drm/amd/display: Fix race condition in DPIA AUX transfer

[Why]
This fix was intended for improving on coding style but in the process
uncovers a race condition, which explains why we are getting incorrect
length in DPIA AUX replies. Due to the call path of DPIA AUX going from
DC back to DM layer then again into DC and the added complexities on top
of current DC AUX implementation, a proper fix to rely on current dc_lock
to address the race condition is difficult without a major overhual
on how DPIA AUX is implemented.

[How]
- Add a mutex dpia_aux_lock to protect DPIA AUX transfers
- Remove DMUB_ASYNC_TO_SYNC_ACCESS_* codes and rely solely on
  aux_return_code_type for error reporting and handling
- Separate SET_CONFIG from DPIA AUX transfer because they have quiet
  different processing logic
- Remove unnecessary type casting to and from void * type

Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Jasdeep Dhillon <jdhillon@amd.com>
Signed-off-by: Stylon Wang <stylon.wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 4 insertions, 6 deletions

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
index e47098fa5aac..6994c9a1ed85 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
@@ -817,9 +817,8 @@ int dm_helper_dmub_aux_transfer_sync(
 		struct aux_payload *payload,
 		enum aux_return_code_type *operation_result)
 {
-	return amdgpu_dm_process_dmub_aux_transfer_sync(true, ctx,
-			link->link_index, (void *)payload,
-			(void *)operation_result);
+	return amdgpu_dm_process_dmub_aux_transfer_sync(ctx, link->link_index, payload,
+			operation_result);
 }
 
 int dm_helpers_dmub_set_config_sync(struct dc_context *ctx,
@@ -827,9 +826,8 @@ int dm_helpers_dmub_set_config_sync(struct dc_context *ctx,
 		struct set_config_cmd_payload *payload,
 		enum set_config_status *operation_result)
 {
-	return amdgpu_dm_process_dmub_aux_transfer_sync(false, ctx,
-			link->link_index, (void *)payload,
-			(void *)operation_result);
+	return amdgpu_dm_process_dmub_set_config_sync(ctx, link->link_index, payload,
+			operation_result);
 }
 
 void dm_set_dcn_clocks(struct dc_context *ctx, struct dc_clocks *clks)