drm/msm: Add an ftrace for gpu register access

With IFPC, there is a probability of accessing a GX domain register when
it is collapsed, which leads to gmu fence errors. To debug this, we need
to trace every gpu register accesses and identify the one just before a
gmu fence error. So, add an ftrace to track all gpu register accesses.

Signed-off-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/673366/
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>

Author: akhilpo-qcom

drivers/gpu/drm/msm/msm_gpu.h

@@ -16,6 +16,7 @@
 
 #include "msm_drv.h"
 #include "msm_fence.h"
+#include "msm_gpu_trace.h"
 #include "msm_ringbuffer.h"
 #include "msm_gem.h"
 
@@ -613,16 +614,19 @@ struct msm_gpu_state {
 
 static inline void gpu_write(struct msm_gpu *gpu, u32 reg, u32 data)
 {
+	trace_msm_gpu_regaccess(reg);
 	writel(data, gpu->mmio + (reg << 2));
 }
 
 static inline u32 gpu_read(struct msm_gpu *gpu, u32 reg)
 {
+	trace_msm_gpu_regaccess(reg);
 	return readl(gpu->mmio + (reg << 2));
 }
 
 static inline void gpu_rmw(struct msm_gpu *gpu, u32 reg, u32 mask, u32 or)
 {
+	trace_msm_gpu_regaccess(reg);
 	msm_rmw(gpu->mmio + (reg << 2), mask, or);
 }
 
@@ -644,16 +648,20 @@ static inline u64 gpu_read64(struct msm_gpu *gpu, u32 reg)
 	 * when the lo is read, so make sure to read the lo first to trigger
 	 * that
 	 */
+	trace_msm_gpu_regaccess(reg);
 	val = (u64) readl(gpu->mmio + (reg << 2));
+	trace_msm_gpu_regaccess(reg+1);
 	val |= ((u64) readl(gpu->mmio + ((reg + 1) << 2)) << 32);
 
 	return val;
 }
 
 static inline void gpu_write64(struct msm_gpu *gpu, u32 reg, u64 val)
 {
+	trace_msm_gpu_regaccess(reg);
 	/* Why not a writeq here? Read the screed above */
 	writel(lower_32_bits(val), gpu->mmio + (reg << 2));
+	trace_msm_gpu_regaccess(reg+1);
 	writel(upper_32_bits(val), gpu->mmio + ((reg + 1) << 2));
 }
 

drivers/gpu/drm/msm/msm_gpu_trace.h

@@ -219,6 +219,18 @@ TRACE_EVENT(msm_mmu_prealloc_cleanup,
 		TP_printk("count=%u, remaining=%u", __entry->count, __entry->remaining)
 );
 
+TRACE_EVENT(msm_gpu_regaccess,
+		TP_PROTO(u32 offset),
+		TP_ARGS(offset),
+		TP_STRUCT__entry(
+			__field(u32, offset)
+			),
+		TP_fast_assign(
+			__entry->offset = offset;
+			),
+		TP_printk("offset=0x%x", __entry->offset)
+);
+
 #endif
 
 #undef TRACE_INCLUDE_PATH