[PATCH v2 4/4] drm/amd/pm: Add sysfs attribute to get pm log

[Lijo Lazar]

Add sysfs attribute to read power management log. A snapshot is
captured to the buffer when the attribute is read.

Signed-off-by: Lijo Lazar <lijo.lazar at amd.com>
---

v2: Pass PAGE_SIZE as the max size of input buffer

 drivers/gpu/drm/amd/pm/amdgpu_pm.c | 40 ++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/drivers/gpu/drm/amd/pm/amdgpu_pm.c b/drivers/gpu/drm/amd/pm/amdgpu_pm.c
index 4c65a2fac028..5a1d21c52672 100644
--- a/drivers/gpu/drm/amd/pm/amdgpu_pm.c
+++ b/drivers/gpu/drm/amd/pm/amdgpu_pm.c
@@ -1794,6 +1794,44 @@ static ssize_t amdgpu_set_apu_thermal_cap(struct device *dev,
 	return count;
 }
 
+static int amdgpu_pmlog_attr_update(struct amdgpu_device *adev,
+				    struct amdgpu_device_attr *attr,
+				    uint32_t mask,
+				    enum amdgpu_device_attr_states *states)
+{
+	if (amdgpu_dpm_get_pm_log(adev, NULL, 0) == -EOPNOTSUPP)
+		*states = ATTR_STATE_UNSUPPORTED;
+
+	return 0;
+}
+
+static ssize_t amdgpu_get_pmlog(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct drm_device *ddev = dev_get_drvdata(dev);
+	struct amdgpu_device *adev = drm_to_adev(ddev);
+	ssize_t size = 0;
+	int ret;
+
+	if (amdgpu_in_reset(adev))
+		return -EPERM;
+	if (adev->in_suspend && !adev->in_runpm)
+		return -EPERM;
+
+	ret = pm_runtime_get_sync(ddev->dev);
+	if (ret < 0) {
+		pm_runtime_put_autosuspend(ddev->dev);
+		return ret;
+	}
+
+	size = amdgpu_dpm_get_pm_log(adev, buf, PAGE_SIZE);
+
+	pm_runtime_mark_last_busy(ddev->dev);
+	pm_runtime_put_autosuspend(ddev->dev);
+
+	return size;
+}
+
 /**
  * DOC: gpu_metrics
  *
@@ -2091,6 +2129,8 @@ static struct amdgpu_device_attr amdgpu_device_attrs[] = {
 	AMDGPU_DEVICE_ATTR_RW(smartshift_bias,				ATTR_FLAG_BASIC,
 			      .attr_update = ss_bias_attr_update),
 	AMDGPU_DEVICE_ATTR_RW(xgmi_plpd_policy,				ATTR_FLAG_BASIC),
+	AMDGPU_DEVICE_ATTR_RO(pmlog,					ATTR_FLAG_BASIC,
+			      .attr_update = amdgpu_pmlog_attr_update),
 };
 
 static int default_attr_update(struct amdgpu_device *adev, struct amdgpu_device_attr *attr,
-- 
2.25.1