[PATCH v7 2/5] drm: Expose wedge recovery methods

[Raag Jadav <raag.jadav@xxxxxxxxx>]

Now that we have device wedged event in place, add wedge_recovery sysfs
attribute which will expose recovery methods supported by the DRM device.
This is useful for userspace consumers in cases where the device supports
multiple recovery methods which can be used as fallbacks.

  $ cat /sys/class/drm/card<N>/wedge_recovery
  rebind
  bus-reset
  reboot

Signed-off-by: Raag Jadav <raag.jadav@xxxxxxxxx>
---
 drivers/gpu/drm/drm_sysfs.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c
index fb3bbb6adcd1..bd77b35ceb8a 100644
--- a/drivers/gpu/drm/drm_sysfs.c
+++ b/drivers/gpu/drm/drm_sysfs.c
@@ -24,6 +24,7 @@
 #include <drm/drm_accel.h>
 #include <drm/drm_connector.h>
 #include <drm/drm_device.h>
+#include <drm/drm_drv.h>
 #include <drm/drm_file.h>
 #include <drm/drm_modes.h>
 #include <drm/drm_print.h>
@@ -508,6 +509,26 @@ void drm_sysfs_connector_property_event(struct drm_connector *connector,
 }
 EXPORT_SYMBOL(drm_sysfs_connector_property_event);
 
+static ssize_t wedge_recovery_show(struct device *device,
+				   struct device_attribute *attr, char *buf)
+{
+	struct drm_minor *minor = to_drm_minor(device);
+	struct drm_device *dev = minor->dev;
+	unsigned int method, count = DRM_WEDGE_RECOVERY_REBIND;
+
+	for_each_set_bit(method, &dev->wedge_recovery, DRM_WEDGE_RECOVERY_MAX)
+		count += sysfs_emit_at(buf, count, "%s\n", drm_wedge_recovery_name(method));
+
+	return count;
+}
+static DEVICE_ATTR_RO(wedge_recovery);
+
+static struct attribute *minor_dev_attrs[] = {
+	&dev_attr_wedge_recovery.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(minor_dev);
+
 struct device *drm_sysfs_minor_alloc(struct drm_minor *minor)
 {
 	const char *minor_str;
@@ -532,6 +553,7 @@ struct device *drm_sysfs_minor_alloc(struct drm_minor *minor)
 		kdev->devt = MKDEV(DRM_MAJOR, minor->index);
 		kdev->class = drm_class;
 		kdev->type = &drm_sysfs_device_minor;
+		kdev->groups = minor_dev_groups;
 	}
 
 	kdev->parent = minor->dev->dev;
-- 
2.34.1