2 files changed, 41 insertions, 10 deletions

diff --git a/drivers/gpu/drm/msm/adreno/a4xx_gpu.c b/drivers/gpu/drm/msm/adreno/a4xx_gpu.c
index 2abf2627f822..5858fb3bad0d 100644
--- a/drivers/gpu/drm/msm/adreno/a4xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a4xx_gpu.c
@@ -520,16 +520,8 @@ static int a4xx_pm_suspend(struct msm_gpu *gpu) {
 
 static int a4xx_get_timestamp(struct msm_gpu *gpu, uint64_t *value)
 {
-	uint32_t hi, lo, tmp;
-
-	tmp = gpu_read(gpu, REG_A4XX_RBBM_PERFCTR_CP_0_HI);
-	do {
-		hi = tmp;
-		lo = gpu_read(gpu, REG_A4XX_RBBM_PERFCTR_CP_0_LO);
-		tmp = gpu_read(gpu, REG_A4XX_RBBM_PERFCTR_CP_0_HI);
-	} while (tmp != hi);
-
-	*value = (((uint64_t)hi) << 32) | lo;
+	*value = gpu_read64(gpu, REG_A4XX_RBBM_PERFCTR_CP_0_LO,
+		REG_A4XX_RBBM_PERFCTR_CP_0_HI);
 
 	return 0;
 }
diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h
index 10954135130d..c4c39d3272c7 100644
--- a/drivers/gpu/drm/msm/msm_gpu.h
+++ b/drivers/gpu/drm/msm/msm_gpu.h
@@ -154,6 +154,45 @@ static inline u32 gpu_read(struct msm_gpu *gpu, u32 reg)
 	return msm_readl(gpu->mmio + (reg << 2));
 }
 
+static inline void gpu_rmw(struct msm_gpu *gpu, u32 reg, u32 mask, u32 or)
+{
+	uint32_t val = gpu_read(gpu, reg);
+
+	val &= ~mask;
+	gpu_write(gpu, reg, val | or);
+}
+
+static inline u64 gpu_read64(struct msm_gpu *gpu, u32 lo, u32 hi)
+{
+	u64 val;
+
+	/*
+	 * Why not a readq here? Two reasons: 1) many of the LO registers are
+	 * not quad word aligned and 2) the GPU hardware designers have a bit
+	 * of a history of putting registers where they fit, especially in
+	 * spins. The longer a GPU family goes the higher the chance that
+	 * we'll get burned.  We could do a series of validity checks if we
+	 * wanted to, but really is a readq() that much better? Nah.
+	 */
+
+	/*
+	 * For some lo/hi registers (like perfcounters), the hi value is latched
+	 * when the lo is read, so make sure to read the lo first to trigger
+	 * that
+	 */
+	val = (u64) msm_readl(gpu->mmio + (lo << 2));
+	val |= ((u64) msm_readl(gpu->mmio + (hi << 2)) << 32);
+
+	return val;
+}
+
+static inline void gpu_write64(struct msm_gpu *gpu, u32 lo, u32 hi, u64 val)
+{
+	/* Why not a writeq here? Read the screed above */
+	msm_writel(lower_32_bits(val), gpu->mmio + (lo << 2));
+	msm_writel(upper_32_bits(val), gpu->mmio + (hi << 2));
+}
+
 int msm_gpu_pm_suspend(struct msm_gpu *gpu);
 int msm_gpu_pm_resume(struct msm_gpu *gpu);