gpu: nvgpu: add explicit wmb() before reg write

Add explict memory barrier wmb() before writing to register values.
Also call writel_relaxed() instead of writel() to skip internal
wmb() call which is conditional on some configs.

Bug 200012037

Change-Id: I9c545138314b6e73fec2a4aff2b1956444fac806
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/421463
Reviewed-by: Krishna Reddy <vdumpa@nvidia.com>
Tested-by: Krishna Reddy <vdumpa@nvidia.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a.h b/drivers/gpu/nvgpu/gk20a/gk20a.h
index da5cc917..9769ac99 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/gk20a.h
@@ -483,7 +483,8 @@ static inline void gk20a_mem_wr32(void *ptr, int w, u32 data)
 static inline void gk20a_writel(struct gk20a *g, u32 r, u32 v)
 {
         gk20a_dbg(gpu_dbg_reg, " r=0x%x v=0x%x", r, v);
-        writel(v, g->regs + r);
+        wmb();
+        writel_relaxed(v, g->regs + r);
 }
 static inline u32 gk20a_readl(struct gk20a *g, u32 r)
 {
@@ -495,7 +496,8 @@ static inline u32 gk20a_readl(struct gk20a *g, u32 r)
 static inline void gk20a_bar1_writel(struct gk20a *g, u32 b, u32 v)
 {
         gk20a_dbg(gpu_dbg_reg, " b=0x%x v=0x%x", b, v);
-        writel(v, g->bar1 + b);
+        wmb();
+        writel_relaxed(v, g->bar1 + b);
 }
 
 static inline u32 gk20a_bar1_readl(struct gk20a *g, u32 b)