[PATCH v3] drm/amdkfd: Fix bug in config_dequeue_wait_counts

[Harish Kasiviswanathan <Harish.Kasiviswanathan@xxxxxxx>]

For certain ASICs where dequeue_wait_count don't need to be initialized,
pm_config_dequeue_wait_counts_v9 return without filling in the packet
information. However, the calling function interprets this as a success
and sends the uninitialized packet to firmware causing hang.

Fix the above bug by not calling pm_config_dequeue_wait_counts_v9 for
ASICs that don't need the value to be initialized.

v2: Removed redudant code.
    Tidy up code based on review comments
v3: Don't call pm_config_dequeue_wait_counts_v9 for certain ASICs

Fixes: <98a5af8103f> ("drm/amdkfd: Add pm_config_dequeue_wait_counts API")

Signed-off-by: Harish Kasiviswanathan <Harish.Kasiviswanathan@xxxxxxx>
---
 .../gpu/drm/amd/amdkfd/kfd_packet_manager.c   | 16 ++++++----
 .../drm/amd/amdkfd/kfd_packet_manager_v9.c    | 30 +++++++++++--------
 2 files changed, 27 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c b/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c
index 3f574d82b5fc..8a47b7259a10 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager.c
@@ -418,6 +418,10 @@ int pm_config_dequeue_wait_counts(struct packet_manager *pm,
 	    !pm->pmf->config_dequeue_wait_counts_size)
 		return 0;
 
+	if (cmd == KFD_DEQUEUE_WAIT_INIT && (KFD_GC_VERSION(pm->dqm->dev) < IP_VERSION(9, 4, 1) ||
+	   KFD_GC_VERSION(pm->dqm->dev) >= IP_VERSION(10, 0, 0)))
+		return 0;
+
 	size = pm->pmf->config_dequeue_wait_counts_size;
 
 	mutex_lock(&pm->lock);
@@ -436,16 +440,16 @@ int pm_config_dequeue_wait_counts(struct packet_manager *pm,
 
 		retval = pm->pmf->config_dequeue_wait_counts(pm, buffer,
 							     cmd, value);
-		if (!retval)
+		if (!retval) {
 			retval = kq_submit_packet(pm->priv_queue);
+
+			/* If default value is modified, cache that in dqm->wait_times */
+			if (!retval && cmd == KFD_DEQUEUE_WAIT_INIT)
+				update_dqm_wait_times(pm->dqm);
+		}
 		else
 			kq_rollback_packet(pm->priv_queue);
 	}
-
-	/* If default value is modified, cache that value in dqm->wait_times */
-	if (!retval && cmd == KFD_DEQUEUE_WAIT_INIT)
-		update_dqm_wait_times(pm->dqm);
-
 out:
 	mutex_unlock(&pm->lock);
 	return retval;
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c b/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c
index d440df602393..f059041902bc 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c
@@ -310,6 +310,13 @@ static inline void pm_build_dequeue_wait_counts_packet_info(struct packet_manage
 		reg_data);
 }
 
+/* pm_config_dequeue_wait_counts_v9: Builds WRITE_DATA packet with
+ *    register/value for configuring dequeue wait counts
+ *
+ * @return: -ve for failure and 0 for success and buffer is
+ *  filled in with packet
+ *
+ **/
 static int pm_config_dequeue_wait_counts_v9(struct packet_manager *pm,
 		uint32_t *buffer,
 		enum kfd_config_dequeue_wait_counts_cmd cmd,
@@ -321,24 +328,21 @@ static int pm_config_dequeue_wait_counts_v9(struct packet_manager *pm,
 
 	switch (cmd) {
 	case KFD_DEQUEUE_WAIT_INIT: {
-		uint32_t sch_wave = 0, que_sleep = 0;
-		/* Reduce CP_IQ_WAIT_TIME2.QUE_SLEEP to 0x1 from default 0x40.
+		uint32_t sch_wave = 0, que_sleep = 1;
+
+		/* For all gfx9 ASICs > gfx941,
+		 * Reduce CP_IQ_WAIT_TIME2.QUE_SLEEP to 0x1 from default 0x40.
 		 * On a 1GHz machine this is roughly 1 microsecond, which is
 		 * about how long it takes to load data out of memory during
 		 * queue connect
 		 * QUE_SLEEP: Wait Count for Dequeue Retry.
+		 *
+		 * Set CWSR grace period to 1x1000 cycle for GFX9.4.3 APU
 		 */
-		if (KFD_GC_VERSION(pm->dqm->dev) >= IP_VERSION(9, 4, 1) &&
-		    KFD_GC_VERSION(pm->dqm->dev) < IP_VERSION(10, 0, 0)) {
-			que_sleep = 1;
-
-			/* Set CWSR grace period to 1x1000 cycle for GFX9.4.3 APU */
-			if (amdgpu_emu_mode == 0 && pm->dqm->dev->adev->gmc.is_app_apu &&
-			(KFD_GC_VERSION(pm->dqm->dev) == IP_VERSION(9, 4, 3)))
-				sch_wave = 1;
-		} else {
-			return 0;
-		}
+		if (amdgpu_emu_mode == 0 && pm->dqm->dev->adev->gmc.is_app_apu &&
+		    (KFD_GC_VERSION(pm->dqm->dev) == IP_VERSION(9, 4, 3)))
+			sch_wave = 1;
+
 		pm_build_dequeue_wait_counts_packet_info(pm, sch_wave, que_sleep,
 			&reg_offset, &reg_data);
 
-- 
2.34.1