[PATCH] drm/msm/a6xx: add module param to enable debugbus snapshot

[Rob Clark <robdclark@gmail.com>]

From: Rob Clark <robdclark@chromium.org>

For production devices, the debugbus sections will typically be fused
off and empty in the gpu device coredump.  But since this may contain
data like cache contents, don't capture it by default.

Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c | 3 ++-
 drivers/gpu/drm/msm/adreno/adreno_device.c  | 4 ++++
 drivers/gpu/drm/msm/adreno/adreno_gpu.h     | 2 ++
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c
index 959656ad6987..b12f5b4a1bea 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu_state.c
@@ -938,7 +938,8 @@ struct msm_gpu_state *a6xx_gpu_state_get(struct msm_gpu *gpu)
 		msm_gem_kernel_put(dumper.bo, gpu->aspace, true);
 	}
 
-	a6xx_get_debugbus(gpu, a6xx_state);
+	if (snapshot_debugbus)
+		a6xx_get_debugbus(gpu, a6xx_state);
 
 	return  &a6xx_state->base;
 }
diff --git a/drivers/gpu/drm/msm/adreno/adreno_device.c b/drivers/gpu/drm/msm/adreno/adreno_device.c
index 4e84f3c76f4f..9eeb46bf2a5d 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_device.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_device.c
@@ -14,6 +14,10 @@ bool hang_debug = false;
 MODULE_PARM_DESC(hang_debug, "Dump registers when hang is detected (can be slow!)");
 module_param_named(hang_debug, hang_debug, bool, 0600);
 
+bool snapshot_debugbus = false;
+MODULE_PARM_DESC(snapshot_debugbus, "Include debugbus sections in GPU devcoredump (if not fused off)");
+module_param_named(snapshot_debugbus, snapshot_debugbus, bool, 0600);
+
 static const struct adreno_info gpulist[] = {
 	{
 		.rev   = ADRENO_REV(2, 0, 0, 0),
diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.h b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
index 99bb468f5f24..e55abae365b5 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.h
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
@@ -21,6 +21,8 @@
 #define REG_SKIP ~0
 #define REG_ADRENO_SKIP(_offset) [_offset] = REG_SKIP
 
+extern bool snapshot_debugbus;
+
 /**
  * adreno_regs: List of registers that are used in across all
  * 3D devices. Each device type has different offset value for the same
-- 
2.26.2