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