| 1 | #ifndef _LINUX_VIRTIO_CONFIG_H |
| 2 | #define _LINUX_VIRTIO_CONFIG_H |
| 3 | |
| 4 | #include <linux/err.h> |
| 5 | #include <linux/bug.h> |
| 6 | #include <linux/virtio.h> |
| 7 | #include <uapi/linux/virtio_config.h> |
| 8 | |
| 9 | /** |
| 10 | * virtio_config_ops - operations for configuring a virtio device |
| 11 | * @get: read the value of a configuration field |
| 12 | * vdev: the virtio_device |
| 13 | * offset: the offset of the configuration field |
| 14 | * buf: the buffer to write the field value into. |
| 15 | * len: the length of the buffer |
| 16 | * @set: write the value of a configuration field |
| 17 | * vdev: the virtio_device |
| 18 | * offset: the offset of the configuration field |
| 19 | * buf: the buffer to read the field value from. |
| 20 | * len: the length of the buffer |
| 21 | * @get_status: read the status byte |
| 22 | * vdev: the virtio_device |
| 23 | * Returns the status byte |
| 24 | * @set_status: write the status byte |
| 25 | * vdev: the virtio_device |
| 26 | * status: the new status byte |
| 27 | * @reset: reset the device |
| 28 | * vdev: the virtio device |
| 29 | * After this, status and feature negotiation must be done again |
| 30 | * Device must not be reset from its vq/config callbacks, or in |
| 31 | * parallel with being added/removed. |
| 32 | * @find_vqs: find virtqueues and instantiate them. |
| 33 | * vdev: the virtio_device |
| 34 | * nvqs: the number of virtqueues to find |
| 35 | * vqs: on success, includes new virtqueues |
| 36 | * callbacks: array of callbacks, for each virtqueue |
| 37 | * include a NULL entry for vqs that do not need a callback |
| 38 | * names: array of virtqueue names (mainly for debugging) |
| 39 | * include a NULL entry for vqs unused by driver |
| 40 | * Returns 0 on success or error status |
| 41 | * @del_vqs: free virtqueues found by find_vqs(). |
| 42 | * @get_features: get the array of feature bits for this device. |
| 43 | * vdev: the virtio_device |
| 44 | * Returns the first 32 feature bits (all we currently need). |
| 45 | * @finalize_features: confirm what device features we'll be using. |
| 46 | * vdev: the virtio_device |
| 47 | * This gives the final feature bits for the device: it can change |
| 48 | * the dev->feature bits if it wants. |
| 49 | * @bus_name: return the bus name associated with the device |
| 50 | * vdev: the virtio_device |
| 51 | * This returns a pointer to the bus name a la pci_name from which |
| 52 | * the caller can then copy. |
| 53 | * @set_vq_affinity: set the affinity for a virtqueue. |
| 54 | */ |
| 55 | typedef void vq_callback_t(struct virtqueue *); |
| 56 | struct virtio_config_ops { |
| 57 | void (*get)(struct virtio_device *vdev, unsigned offset, |
| 58 | void *buf, unsigned len); |
| 59 | void (*set)(struct virtio_device *vdev, unsigned offset, |
| 60 | const void *buf, unsigned len); |
| 61 | u8 (*get_status)(struct virtio_device *vdev); |
| 62 | void (*set_status)(struct virtio_device *vdev, u8 status); |
| 63 | void (*reset)(struct virtio_device *vdev); |
| 64 | int (*find_vqs)(struct virtio_device *, unsigned nvqs, |
| 65 | struct virtqueue *vqs[], |
| 66 | vq_callback_t *callbacks[], |
| 67 | const char *names[]); |
| 68 | void (*del_vqs)(struct virtio_device *); |
| 69 | u32 (*get_features)(struct virtio_device *vdev); |
| 70 | void (*finalize_features)(struct virtio_device *vdev); |
| 71 | const char *(*bus_name)(struct virtio_device *vdev); |
| 72 | int (*set_vq_affinity)(struct virtqueue *vq, int cpu); |
| 73 | }; |
| 74 | |
| 75 | /* If driver didn't advertise the feature, it will never appear. */ |
| 76 | void virtio_check_driver_offered_feature(const struct virtio_device *vdev, |
| 77 | unsigned int fbit); |
| 78 | |
| 79 | /** |
| 80 | * virtio_has_feature - helper to determine if this device has this feature. |
| 81 | * @vdev: the device |
| 82 | * @fbit: the feature bit |
| 83 | */ |
| 84 | static inline bool virtio_has_feature(const struct virtio_device *vdev, |
| 85 | unsigned int fbit) |
| 86 | { |
| 87 | /* Did you forget to fix assumptions on max features? */ |
| 88 | if (__builtin_constant_p(fbit)) |
| 89 | BUILD_BUG_ON(fbit >= 32); |
| 90 | else |
| 91 | BUG_ON(fbit >= 32); |
| 92 | |
| 93 | if (fbit < VIRTIO_TRANSPORT_F_START) |
| 94 | virtio_check_driver_offered_feature(vdev, fbit); |
| 95 | |
| 96 | return test_bit(fbit, vdev->features); |
| 97 | } |
| 98 | |
| 99 | /** |
| 100 | * virtio_config_val - look for a feature and get a virtio config entry. |
| 101 | * @vdev: the virtio device |
| 102 | * @fbit: the feature bit |
| 103 | * @offset: the type to search for. |
| 104 | * @v: a pointer to the value to fill in. |
| 105 | * |
| 106 | * The return value is -ENOENT if the feature doesn't exist. Otherwise |
| 107 | * the config value is copied into whatever is pointed to by v. */ |
| 108 | #define virtio_config_val(vdev, fbit, offset, v) \ |
| 109 | virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v)) |
| 110 | |
| 111 | #define virtio_config_val_len(vdev, fbit, offset, v, len) \ |
| 112 | virtio_config_buf((vdev), (fbit), (offset), (v), (len)) |
| 113 | |
| 114 | static inline int virtio_config_buf(struct virtio_device *vdev, |
| 115 | unsigned int fbit, |
| 116 | unsigned int offset, |
| 117 | void *buf, unsigned len) |
| 118 | { |
| 119 | if (!virtio_has_feature(vdev, fbit)) |
| 120 | return -ENOENT; |
| 121 | |
| 122 | vdev->config->get(vdev, offset, buf, len); |
| 123 | return 0; |
| 124 | } |
| 125 | |
| 126 | static inline |
| 127 | struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev, |
| 128 | vq_callback_t *c, const char *n) |
| 129 | { |
| 130 | vq_callback_t *callbacks[] = { c }; |
| 131 | const char *names[] = { n }; |
| 132 | struct virtqueue *vq; |
| 133 | int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names); |
| 134 | if (err < 0) |
| 135 | return ERR_PTR(err); |
| 136 | return vq; |
| 137 | } |
| 138 | |
| 139 | static inline |
| 140 | const char *virtio_bus_name(struct virtio_device *vdev) |
| 141 | { |
| 142 | if (!vdev->config->bus_name) |
| 143 | return "virtio"; |
| 144 | return vdev->config->bus_name(vdev); |
| 145 | } |
| 146 | |
| 147 | /** |
| 148 | * virtqueue_set_affinity - setting affinity for a virtqueue |
| 149 | * @vq: the virtqueue |
| 150 | * @cpu: the cpu no. |
| 151 | * |
| 152 | * Pay attention the function are best-effort: the affinity hint may not be set |
| 153 | * due to config support, irq type and sharing. |
| 154 | * |
| 155 | */ |
| 156 | static inline |
| 157 | int virtqueue_set_affinity(struct virtqueue *vq, int cpu) |
| 158 | { |
| 159 | struct virtio_device *vdev = vq->vdev; |
| 160 | if (vdev->config->set_vq_affinity) |
| 161 | return vdev->config->set_vq_affinity(vq, cpu); |
| 162 | return 0; |
| 163 | } |
| 164 | |
| 165 | |
| 166 | #endif /* _LINUX_VIRTIO_CONFIG_H */ |