[PATCH 5/8] drm/i915: advertise available metrics via sysfs

[Robert Bragg]

Each metric set is given a sysfs entry like:

/sys/class/drm/card0/metrics/<guid>/id

This allows userspace to enumerate the specific sets that are available
for the current system. The 'id' file contains an unsigned integer that
can be used to open the associated metric set via
DRM_IOCTL_I915_PERF_OPEN. The <guid> is a globally unique ID for a
specific OA unit configuration that can be reliably used as a key to
lookup corresponding counter meta data and normalization equations.

Signed-off-by: Robert Bragg <robert at sixbynine.org>
---
 drivers/gpu/drm/i915/i915_drv.h    |  2 ++
 drivers/gpu/drm/i915/i915_oa_hsw.c | 45 ++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_oa_hsw.h |  4 ++++
 drivers/gpu/drm/i915/i915_perf.c   | 18 ++++++++++++++-
 4 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index e4b9399..b1c60bb 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2086,6 +2086,8 @@ struct drm_i915_private {
 	struct {
 		bool initialized;
 
+		struct kobject *metrics_kobj;
+
 		struct mutex lock;
 		struct list_head streams;
 
diff --git a/drivers/gpu/drm/i915/i915_oa_hsw.c b/drivers/gpu/drm/i915/i915_oa_hsw.c
index 5472aa0..ecd7d2b 100644
--- a/drivers/gpu/drm/i915/i915_oa_hsw.c
+++ b/drivers/gpu/drm/i915/i915_oa_hsw.c
@@ -24,6 +24,8 @@
  *
  */
 
+#include <linux/sysfs.h>
+
 #include "i915_drv.h"
 
 enum metric_set_id {
@@ -130,3 +132,46 @@ int i915_oa_select_metric_set_hsw(struct drm_i915_private *dev_priv)
 		return -ENODEV;
 	}
 }
+
+static ssize_t
+show_render_basic_id(struct device *kdev, struct device_attribute *attr, char *buf)
+{
+        return sprintf(buf, "%d\n", METRIC_SET_ID_RENDER_BASIC);
+}
+
+static struct device_attribute dev_attr_render_basic_id = {
+        .attr = { .name = "id", .mode = S_IRUGO },
+        .show = show_render_basic_id,
+        .store = NULL,
+};
+
+static struct attribute *attrs_render_basic[] = {
+        &dev_attr_render_basic_id.attr,
+        NULL,
+};
+
+static struct attribute_group group_render_basic = {
+        .name = "403d8832-1a27-4aa6-a64e-f5389ce7b212",
+        .attrs =  attrs_render_basic,
+};
+
+int
+i915_perf_init_sysfs_hsw(struct drm_i915_private *dev_priv)
+{
+        int ret;
+
+        ret = sysfs_create_group(dev_priv->perf.metrics_kobj, &group_render_basic);
+        if (ret)
+                goto error_render_basic;
+
+        return 0;
+
+error_render_basic:
+        return ret;
+}
+
+void
+i915_perf_deinit_sysfs_hsw(struct drm_i915_private *dev_priv)
+{
+        sysfs_remove_group(dev_priv->perf.metrics_kobj, &group_render_basic);
+}
diff --git a/drivers/gpu/drm/i915/i915_oa_hsw.h b/drivers/gpu/drm/i915/i915_oa_hsw.h
index b618a1f..e4ba89d 100644
--- a/drivers/gpu/drm/i915/i915_oa_hsw.h
+++ b/drivers/gpu/drm/i915/i915_oa_hsw.h
@@ -31,4 +31,8 @@ extern int i915_oa_n_builtin_metric_sets_hsw;
 
 extern int i915_oa_select_metric_set_hsw(struct drm_i915_private *dev_priv);
 
+extern int i915_perf_init_sysfs_hsw(struct drm_i915_private *dev_priv);
+
+extern void i915_perf_deinit_sysfs_hsw(struct drm_i915_private *dev_priv);
+
 #endif
diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index b54f719..5c08a16 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -1164,6 +1164,11 @@ void i915_perf_init(struct drm_device *dev)
 	if (!IS_HASWELL(dev))
 		return;
 
+	dev_priv->perf.metrics_kobj =
+		kobject_create_and_add("metrics", &dev->primary->kdev->kobj);
+	if (!dev_priv->perf.metrics_kobj)
+		return;
+
 	hrtimer_init(&dev_priv->perf.oa.poll_check_timer,
 		     CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 	dev_priv->perf.oa.poll_check_timer.function = poll_check_timer_cb;
@@ -1187,9 +1192,15 @@ void i915_perf_init(struct drm_device *dev)
 	dev_priv->perf.oa.n_builtin_sets =
 		i915_oa_n_builtin_metric_sets_hsw;
 
-	dev_priv->perf.oa.oa_formats = hsw_oa_formats;
+	if (i915_perf_init_sysfs_hsw(dev_priv)) {
+		kobject_put(dev_priv->perf.metrics_kobj);
+		dev_priv->perf.metrics_kobj = NULL;
+		return;
+	}
 
 	dev_priv->perf.initialized = true;
+
+	return;
 }
 
 void i915_perf_fini(struct drm_device *dev)
@@ -1199,6 +1210,11 @@ void i915_perf_fini(struct drm_device *dev)
 	if (!dev_priv->perf.initialized)
 		return;
 
+	i915_perf_deinit_sysfs_hsw(dev_priv);
+
+	kobject_put(dev_priv->perf.metrics_kobj);
+	dev_priv->perf.metrics_kobj = NULL;
+
 	dev_priv->perf.oa.ops.init_oa_buffer = NULL;
 
 	dev_priv->perf.initialized = false;
-- 
2.7.0