diff options
| -rw-r--r-- | drivers/Kconfig | 2 | ||||
| -rw-r--r-- | drivers/Makefile | 1 | ||||
| -rw-r--r-- | drivers/virtio/Kconfig | 3 | ||||
| -rw-r--r-- | drivers/virtio/Makefile | 1 | ||||
| -rw-r--r-- | drivers/virtio/config.c | 13 | ||||
| -rw-r--r-- | drivers/virtio/virtio.c | 171 | ||||
| -rw-r--r-- | include/linux/Kbuild | 1 | ||||
| -rw-r--r-- | include/linux/mod_devicetable.h | 6 | ||||
| -rw-r--r-- | include/linux/virtio.h | 110 | ||||
| -rw-r--r-- | include/linux/virtio_config.h | 111 |
10 files changed, 419 insertions, 0 deletions
diff --git a/drivers/Kconfig b/drivers/Kconfig index d945ffc..f4076d9 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -93,4 +93,6 @@ source "drivers/auxdisplay/Kconfig" source "drivers/kvm/Kconfig" source "drivers/uio/Kconfig" + +source "drivers/virtio/Kconfig" endmenu diff --git a/drivers/Makefile b/drivers/Makefile index cfe38ff..560496b 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -91,3 +91,4 @@ obj-$(CONFIG_HID) += hid/ obj-$(CONFIG_PPC_PS3) += ps3/ obj-$(CONFIG_OF) += of/ obj-$(CONFIG_SSB) += ssb/ +obj-$(CONFIG_VIRTIO) += virtio/ diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig new file mode 100644 index 0000000..bce84b5 --- /dev/null +++ b/drivers/virtio/Kconfig @@ -0,0 +1,3 @@ +# Virtio always gets selected by whoever wants it. +config VIRTIO + bool diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile new file mode 100644 index 0000000..af0d57d --- /dev/null +++ b/drivers/virtio/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_VIRTIO) += virtio.o diff --git a/drivers/virtio/config.c b/drivers/virtio/config.c new file mode 100644 index 0000000..983d482 --- /dev/null +++ b/drivers/virtio/config.c @@ -0,0 +1,13 @@ +/* Configuration space parsing helpers for virtio. + * + * The configuration is [type][len][... len bytes ...] fields. + * + * Copyright 2007 Rusty Russell, IBM Corporation. + * GPL v2 or later. + */ +#include <linux/err.h> +#include <linux/virtio.h> +#include <linux/virtio_config.h> +#include <linux/bug.h> +#include <asm/system.h> + diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c new file mode 100644 index 0000000..f640e0b --- /dev/null +++ b/drivers/virtio/virtio.c @@ -0,0 +1,171 @@ +#include <linux/virtio.h> +#include <linux/spinlock.h> +#include <linux/virtio_config.h> + +static ssize_t device_show(struct device *_d, + struct device_attribute *attr, char *buf) +{ + struct virtio_device *dev = container_of(_d,struct virtio_device,dev); + return sprintf(buf, "%hu", dev->id.device); +} +static ssize_t vendor_show(struct device *_d, + struct device_attribute *attr, char *buf) +{ + struct virtio_device *dev = container_of(_d,struct virtio_device,dev); + return sprintf(buf, "%hu", dev->id.vendor); +} +static ssize_t status_show(struct device *_d, + struct device_attribute *attr, char *buf) +{ + struct virtio_device *dev = container_of(_d,struct virtio_device,dev); + return sprintf(buf, "0x%08x", dev->config->get_status(dev)); +} +static struct device_attribute virtio_dev_attrs[] = { + __ATTR_RO(device), + __ATTR_RO(vendor), + __ATTR_RO(status), + __ATTR_NULL +}; + +static inline int virtio_id_match(const struct virtio_device *dev, + const struct virtio_device_id *id) +{ + if (id->device != dev->id.device) + return 0; + + return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor != dev->id.vendor; +} + +/* This looks through all the IDs a driver claims to support. If any of them + * match, we return 1 and the kernel will call virtio_dev_probe(). */ +static int virtio_dev_match(struct device *_dv, struct device_driver *_dr) +{ + unsigned int i; + struct virtio_device *dev = container_of(_dv,struct virtio_device,dev); + const struct virtio_device_id *ids; + + ids = container_of(_dr, struct virtio_driver, driver)->id_table; + for (i = 0; ids[i].device; i++) + if (virtio_id_match(dev, &ids[i])) + return 1; + return 0; +} + +static struct bus_type virtio_bus = { + .name = "virtio", + .match = virtio_dev_match, + .dev_attrs = virtio_dev_attrs, +}; + +static void add_status(struct virtio_device *dev, unsigned status) +{ + dev->config->set_status(dev, dev->config->get_status(dev) | status); +} + +static int virtio_dev_probe(struct device *_d) +{ + int err; + struct virtio_device *dev = container_of(_d,struct virtio_device,dev); + struct virtio_driver *drv = container_of(dev->dev.driver, + struct virtio_driver, driver); + + add_status(dev, VIRTIO_CONFIG_S_DRIVER); + err = drv->probe(dev); + if (err) + add_status(dev, VIRTIO_CONFIG_S_FAILED); + else + add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); + return err; +} + +int register_virtio_driver(struct virtio_driver *driver) +{ + driver->driver.bus = &virtio_bus; + driver->driver.probe = virtio_dev_probe; + return driver_register(&driver->driver); +} +EXPORT_SYMBOL_GPL(register_virtio_driver); + +void unregister_virtio_driver(struct virtio_driver *driver) +{ + driver_unregister(&driver->driver); +} +EXPORT_SYMBOL_GPL(unregister_virtio_driver); + +int register_virtio_device(struct virtio_device *dev) +{ + int err; + + dev->dev.bus = &virtio_bus; + sprintf(dev->dev.bus_id, "%u", dev->index); + + /* Acknowledge that we've seen the device. */ + add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); + + /* device_register() causes the bus infrastructure to look for a + * matching driver. */ + err = device_register(&dev->dev); + if (err) + add_status(dev, VIRTIO_CONFIG_S_FAILED); + return err; +} +EXPORT_SYMBOL_GPL(register_virtio_device); + +void unregister_virtio_device(struct virtio_device *dev) +{ + device_unregister(&dev->dev); +} +EXPORT_SYMBOL_GPL(unregister_virtio_device); + +int __virtio_config_val(struct virtio_device *vdev, + u8 type, void *val, size_t size) +{ + void *token; + unsigned int len; + + token = vdev->config->find(vdev, type, &len); + if (!token) + return -ENOENT; + + if (len != size) + return -EIO; + + vdev->config->get(vdev, token, val, size); + return 0; +} +EXPORT_SYMBOL_GPL(__virtio_config_val); + +int virtio_use_bit(struct virtio_device *vdev, + void *token, unsigned int len, unsigned int bitnum) +{ + unsigned long bits[16]; + + /* This makes it convenient to pass-through find() results. */ + if (!token) + return 0; + + /* bit not in range of this bitfield? */ + if (bitnum * 8 >= len / 2) + return 0; + + /* Giant feature bitfields are silly. */ + BUG_ON(len > sizeof(bits)); + vdev->config->get(vdev, token, bits, len); + + if (!test_bit(bitnum, bits)) + return 0; + + /* Set acknowledge bit, and write it back. */ + set_bit(bitnum + len * 8 / 2, bits); + vdev->config->set(vdev, token, bits, len); + return 1; +} +EXPORT_SYMBOL_GPL(virtio_use_bit); + +static int virtio_init(void) +{ + if (bus_register(&virtio_bus) != 0) + panic("virtio bus registration failed"); + return 0; +} +core_initcall(virtio_init); diff --git a/include/linux/Kbuild b/include/linux/Kbuild index 7588345..e5208f2 100644 --- a/include/linux/Kbuild +++ b/include/linux/Kbuild @@ -343,6 +343,7 @@ unifdef-y += user.h unifdef-y += utsname.h unifdef-y += videodev2.h unifdef-y += videodev.h +unifdef-y += virtio_config.h unifdef-y += wait.h unifdef-y += wanrouter.h unifdef-y += watchdog.h diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h index 522b0dd..e9fddb4 100644 --- a/include/linux/mod_devicetable.h +++ b/include/linux/mod_devicetable.h @@ -361,4 +361,10 @@ struct ssb_device_id { #define SSB_ANY_ID 0xFFFF #define SSB_ANY_REV 0xFF +struct virtio_device_id { + __u32 device; + __u32 vendor; +}; +#define VIRTIO_DEV_ANY_ID 0xffffffff + #endif /* LINUX_MOD_DEVICETABLE_H */ diff --git a/include/linux/virtio.h b/include/linux/virtio.h new file mode 100644 index 0000000..14e1379 --- /dev/null +++ b/include/linux/virtio.h @@ -0,0 +1,110 @@ +#ifndef _LINUX_VIRTIO_H +#define _LINUX_VIRTIO_H +/* Everything a virtio driver needs to work with any particular virtio + * implementation. */ +#include <linux/types.h> +#include <linux/scatterlist.h> +#include <linux/spinlock.h> +#include <linux/device.h> +#include <linux/mod_devicetable.h> + +/** + * virtqueue - a queue to register buffers for sending or receiving. + * @callback: the function to call when buffers are consumed (can be NULL). + * If this returns false, callbacks are suppressed until vq_ops->restart + * is called. + * @vdev: the virtio device this queue was created for. + * @vq_ops: the operations for this virtqueue (see below). + * @priv: a pointer for the virtqueue implementation to use. + */ +struct virtqueue +{ + bool (*callback)(struct virtqueue *vq); + struct virtio_device *vdev; + struct virtqueue_ops *vq_ops; + void *priv; +}; + +/** + * virtqueue_ops - operations for virtqueue abstraction layer + * @add_buf: expose buffer to other end + * vq: the struct virtqueue we're talking about. + * sg: the description of the buffer(s). + * out_num: the number of sg readable by other side + * in_num: the number of sg which are writable (after readable ones) + * data: the token identifying the buffer. + * Returns 0 or an error. + * @kick: update after add_buf + * vq: the struct virtqueue + * After one or more add_buf calls, invoke this to kick the other side. + * @get_buf: get the next used buffer + * vq: the struct virtqueue we're talking about. + * len: the length written into the buffer + * Returns NULL or the "data" token handed to add_buf. + * @restart: restart callbacks after callback returned false. + * vq: the struct virtqueue we're talking about. + * This returns "false" (and doesn't re-enable) if there are pending + * buffers in the queue, to avoid a race. + * @shutdown: "unadd" all buffers. + * vq: the struct virtqueue we're talking about. + * Remove everything from the queue. + * + * Locking rules are straightforward: the driver is responsible for + * locking. No two operations may be invoked simultaneously. + * + * All operations can be called in any context. + */ +struct virtqueue_ops { + int (*add_buf)(struct virtqueue *vq, + struct scatterlist sg[], + unsigned int out_num, + unsigned int in_num, + void *data); + + void (*kick)(struct virtqueue *vq); + + void *(*get_buf)(struct virtqueue *vq, unsigned int *len); + + bool (*restart)(struct virtqueue *vq); + + void (*shutdown)(struct virtqueue *vq); +}; + +/** + * virtio_device - representation of a device using virtio + * @index: unique position on the virtio bus + * @dev: underlying device. + * @id: the device type identification (used to match it with a driver). + * @config: the configuration ops for this device. + * @priv: private pointer for the driver's use. + */ +struct virtio_device +{ + int index; + struct device dev; + struct virtio_device_id id; + struct virtio_config_ops *config; + void *priv; +}; + +int register_virtio_device(struct virtio_device *dev); +void unregister_virtio_device(struct virtio_device *dev); + +/** + * virtio_driver - operations for a virtio I/O driver + * @driver: underlying device driver (populate name and owner). + * @id_table: the ids serviced by this driver. + * @probe: the function to call when a device is found. Returns a token for + * remove, or PTR_ERR(). + * @remove: the function when a device is removed. + */ +struct virtio_driver { + struct device_driver driver; + const struct virtio_device_id *id_table; + int (*probe)(struct virtio_device *dev); + void (*remove)(struct virtio_device *dev); +}; + +int register_virtio_driver(struct virtio_driver *drv); +void unregister_virtio_driver(struct virtio_driver *drv); +#endif /* _LINUX_VIRTIO_H */ diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h new file mode 100644 index 0000000..bcc0188 --- /dev/null +++ b/include/linux/virtio_config.h @@ -0,0 +1,111 @@ +#ifndef _LINUX_VIRTIO_CONFIG_H +#define _LINUX_VIRTIO_CONFIG_H +/* Virtio devices use a standardized configuration space to define their + * features and pass configuration information, but each implementation can + * store and access that space differently. */ +#include <linux/types.h> + +/* Status byte for guest to report progress, and synchronize config. */ +/* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */ +#define VIRTIO_CONFIG_S_ACKNOWLEDGE 1 +/* We have found a driver for the device. */ +#define VIRTIO_CONFIG_S_DRIVER 2 +/* Driver has used its parts of the config, and is happy */ +#define VIRTIO_CONFIG_S_DRIVER_OK 4 +/* We've given up on this device. */ +#define VIRTIO_CONFIG_S_FAILED 0x80 + +/* Feature byte (actually 7 bits availabe): */ +/* Requirements/features of the virtio implementation. */ +#define VIRTIO_CONFIG_F_VIRTIO 1 +/* Requirements/features of the virtqueue (may have more than one). */ +#define VIRTIO_CONFIG_F_VIRTQUEUE 2 + +#ifdef __KERNEL__ +struct virtio_device; + +/** + * virtio_config_ops - operations for configuring a virtio device + * @find: search for the next configuration field of the given type. + * vdev: the virtio_device + * type: the feature type + * len: the (returned) length of the field if found. + * Returns a token if found, or NULL. Never returnes the same field twice + * (ie. it's used up). + * @get: read the value of a configuration field after find(). + * vdev: the virtio_device + * token: the token returned from find(). + * buf: the buffer to write the field value into. + * len: the length of the buffer (given by find()). + * Note that contents are conventionally little-endian. + * @set: write the value of a configuration field after find(). + * vdev: the virtio_device + * token: the token returned from find(). + * buf: the buffer to read the field value from. + * len: the length of the buffer (given by find()). + * Note that contents are conventionally little-endian. + * @get_status: read the status byte + * vdev: the virtio_device + * Returns the status byte + * @set_status: write the status byte + * vdev: the virtio_device + * status: the new status byte + * @find_vq: find the first VIRTIO_CONFIG_F_VIRTQUEUE and create a virtqueue. + * vdev: the virtio_device + * callback: the virqtueue callback + * Returns the new virtqueue or ERR_PTR(). + * @del_vq: free a virtqueue found by find_vq(). + */ +struct virtio_config_ops +{ + void *(*find)(struct virtio_device *vdev, u8 type, unsigned *len); + void (*get)(struct virtio_device *vdev, void *token, + void *buf, unsigned len); + void (*set)(struct virtio_device *vdev, void *token, + const void *buf, unsigned len); + u8 (*get_status)(struct virtio_device *vdev); + void (*set_status)(struct virtio_device *vdev, u8 status); + struct virtqueue *(*find_vq)(struct virtio_device *vdev, + bool (*callback)(struct virtqueue *)); + void (*del_vq)(struct virtqueue *vq); +}; + +/** + * virtio_config_val - get a single virtio config and mark it used. + * @config: the virtio config space + * @type: the type to search for. + * @val: a pointer to the value to fill in. + * + * Once used, the config type is marked with VIRTIO_CONFIG_F_USED so it can't + * be found again. This version does endian conversion. */ +#define virtio_config_val(vdev, type, v) ({ \ + int _err = __virtio_config_val((vdev),(type),(v),sizeof(*(v))); \ + \ + BUILD_BUG_ON(sizeof(*(v)) != 1 && sizeof(*(v)) != 2 \ + && sizeof(*(v)) != 4 && sizeof(*(v)) != 8); \ + if (!_err) { \ + switch (sizeof(*(v))) { \ + case 2: le16_to_cpus((__u16 *) v); break; \ + case 4: le32_to_cpus((__u32 *) v); break; \ + case 8: le64_to_cpus((__u64 *) v); break; \ + } \ + } \ + _err; \ +}) + +int __virtio_config_val(struct virtio_device *dev, + u8 type, void *val, size_t size); + +/** + * virtio_use_bit - helper to use a feature bit in a bitfield value. + * @dev: the virtio device + * @token: the token as returned from vdev->config->find(). + * @len: the length of the field. + * @bitnum: the bit to test. + * + * If handed a NULL token, it returns false, otherwise returns bit status. + * If it's one, it sets the mirroring acknowledgement bit. */ +int virtio_use_bit(struct virtio_device *vdev, + void *token, unsigned int len, unsigned int bitnum); +#endif /* __KERNEL__ */ +#endif /* _LINUX_VIRTIO_CONFIG_H */ |