[PATCH 3/7] drm/msm: spin helper

[Rob Clark]

Helper macro to simplify places where we need to poll with timeout
waiting for gpu.

Signed-off-by: Rob Clark <robdclark at gmail.com>
---
 drivers/gpu/drm/msm/adreno/a3xx_gpu.c   | 14 +++--------
 drivers/gpu/drm/msm/adreno/adreno_gpu.c | 41 ++++++++++++---------------------
 drivers/gpu/drm/msm/adreno/adreno_gpu.h | 15 +++++++++++-
 3 files changed, 32 insertions(+), 38 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a3xx_gpu.c b/drivers/gpu/drm/msm/adreno/a3xx_gpu.c
index 8b6fb84..59ed762 100644
--- a/drivers/gpu/drm/msm/adreno/a3xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a3xx_gpu.c
@@ -326,21 +326,13 @@ static void a3xx_destroy(struct msm_gpu *gpu)
 
 static void a3xx_idle(struct msm_gpu *gpu)
 {
-	unsigned long t;
-
 	/* wait for ringbuffer to drain: */
 	adreno_idle(gpu);
 
-	t = jiffies + ADRENO_IDLE_TIMEOUT;
-
 	/* then wait for GPU to finish: */
-	do {
-		uint32_t rbbm_status = gpu_read(gpu, REG_A3XX_RBBM_STATUS);
-		if (!(rbbm_status & A3XX_RBBM_STATUS_GPU_BUSY))
-			return;
-	} while(time_before(jiffies, t));
-
-	DRM_ERROR("timeout waiting for %s to idle!\n", gpu->name);
+	if (spin_until(!(gpu_read(gpu, REG_A3XX_RBBM_STATUS) &
+			A3XX_RBBM_STATUS_GPU_BUSY)))
+		DRM_ERROR("%s: timeout waiting for GPU to idle!\n", gpu->name);
 
 	/* TODO maybe we need to reset GPU here to recover from hang? */
 }
diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
index cf6eb97..7a11563 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
@@ -225,19 +225,11 @@ void adreno_flush(struct msm_gpu *gpu)
 void adreno_idle(struct msm_gpu *gpu)
 {
 	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
-	uint32_t rptr, wptr = get_wptr(gpu->rb);
-	unsigned long t;
-
-	t = jiffies + ADRENO_IDLE_TIMEOUT;
-
-	/* then wait for CP to drain ringbuffer: */
-	do {
-		rptr = adreno_gpu->memptrs->rptr;
-		if (rptr == wptr)
-			return;
-	} while(time_before(jiffies, t));
+	uint32_t wptr = get_wptr(gpu->rb);
 
-	DRM_ERROR("%s: timeout waiting to drain ringbuffer!\n", gpu->name);
+	/* wait for CP to drain ringbuffer: */
+	if (spin_until(adreno_gpu->memptrs->rptr == wptr))
+		DRM_ERROR("%s: timeout waiting to drain ringbuffer!\n", gpu->name);
 
 	/* TODO maybe we need to reset GPU here to recover from hang? */
 }
@@ -278,22 +270,19 @@ void adreno_dump(struct msm_gpu *gpu)
 
 }
 
-void adreno_wait_ring(struct msm_gpu *gpu, uint32_t ndwords)
+static uint32_t ring_freewords(struct msm_gpu *gpu)
 {
 	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
-	uint32_t freedwords;
-	unsigned long t = jiffies + ADRENO_IDLE_TIMEOUT;
-	do {
-		uint32_t size = gpu->rb->size / 4;
-		uint32_t wptr = get_wptr(gpu->rb);
-		uint32_t rptr = adreno_gpu->memptrs->rptr;
-		freedwords = (rptr + (size - 1) - wptr) % size;
-
-		if (time_after(jiffies, t)) {
-			DRM_ERROR("%s: timeout waiting for ringbuffer space\n", gpu->name);
-			break;
-		}
-	} while(freedwords < ndwords);
+	uint32_t size = gpu->rb->size / 4;
+	uint32_t wptr = get_wptr(gpu->rb);
+	uint32_t rptr = adreno_gpu->memptrs->rptr;
+	return (rptr + (size - 1) - wptr) % size;
+}
+
+void adreno_wait_ring(struct msm_gpu *gpu, uint32_t ndwords)
+{
+	if (spin_until(ring_freewords(gpu) >= ndwords))
+		DRM_ERROR("%s: timeout waiting for ringbuffer space\n", gpu->name);
 }
 
 static const char *iommu_ports[] = {
diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.h b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
index e16200d..63c36ce 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.h
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
@@ -76,7 +76,20 @@ struct adreno_platform_config {
 #endif
 };
 
-#define ADRENO_IDLE_TIMEOUT (20 * 1000)
+#define ADRENO_IDLE_TIMEOUT msecs_to_jiffies(1000)
+
+#define spin_until(X) ({                                   \
+	int __ret = -ETIMEDOUT;                            \
+	unsigned long __t = jiffies + ADRENO_IDLE_TIMEOUT; \
+	do {                                               \
+		if (X) {                                   \
+			__ret = 0;                         \
+			break;                             \
+		}                                          \
+	} while (time_before(jiffies, __t));               \
+	__ret;                                             \
+})
+
 
 static inline bool adreno_is_a3xx(struct adreno_gpu *gpu)
 {
-- 
1.8.5.3