drm/etnaviv: add 'sync point' support

In order to support performance counters in a sane way we need to provide
a method to sync the GPU with the CPU. The GPU can process multpile command
buffers/events per irq. With the help of a 'sync point' we can trigger an event
and stop the GPU/FE immediately. When the CPU is done with is processing it
simply needs to restart the FE and the GPU will process the command stream.

Changes from v1 -> v2:
- process sync point with a work item to keep irq as fast as possible

Changes from v4 -> v5:
- renamed pmrs_* to sync_point_*
- call event_free(..) in sync_point_worker(..)

Signed-off-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

1 files changed, 26 insertions, 0 deletions

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index 7b61071af0de..cd70e7c04305 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -25,6 +25,7 @@
 #include "etnaviv_gpu.h"
 #include "etnaviv_gem.h"
 #include "etnaviv_mmu.h"
+#include "etnaviv_perfmon.h"
 #include "common.xml.h"
 #include "state.xml.h"
 #include "state_hi.xml.h"
@@ -1364,6 +1365,7 @@ int etnaviv_gpu_submit(struct etnaviv_gpu *gpu,
 	}
 
 	gpu->event[event].fence = fence;
+	gpu->event[event].sync_point = NULL;
 	submit->fence = dma_fence_get(fence);
 	gpu->active_fence = submit->fence->seqno;
 
@@ -1409,6 +1411,24 @@ out_pm_put:
 	return ret;
 }
 
+static void etnaviv_process_sync_point(struct etnaviv_gpu *gpu,
+	struct etnaviv_event *event)
+{
+	u32 addr = gpu_read(gpu, VIVS_FE_DMA_ADDRESS);
+
+	event->sync_point(gpu, event);
+	etnaviv_gpu_start_fe(gpu, addr + 2, 2);
+}
+
+static void sync_point_worker(struct work_struct *work)
+{
+	struct etnaviv_gpu *gpu = container_of(work, struct etnaviv_gpu,
+					       sync_point_work);
+
+	etnaviv_process_sync_point(gpu, &gpu->event[gpu->sync_point_event]);
+	event_free(gpu, gpu->sync_point_event);
+}
+
 /*
  * Init/Cleanup:
  */
@@ -1455,6 +1475,11 @@ static irqreturn_t irq_handler(int irq, void *data)
 
 			dev_dbg(gpu->dev, "event %u\n", event);
 
+			if (gpu->event[event].sync_point) {
+				gpu->sync_point_event = event;
+				etnaviv_queue_work(gpu->drm, &gpu->sync_point_work);
+			}
+
 			fence = gpu->event[event].fence;
 			gpu->event[event].fence = NULL;
 			dma_fence_signal(fence);
@@ -1660,6 +1685,7 @@ static int etnaviv_gpu_bind(struct device *dev, struct device *master,
 
 	INIT_LIST_HEAD(&gpu->active_cmd_list);
 	INIT_WORK(&gpu->retire_work, retire_worker);
+	INIT_WORK(&gpu->sync_point_work, sync_point_worker);
 	INIT_WORK(&gpu->recover_work, recover_worker);
 	init_waitqueue_head(&gpu->fence_event);