------------------------------------------------+
> > + * | | 11:8 | RESERVED = MBZ |
> > + * | +-------+--------------------------------------------------------------+
> > + * | | 7:0 | NUM_DWORDS = length (in dwords) of the embedded HXG message |
> > + * +---+-------+--------------------------------------------------------------+
> > + * | 1 | 31:0 | +--------------------------------------------------------+ |
> > + * +---+-------+ | | |
> > + * |...| | | Embedded `HXG Message`_ | |
> > + * +---+-------+ | | |
> > + * | n | 31:0 | +--------------------------------------------------------+ |
> > + * +---+-------+--------------------------------------------------------------+
> > + */
> > +
> > +#define GUC_CTB_HXG_MSG_MIN_LEN (GUC_CTB_MSG_MIN_LEN + GUC_HXG_MSG_MIN_LEN)
> > +#define GUC_CTB_HXG_MSG_MAX_LEN GUC_CTB_MSG_MAX_LEN
> > +
> > /**
> > * DOC: CTB based communication
> > *
> > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> > index 6a29be779cc9..729f29bc2a57 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> > @@ -365,24 +365,6 @@ static void write_barrier(struct intel_guc_ct *ct)
> > }
> > }
> > -/**
> > - * DOC: CTB Host to GuC request
> > - *
> > - * Format of the CTB Host to GuC request message is as follows::
> > - *
> > - * +------------+---------+---------+---------+---------+
> > - * | msg[0] | [1] | [2] | ... | [n-1] |
> > - * +------------+---------+---------+---------+---------+
> > - * | MESSAGE | MESSAGE PAYLOAD |
> > - * + HEADER +---------+---------+---------+---------+
> > - * | | 0 | 1 | ... | n |
> > - * +============+=========+=========+=========+=========+
> > - * | len >= 1 | FENCE | request specific data |
> > - * +------+-----+---------+---------+---------+---------+
> > - *
> > - * ^-----------------len-------------------^
> > - */
> > -
> > static int ct_write(struct intel_guc_ct *ct,
> > const u32 *action,
> > u32 len /* in dwords */,
> > @@ -395,6 +377,7 @@ static int ct_write(struct intel_guc_ct *ct,
> > u32 size = ctb->size;
> > u32 used;
> > u32 header;
> > + u32 hxg;
> > u32 *cmds = ctb->cmds;
> > unsigned int i;
> > @@ -425,22 +408,24 @@ static int ct_write(struct intel_guc_ct *ct,
> > return -ENOSPC;
>
> Doesn't the free space math up here need updating, since now we have an
> extra header dword?
>
No, action[0] is included in the HXG header so the match is the same.
I will update the comment below to better relect this.
> > /*
> > - * Write the message. The format is the following:
> > - * DW0: header (including action code)
> > - * DW1: fence
> > - * DW2+: action data
> > + * dw0: CT header (including fence)
> > + * dw1: HXG header
>
> maybe better as:
>
> * dw1+: HXG message
Going to be:
/*
* dw0: CT header (including fence)
* dw1: HXG header (including action code)
* dw2+: action data
*/
>
> > */
> > - header = (len << GUC_CT_MSG_LEN_SHIFT) |
> > - GUC_CT_MSG_SEND_STATUS |
> > - (action[0] << GUC_CT_MSG_ACTION_SHIFT);
> > + header = FIELD_PREP(GUC_CTB_MSG_0_FORMAT, GUC_CTB_FORMAT_HXG) |
> > + FIELD_PREP(GUC_CTB_MSG_0_NUM_DWORDS, len) |
> > + FIELD_PREP(GUC_CTB_MSG_0_FENCE, fence);
> > +
> > + hxg = FIELD_PREP(GUC_HXG_MSG_0_TYPE, GUC_HXG_TYPE_REQUEST) |
>
> Do we have a case where we might want to use a different type? e.g. a
> response to a request from GuC?
>
> > + FIELD_PREP(GUC_HXG_REQUEST_MSG_0_ACTION |
> > + GUC_HXG_REQUEST_MSG_0_DATA0, action[0]);
>
> See macro suggestion for the hxg header in previous patch review.
>
Michal says we can do in follow, I agree with him on that.
> > - CT_DEBUG(ct, "writing %*ph %*ph %*ph\n",
> > - 4, &header, 4, &fence, 4 * (len - 1), &action[1]);
> > + CT_DEBUG(ct, "writing (tail %u) %*ph %*ph %*ph\n",
> > + tail, 4, &header, 4, &hxg, 4 * (len - 1), &action[1]);
> > cmds[tail] = header;
> > tail = (tail + 1) % size;
> > - cmds[tail] = fence;
> > + cmds[tail] = hxg;
> > tail = (tail + 1) % size;
> > for (i = 1; i < len; i++) {
> > @@ -598,21 +583,6 @@ int intel_guc_ct_send(struct intel_guc_ct *ct, const u32 *action, u32 len,
> > return ret;
> > }
> > -static inline unsigned int ct_header_get_len(u32 header)
> > -{
> > - return (header >> GUC_CT_MSG_LEN_SHIFT) & GUC_CT_MSG_LEN_MASK;
> > -}
> > -
> > -static inline unsigned int ct_header_get_action(u32 header)
> > -{
> > - return (header >> GUC_CT_MSG_ACTION_SHIFT) & GUC_CT_MSG_ACTION_MASK;
> > -}
> > -
> > -static inline bool ct_header_is_response(u32 header)
> > -{
> > - return !!(header & GUC_CT_MSG_IS_RESPONSE);
> > -}
> > -
> > static struct ct_incoming_msg *ct_alloc_msg(u32 num_dwords)
> > {
> > struct ct_incoming_msg *msg;
> > @@ -675,7 +645,7 @@ static int ct_read(struct intel_guc_ct *ct, struct ct_incoming_msg **msg)
> > head = (head + 1) % size;
> > /* message len with header */
> > - len = ct_header_get_len(header) + 1;
> > + len = FIELD_GET(GUC_CTB_MSG_0_NUM_DWORDS, header) + GUC_CTB_MSG_MIN_LEN;
> > if (unlikely(len > (u32)available)) {
> > CT_ERROR(ct, "Incomplete message %*ph %*ph %*ph\n",
> > 4, &header,
> > @@ -718,55 +688,24 @@ static int ct_read(struct intel_guc_ct *ct, struct ct_incoming_msg **msg)
> > return -EPIPE;
> > }
> > -/**
> > - * DOC: CTB GuC to Host response
> > - *
> > - * Format of the CTB GuC to Host response message is as follows::
> > - *
> > - * +------------+---------+---------+---------+---------+---------+
> > - * | msg[0] | [1] | [2] | [3] | ... | [n-1] |
> > - * +------------+---------+---------+---------+---------+---------+
> > - * | MESSAGE | MESSAGE PAYLOAD |
> > - * + HEADER +---------+---------+---------+---------+---------+
> > - * | | 0 | 1 | 2 | ... | n |
> > - * +============+=========+=========+=========+=========+=========+
> > - * | len >= 2 | FENCE | STATUS | response specific data |
> > - * +------+-----+---------+---------+---------+---------+---------+
> > - *
> > - * ^-----------------------len-----------------------^
> > - */
> > -
> > static int ct_handle_response(struct intel_guc_ct *ct, struct ct_incoming_msg *response)
> > {
> > - u32 header = response->msg[0];
> > - u32 len = ct_header_get_len(header);
> > - u32 fence;
> > - u32 status;
> > - u32 datalen;
> > + u32 len = FIELD_GET(GUC_CTB_MSG_0_NUM_DWORDS, response->msg[0]);
> > + u32 fence = FIELD_GET(GUC_CTB_MSG_0_FENCE, response->msg[0]);
> > + const u32 *hxg = &response->msg[GUC_CTB_MSG_MIN_LEN];
>
> IMO it'd be better to just save the hxg in the msg field. We can save the
> fence as an extra field in the ct_incoming_msg. That way we won't have to
> convert from CTB to HXG in multiple places in the code (I count 4 total in
> this patch).
>
Not really sure I follow this but assume this isn't a blocker as this not
a functional change. We can always revisit in a follow up.
Matt
> Daniele
>
> > + const u32 *data = &hxg[GUC_HXG_MSG_MIN_LEN];
> > + u32 datalen = len - GUC_HXG_MSG_MIN_LEN;
> > struct ct_request *req;
> > unsigned long flags;
> > bool found = false;
> > int err = 0;
> > - GEM_BUG_ON(!ct_header_is_response(header));
> > + GEM_BUG_ON(len < GUC_HXG_MSG_MIN_LEN);
> > + GEM_BUG_ON(FIELD_GET(GUC_HXG_MSG_0_ORIGIN, hxg[0]) != GUC_HXG_ORIGIN_GUC);
> > + GEM_BUG_ON(FIELD_GET(GUC_HXG_MSG_0_TYPE, hxg[0]) != GUC_HXG_TYPE_RESPONSE_SUCCESS &&
> > + FIELD_GET(GUC_HXG_MSG_0_TYPE, hxg[0]) != GUC_HXG_TYPE_RESPONSE_FAILURE);
> > - /* Response payload shall at least include fence and status */
> > - if (unlikely(len < 2)) {
> > - CT_ERROR(ct, "Corrupted response (len %u)\n", len);
> > - return -EPROTO;
> > - }
> > -
> > - fence = response->msg[1];
> > - status = response->msg[2];
> > - datalen = len - 2;
> > -
> > - /* Format of the status dword follows HXG header */
> > - if (unlikely(FIELD_GET(GUC_HXG_MSG_0_ORIGIN, status) != GUC_HXG_ORIGIN_GUC)) {
> > - CT_ERROR(ct, "Corrupted response (status %#x)\n", status);
> > - return -EPROTO;
> > - }
> > -
> > - CT_DEBUG(ct, "response fence %u status %#x\n", fence, status);
> > + CT_DEBUG(ct, "response fence %u status %#x\n", fence, hxg[0]);
> > spin_lock_irqsave(&ct->requests.lock, flags);
> > list_for_each_entry(req, &ct->requests.pending, link) {
> > @@ -782,9 +721,9 @@ static int ct_handle_response(struct intel_guc_ct *ct, struct ct_incoming_msg *r
> > err = -EMSGSIZE;
> > }
> > if (datalen)
> > - memcpy(req->response_buf, response->msg + 3, 4 * datalen);
> > + memcpy(req->response_buf, data, 4 * datalen);
> > req->response_len = datalen;
> > - WRITE_ONCE(req->status, status);
> > + WRITE_ONCE(req->status, hxg[0]);
> > found = true;
> > break;
> > }
> > @@ -805,14 +744,16 @@ static int ct_handle_response(struct intel_guc_ct *ct, struct ct_incoming_msg *r
> > static int ct_process_request(struct intel_guc_ct *ct, struct ct_incoming_msg *request)
> > {
> > struct intel_guc *guc = ct_to_guc(ct);
> > - u32 header, action, len;
> > + const u32 *hxg;
> > const u32 *payload;
> > + u32 hxg_len, action, len;
> > int ret;
> > - header = request->msg[0];
> > - payload = &request->msg[1];
> > - action = ct_header_get_action(header);
> > - len = ct_header_get_len(header);
> > + hxg = &request->msg[GUC_CTB_MSG_MIN_LEN];
> > + hxg_len = request->size - GUC_CTB_MSG_MIN_LEN;
> > + payload = &hxg[GUC_HXG_MSG_MIN_LEN];
> > + action = FIELD_GET(GUC_HXG_EVENT_MSG_0_ACTION, hxg[0]);
> > + len = hxg_len - GUC_HXG_MSG_MIN_LEN;
> > CT_DEBUG(ct, "request %x %*ph\n", action, 4 * len, payload);
> > @@ -874,29 +815,12 @@ static void ct_incoming_request_worker_func(struct work_struct *w)
> > queue_work(system_unbound_wq, &ct->requests.worker);
> > }
> > -/**
> > - * DOC: CTB GuC to Host request
> > - *
> > - * Format of the CTB GuC to Host request message is as follows::
> > - *
> > - * +------------+---------+---------+---------+---------+---------+
> > - * | msg[0] | [1] | [2] | [3] | ... | [n-1] |
> > - * +------------+---------+---------+---------+---------+---------+
> > - * | MESSAGE | MESSAGE PAYLOAD |
> > - * + HEADER +---------+---------+---------+---------+---------+
> > - * | | 0 | 1 | 2 | ... | n |
> > - * +============+=========+=========+=========+=========+=========+
> > - * | len | request specific data |
> > - * +------+-----+---------+---------+---------+---------+---------+
> > - *
> > - * ^-----------------------len-----------------------^
> > - */
> > -
> > -static int ct_handle_request(struct intel_guc_ct *ct, struct ct_incoming_msg *request)
> > +static int ct_handle_event(struct intel_guc_ct *ct, struct ct_incoming_msg *request)
> > {
> > + const u32 *hxg = &request->msg[GUC_CTB_MSG_MIN_LEN];
> > unsigned long flags;
> > - GEM_BUG_ON(ct_header_is_response(request->msg[0]));
> > + GEM_BUG_ON(FIELD_GET(GUC_HXG_MSG_0_TYPE, hxg[0]) != GUC_HXG_TYPE_EVENT);
> > spin_lock_irqsave(&ct->requests.lock, flags);
> > list_add_tail(&request->link, &ct->requests.incoming);
> > @@ -906,15 +830,53 @@ static int ct_handle_request(struct intel_guc_ct *ct, struct ct_incoming_msg *re
> > return 0;
> > }
> > -static void ct_handle_msg(struct intel_guc_ct *ct, struct ct_incoming_msg *msg)
> > +static int ct_handle_hxg(struct intel_guc_ct *ct, struct ct_incoming_msg *msg)
> > {
> > - u32 header = msg->msg[0];
> > + u32 origin, type;
> > + u32 *hxg;
> > int err;
> > - if (ct_header_is_response(header))
> > + if (unlikely(msg->size < GUC_CTB_HXG_MSG_MIN_LEN))
> > + return -EBADMSG;
> > +
> > + hxg = &msg->msg[GUC_CTB_MSG_MIN_LEN];
> > +
> > + origin = FIELD_GET(GUC_HXG_MSG_0_ORIGIN, hxg[0]);
> > + if (unlikely(origin != GUC_HXG_ORIGIN_GUC)) {
> > + err = -EPROTO;
> > + goto failed;
> > + }
> > +
> > + type = FIELD_GET(GUC_HXG_MSG_0_TYPE, hxg[0]);
> > + switch (type) {
> > + case GUC_HXG_TYPE_EVENT:
> > + err = ct_handle_event(ct, msg);
> > + break;
> > + case GUC_HXG_TYPE_RESPONSE_SUCCESS:
> > + case GUC_HXG_TYPE_RESPONSE_FAILURE:
> > err = ct_handle_response(ct, msg);
> > + break;
> > + default:
> > + err = -EOPNOTSUPP;
> > + }
> > +
> > + if (unlikely(err)) {
> > +failed:
> > + CT_ERROR(ct, "Failed to handle HXG message (%pe) %*ph\n",
> > + ERR_PTR(err), 4 * GUC_HXG_MSG_MIN_LEN, hxg);
> > + }
> > + return err;
> > +}
> > +
> > +static void ct_handle_msg(struct intel_guc_ct *ct, struct ct_incoming_msg *msg)
> > +{
> > + u32 format = FIELD_GET(GUC_CTB_MSG_0_FORMAT, msg->msg[0]);
> > + int err;
> > +
> > + if (format == GUC_CTB_FORMAT_HXG)
> > + err = ct_handle_hxg(ct, msg);
> > else
> > - err = ct_handle_request(ct, msg);
> > + err = -EOPNOTSUPP;
> > if (unlikely(err)) {
> > CT_ERROR(ct, "Failed to process CT message (%pe) %*ph\n",
> > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h
> > index 905202caaad3..1ae2dde6db93 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h
> > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h
> > @@ -61,7 +61,7 @@ struct intel_guc_ct {
> > struct tasklet_struct receive_tasklet;
> > struct {
> > - u32 last_fence; /* last fence used to send request */
> > + u16 last_fence; /* last fence used to send request */
> > spinlock_t lock; /* protects pending requests list */
> > struct list_head pending; /* requests waiting for response */
>
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