drm: add atomic properties

Once a driver is using atomic helpers for modeset, the next step is to
switch over to atomic properties.  To do this, make sure that any
modeset objects have their ->atomic_{get,set}_property() vfuncs suitably
populated if they have custom properties (you did already remember to
plug in atomic-helper func for the legacy ->set_property() vfuncs,
right?), and then set DRIVER_ATOMIC bit in driver_features flag.

A new cap is introduced, DRM_CLIENT_CAP_ATOMIC, for the purposes of
shielding legacy userspace from atomic properties.  Mostly for the
benefit of legacy DDX drivers that do silly things like getting/setting
each property at startup (since some of the new atomic properties will
be able to trigger modeset).

Signed-off-by: Rob Clark <[email protected]>
[danvet: Squash in fixup patch to check for DRM_MODE_PROP_ATOMIC
instaed of the CAP define when filtering properties. Reported by
Tvrtko Uruslin, acked by Rob.]
Signed-off-by: Daniel Vetter <[email protected]>

Documentation/DocBook/drm.tmpl

@@ -239,6 +239,14 @@
               Driver supports dedicated render nodes.
             </para></listitem>
           </varlistentry>
+          <varlistentry>
+            <term>DRIVER_ATOMIC</term>
+            <listitem><para>
+              Driver supports atomic properties.  In this case the driver
+              must implement appropriate obj->atomic_get_property() vfuncs
+              for any modeset objects with driver specific properties.
+            </para></listitem>
+          </varlistentry>
         </variablelist>
       </sect3>
       <sect3>

drivers/gpu/drm/drm_atomic.c

@@ -520,6 +520,51 @@ int drm_atomic_connector_get_property(struct drm_connector *connector,
 }
 EXPORT_SYMBOL(drm_atomic_connector_get_property);
 
+/**
+ * drm_atomic_get_property - helper to read atomic property
+ * @obj: drm mode object whose property to read
+ * @property: the property to read
+ * @val: the read value, returned by reference
+ *
+ * RETURNS:
+ * Zero on success, error code on failure
+ */
+int drm_atomic_get_property(struct drm_mode_object *obj,
+		struct drm_property *property, uint64_t *val)
+{
+	struct drm_device *dev = property->dev;
+	int ret;
+
+	switch (obj->type) {
+	case DRM_MODE_OBJECT_CONNECTOR: {
+		struct drm_connector *connector = obj_to_connector(obj);
+		WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
+		ret = drm_atomic_connector_get_property(connector,
+				connector->state, property, val);
+		break;
+	}
+	case DRM_MODE_OBJECT_CRTC: {
+		struct drm_crtc *crtc = obj_to_crtc(obj);
+		WARN_ON(!drm_modeset_is_locked(&crtc->mutex));
+		ret = drm_atomic_crtc_get_property(crtc,
+				crtc->state, property, val);
+		break;
+	}
+	case DRM_MODE_OBJECT_PLANE: {
+		struct drm_plane *plane = obj_to_plane(obj);
+		WARN_ON(!drm_modeset_is_locked(&plane->mutex));
+		ret = drm_atomic_plane_get_property(plane,
+				plane->state, property, val);
+		break;
+	}
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
 /**
  * drm_atomic_set_crtc_for_plane - set crtc for plane
  * @plane_state: the plane whose incoming state to update

drivers/gpu/drm/drm_crtc.c

@@ -38,6 +38,7 @@
 #include <drm/drm_edid.h>
 #include <drm/drm_fourcc.h>
 #include <drm/drm_modeset_lock.h>
+#include <drm/drm_atomic.h>
 
 #include "drm_crtc_internal.h"
 #include "drm_internal.h"
@@ -1992,19 +1993,25 @@ static struct drm_encoder *drm_connector_get_encoder(struct drm_connector *conne
 }
 
 /* helper for getconnector and getproperties ioctls */
-static int get_properties(struct drm_mode_object *obj,
+static int get_properties(struct drm_mode_object *obj, bool atomic,
 		uint32_t __user *prop_ptr, uint64_t __user *prop_values,
 		uint32_t *arg_count_props)
 {
-	int props_count = obj->properties->count;
-	int i, ret, copied = 0;
+	int props_count;
+	int i, ret, copied;
+
+	props_count = obj->properties->count;
+	if (!atomic)
+		props_count -= obj->properties->atomic_count;
 
 	if ((*arg_count_props >= props_count) && props_count) {
-		copied = 0;
-		for (i = 0; i < props_count; i++) {
+		for (i = 0, copied = 0; copied < props_count; i++) {
 			struct drm_property *prop = obj->properties->properties[i];
 			uint64_t val;
 
+			if ((prop->flags & DRM_MODE_PROP_ATOMIC) && !atomic)
+				continue;
+
 			ret = drm_object_property_get_value(obj, prop, &val);
 			if (ret)
 				return ret;
@@ -2118,7 +2125,7 @@ int drm_mode_getconnector(struct drm_device *dev, void *data,
 	}
 	out_resp->count_modes = mode_count;
 
-	ret = get_properties(&connector->base,
+	ret = get_properties(&connector->base, file_priv->atomic,
 			(uint32_t __user *)(unsigned long)(out_resp->props_ptr),
 			(uint64_t __user *)(unsigned long)(out_resp->prop_values_ptr),
 			&out_resp->count_props);
@@ -3832,6 +3839,8 @@ void drm_object_attach_property(struct drm_mode_object *obj,
 	obj->properties->properties[count] = property;
 	obj->properties->values[count] = init_val;
 	obj->properties->count++;
+	if (property->flags & DRM_MODE_PROP_ATOMIC)
+		obj->properties->atomic_count++;
 }
 EXPORT_SYMBOL(drm_object_attach_property);
 
@@ -3883,6 +3892,14 @@ int drm_object_property_get_value(struct drm_mode_object *obj,
 {
 	int i;
 
+	/* read-only properties bypass atomic mechanism and still store
+	 * their value in obj->properties->values[].. mostly to avoid
+	 * having to deal w/ EDID and similar props in atomic paths:
+	 */
+	if (drm_core_check_feature(property->dev, DRIVER_ATOMIC) &&
+			!(property->flags & DRM_MODE_PROP_IMMUTABLE))
+		return drm_atomic_get_property(obj, property, val);
+
 	for (i = 0; i < obj->properties->count; i++) {
 		if (obj->properties->properties[i] == property) {
 			*val = obj->properties->values[i];
@@ -4413,7 +4430,7 @@ int drm_mode_obj_get_properties_ioctl(struct drm_device *dev, void *data,
 		goto out;
 	}
 
-	ret = get_properties(obj,
+	ret = get_properties(obj, file_priv->atomic,
 			(uint32_t __user *)(unsigned long)(arg->props_ptr),
 			(uint64_t __user *)(unsigned long)(arg->prop_values_ptr),
 			&arg->count_props);

drivers/gpu/drm/drm_drv.c

@@ -40,15 +40,19 @@
 unsigned int drm_debug = 0;	/* 1 to enable debug output */
 EXPORT_SYMBOL(drm_debug);
 
+bool drm_atomic = 0;
+
 MODULE_AUTHOR(CORE_AUTHOR);
 MODULE_DESCRIPTION(CORE_DESC);
 MODULE_LICENSE("GPL and additional rights");
 MODULE_PARM_DESC(debug, "Enable debug output");
+MODULE_PARM_DESC(atomic, "Enable experimental atomic KMS API");
 MODULE_PARM_DESC(vblankoffdelay, "Delay until vblank irq auto-disable [msecs] (0: never disable, <0: disable immediately)");
 MODULE_PARM_DESC(timestamp_precision_usec, "Max. error on timestamps [usecs]");
 MODULE_PARM_DESC(timestamp_monotonic, "Use monotonic timestamps");
 
 module_param_named(debug, drm_debug, int, 0600);
+module_param_named_unsafe(atomic, drm_atomic, bool, 0600);
 
 static DEFINE_SPINLOCK(drm_minor_lock);
 static struct idr drm_minors_idr;

drivers/gpu/drm/drm_ioctl.c

@@ -345,6 +345,16 @@ drm_setclientcap(struct drm_device *dev, void *data, struct drm_file *file_priv)
 			return -EINVAL;
 		file_priv->universal_planes = req->value;
 		break;
+	case DRM_CLIENT_CAP_ATOMIC:
+		/* for now, hide behind experimental drm.atomic moduleparam */
+		if (!drm_atomic)
+			return -EINVAL;
+		if (!drm_core_check_feature(dev, DRIVER_ATOMIC))
+			return -EINVAL;
+		if (req->value > 1)
+			return -EINVAL;
+		file_priv->atomic = req->value;
+		break;
 	default:
 		return -EINVAL;
 	}

include/drm/drmP.h

@@ -143,6 +143,7 @@ void drm_err(const char *format, ...);
 #define DRIVER_MODESET     0x2000
 #define DRIVER_PRIME       0x4000
 #define DRIVER_RENDER      0x8000
+#define DRIVER_ATOMIC      0x10000
 
 /***********************************************************************/
 /** \name Macros to make printk easier */
@@ -283,6 +284,8 @@ struct drm_file {
 	 * in the plane list
 	 */
 	unsigned universal_planes:1;
+	/* true if client understands atomic properties */
+	unsigned atomic:1;
 
 	struct pid *pid;
 	kuid_t uid;
@@ -950,6 +953,7 @@ extern void drm_master_put(struct drm_master **master);
 extern void drm_put_dev(struct drm_device *dev);
 extern void drm_unplug_dev(struct drm_device *dev);
 extern unsigned int drm_debug;
+extern bool drm_atomic;
 
 				/* Debugfs support */
 #if defined(CONFIG_DEBUG_FS)

include/drm/drm_atomic.h

@@ -63,6 +63,9 @@ int drm_atomic_connector_get_property(struct drm_connector *connector,
 		const struct drm_connector_state *state,
 		struct drm_property *property, uint64_t *val);
 
+int drm_atomic_get_property(struct drm_mode_object *obj,
+			   struct drm_property *property, uint64_t *val);
+
 int __must_check
 drm_atomic_set_crtc_for_plane(struct drm_plane_state *plane_state,
 			      struct drm_crtc *crtc);

include/drm/drm_crtc.h

@@ -63,7 +63,7 @@ struct drm_mode_object {
 
 #define DRM_OBJECT_MAX_PROPERTY 24
 struct drm_object_properties {
-	int count;
+	int count, atomic_count;
 	/* NOTE: if we ever start dynamically destroying properties (ie.
 	 * not at drm_mode_config_cleanup() time), then we'd have to do
 	 * a better job of detaching property from mode objects to avoid

include/uapi/drm/drm.h

@@ -654,6 +654,13 @@ struct drm_get_cap {
  */
 #define DRM_CLIENT_CAP_UNIVERSAL_PLANES  2
 
+/**
+ * DRM_CLIENT_CAP_ATOMIC
+ *
+ * If set to 1, the DRM core will expose atomic properties to userspace
+ */
+#define DRM_CLIENT_CAP_ATOMIC	3
+
 /** DRM_IOCTL_SET_CLIENT_CAP ioctl argument type */
 struct drm_set_client_cap {
 	__u64 capability;

include/uapi/drm/drm_mode.h

@@ -272,6 +272,13 @@ struct drm_mode_get_connector {
 #define DRM_MODE_PROP_OBJECT		DRM_MODE_PROP_TYPE(1)
 #define DRM_MODE_PROP_SIGNED_RANGE	DRM_MODE_PROP_TYPE(2)
 
+/* the PROP_ATOMIC flag is used to hide properties from userspace that
+ * is not aware of atomic properties.  This is mostly to work around
+ * older userspace (DDX drivers) that read/write each prop they find,
+ * witout being aware that this could be triggering a lengthy modeset.
+ */
+#define DRM_MODE_PROP_ATOMIC        0x80000000
+
 struct drm_mode_property_enum {
 	__u64 value;
 	char name[DRM_PROP_NAME_LEN];