From: Michal Wajdeczko <michal.wajdec...@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

v2:
 (Daniele)
  - Better comment in ct_write()

Signed-off-by: Michal Wajdeczko <michal.wajdec...@intel.com>
Signed-off-by: Matthew Brost <matthew.br...@intel.com>
Cc: Piotr PiĆ³rkowski <piotr.piorkow...@intel.com>
---
 .../gt/uc/abi/guc_communication_ctb_abi.h     |  56 +++++
 drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c     | 195 +++++++-----------
 drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h     |   2 +-
 3 files changed, 136 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 6735f1fdaa2a..d3a2e002b6c0 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
@@ -58,6 +58,62 @@ 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..43409044528e 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 +408,25 @@ static int ct_write(struct intel_guc_ct *ct,
                return -ENOSPC;
 
        /*
-        * 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 (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) |
+             FIELD_PREP(GUC_HXG_REQUEST_MSG_0_ACTION |
+                        GUC_HXG_REQUEST_MSG_0_DATA0, action[0]);
 
-       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 +584,6 @@ 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 +646,7 @@ 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 +689,24 @@ 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];
+       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 +722,9 @@ 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 +745,16 @@ 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 +816,12 @@ 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 +831,53 @@ 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 */
-- 
2.28.0

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