423 lines
10 KiB
C
423 lines
10 KiB
C
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#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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#include <linux/module.h>
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#include <linux/idr.h>
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#include <uapi/linux/virtio_ids.h>
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/* Unique numbering for virtio devices. */
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static DEFINE_IDA(virtio_index_ida);
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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 = dev_to_virtio(_d);
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return sprintf(buf, "0x%04x\n", dev->id.device);
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}
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static DEVICE_ATTR_RO(device);
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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 = dev_to_virtio(_d);
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return sprintf(buf, "0x%04x\n", dev->id.vendor);
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}
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static DEVICE_ATTR_RO(vendor);
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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 = dev_to_virtio(_d);
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return sprintf(buf, "0x%08x\n", dev->config->get_status(dev));
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}
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static DEVICE_ATTR_RO(status);
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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 = dev_to_virtio(_d);
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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 DEVICE_ATTR_RO(modalias);
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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 = dev_to_virtio(_d);
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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 < sizeof(dev->features)*8; i++)
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len += sprintf(buf+len, "%c",
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__virtio_test_bit(dev, i) ? '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 DEVICE_ATTR_RO(features);
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static struct attribute *virtio_dev_attrs[] = {
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&dev_attr_device.attr,
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&dev_attr_vendor.attr,
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&dev_attr_status.attr,
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&dev_attr_modalias.attr,
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&dev_attr_features.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(virtio_dev);
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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 = dev_to_virtio(_dv);
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const struct virtio_device_id *ids;
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ids = drv_to_virtio(_dr)->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 = dev_to_virtio(_dv);
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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 = drv_to_virtio(vdev->dev.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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if (drv->feature_table_legacy) {
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for (i = 0; i < drv->feature_table_size_legacy; i++)
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if (drv->feature_table_legacy[i] == fbit)
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return;
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}
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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 void __virtio_config_changed(struct virtio_device *dev)
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{
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struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
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if (!dev->config_enabled)
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dev->config_change_pending = true;
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else if (drv && drv->config_changed)
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drv->config_changed(dev);
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}
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void virtio_config_changed(struct virtio_device *dev)
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{
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unsigned long flags;
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spin_lock_irqsave(&dev->config_lock, flags);
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__virtio_config_changed(dev);
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spin_unlock_irqrestore(&dev->config_lock, flags);
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}
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EXPORT_SYMBOL_GPL(virtio_config_changed);
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static void virtio_config_disable(struct virtio_device *dev)
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{
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spin_lock_irq(&dev->config_lock);
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dev->config_enabled = false;
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spin_unlock_irq(&dev->config_lock);
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}
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static void virtio_config_enable(struct virtio_device *dev)
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{
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spin_lock_irq(&dev->config_lock);
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dev->config_enabled = true;
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if (dev->config_change_pending)
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__virtio_config_changed(dev);
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dev->config_change_pending = false;
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spin_unlock_irq(&dev->config_lock);
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}
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static int virtio_finalize_features(struct virtio_device *dev)
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{
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int ret = dev->config->finalize_features(dev);
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unsigned status;
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if (ret)
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return ret;
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if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
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return 0;
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add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
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status = dev->config->get_status(dev);
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if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
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dev_err(&dev->dev, "virtio: device refuses features: %x\n",
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status);
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return -ENODEV;
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}
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return 0;
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}
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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 = dev_to_virtio(_d);
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struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
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u64 device_features;
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u64 driver_features;
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u64 driver_features_legacy;
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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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/* Figure out what features the driver supports. */
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driver_features = 0;
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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 >= 64);
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driver_features |= (1ULL << f);
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}
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/* Some drivers have a separate feature table for virtio v1.0 */
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if (drv->feature_table_legacy) {
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driver_features_legacy = 0;
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for (i = 0; i < drv->feature_table_size_legacy; i++) {
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unsigned int f = drv->feature_table_legacy[i];
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BUG_ON(f >= 64);
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driver_features_legacy |= (1ULL << f);
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}
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} else {
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driver_features_legacy = driver_features;
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}
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if (device_features & (1ULL << VIRTIO_F_VERSION_1))
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dev->features = driver_features & device_features;
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else
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dev->features = driver_features_legacy & device_features;
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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 & (1ULL << i))
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__virtio_set_bit(dev, i);
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err = virtio_finalize_features(dev);
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if (err)
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goto err;
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err = drv->probe(dev);
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if (err)
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goto err;
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/* If probe didn't do it, mark device DRIVER_OK ourselves. */
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if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
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virtio_device_ready(dev);
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if (drv->scan)
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drv->scan(dev);
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virtio_config_enable(dev);
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return 0;
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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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static int virtio_dev_remove(struct device *_d)
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{
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struct virtio_device *dev = dev_to_virtio(_d);
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struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
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virtio_config_disable(dev);
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drv->remove(dev);
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/* Driver should have reset device. */
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WARN_ON_ONCE(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_groups = virtio_dev_groups,
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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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err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL);
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if (err < 0)
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goto out;
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dev->index = err;
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dev_set_name(&dev->dev, "virtio%u", dev->index);
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spin_lock_init(&dev->config_lock);
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dev->config_enabled = false;
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dev->config_change_pending = false;
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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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ida_simple_remove(&virtio_index_ida, dev->index);
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out:
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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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int index = dev->index; /* save for after device release */
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device_unregister(&dev->dev);
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ida_simple_remove(&virtio_index_ida, index);
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}
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EXPORT_SYMBOL_GPL(unregister_virtio_device);
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#ifdef CONFIG_PM_SLEEP
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int virtio_device_freeze(struct virtio_device *dev)
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{
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struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
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virtio_config_disable(dev);
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dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
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if (drv && drv->freeze)
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return drv->freeze(dev);
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return 0;
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}
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EXPORT_SYMBOL_GPL(virtio_device_freeze);
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int virtio_device_restore(struct virtio_device *dev)
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{
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struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
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int ret;
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/* We always start by resetting the device, in case a previous
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* driver messed it up. */
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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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/* Maybe driver failed before freeze.
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* Restore the failed status, for debugging. */
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||
|
|
if (dev->failed)
|
||
|
|
add_status(dev, VIRTIO_CONFIG_S_FAILED);
|
||
|
|
|
||
|
|
if (!drv)
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
/* We have a driver! */
|
||
|
|
add_status(dev, VIRTIO_CONFIG_S_DRIVER);
|
||
|
|
|
||
|
|
ret = virtio_finalize_features(dev);
|
||
|
|
if (ret)
|
||
|
|
goto err;
|
||
|
|
|
||
|
|
if (drv->restore) {
|
||
|
|
ret = drv->restore(dev);
|
||
|
|
if (ret)
|
||
|
|
goto err;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Finally, tell the device we're all set */
|
||
|
|
add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
|
||
|
|
|
||
|
|
virtio_config_enable(dev);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
err:
|
||
|
|
add_status(dev, VIRTIO_CONFIG_S_FAILED);
|
||
|
|
return ret;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL_GPL(virtio_device_restore);
|
||
|
|
#endif
|
||
|
|
|
||
|
|
static int virtio_init(void)
|
||
|
|
{
|
||
|
|
if (bus_register(&virtio_bus) != 0)
|
||
|
|
panic("virtio bus registration failed");
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static void __exit virtio_exit(void)
|
||
|
|
{
|
||
|
|
bus_unregister(&virtio_bus);
|
||
|
|
ida_destroy(&virtio_index_ida);
|
||
|
|
}
|
||
|
|
core_initcall(virtio_init);
|
||
|
|
module_exit(virtio_exit);
|
||
|
|
|
||
|
|
MODULE_LICENSE("GPL");
|