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/dma-mapping.h>
13 
14 /**
15  * struct 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  * @num_max: the maximum number of elements supported by the device.
24  * @reset: vq is in reset state or not.
25  *
26  * A note on @num_free: with indirect buffers, each buffer needs one
27  * element in the queue, otherwise a buffer will need one element per
28  * sg element.
29  */
30 struct virtqueue {
31 	struct list_head list;
32 	void (*callback)(struct virtqueue *vq);
33 	const char *name;
34 	struct virtio_device *vdev;
35 	unsigned int index;
36 	unsigned int num_free;
37 	unsigned int num_max;
38 	bool reset;
39 	void *priv;
40 };
41 
42 int virtqueue_add_outbuf(struct virtqueue *vq,
43 			 struct scatterlist sg[], unsigned int num,
44 			 void *data,
45 			 gfp_t gfp);
46 
47 int virtqueue_add_inbuf(struct virtqueue *vq,
48 			struct scatterlist sg[], unsigned int num,
49 			void *data,
50 			gfp_t gfp);
51 
52 int virtqueue_add_inbuf_ctx(struct virtqueue *vq,
53 			    struct scatterlist sg[], unsigned int num,
54 			    void *data,
55 			    void *ctx,
56 			    gfp_t gfp);
57 
58 int virtqueue_add_sgs(struct virtqueue *vq,
59 		      struct scatterlist *sgs[],
60 		      unsigned int out_sgs,
61 		      unsigned int in_sgs,
62 		      void *data,
63 		      gfp_t gfp);
64 
65 struct device *virtqueue_dma_dev(struct virtqueue *vq);
66 
67 bool virtqueue_kick(struct virtqueue *vq);
68 
69 bool virtqueue_kick_prepare(struct virtqueue *vq);
70 
71 bool virtqueue_notify(struct virtqueue *vq);
72 
73 void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
74 
75 void *virtqueue_get_buf_ctx(struct virtqueue *vq, unsigned int *len,
76 			    void **ctx);
77 
78 void virtqueue_disable_cb(struct virtqueue *vq);
79 
80 bool virtqueue_enable_cb(struct virtqueue *vq);
81 
82 unsigned virtqueue_enable_cb_prepare(struct virtqueue *vq);
83 
84 int virtqueue_set_dma_premapped(struct virtqueue *_vq);
85 
86 bool virtqueue_poll(struct virtqueue *vq, unsigned);
87 
88 bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
89 
90 void *virtqueue_detach_unused_buf(struct virtqueue *vq);
91 
92 unsigned int virtqueue_get_vring_size(const struct virtqueue *vq);
93 
94 bool virtqueue_is_broken(const struct virtqueue *vq);
95 
96 const struct vring *virtqueue_get_vring(const struct virtqueue *vq);
97 dma_addr_t virtqueue_get_desc_addr(const struct virtqueue *vq);
98 dma_addr_t virtqueue_get_avail_addr(const struct virtqueue *vq);
99 dma_addr_t virtqueue_get_used_addr(const struct virtqueue *vq);
100 
101 int virtqueue_resize(struct virtqueue *vq, u32 num,
102 		     void (*recycle)(struct virtqueue *vq, void *buf));
103 int virtqueue_reset(struct virtqueue *vq,
104 		    void (*recycle)(struct virtqueue *vq, void *buf));
105 
106 /**
107  * struct virtio_device - representation of a device using virtio
108  * @index: unique position on the virtio bus
109  * @failed: saved value for VIRTIO_CONFIG_S_FAILED bit (for restore)
110  * @config_enabled: configuration change reporting enabled
111  * @config_change_pending: configuration change reported while disabled
112  * @config_lock: protects configuration change reporting
113  * @vqs_list_lock: protects @vqs.
114  * @dev: underlying device.
115  * @id: the device type identification (used to match it with a driver).
116  * @config: the configuration ops for this device.
117  * @vringh_config: configuration ops for host vrings.
118  * @vqs: the list of virtqueues for this device.
119  * @features: the features supported by both driver and device.
120  * @priv: private pointer for the driver's use.
121  */
122 struct virtio_device {
123 	int index;
124 	bool failed;
125 	bool config_enabled;
126 	bool config_change_pending;
127 	spinlock_t config_lock;
128 	spinlock_t vqs_list_lock;
129 	struct device dev;
130 	struct virtio_device_id id;
131 	const struct virtio_config_ops *config;
132 	const struct vringh_config_ops *vringh_config;
133 	struct list_head vqs;
134 	u64 features;
135 	void *priv;
136 };
137 
138 #define dev_to_virtio(_dev)	container_of_const(_dev, struct virtio_device, dev)
139 
140 void virtio_add_status(struct virtio_device *dev, unsigned int status);
141 int register_virtio_device(struct virtio_device *dev);
142 void unregister_virtio_device(struct virtio_device *dev);
143 bool is_virtio_device(struct device *dev);
144 
145 void virtio_break_device(struct virtio_device *dev);
146 void __virtio_unbreak_device(struct virtio_device *dev);
147 
148 void __virtqueue_break(struct virtqueue *_vq);
149 void __virtqueue_unbreak(struct virtqueue *_vq);
150 
151 void virtio_config_changed(struct virtio_device *dev);
152 #ifdef CONFIG_PM_SLEEP
153 int virtio_device_freeze(struct virtio_device *dev);
154 int virtio_device_restore(struct virtio_device *dev);
155 #endif
156 void virtio_reset_device(struct virtio_device *dev);
157 
158 size_t virtio_max_dma_size(const struct virtio_device *vdev);
159 
160 #define virtio_device_for_each_vq(vdev, vq) \
161 	list_for_each_entry(vq, &vdev->vqs, list)
162 
163 /**
164  * struct virtio_driver - operations for a virtio I/O driver
165  * @driver: underlying device driver (populate name and owner).
166  * @id_table: the ids serviced by this driver.
167  * @feature_table: an array of feature numbers supported by this driver.
168  * @feature_table_size: number of entries in the feature table array.
169  * @feature_table_legacy: same as feature_table but when working in legacy mode.
170  * @feature_table_size_legacy: number of entries in feature table legacy array.
171  * @validate: the function to call to validate features and config space.
172  *            Returns 0 or -errno.
173  * @probe: the function to call when a device is found.  Returns 0 or -errno.
174  * @scan: optional function to call after successful probe; intended
175  *    for virtio-scsi to invoke a scan.
176  * @remove: the function to call when a device is removed.
177  * @config_changed: optional function to call when the device configuration
178  *    changes; may be called in interrupt context.
179  * @freeze: optional function to call during suspend/hibernation.
180  * @restore: optional function to call on resume.
181  */
182 struct virtio_driver {
183 	struct device_driver driver;
184 	const struct virtio_device_id *id_table;
185 	const unsigned int *feature_table;
186 	unsigned int feature_table_size;
187 	const unsigned int *feature_table_legacy;
188 	unsigned int feature_table_size_legacy;
189 	int (*validate)(struct virtio_device *dev);
190 	int (*probe)(struct virtio_device *dev);
191 	void (*scan)(struct virtio_device *dev);
192 	void (*remove)(struct virtio_device *dev);
193 	void (*config_changed)(struct virtio_device *dev);
194 	int (*freeze)(struct virtio_device *dev);
195 	int (*restore)(struct virtio_device *dev);
196 };
197 
drv_to_virtio(struct device_driver * drv)198 static inline struct virtio_driver *drv_to_virtio(struct device_driver *drv)
199 {
200 	return container_of(drv, struct virtio_driver, driver);
201 }
202 
203 int register_virtio_driver(struct virtio_driver *drv);
204 void unregister_virtio_driver(struct virtio_driver *drv);
205 
206 /* module_virtio_driver() - Helper macro for drivers that don't do
207  * anything special in module init/exit.  This eliminates a lot of
208  * boilerplate.  Each module may only use this macro once, and
209  * calling it replaces module_init() and module_exit()
210  */
211 #define module_virtio_driver(__virtio_driver) \
212 	module_driver(__virtio_driver, register_virtio_driver, \
213 			unregister_virtio_driver)
214 
215 dma_addr_t virtqueue_dma_map_single_attrs(struct virtqueue *_vq, void *ptr, size_t size,
216 					  enum dma_data_direction dir, unsigned long attrs);
217 void virtqueue_dma_unmap_single_attrs(struct virtqueue *_vq, dma_addr_t addr,
218 				      size_t size, enum dma_data_direction dir,
219 				      unsigned long attrs);
220 int virtqueue_dma_mapping_error(struct virtqueue *_vq, dma_addr_t addr);
221 
222 bool virtqueue_dma_need_sync(struct virtqueue *_vq, dma_addr_t addr);
223 void virtqueue_dma_sync_single_range_for_cpu(struct virtqueue *_vq, dma_addr_t addr,
224 					     unsigned long offset, size_t size,
225 					     enum dma_data_direction dir);
226 void virtqueue_dma_sync_single_range_for_device(struct virtqueue *_vq, dma_addr_t addr,
227 						unsigned long offset, size_t size,
228 						enum dma_data_direction dir);
229 #endif /* _LINUX_VIRTIO_H */
230