195 lines
7.3 KiB
C
195 lines
7.3 KiB
C
#ifndef _LINUX_VIRTIO_CONFIG_H
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#define _LINUX_VIRTIO_CONFIG_H
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/* This header, excluding the #ifdef __KERNEL__ part, is BSD licensed so
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* anyone can use the definitions to implement compatible drivers/servers.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of IBM nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE. */
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/* Virtio devices use a standardized configuration space to define their
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* features and pass configuration information, but each implementation can
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* store and access that space differently. */
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#include <linux/types.h>
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/* Status byte for guest to report progress, and synchronize features. */
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/* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */
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#define VIRTIO_CONFIG_S_ACKNOWLEDGE 1
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/* We have found a driver for the device. */
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#define VIRTIO_CONFIG_S_DRIVER 2
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/* Driver has used its parts of the config, and is happy */
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#define VIRTIO_CONFIG_S_DRIVER_OK 4
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/* We've given up on this device. */
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#define VIRTIO_CONFIG_S_FAILED 0x80
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/* Some virtio feature bits (currently bits 28 through 31) are reserved for the
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* transport being used (eg. virtio_ring), the rest are per-device feature
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* bits. */
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#define VIRTIO_TRANSPORT_F_START 28
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#define VIRTIO_TRANSPORT_F_END 32
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/* Do we get callbacks when the ring is completely used, even if we've
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* suppressed them? */
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#define VIRTIO_F_NOTIFY_ON_EMPTY 24
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#ifdef __KERNEL__
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#include <linux/err.h>
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#include <linux/bug.h>
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#include <linux/virtio.h>
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/**
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* virtio_config_ops - operations for configuring a virtio device
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* @get: read the value of a configuration field
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* vdev: the virtio_device
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* offset: the offset of the configuration field
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* buf: the buffer to write the field value into.
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* len: the length of the buffer
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* @set: write the value of a configuration field
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* vdev: the virtio_device
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* offset: the offset of the configuration field
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* buf: the buffer to read the field value from.
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* len: the length of the buffer
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* @get_status: read the status byte
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* vdev: the virtio_device
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* Returns the status byte
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* @set_status: write the status byte
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* vdev: the virtio_device
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* status: the new status byte
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* @reset: reset the device
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* vdev: the virtio device
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* After this, status and feature negotiation must be done again
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* Device must not be reset from its vq/config callbacks, or in
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* parallel with being added/removed.
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* @find_vqs: find virtqueues and instantiate them.
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* vdev: the virtio_device
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* nvqs: the number of virtqueues to find
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* vqs: on success, includes new virtqueues
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* callbacks: array of callbacks, for each virtqueue
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* names: array of virtqueue names (mainly for debugging)
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* Returns 0 on success or error status
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* @del_vqs: free virtqueues found by find_vqs().
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* @get_features: get the array of feature bits for this device.
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* vdev: the virtio_device
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* Returns the first 32 feature bits (all we currently need).
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* @finalize_features: confirm what device features we'll be using.
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* vdev: the virtio_device
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* This gives the final feature bits for the device: it can change
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* the dev->feature bits if it wants.
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* @bus_name: return the bus name associated with the device
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* vdev: the virtio_device
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* This returns a pointer to the bus name a la pci_name from which
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* the caller can then copy.
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*/
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typedef void vq_callback_t(struct virtqueue *);
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struct virtio_config_ops {
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void (*get)(struct virtio_device *vdev, unsigned offset,
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void *buf, unsigned len);
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void (*set)(struct virtio_device *vdev, unsigned offset,
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const void *buf, unsigned len);
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u8 (*get_status)(struct virtio_device *vdev);
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void (*set_status)(struct virtio_device *vdev, u8 status);
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void (*reset)(struct virtio_device *vdev);
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int (*find_vqs)(struct virtio_device *, unsigned nvqs,
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struct virtqueue *vqs[],
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vq_callback_t *callbacks[],
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const char *names[]);
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void (*del_vqs)(struct virtio_device *);
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u32 (*get_features)(struct virtio_device *vdev);
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void (*finalize_features)(struct virtio_device *vdev);
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const char *(*bus_name)(struct virtio_device *vdev);
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};
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/* If driver didn't advertise the feature, it will never appear. */
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void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
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unsigned int fbit);
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/**
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* virtio_has_feature - helper to determine if this device has this feature.
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* @vdev: the device
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* @fbit: the feature bit
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*/
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static inline bool virtio_has_feature(const struct virtio_device *vdev,
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unsigned int fbit)
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{
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/* Did you forget to fix assumptions on max features? */
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if (__builtin_constant_p(fbit))
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BUILD_BUG_ON(fbit >= 32);
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else
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BUG_ON(fbit >= 32);
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if (fbit < VIRTIO_TRANSPORT_F_START)
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virtio_check_driver_offered_feature(vdev, fbit);
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return test_bit(fbit, vdev->features);
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}
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/**
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* virtio_config_val - look for a feature and get a virtio config entry.
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* @vdev: the virtio device
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* @fbit: the feature bit
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* @offset: the type to search for.
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* @v: a pointer to the value to fill in.
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*
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* The return value is -ENOENT if the feature doesn't exist. Otherwise
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* the config value is copied into whatever is pointed to by v. */
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#define virtio_config_val(vdev, fbit, offset, v) \
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virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v))
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#define virtio_config_val_len(vdev, fbit, offset, v, len) \
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virtio_config_buf((vdev), (fbit), (offset), (v), (len))
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static inline int virtio_config_buf(struct virtio_device *vdev,
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unsigned int fbit,
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unsigned int offset,
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void *buf, unsigned len)
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{
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if (!virtio_has_feature(vdev, fbit))
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return -ENOENT;
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vdev->config->get(vdev, offset, buf, len);
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return 0;
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}
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static inline
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struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
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vq_callback_t *c, const char *n)
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{
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vq_callback_t *callbacks[] = { c };
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const char *names[] = { n };
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struct virtqueue *vq;
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int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names);
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if (err < 0)
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return ERR_PTR(err);
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return vq;
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}
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static inline
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const char *virtio_bus_name(struct virtio_device *vdev)
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{
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if (!vdev->config->bus_name)
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return "virtio";
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return vdev->config->bus_name(vdev);
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}
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#endif /* __KERNEL__ */
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#endif /* _LINUX_VIRTIO_CONFIG_H */
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