drivers/virtio/virtio.c

   1 #include <linux/virtio.h>
   2 #include <linux/spinlock.h>
   3 #include <linux/virtio_config.h>
   4
   5 static ssize_t device_show(struct device *_d,
   6                            struct device_attribute *attr, char *buf)
   7 {
   8         struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
   9         return sprintf(buf, "%hu", dev->id.device);
  10 }
  11 static ssize_t vendor_show(struct device *_d,
  12                            struct device_attribute *attr, char *buf)
  13 {
  14         struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
  15         return sprintf(buf, "%hu", dev->id.vendor);
  16 }
  17 static ssize_t status_show(struct device *_d,
  18                            struct device_attribute *attr, char *buf)
  19 {
  20         struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
  21         return sprintf(buf, "0x%08x", dev->config->get_status(dev));
  22 }
  23 static ssize_t modalias_show(struct device *_d,
  24                              struct device_attribute *attr, char *buf)
  25 {
  26         struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
  27
  28         return sprintf(buf, "virtio:d%08Xv%08X\n",
  29                        dev->id.device, dev->id.vendor);
  30 }
  31 static struct device_attribute virtio_dev_attrs[] = {
  32         __ATTR_RO(device),
  33         __ATTR_RO(vendor),
  34         __ATTR_RO(status),
  35         __ATTR_RO(modalias),
  36         __ATTR_NULL
  37 };
  38
  39 static inline int virtio_id_match(const struct virtio_device *dev,
  40                                   const struct virtio_device_id *id)
  41 {
  42         if (id->device != dev->id.device)
  43                 return 0;
  44
  45         return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor != dev->id.vendor;
  46 }
  47
  48 /* This looks through all the IDs a driver claims to support.  If any of them
  49  * match, we return 1 and the kernel will call virtio_dev_probe(). */
  50 static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
  51 {
  52         unsigned int i;
  53         struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
  54         const struct virtio_device_id *ids;
  55
  56         ids = container_of(_dr, struct virtio_driver, driver)->id_table;
  57         for (i = 0; ids[i].device; i++)
  58                 if (virtio_id_match(dev, &ids[i]))
  59                         return 1;
  60         return 0;
  61 }
  62
  63 static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
  64 {
  65         struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
  66
  67         return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
  68                               dev->id.device, dev->id.vendor);
  69 }
  70
  71 static struct bus_type virtio_bus = {
  72         .name  = "virtio",
  73         .match = virtio_dev_match,
  74         .dev_attrs = virtio_dev_attrs,
  75         .uevent = virtio_uevent,
  76 };
  77
  78 static void add_status(struct virtio_device *dev, unsigned status)
  79 {
  80         dev->config->set_status(dev, dev->config->get_status(dev) | status);
  81 }
  82
  83 static int virtio_dev_probe(struct device *_d)
  84 {
  85         int err;
  86         struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
  87         struct virtio_driver *drv = container_of(dev->dev.driver,
  88                                                  struct virtio_driver, driver);
  89
  90         add_status(dev, VIRTIO_CONFIG_S_DRIVER);
  91         err = drv->probe(dev);
  92         if (err)
  93                 add_status(dev, VIRTIO_CONFIG_S_FAILED);
  94         else
  95                 add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
  96         return err;
  97 }
  98
  99 static int virtio_dev_remove(struct device *_d)
 100 {
 101         struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
 102         struct virtio_driver *drv = container_of(dev->dev.driver,
 103                                                  struct virtio_driver, driver);
 104
 105         dev->config->set_status(dev, dev->config->get_status(dev)
 106                                 & ~VIRTIO_CONFIG_S_DRIVER);
 107         drv->remove(dev);
 108         return 0;
 109 }
 110
 111 int register_virtio_driver(struct virtio_driver *driver)
 112 {
 113         driver->driver.bus = &virtio_bus;
 114         driver->driver.probe = virtio_dev_probe;
 115         driver->driver.remove = virtio_dev_remove;
 116         return driver_register(&driver->driver);
 117 }
 118 EXPORT_SYMBOL_GPL(register_virtio_driver);
 119
 120 void unregister_virtio_driver(struct virtio_driver *driver)
 121 {
 122         driver_unregister(&driver->driver);
 123 }
 124 EXPORT_SYMBOL_GPL(unregister_virtio_driver);
 125
 126 int register_virtio_device(struct virtio_device *dev)
 127 {
 128         int err;
 129
 130         dev->dev.bus = &virtio_bus;
 131         sprintf(dev->dev.bus_id, "%u", dev->index);
 132
 133         /* Acknowledge that we've seen the device. */
 134         add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
 135
 136         /* device_register() causes the bus infrastructure to look for a
 137          * matching driver. */
 138         err = device_register(&dev->dev);
 139         if (err)
 140                 add_status(dev, VIRTIO_CONFIG_S_FAILED);
 141         return err;
 142 }
 143 EXPORT_SYMBOL_GPL(register_virtio_device);
 144
 145 void unregister_virtio_device(struct virtio_device *dev)
 146 {
 147         device_unregister(&dev->dev);
 148 }
 149 EXPORT_SYMBOL_GPL(unregister_virtio_device);
 150
 151 int __virtio_config_val(struct virtio_device *vdev,
 152                         u8 type, void *val, size_t size)
 153 {
 154         void *token;
 155         unsigned int len;
 156
 157         token = vdev->config->find(vdev, type, &len);
 158         if (!token)
 159                 return -ENOENT;
 160
 161         if (len != size)
 162                 return -EIO;
 163
 164         vdev->config->get(vdev, token, val, size);
 165         return 0;
 166 }
 167 EXPORT_SYMBOL_GPL(__virtio_config_val);
 168
 169 int virtio_use_bit(struct virtio_device *vdev,
 170                    void *token, unsigned int len, unsigned int bitnum)
 171 {
 172         unsigned long bits[16];
 173
 174         /* This makes it convenient to pass-through find() results. */
 175         if (!token)
 176                 return 0;
 177
 178         /* bit not in range of this bitfield? */
 179         if (bitnum * 8 >= len / 2)
 180                 return 0;
 181
 182         /* Giant feature bitfields are silly. */
 183         BUG_ON(len > sizeof(bits));
 184         vdev->config->get(vdev, token, bits, len);
 185
 186         if (!test_bit(bitnum, bits))
 187                 return 0;
 188
 189         /* Set acknowledge bit, and write it back. */
 190         set_bit(bitnum + len * 8 / 2, bits);
 191         vdev->config->set(vdev, token, bits, len);
 192         return 1;
 193 }
 194 EXPORT_SYMBOL_GPL(virtio_use_bit);
 195
 196 static int virtio_init(void)
 197 {
 198         if (bus_register(&virtio_bus) != 0)
 199                 panic("virtio bus registration failed");
 200         return 0;
 201 }
 202 core_initcall(virtio_init);