msm: kgsl: Standardize ringbuffers in the snapshot

'start' and 'stop' in the snapshot ringbuffer header are supposed to
be the dword offset that the data starts and stops at respectively.
For the current ringbuffer which is parsed 'start' and 'stop' are
equal to the CP wptr but all other ringbuffers are just dumped from
start to finish so 'start' and stop' should be 0 and KGSL_RB_DWORDS.
And having said that, why are we bothering to make the current
ringbuffer special anyway? In every case we are dumping the entire
ringbuffer so we might as well dump it in order. While messing about
in this code go a few more steps to make sure that we don't dump the
same ringbuffer more than once.

Change-Id: Ic0dedbada33adda660b7f0bf5eb165b0aa159004
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>

drivers/gpu/msm/adreno_snapshot.c

@@ -293,7 +293,7 @@ static void dump_all_ibs(struct kgsl_device *device,
  * @snapshot: Pointer to information about the current snapshot being taken
  */
 static void snapshot_rb_ibs(struct kgsl_device *device,
-		struct adreno_ringbuffer *rb, unsigned int *data,
+		struct adreno_ringbuffer *rb,
 		struct kgsl_snapshot *snapshot)
 {
 	struct adreno_device *adreno_dev = ADRENO_DEVICE(device);
@@ -356,7 +356,6 @@ static void snapshot_rb_ibs(struct kgsl_device *device,
 	 */
 
 	if (index == rb->wptr) {
-		memcpy(data, rb->buffer_desc.hostptr, KGSL_RB_SIZE);
 		dump_all_ibs(device, rb, snapshot);
 		return;
 	}
@@ -399,14 +398,12 @@ static void snapshot_rb_ibs(struct kgsl_device *device,
 	ib_parse_start = index;
 
 	/*
-	 * Loop through the RB, copying the data and looking for indirect
-	 * buffers and MMU pagetable changes
+	 * Loop through the RB, looking for indirect buffers and MMU pagetable
+	 * changes
 	 */
 
 	index = rb->wptr;
 	for (i = 0; i < KGSL_RB_DWORDS; i++) {
-		*data = rbptr[index];
-
 		/*
 		 * Only parse IBs between the start and the rptr or the next
 		 * context switch, whichever comes first
@@ -443,12 +440,7 @@ static void snapshot_rb_ibs(struct kgsl_device *device,
 				ibaddr, ibsize);
 		}
 
-		index = index + 1;
-
-		if (index == KGSL_RB_DWORDS)
-			index = 0;
-
-		data++;
+		index = (index + 1) % KGSL_RB_DWORDS;
 	}
 
 }
@@ -475,8 +467,8 @@ static size_t snapshot_rb(struct kgsl_device *device, u8 *buf,
 	}
 
 	/* Write the sub-header for the section */
-	header->start = rb->wptr;
-	header->end = rb->wptr;
+	header->start = 0;
+	header->end = KGSL_RB_DWORDS;
 	header->wptr = rb->wptr;
 	header->rptr = rb->rptr;
 	header->rbsize = KGSL_RB_DWORDS;
@@ -488,12 +480,12 @@ static size_t snapshot_rb(struct kgsl_device *device, u8 *buf,
 	header->gpuaddr = rb->buffer_desc.gpuaddr;
 	header->id = rb->id;
 
-	if (rb == adreno_dev->cur_rb) {
-		snapshot_rb_ibs(device, rb, data, snapshot);
-	} else {
-		/* Just copy the ringbuffer, there are no active IBs */
-		memcpy(data, rb->buffer_desc.hostptr, KGSL_RB_SIZE);
-	}
+	if (rb == adreno_dev->cur_rb)
+		snapshot_rb_ibs(device, rb, snapshot);
+
+	/* Just copy the ringbuffer, there are no active IBs */
+	memcpy(data, rb->buffer_desc.hostptr, KGSL_RB_SIZE);
+
 	/* Return the size of the section */
 	return KGSL_RB_SIZE + sizeof(*header);
 }
@@ -817,6 +809,21 @@ static void adreno_snapshot_iommu(struct kgsl_device *device,
 			snapshot, snapshot_global, &iommu->smmu_info);
 }
 
+static void adreno_snapshot_ringbuffer(struct kgsl_device *device,
+		struct kgsl_snapshot *snapshot, struct adreno_ringbuffer *rb)
+{
+	struct snapshot_rb_params params = {
+		.snapshot = snapshot,
+		.rb = rb,
+	};
+
+	if (rb == NULL)
+		return;
+
+	kgsl_snapshot_add_section(device, KGSL_SNAPSHOT_SECTION_RB_V2, snapshot,
+		snapshot_rb, &params);
+}
+
 /* adreno_snapshot - Snapshot the Adreno GPU state
  * @device - KGSL device to snapshot
  * @snapshot - Pointer to the snapshot instance
@@ -834,7 +841,6 @@ void adreno_snapshot(struct kgsl_device *device, struct kgsl_snapshot *snapshot,
 	struct adreno_device *adreno_dev = ADRENO_DEVICE(device);
 	struct adreno_gpudev *gpudev = ADRENO_GPU_DEVICE(adreno_dev);
 	struct adreno_ringbuffer *rb;
-	struct snapshot_rb_params snap_rb_params;
 
 	ib_max_objs = 0;
 	/* Reset the list of objects */
@@ -845,25 +851,17 @@ void adreno_snapshot(struct kgsl_device *device, struct kgsl_snapshot *snapshot,
 	setup_fault_process(device, snapshot,
 			context ? context->proc_priv : NULL);
 
-	/* Dump the current ringbuffer */
-	snap_rb_params.snapshot = snapshot;
-	snap_rb_params.rb = adreno_dev->cur_rb;
-	kgsl_snapshot_add_section(device, KGSL_SNAPSHOT_SECTION_RB_V2, snapshot,
-			snapshot_rb, &snap_rb_params);
+	adreno_snapshot_ringbuffer(device, snapshot, adreno_dev->cur_rb);
 
 	/* Dump the prev ringbuffer */
-	if (adreno_dev->prev_rb) {
-		snap_rb_params.rb = adreno_dev->prev_rb;
-		kgsl_snapshot_add_section(device, KGSL_SNAPSHOT_SECTION_RB_V2,
-			snapshot, snapshot_rb, &snap_rb_params);
-	}
+	if (adreno_dev->prev_rb != adreno_dev->cur_rb)
+		adreno_snapshot_ringbuffer(device, snapshot,
+			adreno_dev->prev_rb);
 
-	/* Dump next ringbuffer */
-	if (adreno_dev->next_rb) {
-		snap_rb_params.rb = adreno_dev->next_rb;
-		kgsl_snapshot_add_section(device, KGSL_SNAPSHOT_SECTION_RB_V2,
-			snapshot, snapshot_rb, &snap_rb_params);
-	}
+	if ((adreno_dev->next_rb != adreno_dev->prev_rb) &&
+		 (adreno_dev->next_rb != adreno_dev->cur_rb))
+		adreno_snapshot_ringbuffer(device, snapshot,
+			adreno_dev->next_rb);
 
 	adreno_readreg64(adreno_dev, ADRENO_REG_CP_IB1_BASE,
 			ADRENO_REG_CP_IB1_BASE_HI, &ib1base);