1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_VIRTIO_H
3 #define _LINUX_VIRTIO_H
4 /* Everything a virtio driver needs to work with any particular virtio
5  * implementation. */
6 #include <linux/types.h>
7 #include <linux/scatterlist.h>
8 #include <linux/spinlock.h>
9 #include <linux/device.h>
10 #include <linux/mod_devicetable.h>
11 #include <linux/gfp.h>
12 #include <linux/vringh.h>
13 
14 /**
15  * virtqueue - a queue to register buffers for sending or receiving.
16  * @list: the chain of virtqueues for this device
17  * @callback: the function to call when buffers are consumed (can be NULL).
18  * @name: the name of this virtqueue (mainly for debugging)
19  * @vdev: the virtio device this queue was created for.
20  * @priv: a pointer for the virtqueue implementation to use.
21  * @index: the zero-based ordinal number for this queue.
22  * @num_free: number of elements we expect to be able to fit.
23  *
24  * A note on @num_free: with indirect buffers, each buffer needs one
25  * element in the queue, otherwise a buffer will need one element per
26  * sg element.
27  */
28 struct virtqueue {
29 	struct list_head list;
30 	void (*callback)(struct virtqueue *vq);
31 	const char *name;
32 	struct virtio_device *vdev;
33 	unsigned int index;
34 	unsigned int num_free;
35 	void *priv;
36 };
37 
38 int virtqueue_add_outbuf(struct virtqueue *vq,
39 			 struct scatterlist sg[], unsigned int num,
40 			 void *data,
41 			 gfp_t gfp);
42 
43 int virtqueue_add_inbuf(struct virtqueue *vq,
44 			struct scatterlist sg[], unsigned int num,
45 			void *data,
46 			gfp_t gfp);
47 
48 int virtqueue_add_inbuf_ctx(struct virtqueue *vq,
49 			    struct scatterlist sg[], unsigned int num,
50 			    void *data,
51 			    void *ctx,
52 			    gfp_t gfp);
53 
54 int virtqueue_add_sgs(struct virtqueue *vq,
55 		      struct scatterlist *sgs[],
56 		      unsigned int out_sgs,
57 		      unsigned int in_sgs,
58 		      void *data,
59 		      gfp_t gfp);
60 
61 bool virtqueue_kick(struct virtqueue *vq);
62 
63 bool virtqueue_kick_prepare(struct virtqueue *vq);
64 
65 bool virtqueue_notify(struct virtqueue *vq);
66 
67 void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
68 
69 void *virtqueue_get_buf_ctx(struct virtqueue *vq, unsigned int *len,
70 			    void **ctx);
71 
72 void virtqueue_disable_cb(struct virtqueue *vq);
73 
74 bool virtqueue_enable_cb(struct virtqueue *vq);
75 
76 unsigned virtqueue_enable_cb_prepare(struct virtqueue *vq);
77 
78 bool virtqueue_poll(struct virtqueue *vq, unsigned);
79 
80 bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
81 
82 void *virtqueue_detach_unused_buf(struct virtqueue *vq);
83 
84 unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
85 
86 bool virtqueue_is_broken(struct virtqueue *vq);
87 
88 const struct vring *virtqueue_get_vring(struct virtqueue *vq);
89 dma_addr_t virtqueue_get_desc_addr(struct virtqueue *vq);
90 dma_addr_t virtqueue_get_avail_addr(struct virtqueue *vq);
91 dma_addr_t virtqueue_get_used_addr(struct virtqueue *vq);
92 
93 /*
94  * Legacy accessors -- in almost all cases, these are the wrong functions
95  * to use.
96  */
virtqueue_get_desc(struct virtqueue * vq)97 static inline void *virtqueue_get_desc(struct virtqueue *vq)
98 {
99 	return virtqueue_get_vring(vq)->desc;
100 }
virtqueue_get_avail(struct virtqueue * vq)101 static inline void *virtqueue_get_avail(struct virtqueue *vq)
102 {
103 	return virtqueue_get_vring(vq)->avail;
104 }
virtqueue_get_used(struct virtqueue * vq)105 static inline void *virtqueue_get_used(struct virtqueue *vq)
106 {
107 	return virtqueue_get_vring(vq)->used;
108 }
109 
110 /**
111  * virtio_device - representation of a device using virtio
112  * @index: unique position on the virtio bus
113  * @failed: saved value for VIRTIO_CONFIG_S_FAILED bit (for restore)
114  * @config_enabled: configuration change reporting enabled
115  * @config_change_pending: configuration change reported while disabled
116  * @config_lock: protects configuration change reporting
117  * @dev: underlying device.
118  * @id: the device type identification (used to match it with a driver).
119  * @config: the configuration ops for this device.
120  * @vringh_config: configuration ops for host vrings.
121  * @vqs: the list of virtqueues for this device.
122  * @features: the features supported by both driver and device.
123  * @priv: private pointer for the driver's use.
124  */
125 struct virtio_device {
126 	int index;
127 	bool failed;
128 	bool config_enabled;
129 	bool config_change_pending;
130 	spinlock_t config_lock;
131 	struct device dev;
132 	struct virtio_device_id id;
133 	const struct virtio_config_ops *config;
134 	const struct vringh_config_ops *vringh_config;
135 	struct list_head vqs;
136 	u64 features;
137 	void *priv;
138 };
139 
dev_to_virtio(struct device * _dev)140 static inline struct virtio_device *dev_to_virtio(struct device *_dev)
141 {
142 	return container_of(_dev, struct virtio_device, dev);
143 }
144 
145 void virtio_add_status(struct virtio_device *dev, unsigned int status);
146 int register_virtio_device(struct virtio_device *dev);
147 void unregister_virtio_device(struct virtio_device *dev);
148 
149 void virtio_break_device(struct virtio_device *dev);
150 
151 void virtio_config_changed(struct virtio_device *dev);
152 void virtio_config_disable(struct virtio_device *dev);
153 void virtio_config_enable(struct virtio_device *dev);
154 #ifdef CONFIG_PM_SLEEP
155 int virtio_device_freeze(struct virtio_device *dev);
156 int virtio_device_restore(struct virtio_device *dev);
157 #endif
158 
159 #define virtio_device_for_each_vq(vdev, vq) \
160 	list_for_each_entry(vq, &vdev->vqs, list)
161 
162 /**
163  * virtio_driver - operations for a virtio I/O driver
164  * @driver: underlying device driver (populate name and owner).
165  * @id_table: the ids serviced by this driver.
166  * @feature_table: an array of feature numbers supported by this driver.
167  * @feature_table_size: number of entries in the feature table array.
168  * @feature_table_legacy: same as feature_table but when working in legacy mode.
169  * @feature_table_size_legacy: number of entries in feature table legacy array.
170  * @probe: the function to call when a device is found.  Returns 0 or -errno.
171  * @scan: optional function to call after successful probe; intended
172  *    for virtio-scsi to invoke a scan.
173  * @remove: the function to call when a device is removed.
174  * @config_changed: optional function to call when the device configuration
175  *    changes; may be called in interrupt context.
176  * @freeze: optional function to call during suspend/hibernation.
177  * @restore: optional function to call on resume.
178  */
179 struct virtio_driver {
180 	struct device_driver driver;
181 	const struct virtio_device_id *id_table;
182 	const unsigned int *feature_table;
183 	unsigned int feature_table_size;
184 	const unsigned int *feature_table_legacy;
185 	unsigned int feature_table_size_legacy;
186 	int (*validate)(struct virtio_device *dev);
187 	int (*probe)(struct virtio_device *dev);
188 	void (*scan)(struct virtio_device *dev);
189 	void (*remove)(struct virtio_device *dev);
190 	void (*config_changed)(struct virtio_device *dev);
191 #ifdef CONFIG_PM
192 	int (*freeze)(struct virtio_device *dev);
193 	int (*restore)(struct virtio_device *dev);
194 #endif
195 };
196 
drv_to_virtio(struct device_driver * drv)197 static inline struct virtio_driver *drv_to_virtio(struct device_driver *drv)
198 {
199 	return container_of(drv, struct virtio_driver, driver);
200 }
201 
202 int register_virtio_driver(struct virtio_driver *drv);
203 void unregister_virtio_driver(struct virtio_driver *drv);
204 
205 /* module_virtio_driver() - Helper macro for drivers that don't do
206  * anything special in module init/exit.  This eliminates a lot of
207  * boilerplate.  Each module may only use this macro once, and
208  * calling it replaces module_init() and module_exit()
209  */
210 #define module_virtio_driver(__virtio_driver) \
211 	module_driver(__virtio_driver, register_virtio_driver, \
212 			unregister_virtio_driver)
213 #endif /* _LINUX_VIRTIO_H */
214