#ifndef _LINUX_VIRTIO_CONFIG_H
#define _LINUX_VIRTIO_CONFIG_H
+/* This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
+ * anyone can use the definitions to implement compatible drivers/servers. */
+
/* Virtio devices use a standardized configuration space to define their
* features and pass configuration information, but each implementation can
* store and access that space differently. */
/* We've given up on this device. */
#define VIRTIO_CONFIG_S_FAILED 0x80
+/* Some virtio feature bits (currently bits 28 through 31) are reserved for the
+ * transport being used (eg. virtio_ring), the rest are per-device feature
+ * bits. */
+#define VIRTIO_TRANSPORT_F_START 28
+#define VIRTIO_TRANSPORT_F_END 32
+
+/* Do we get callbacks when the ring is completely used, even if we've
+ * suppressed them? */
+#define VIRTIO_F_NOTIFY_ON_EMPTY 24
+
#ifdef __KERNEL__
-struct virtio_device;
+#include <linux/err.h>
+#include <linux/virtio.h>
/**
* 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
* buf: the buffer to write the field value into.
* len: the length of the buffer
- * Note that contents are conventionally little-endian.
* @set: write the value of a configuration field
* vdev: the virtio_device
* offset: the offset of the configuration field
* buf: the buffer to read the field value from.
* len: the length of the buffer
- * Note that contents are conventionally little-endian.
* @get_status: read the status byte
* vdev: the virtio_device
* Returns the status byte
* @set_status: write the status byte
* vdev: the virtio_device
* status: the new status byte
- * @find_vq: find a virtqueue and instantiate it.
+ * @request_vqs: request the specified number of virtqueues
+ * vdev: the virtio_device
+ * max_vqs: the max number of virtqueues we want
+ * If supplied, must call before any virtqueues are instantiated.
+ * To modify the max number of virtqueues after request_vqs has been
+ * called, call free_vqs and then request_vqs with a new value.
+ * @free_vqs: cleanup resources allocated by request_vqs
+ * vdev: the virtio_device
+ * If supplied, must call after all virtqueues have been deleted.
+ * @reset: reset the device
+ * vdev: the virtio device
+ * After this, status and feature negotiation must be done again
+ * @find_vqs: find virtqueues and instantiate them.
+ * vdev: the virtio_device
+ * nvqs: the number of virtqueues to find
+ * vqs: on success, includes new virtqueues
+ * callbacks: array of callbacks, for each virtqueue
+ * names: array of virtqueue names (mainly for debugging)
+ * Returns 0 on success or error status
+ * @del_vqs: free virtqueues found by find_vqs().
+ * @get_features: get the array of feature bits for this device.
* vdev: the virtio_device
- * index: the 0-based virtqueue number in case there's more than one.
- * callback: the virqtueue callback
- * Returns the new virtqueue or ERR_PTR() (eg. -ENOENT).
- * @del_vq: free a virtqueue found by find_vq().
+ * Returns the first 32 feature bits (all we currently need).
+ * @finalize_features: confirm what device features we'll be using.
+ * vdev: the virtio_device
+ * This gives the final feature bits for the device: it can change
+ * the dev->feature bits if it wants.
*/
-struct virtio_config_ops
-{
- bool (*feature)(struct virtio_device *vdev, unsigned bit);
+typedef void vq_callback_t(struct virtqueue *);
+struct virtio_config_ops {
void (*get)(struct virtio_device *vdev, unsigned offset,
void *buf, unsigned len);
void (*set)(struct virtio_device *vdev, unsigned offset,
const void *buf, unsigned len);
u8 (*get_status)(struct virtio_device *vdev);
void (*set_status)(struct virtio_device *vdev, u8 status);
- struct virtqueue *(*find_vq)(struct virtio_device *vdev,
- unsigned index,
- bool (*callback)(struct virtqueue *));
- void (*del_vq)(struct virtqueue *vq);
+ void (*reset)(struct virtio_device *vdev);
+ int (*find_vqs)(struct virtio_device *, unsigned nvqs,
+ struct virtqueue *vqs[],
+ vq_callback_t *callbacks[],
+ const char *names[]);
+ void (*del_vqs)(struct virtio_device *);
+ u32 (*get_features)(struct virtio_device *vdev);
+ void (*finalize_features)(struct virtio_device *vdev);
};
+/* 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_config_val - look for a feature and get a single virtio config.
- * @vdev: the virtio device
+ * virtio_has_feature - helper to determine if this device has this feature.
+ * @vdev: the device
* @fbit: the feature bit
- * @offset: the type to search for.
- * @val: a pointer to the value to fill in.
- *
- * The return value is -ENOENT if the feature doesn't exist. Otherwise
- * the value is endian-corrected and returned in v. */
-#define virtio_config_val(vdev, fbit, offset, v) ({ \
- int _err; \
- if ((vdev)->config->feature((vdev), (fbit))) { \
- __virtio_config_val((vdev), (offset), (v)); \
- _err = 0; \
- } else \
- _err = -ENOENT; \
- _err; \
-})
+ */
+static inline bool virtio_has_feature(const struct virtio_device *vdev,
+ unsigned int fbit)
+{
+ /* Did you forget to fix assumptions on max features? */
+ MAYBE_BUILD_BUG_ON(fbit >= 32);
+
+ if (fbit < VIRTIO_TRANSPORT_F_START)
+ virtio_check_driver_offered_feature(vdev, fbit);
+
+ return test_bit(fbit, vdev->features);
+}
/**
- * __virtio_config_val - get a single virtio config without feature check.
+ * virtio_config_val - look for a feature and get a virtio config entry.
* @vdev: the virtio device
+ * @fbit: the feature bit
* @offset: the type to search for.
* @val: a pointer to the value to fill in.
*
- * The value is endian-corrected and returned in v. */
-#define __virtio_config_val(vdev, offset, v) do { \
- BUILD_BUG_ON(sizeof(*(v)) != 1 && sizeof(*(v)) != 2 \
- && sizeof(*(v)) != 4 && sizeof(*(v)) != 8); \
- (vdev)->config->get((vdev), (offset), (v), sizeof(*(v))); \
- switch (sizeof(*(v))) { \
- case 2: le16_to_cpus((__u16 *) v); break; \
- case 4: le32_to_cpus((__u32 *) v); break; \
- case 8: le64_to_cpus((__u64 *) v); break; \
- } \
-} while(0)
+ * The return value is -ENOENT if the feature doesn't exist. Otherwise
+ * the config value is copied into whatever is pointed to by v. */
+#define virtio_config_val(vdev, fbit, offset, v) \
+ virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v))
+
+static inline int virtio_config_buf(struct virtio_device *vdev,
+ unsigned int fbit,
+ unsigned int offset,
+ void *buf, unsigned len)
+{
+ if (!virtio_has_feature(vdev, fbit))
+ return -ENOENT;
+
+ vdev->config->get(vdev, offset, buf, len);
+ return 0;
+}
+
+static inline
+struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
+ vq_callback_t *c, const char *n)
+{
+ vq_callback_t *callbacks[] = { c };
+ const char *names[] = { n };
+ struct virtqueue *vq;
+ int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names);
+ if (err < 0)
+ return ERR_PTR(err);
+ return vq;
+}
#endif /* __KERNEL__ */
#endif /* _LINUX_VIRTIO_CONFIG_H */
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff