237 lines
6.5 KiB
C
237 lines
6.5 KiB
C
#include <linux/virtio.h>
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#include <linux/spinlock.h>
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#include <linux/virtio_config.h>
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/* Unique numbering for virtio devices. */
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static unsigned int dev_index;
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static ssize_t device_show(struct device *_d,
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struct device_attribute *attr, char *buf)
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{
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struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
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return sprintf(buf, "%hu", dev->id.device);
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}
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static ssize_t vendor_show(struct device *_d,
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struct device_attribute *attr, char *buf)
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{
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struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
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return sprintf(buf, "%hu", dev->id.vendor);
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}
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static ssize_t status_show(struct device *_d,
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struct device_attribute *attr, char *buf)
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{
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struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
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return sprintf(buf, "0x%08x", dev->config->get_status(dev));
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}
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static ssize_t modalias_show(struct device *_d,
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struct device_attribute *attr, char *buf)
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{
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struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
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return sprintf(buf, "virtio:d%08Xv%08X\n",
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dev->id.device, dev->id.vendor);
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}
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static ssize_t features_show(struct device *_d,
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struct device_attribute *attr, char *buf)
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{
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struct virtio_device *dev = container_of(_d, struct virtio_device, dev);
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unsigned int i;
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ssize_t len = 0;
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/* We actually represent this as a bitstring, as it could be
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* arbitrary length in future. */
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for (i = 0; i < ARRAY_SIZE(dev->features)*BITS_PER_LONG; i++)
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len += sprintf(buf+len, "%c",
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test_bit(i, dev->features) ? '1' : '0');
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len += sprintf(buf+len, "\n");
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return len;
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}
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static struct device_attribute virtio_dev_attrs[] = {
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__ATTR_RO(device),
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__ATTR_RO(vendor),
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__ATTR_RO(status),
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__ATTR_RO(modalias),
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__ATTR_RO(features),
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__ATTR_NULL
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};
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static inline int virtio_id_match(const struct virtio_device *dev,
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const struct virtio_device_id *id)
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{
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if (id->device != dev->id.device && id->device != VIRTIO_DEV_ANY_ID)
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return 0;
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return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor == dev->id.vendor;
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}
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/* This looks through all the IDs a driver claims to support. If any of them
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* match, we return 1 and the kernel will call virtio_dev_probe(). */
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static int virtio_dev_match(struct device *_dv, struct device_driver *_dr)
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{
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unsigned int i;
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struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
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const struct virtio_device_id *ids;
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ids = container_of(_dr, struct virtio_driver, driver)->id_table;
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for (i = 0; ids[i].device; i++)
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if (virtio_id_match(dev, &ids[i]))
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return 1;
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return 0;
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}
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static int virtio_uevent(struct device *_dv, struct kobj_uevent_env *env)
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{
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struct virtio_device *dev = container_of(_dv,struct virtio_device,dev);
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return add_uevent_var(env, "MODALIAS=virtio:d%08Xv%08X",
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dev->id.device, dev->id.vendor);
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}
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static void add_status(struct virtio_device *dev, unsigned status)
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{
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dev->config->set_status(dev, dev->config->get_status(dev) | status);
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}
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void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
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unsigned int fbit)
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{
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unsigned int i;
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struct virtio_driver *drv = container_of(vdev->dev.driver,
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struct virtio_driver, driver);
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for (i = 0; i < drv->feature_table_size; i++)
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if (drv->feature_table[i] == fbit)
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return;
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BUG();
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}
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EXPORT_SYMBOL_GPL(virtio_check_driver_offered_feature);
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static int virtio_dev_probe(struct device *_d)
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{
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int err, i;
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struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
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struct virtio_driver *drv = container_of(dev->dev.driver,
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struct virtio_driver, driver);
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u32 device_features;
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/* We have a driver! */
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add_status(dev, VIRTIO_CONFIG_S_DRIVER);
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/* Figure out what features the device supports. */
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device_features = dev->config->get_features(dev);
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/* Features supported by both device and driver into dev->features. */
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memset(dev->features, 0, sizeof(dev->features));
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for (i = 0; i < drv->feature_table_size; i++) {
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unsigned int f = drv->feature_table[i];
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BUG_ON(f >= 32);
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if (device_features & (1 << f))
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set_bit(f, dev->features);
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}
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/* Transport features always preserved to pass to finalize_features. */
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for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
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if (device_features & (1 << i))
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set_bit(i, dev->features);
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dev->config->finalize_features(dev);
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err = drv->probe(dev);
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if (err)
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add_status(dev, VIRTIO_CONFIG_S_FAILED);
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else
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add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
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return err;
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}
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static int virtio_dev_remove(struct device *_d)
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{
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struct virtio_device *dev = container_of(_d,struct virtio_device,dev);
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struct virtio_driver *drv = container_of(dev->dev.driver,
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struct virtio_driver, driver);
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drv->remove(dev);
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/* Driver should have reset device. */
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BUG_ON(dev->config->get_status(dev));
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/* Acknowledge the device's existence again. */
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add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
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return 0;
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}
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static struct bus_type virtio_bus = {
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.name = "virtio",
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.match = virtio_dev_match,
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.dev_attrs = virtio_dev_attrs,
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.uevent = virtio_uevent,
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.probe = virtio_dev_probe,
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.remove = virtio_dev_remove,
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};
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int register_virtio_driver(struct virtio_driver *driver)
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{
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/* Catch this early. */
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BUG_ON(driver->feature_table_size && !driver->feature_table);
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driver->driver.bus = &virtio_bus;
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return driver_register(&driver->driver);
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}
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EXPORT_SYMBOL_GPL(register_virtio_driver);
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void unregister_virtio_driver(struct virtio_driver *driver)
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{
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driver_unregister(&driver->driver);
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}
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EXPORT_SYMBOL_GPL(unregister_virtio_driver);
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int register_virtio_device(struct virtio_device *dev)
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{
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int err;
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dev->dev.bus = &virtio_bus;
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/* Assign a unique device index and hence name. */
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dev->index = dev_index++;
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dev_set_name(&dev->dev, "virtio%u", dev->index);
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/* We always start by resetting the device, in case a previous
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* driver messed it up. This also tests that code path a little. */
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dev->config->reset(dev);
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/* Acknowledge that we've seen the device. */
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add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
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INIT_LIST_HEAD(&dev->vqs);
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/* device_register() causes the bus infrastructure to look for a
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* matching driver. */
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err = device_register(&dev->dev);
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if (err)
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add_status(dev, VIRTIO_CONFIG_S_FAILED);
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return err;
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}
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EXPORT_SYMBOL_GPL(register_virtio_device);
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void unregister_virtio_device(struct virtio_device *dev)
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{
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device_unregister(&dev->dev);
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}
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EXPORT_SYMBOL_GPL(unregister_virtio_device);
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static int virtio_init(void)
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{
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if (bus_register(&virtio_bus) != 0)
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panic("virtio bus registration failed");
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return 0;
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}
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static void __exit virtio_exit(void)
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{
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bus_unregister(&virtio_bus);
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}
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core_initcall(virtio_init);
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module_exit(virtio_exit);
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MODULE_LICENSE("GPL");
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