[PATCH 06/14] drm/i915/guc: New definition of the CTB descriptor
Matthew Brost
matthew.brost at intel.com
Thu Jun 10 16:15:45 UTC 2021
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.
v2:
(Daniele)
- Drop GUC_CTB_STATUS_NO_BACKCHANNEL, GUC_CTB_STATUS_NO_BACKCHANNEL
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 | 68 +++++++++++++-----
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, 83 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..88f1fc2a19e0 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 +7,56 @@
#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
+ */
+
+/**
+ * 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) |
+ * +---+-------+--------------------------------------------------------------+
+ * |...| | 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)
+ u32 reserved[13];
+} __packed;
+static_assert(sizeof(struct guc_ct_buffer_desc) == 64);
/**
* DOC: CTB based communication
@@ -60,24 +110,6 @@
* - **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)
{
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 {
--
2.28.0
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