Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-2.6

[linux-2.6-omap-h63xx.git] / include / linux / virtio_config.h

diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 475572e976feccbb27c9138a08db76e92d3c0640..50db245c81ad94f1131d88b512c100219475717b 100644 (file)
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -20,11 +20,6 @@
 
 /**
  * virtio_config_ops - operations for configuring a virtio device
- * @feature: search for a feature in this config
- *     vdev: the virtio_device
- *     bit: the feature bit
- *     Returns true if the feature is supported.  Acknowledges the feature
- *     so the host can see it.
  * @get: read the value of a configuration field
  *     vdev: the virtio_device
  *     offset: the offset of the configuration field
@@ -50,10 +45,15 @@
  *     callback: the virqtueue callback
  *     Returns the new virtqueue or ERR_PTR() (eg. -ENOENT).
  * @del_vq: free a virtqueue found by find_vq().
+ * @get_features: get the array of feature bits for this device.
+ *     vdev: the virtio_device
+ *     Returns the first 32 feature bits (all we currently need).
+ * @set_features: confirm what device features we'll be using.
+ *     vdev: the virtio_device
+ *     feature: the first 32 feature bits
  */
 struct virtio_config_ops
 {
-       bool (*feature)(struct virtio_device *vdev, unsigned bit);
        void (*get)(struct virtio_device *vdev, unsigned offset,
                    void *buf, unsigned len);
        void (*set)(struct virtio_device *vdev, unsigned offset,
@@ -65,8 +65,30 @@ struct virtio_config_ops
                                     unsigned index,
                                     void (*callback)(struct virtqueue *));
        void (*del_vq)(struct virtqueue *vq);
+       u32 (*get_features)(struct virtio_device *vdev);
+       void (*set_features)(struct virtio_device *vdev, u32 features);
 };
 
+/* If driver didn't advertise the feature, it will never appear. */
+void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
+                                        unsigned int fbit);
+
+/**
+ * virtio_has_feature - helper to determine if this device has this feature.
+ * @vdev: the device
+ * @fbit: the feature bit
+ */
+static inline bool virtio_has_feature(const struct virtio_device *vdev,
+                                     unsigned int fbit)
+{
+       /* Did you forget to fix assumptions on max features? */
+       if (__builtin_constant_p(fbit))
+               BUILD_BUG_ON(fbit >= 32);
+
+       virtio_check_driver_offered_feature(vdev, fbit);
+       return test_bit(fbit, vdev->features);
+}
+
 /**
  * virtio_config_val - look for a feature and get a virtio config entry.
  * @vdev: the virtio device
@@ -84,7 +106,7 @@ static inline int virtio_config_buf(struct virtio_device *vdev,
                                    unsigned int offset,
                                    void *buf, unsigned len)
 {
-       if (!vdev->config->feature(vdev, fbit))
+       if (!virtio_has_feature(vdev, fbit))
                return -ENOENT;
 
        vdev->config->get(vdev, offset, buf, len);