[Intel-gfx] [PATCH 06/13] drm/i915/guc: New definition of the CTB descriptor
Daniele Ceraolo Spurio
daniele.ceraolospurio at intel.com
Tue Jun 8 00:59:22 UTC 2021
On 6/7/2021 11:03 AM, Matthew Brost wrote:
> From: Michal Wajdeczko <michal.wajdeczko at intel.com>
>
> Definition of the CTB descriptor has changed, leaving only
> minimal shared fields like HEAD/TAIL/STATUS.
>
> Both HEAD and TAIL are now in dwords.
>
> Add some ABI documentation and implement required changes.
>
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
> Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> ---
> .../gt/uc/abi/guc_communication_ctb_abi.h | 70 ++++++++++++++-----
> drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c | 70 +++++++++----------
> drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h | 2 +-
> 3 files changed, 85 insertions(+), 57 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 d38935f47ecf..c2a069a78e01 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
> @@ -7,6 +7,58 @@
> #define _ABI_GUC_COMMUNICATION_CTB_ABI_H
>
> #include <linux/types.h>
> +#include <linux/build_bug.h>
> +
> +#include "guc_messages_abi.h"
> +
> +/**
> + * DOC: CT Buffer
> + *
> + * TBD
What's the plan with this TBD here?
> + */
> +
> +/**
> + * DOC: CTB Descriptor
> + *
> + * +---+-------+--------------------------------------------------------------+
> + * | | Bits | Description |
> + * +===+=======+==============================================================+
> + * | 0 | 31:0 | **HEAD** - offset (in dwords) to the last dword that was |
> + * | | | read from the `CT Buffer`_. |
> + * | | | It can only be updated by the receiver. |
> + * +---+-------+--------------------------------------------------------------+
> + * | 1 | 31:0 | **TAIL** - offset (in dwords) to the last dword that was |
> + * | | | written to the `CT Buffer`_. |
> + * | | | It can only be updated by the sender. |
> + * +---+-------+--------------------------------------------------------------+
> + * | 2 | 31:0 | **STATUS** - status of the CTB |
> + * | | | |
> + * | | | - _`GUC_CTB_STATUS_NO_ERROR` = 0 (normal operation) |
> + * | | | - _`GUC_CTB_STATUS_OVERFLOW` = 1 (head/tail too large) |
> + * | | | - _`GUC_CTB_STATUS_UNDERFLOW` = 2 (truncated message) |
> + * | | | - _`GUC_CTB_STATUS_MISMATCH` = 4 (head/tail modified) |
> + * | | | - _`GUC_CTB_STATUS_NO_BACKCHANNEL` = 8 |
> + * | | | - _`GUC_CTB_STATUS_MALFORMED_MSG` = 16 |
I don't see the last 2 error (8 & 16) in the 62.0.0 specs. Where is the
reference for them?
> + * +---+-------+--------------------------------------------------------------+
> + * |...| | RESERVED = MBZ |
> + * +---+-------+--------------------------------------------------------------+
> + * | 15| 31:0 | RESERVED = MBZ |
> + * +---+-------+--------------------------------------------------------------+
> + */
> +
> +struct guc_ct_buffer_desc {
> + u32 head;
> + u32 tail;
> + u32 status;
> +#define GUC_CTB_STATUS_NO_ERROR 0
> +#define GUC_CTB_STATUS_OVERFLOW (1 << 0)
> +#define GUC_CTB_STATUS_UNDERFLOW (1 << 1)
> +#define GUC_CTB_STATUS_MISMATCH (1 << 2)
> +#define GUC_CTB_STATUS_NO_BACKCHANNEL (1 << 3)
> +#define GUC_CTB_STATUS_MALFORMED_MSG (1 << 4)
use BIT() ?
> + u32 reserved[13];
> +} __packed;
> +static_assert(sizeof(struct guc_ct_buffer_desc) == 64);
>
> /**
> * DOC: CTB based communication
> @@ -60,24 +112,6 @@
> * - **flags**, holds various bits to control message handling
> */
>
> -/*
> - * Describes single command transport buffer.
> - * Used by both guc-master and clients.
> - */
> -struct guc_ct_buffer_desc {
> - u32 addr; /* gfx address */
> - u64 host_private; /* host private data */
> - u32 size; /* size in bytes */
> - u32 head; /* offset updated by GuC*/
> - u32 tail; /* offset updated by owner */
> - u32 is_in_error; /* error indicator */
> - u32 reserved1;
> - u32 reserved2;
> - u32 owner; /* id of the channel owner */
> - u32 owner_sub_id; /* owner-defined field for extra tracking */
> - u32 reserved[5];
> -} __packed;
> -
> /* Type of command transport buffer */
> #define INTEL_GUC_CT_BUFFER_TYPE_SEND 0x0u
> #define INTEL_GUC_CT_BUFFER_TYPE_RECV 0x1u
> 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 63056ea0631e..3241a477196f 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> @@ -112,32 +112,28 @@ static inline const char *guc_ct_buffer_type_to_str(u32 type)
> }
> }
>
> -static void guc_ct_buffer_desc_init(struct guc_ct_buffer_desc *desc,
> - u32 cmds_addr, u32 size)
> +static void guc_ct_buffer_desc_init(struct guc_ct_buffer_desc *desc)
this function is called from only 1 place and only does a memset now, so
IMO we can just drop it and inline the memset.
The logic below matches the specs.
Daniele
> {
> memset(desc, 0, sizeof(*desc));
> - desc->addr = cmds_addr;
> - desc->size = size;
> - desc->owner = CTB_OWNER_HOST;
> }
>
> -static void guc_ct_buffer_reset(struct intel_guc_ct_buffer *ctb, u32 cmds_addr)
> +static void guc_ct_buffer_reset(struct intel_guc_ct_buffer *ctb)
> {
> ctb->broken = false;
> - guc_ct_buffer_desc_init(ctb->desc, cmds_addr, ctb->size);
> + guc_ct_buffer_desc_init(ctb->desc);
> }
>
> static void guc_ct_buffer_init(struct intel_guc_ct_buffer *ctb,
> struct guc_ct_buffer_desc *desc,
> - u32 *cmds, u32 size)
> + u32 *cmds, u32 size_in_bytes)
> {
> - GEM_BUG_ON(size % 4);
> + GEM_BUG_ON(size_in_bytes % 4);
>
> ctb->desc = desc;
> ctb->cmds = cmds;
> - ctb->size = size;
> + ctb->size = size_in_bytes / 4;
>
> - guc_ct_buffer_reset(ctb, 0);
> + guc_ct_buffer_reset(ctb);
> }
>
> static int guc_action_register_ct_buffer(struct intel_guc *guc,
> @@ -279,10 +275,10 @@ int intel_guc_ct_enable(struct intel_guc_ct *ct)
>
> /* (re)initialize descriptors */
> cmds = base + ptrdiff(ct->ctbs.send.cmds, blob);
> - guc_ct_buffer_reset(&ct->ctbs.send, cmds);
> + guc_ct_buffer_reset(&ct->ctbs.send);
>
> cmds = base + ptrdiff(ct->ctbs.recv.cmds, blob);
> - guc_ct_buffer_reset(&ct->ctbs.recv, cmds);
> + guc_ct_buffer_reset(&ct->ctbs.recv);
>
> /*
> * Register both CT buffers starting with RECV buffer.
> @@ -391,17 +387,15 @@ static int ct_write(struct intel_guc_ct *ct,
> if (unlikely(ctb->broken))
> return -EPIPE;
>
> - if (unlikely(desc->is_in_error))
> + if (unlikely(desc->status))
> goto corrupted;
>
> - if (unlikely(!IS_ALIGNED(head | tail, 4) ||
> - (tail | head) >= size))
> + if (unlikely((tail | head) >= size)) {
> + CT_ERROR(ct, "Invalid offsets head=%u tail=%u (size=%u)\n",
> + head, tail, size);
> + desc->status |= GUC_CTB_STATUS_OVERFLOW;
> goto corrupted;
> -
> - /* later calculations will be done in dwords */
> - head /= 4;
> - tail /= 4;
> - size /= 4;
> + }
>
> /*
> * tail == head condition indicates empty. GuC FW does not support
> @@ -447,14 +441,14 @@ static int ct_write(struct intel_guc_ct *ct,
> */
> write_barrier(ct);
>
> - /* now update desc tail (back in bytes) */
> - desc->tail = tail * 4;
> + /* now update descriptor */
> + WRITE_ONCE(desc->tail, tail);
> +
> return 0;
>
> corrupted:
> - CT_ERROR(ct, "Corrupted descriptor addr=%#x head=%u tail=%u size=%u\n",
> - desc->addr, desc->head, desc->tail, desc->size);
> - desc->is_in_error = 1;
> + CT_ERROR(ct, "Corrupted descriptor head=%u tail=%u status=%#x\n",
> + desc->head, desc->tail, desc->status);
> ctb->broken = true;
> return -EPIPE;
> }
> @@ -640,17 +634,15 @@ static int ct_read(struct intel_guc_ct *ct, struct ct_incoming_msg **msg)
> if (unlikely(ctb->broken))
> return -EPIPE;
>
> - if (unlikely(desc->is_in_error))
> + if (unlikely(desc->status))
> goto corrupted;
>
> - if (unlikely(!IS_ALIGNED(head | tail, 4) ||
> - (tail | head) >= size))
> + if (unlikely((tail | head) >= size)) {
> + CT_ERROR(ct, "Invalid offsets head=%u tail=%u (size=%u)\n",
> + head, tail, size);
> + desc->status |= GUC_CTB_STATUS_OVERFLOW;
> goto corrupted;
> -
> - /* later calculations will be done in dwords */
> - head /= 4;
> - tail /= 4;
> - size /= 4;
> + }
>
> /* tail == head condition indicates empty */
> available = tail - head;
> @@ -677,6 +669,7 @@ static int ct_read(struct intel_guc_ct *ct, struct ct_incoming_msg **msg)
> size - head : available - 1), &cmds[head],
> 4 * (head + available - 1 > size ?
> available - 1 - size + head : 0), &cmds[0]);
> + desc->status |= GUC_CTB_STATUS_UNDERFLOW;
> goto corrupted;
> }
>
> @@ -699,13 +692,14 @@ static int ct_read(struct intel_guc_ct *ct, struct ct_incoming_msg **msg)
> }
> CT_DEBUG(ct, "received %*ph\n", 4 * len, (*msg)->msg);
>
> - desc->head = head * 4;
> + /* now update descriptor */
> + WRITE_ONCE(desc->head, head);
> +
> return available - len;
>
> corrupted:
> - CT_ERROR(ct, "Corrupted descriptor addr=%#x head=%u tail=%u size=%u\n",
> - desc->addr, desc->head, desc->tail, desc->size);
> - desc->is_in_error = 1;
> + CT_ERROR(ct, "Corrupted descriptor head=%u tail=%u status=%#x\n",
> + desc->head, desc->tail, desc->status);
> ctb->broken = true;
> return -EPIPE;
> }
> 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 7d3cd375d6a7..905202caaad3 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h
> @@ -31,7 +31,7 @@ struct intel_guc;
> * @lock: protects access to the commands buffer and buffer descriptor
> * @desc: pointer to the buffer descriptor
> * @cmds: pointer to the commands buffer
> - * @size: size of the commands buffer
> + * @size: size of the commands buffer in dwords
> * @broken: flag to indicate if descriptor data is broken
> */
> struct intel_guc_ct_buffer {
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