drm: Introduce drm_dev_set_unique()

Add a helper function that allows drivers to statically set the unique
name of the device. This will allow platform and USB drivers to get rid
of their DRM bus implementations and directly use drm_dev_alloc() and
drm_dev_register().

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
(cherry picked from commit ca8e2ad71013049bc88a10b11d83712bfe56cdd4)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 89ba74b..22f50f8 100644 (file)
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -127,13 +127,25 @@ static int drm_set_busid(struct drm_device *dev, struct drm_file *file_priv)
        if (master->unique != NULL)
                drm_unset_busid(dev, master);
 
-       ret = dev->driver->bus->set_busid(dev, master);
-       if (ret)
-               goto err;
+       if (dev->driver->bus && dev->driver->bus->set_busid) {
+               ret = dev->driver->bus->set_busid(dev, master);
+               if (ret) {
+                       drm_unset_busid(dev, master);
+                       return ret;
+               }
+       } else {
+               if (WARN(dev->unique == NULL,
+                        "No drm_bus.set_busid() implementation provided by "
+                        "%ps. Use drm_dev_set_unique() to set the unique "
+                        "name explicitly.", dev->driver))
+                       return -EINVAL;
+
+               master->unique = kstrdup(dev->unique, GFP_KERNEL);
+               if (master->unique)
+                       master->unique_len = strlen(dev->unique);
+       }
+
        return 0;
-err:
-       drm_unset_busid(dev, master);
-       return ret;
 }
 
 /**

diff --git a/drivers/gpu/drm/drm_stub.c b/drivers/gpu/drm/drm_stub.c
index fb3cb57..c7fc68d 100644 (file)
--- a/drivers/gpu/drm/drm_stub.c
+++ b/drivers/gpu/drm/drm_stub.c
@@ -593,6 +593,7 @@ void drm_dev_free(struct drm_device *dev)
        drm_fs_inode_free(dev->anon_inode);
 
        mutex_destroy(&dev->master_mutex);
+       kfree(dev->unique);
        kfree(dev);
 }
 EXPORT_SYMBOL(drm_dev_free);
@@ -688,3 +689,28 @@ void drm_dev_unregister(struct drm_device *dev)
        drm_unplug_minor(dev->primary);
 }
 EXPORT_SYMBOL(drm_dev_unregister);
+
+/**
+ * drm_dev_set_unique - Set the unique name of a DRM device
+ * @dev: device of which to set the unique name
+ * @fmt: format string for unique name
+ *
+ * Sets the unique name of a DRM device using the specified format string and
+ * a variable list of arguments. Drivers can use this at driver probe time if
+ * the unique name of the devices they drive is static.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int drm_dev_set_unique(struct drm_device *dev, const char *fmt, ...)
+{
+       va_list ap;
+
+       kfree(dev->unique);
+
+       va_start(ap, fmt);
+       dev->unique = kvasprintf(GFP_KERNEL, fmt, ap);
+       va_end(ap);
+
+       return dev->unique ? 0 : -ENOMEM;
+}
+EXPORT_SYMBOL(drm_dev_set_unique);

diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 258bf4a..134ca01 100644 (file)
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1108,6 +1108,7 @@ struct drm_device {
        struct drm_minor *render;               /**< Render node */
        atomic_t unplugged;                     /**< Flag whether dev is dead */
        struct inode *anon_inode;               /**< inode for private address-space */
+       char *unique;                           /**< unique name of the device */
        /*@} */
 
        /** \name Locks */
@@ -1680,6 +1681,7 @@ struct drm_device *drm_dev_alloc(struct drm_driver *driver,
 void drm_dev_free(struct drm_device *dev);
 int drm_dev_register(struct drm_device *dev, unsigned long flags);
 void drm_dev_unregister(struct drm_device *dev);
+int drm_dev_set_unique(struct drm_device *dev, const char *fmt, ...);
 
 struct drm_minor *drm_minor_acquire(unsigned int minor_id);
 void drm_minor_release(struct drm_minor *minor);