drm/amd/display: Read all the trace entry if it is not empty

[Why]
If interval of two interrupt from dmub outbox0 is too short,
some event might be skipped

[How]
Compare read pointer and write pointer until all the event
entry is processed
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Yongqiang Sun <yongqiang.sun@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Eryk Brol <eryk.brol@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dmub/src/dmub_srv.c

@@ -517,7 +517,7 @@ enum dmub_status dmub_srv_hw_init(struct dmub_srv *dmub,
 	dmub_memset(&outbox0_rb_params, 0, sizeof(outbox0_rb_params));
 	outbox0_rb_params.ctx = dmub;
 	outbox0_rb_params.base_address = (void *)((uint64_t)(tracebuff_fb->cpu_addr) + TRACE_BUFFER_ENTRY_OFFSET);
-	outbox0_rb_params.capacity = tracebuff_fb->size - TRACE_BUFFER_ENTRY_OFFSET;
+	outbox0_rb_params.capacity = tracebuff_fb->size - dmub_align(TRACE_BUFFER_ENTRY_OFFSET, 64);
 	dmub_rb_init(&dmub->outbox0_rb, &outbox0_rb_params);
 
 	if (dmub->hw_funcs.reset_release)
@@ -719,10 +719,10 @@ enum dmub_status dmub_srv_cmd_with_reply_data(struct dmub_srv *dmub,
 	return status;
 }
 
-static inline void dmub_rb_out_trace_buffer_front(struct dmub_rb *rb,
+static inline bool dmub_rb_out_trace_buffer_front(struct dmub_rb *rb,
 				 void *entry)
 {
-	const uint64_t *src = (const uint64_t *)(rb->base_address) + rb->wrpt / sizeof(uint64_t);
+	const uint64_t *src = (const uint64_t *)(rb->base_address) + rb->rptr / sizeof(uint64_t);
 	uint64_t *dst = (uint64_t *)entry;
 	uint8_t i;
 
@@ -730,13 +730,22 @@ static inline void dmub_rb_out_trace_buffer_front(struct dmub_rb *rb,
 	for (i = 0; i < sizeof(struct dmcub_trace_buf_entry) / sizeof(uint64_t); i++)
 		*dst++ = *src++;
 
+	rb->rptr += sizeof(struct dmcub_trace_buf_entry);
+
+	rb->rptr %= rb->capacity;
+
+	if (rb->rptr == rb->wrpt)
+		return true;
+
+	return false;
 }
 
 enum dmub_status dmub_srv_get_outbox0_msg(struct dmub_srv *dmub, struct dmcub_trace_buf_entry *entry)
 {
 	dmub->outbox0_rb.wrpt = dmub->hw_funcs.get_outbox0_wptr(dmub);
 
-	dmub_rb_out_trace_buffer_front(&dmub->outbox0_rb, (void *)entry);
-
+	if (dmub_rb_out_trace_buffer_front(&dmub->outbox0_rb, (void *)entry))
 		return DMUB_STATUS_OK;
+
+	return DMUB_STATUS_QUEUE_FULL;
 }