drm/i915/guc: Sanitize GuC client initialization

Started adding proper teardown to guc_client_alloc, ended up removing
quite a few dead ends where errors communicating with the GuC were
silently ignored. There also seemed to be quite a few erronous
teardown actions performed in case of an error (ordering wrong).

v2:
  - Increase function symmetry/proximity (Michal/Daniele)
  - Fix __reserve_doorbell accounting for high priority (Daniele)
  - Call __update_doorbell_desc! (Daniele)
  - Isolate __guc_{,de}allocate_doorbell (Michal/Daniele)

v3:
  - "Select" a cacheline is a more accurate verb than "reserve" (Daniele).
  - We cannot update & create the doorbell without reserving it first, so
    move the whole doorbell creation for execbuf_client to the submission
    enable (Oscar).i
  - Add a fixme for ignoring possible doorbell destroy errors.

v4:
  - Remove comment about is_high_priority (Daniele)
  - Debug message typo (Daniele)
  - Reuse __get_doorbell in more places (Daniele)
  - Do not do arithmetic on void pointers (Daniele)
  - Add comment to __reset_doorbell (Daniele)

v5:
  - gccisms like arithmetic on void pointers are not frowned upon (Oscar)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -2473,7 +2473,7 @@ static void i915_guc_client_info(struct seq_file *m,
 
 	seq_printf(m, "\tPriority %d, GuC ctx index: %u, PD offset 0x%x\n",
 		client->priority, client->ctx_index, client->proc_desc_offset);
-	seq_printf(m, "\tDoorbell id %d, offset: 0x%x, cookie 0x%x\n",
+	seq_printf(m, "\tDoorbell id %d, offset: 0x%lx, cookie 0x%x\n",
 		client->doorbell_id, client->doorbell_offset, client->doorbell_cookie);
 	seq_printf(m, "\tWQ size %d, offset: 0x%x, tail %d\n",
 		client->wq_size, client->wq_offset, client->wq_tail);
@@ -2508,7 +2508,7 @@ static int i915_guc_info(struct seq_file *m, void *data)
 	}
 
 	seq_printf(m, "Doorbell map:\n");
-	seq_printf(m, "\t%*pb\n", GUC_MAX_DOORBELLS, guc->doorbell_bitmap);
+	seq_printf(m, "\t%*pb\n", GUC_NUM_DOORBELLS, guc->doorbell_bitmap);
 	seq_printf(m, "Doorbell next cacheline: 0x%x\n\n", guc->db_cacheline);
 
 	seq_printf(m, "GuC total action count: %llu\n", guc->action_count);

drivers/gpu/drm/i915/intel_guc_fwif.h

@@ -241,8 +241,8 @@ union guc_doorbell_qw {
 	u64 value_qw;
 } __packed;
 
-#define GUC_MAX_DOORBELLS		256
-#define GUC_INVALID_DOORBELL_ID		(GUC_MAX_DOORBELLS)
+#define GUC_NUM_DOORBELLS	256
+#define GUC_DOORBELL_INVALID	(GUC_NUM_DOORBELLS)
 
 #define GUC_DB_SIZE			(PAGE_SIZE)
 #define GUC_WQ_SIZE			(PAGE_SIZE * 2)

drivers/gpu/drm/i915/intel_uc.h

@@ -72,13 +72,12 @@ struct i915_guc_client {
 
 	uint32_t engines;		/* bitmap of (host) engine ids	*/
 	uint32_t priority;
-	uint32_t ctx_index;
+	u32 ctx_index;
 	uint32_t proc_desc_offset;
 
-	uint32_t doorbell_offset;
-	uint32_t doorbell_cookie;
-	uint16_t doorbell_id;
-	uint16_t padding[3];		/* Maintain alignment		*/
+	u16 doorbell_id;
+	unsigned long doorbell_offset;
+	u32 doorbell_cookie;
 
 	spinlock_t wq_lock;
 	uint32_t wq_offset;
@@ -159,7 +158,7 @@ struct intel_guc {
 
 	struct i915_guc_client *execbuf_client;
 
-	DECLARE_BITMAP(doorbell_bitmap, GUC_MAX_DOORBELLS);
+	DECLARE_BITMAP(doorbell_bitmap, GUC_NUM_DOORBELLS);
 	uint32_t db_cacheline;		/* Cyclic counter mod pagesize	*/
 
 	/* Action status & statistics */