linux-kernel - [PATCH 2/2] drm/msm: Add param for userspace to query suspend count

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Message-Id: <20210325012358.1759770-3-robdclark@gmail.com>
Date:   Wed, 24 Mar 2021 18:23:53 -0700
From:   Rob Clark <robdclark@...il.com>
To:     dri-devel@...ts.freedesktop.org
Cc:     Rob Clark <robdclark@...omium.org>,
        Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Jordan Crouse <jcrouse@...eaurora.org>,
        Jonathan Marek <jonathan@...ek.ca>,
        Dave Airlie <airlied@...hat.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Sharat Masetty <smasetty@...eaurora.org>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Akhil P Oommen <akhilpo@...eaurora.org>,
        linux-arm-msm@...r.kernel.org (open list:DRM DRIVER FOR MSM ADRENO GPU),
        freedreno@...ts.freedesktop.org (open list:DRM DRIVER FOR MSM ADRENO
        GPU), linux-kernel@...r.kernel.org (open list)
Subject: [PATCH 2/2] drm/msm: Add param for userspace to query suspend count

From: Rob Clark <robdclark@...omium.org>

Performance counts, and ALWAYS_ON counters used for capturing GPU
timestamps, lose their state across suspend/resume cycles.  Userspace
tooling for performance monitoring needs to be aware of this.  For
example, after a suspend userspace needs to recalibrate it's offset
between CPU and GPU time.

Signed-off-by: Rob Clark <robdclark@...omium.org>
---
 drivers/gpu/drm/msm/adreno/adreno_gpu.c | 3 +++
 drivers/gpu/drm/msm/msm_drv.c           | 1 +
 drivers/gpu/drm/msm/msm_gpu.c           | 2 ++
 drivers/gpu/drm/msm/msm_gpu.h           | 2 ++
 include/uapi/drm/msm_drm.h              | 1 +
 5 files changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
index f09175698827..e473b7c9ff7f 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
@@ -280,6 +280,9 @@ int adreno_get_param(struct msm_gpu *gpu, uint32_t param, uint64_t *value)
 	case MSM_PARAM_FAULTS:
 		*value = gpu->global_faults;
 		return 0;
+	case MSM_PARAM_SUSPENDS:
+		*value = gpu->suspend_count;
+		return 0;
 	default:
 		DBG("%s: invalid param: %u", gpu->name, param);
 		return -EINVAL;
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index b29e439eb299..4f9fa0189a07 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -39,6 +39,7 @@
  *           GEM object's debug name
  * - 1.5.0 - Add SUBMITQUERY_QUERY ioctl
  * - 1.6.0 - Syncobj support
+ * - 1.7.0 - Add MSM_PARAM_SUSPENDS to access suspend count
  */
 #define MSM_VERSION_MAJOR	1
 #define MSM_VERSION_MINOR	6
diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index 7bdb01f202f4..ab888d83b887 100644
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -256,6 +256,8 @@ int msm_gpu_pm_suspend(struct msm_gpu *gpu)
 	if (ret)
 		return ret;
 
+	gpu->suspend_count++;
+
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h
index d7cd02cd2109..18baf935e143 100644
--- a/drivers/gpu/drm/msm/msm_gpu.h
+++ b/drivers/gpu/drm/msm/msm_gpu.h
@@ -152,6 +152,8 @@ struct msm_gpu {
 		ktime_t time;
 	} devfreq;
 
+	uint32_t suspend_count;
+
 	struct msm_gpu_state *crashstate;
 	/* True if the hardware supports expanded apriv (a650 and newer) */
 	bool hw_apriv;
diff --git a/include/uapi/drm/msm_drm.h b/include/uapi/drm/msm_drm.h
index a6c1f3eb2623..5596d7c37f9e 100644
--- a/include/uapi/drm/msm_drm.h
+++ b/include/uapi/drm/msm_drm.h
@@ -76,6 +76,7 @@ struct drm_msm_timespec {
 #define MSM_PARAM_NR_RINGS   0x07
 #define MSM_PARAM_PP_PGTABLE 0x08  /* => 1 for per-process pagetables, else 0 */
 #define MSM_PARAM_FAULTS     0x09
+#define MSM_PARAM_SUSPENDS   0x0a
 
 struct drm_msm_param {
 	__u32 pipe;           /* in, MSM_PIPE_x */
-- 
2.29.2