drm/msm: add param to retrieve # of GPU faults (global)

For KHR_robustness, userspace wants to know two things, the count of GPU
faults globally, and the count of faults attributed to a given context.
This patch providees the former, and the next patch provides the latter.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Jordan Crouse <jcrouse@codeaurora.org>

drivers/gpu/drm/msm/adreno/adreno_gpu.c

@@ -66,6 +66,9 @@ int adreno_get_param(struct msm_gpu *gpu, uint32_t param, uint64_t *value)
 	case MSM_PARAM_PP_PGTABLE:
 		*value = 0;
 		return 0;
+	case MSM_PARAM_FAULTS:
+		*value = gpu->global_faults;
+		return 0;
 	default:
 		DBG("%s: invalid param: %u", gpu->name, param);
 		return -EINVAL;

drivers/gpu/drm/msm/msm_gpu.c

@@ -443,6 +443,9 @@ static void recover_worker(struct work_struct *work)
 	if (submit) {
 		struct task_struct *task;
 
+		/* Increment the fault count */
+		gpu->global_faults++;
+
 		task = get_pid_task(submit->pid, PIDTYPE_PID);
 		if (task) {
 			comm = kstrdup(task->comm, GFP_KERNEL);

drivers/gpu/drm/msm/msm_gpu.h

@@ -104,6 +104,9 @@ struct msm_gpu {
 	/* does gpu need hw_init? */
 	bool needs_hw_init;
 
+	/* number of GPU hangs (for all contexts) */
+	int global_faults;
+
 	/* worker for handling active-list retiring: */
 	struct work_struct retire_work;
 

include/uapi/drm/msm_drm.h

@@ -75,6 +75,7 @@ struct drm_msm_timespec {
 #define MSM_PARAM_GMEM_BASE  0x06
 #define MSM_PARAM_NR_RINGS   0x07
 #define MSM_PARAM_PP_PGTABLE 0x08  /* => 1 for per-process pagetables, else 0 */
+#define MSM_PARAM_FAULTS     0x09
 
 struct drm_msm_param {
 	__u32 pipe;           /* in, MSM_PIPE_x */