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Diffstat (limited to 'kernel/include/linux/virtio_config.h')
| -rw-r--r-- | kernel/include/linux/virtio_config.h | 398 |
1 files changed, 398 insertions, 0 deletions
diff --git a/kernel/include/linux/virtio_config.h b/kernel/include/linux/virtio_config.h new file mode 100644 index 000000000..1e306f727 --- /dev/null +++ b/kernel/include/linux/virtio_config.h @@ -0,0 +1,398 @@ +#ifndef _LINUX_VIRTIO_CONFIG_H +#define _LINUX_VIRTIO_CONFIG_H + +#include <linux/err.h> +#include <linux/bug.h> +#include <linux/virtio.h> +#include <linux/virtio_byteorder.h> +#include <uapi/linux/virtio_config.h> + +/** + * virtio_config_ops - operations for configuring a virtio device + * @get: read the value of a configuration field + * vdev: the virtio_device + * offset: the offset of the configuration field + * buf: the buffer to write the field value into. + * len: the length of the buffer + * @set: write the value of a configuration field + * vdev: the virtio_device + * offset: the offset of the configuration field + * buf: the buffer to read the field value from. + * len: the length of the buffer + * @generation: config generation counter + * vdev: the virtio_device + * Returns the config generation counter + * @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 + * @reset: reset the device + * vdev: the virtio device + * After this, status and feature negotiation must be done again + * Device must not be reset from its vq/config callbacks, or in + * parallel with being added/removed. + * @find_vqs: find virtqueues and instantiate them. + * vdev: the virtio_device + * nvqs: the number of virtqueues to find + * vqs: on success, includes new virtqueues + * callbacks: array of callbacks, for each virtqueue + * include a NULL entry for vqs that do not need a callback + * names: array of virtqueue names (mainly for debugging) + * include a NULL entry for vqs unused by driver + * Returns 0 on success or error status + * @del_vqs: free virtqueues found by find_vqs(). + * @get_features: get the array of feature bits for this device. + * vdev: the virtio_device + * Returns the first 32 feature bits (all we currently need). + * @finalize_features: confirm what device features we'll be using. + * vdev: the virtio_device + * This gives the final feature bits for the device: it can change + * the dev->feature bits if it wants. + * Returns 0 on success or error status + * @bus_name: return the bus name associated with the device + * vdev: the virtio_device + * This returns a pointer to the bus name a la pci_name from which + * the caller can then copy. + * @set_vq_affinity: set the affinity for a virtqueue. + */ +typedef void vq_callback_t(struct virtqueue *); +struct virtio_config_ops { + void (*get)(struct virtio_device *vdev, unsigned offset, + void *buf, unsigned len); + void (*set)(struct virtio_device *vdev, unsigned offset, + const void *buf, unsigned len); + u32 (*generation)(struct virtio_device *vdev); + u8 (*get_status)(struct virtio_device *vdev); + void (*set_status)(struct virtio_device *vdev, u8 status); + void (*reset)(struct virtio_device *vdev); + int (*find_vqs)(struct virtio_device *, unsigned nvqs, + struct virtqueue *vqs[], + vq_callback_t *callbacks[], + const char *names[]); + void (*del_vqs)(struct virtio_device *); + u64 (*get_features)(struct virtio_device *vdev); + int (*finalize_features)(struct virtio_device *vdev); + const char *(*bus_name)(struct virtio_device *vdev); + int (*set_vq_affinity)(struct virtqueue *vq, int cpu); +}; + +/* If driver didn't advertise the feature, it will never appear. */ +void virtio_check_driver_offered_feature(const struct virtio_device *vdev, + unsigned int fbit); + +/** + * __virtio_test_bit - helper to test feature bits. For use by transports. + * Devices should normally use virtio_has_feature, + * which includes more checks. + * @vdev: the device + * @fbit: the feature bit + */ +static inline bool __virtio_test_bit(const struct virtio_device *vdev, + unsigned int fbit) +{ + /* Did you forget to fix assumptions on max features? */ + if (__builtin_constant_p(fbit)) + BUILD_BUG_ON(fbit >= 64); + else + BUG_ON(fbit >= 64); + + return vdev->features & BIT_ULL(fbit); +} + +/** + * __virtio_set_bit - helper to set feature bits. For use by transports. + * @vdev: the device + * @fbit: the feature bit + */ +static inline void __virtio_set_bit(struct virtio_device *vdev, + unsigned int fbit) +{ + /* Did you forget to fix assumptions on max features? */ + if (__builtin_constant_p(fbit)) + BUILD_BUG_ON(fbit >= 64); + else + BUG_ON(fbit >= 64); + + vdev->features |= BIT_ULL(fbit); +} + +/** + * __virtio_clear_bit - helper to clear feature bits. For use by transports. + * @vdev: the device + * @fbit: the feature bit + */ +static inline void __virtio_clear_bit(struct virtio_device *vdev, + unsigned int fbit) +{ + /* Did you forget to fix assumptions on max features? */ + if (__builtin_constant_p(fbit)) + BUILD_BUG_ON(fbit >= 64); + else + BUG_ON(fbit >= 64); + + vdev->features &= ~BIT_ULL(fbit); +} + +/** + * virtio_has_feature - helper to determine if this device has this feature. + * @vdev: the device + * @fbit: the feature bit + */ +static inline bool virtio_has_feature(const struct virtio_device *vdev, + unsigned int fbit) +{ + if (fbit < VIRTIO_TRANSPORT_F_START) + virtio_check_driver_offered_feature(vdev, fbit); + + return __virtio_test_bit(vdev, fbit); +} + +static inline +struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev, + vq_callback_t *c, const char *n) +{ + vq_callback_t *callbacks[] = { c }; + const char *names[] = { n }; + struct virtqueue *vq; + int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names); + if (err < 0) + return ERR_PTR(err); + return vq; +} + +/** + * virtio_device_ready - enable vq use in probe function + * @vdev: the device + * + * Driver must call this to use vqs in the probe function. + * + * Note: vqs are enabled automatically after probe returns. + */ +static inline +void virtio_device_ready(struct virtio_device *dev) +{ + unsigned status = dev->config->get_status(dev); + + BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK); + dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK); +} + +static inline +const char *virtio_bus_name(struct virtio_device *vdev) +{ + if (!vdev->config->bus_name) + return "virtio"; + return vdev->config->bus_name(vdev); +} + +/** + * virtqueue_set_affinity - setting affinity for a virtqueue + * @vq: the virtqueue + * @cpu: the cpu no. + * + * Pay attention the function are best-effort: the affinity hint may not be set + * due to config support, irq type and sharing. + * + */ +static inline +int virtqueue_set_affinity(struct virtqueue *vq, int cpu) +{ + struct virtio_device *vdev = vq->vdev; + if (vdev->config->set_vq_affinity) + return vdev->config->set_vq_affinity(vq, cpu); + return 0; +} + +/* Memory accessors */ +static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val) +{ + return __virtio16_to_cpu(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val); +} + +static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val) +{ + return __cpu_to_virtio16(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val); +} + +static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val) +{ + return __virtio32_to_cpu(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val); +} + +static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val) +{ + return __cpu_to_virtio32(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val); +} + +static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val) +{ + return __virtio64_to_cpu(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val); +} + +static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val) +{ + return __cpu_to_virtio64(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val); +} + +/* Config space accessors. */ +#define virtio_cread(vdev, structname, member, ptr) \ + do { \ + /* Must match the member's type, and be integer */ \ + if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \ + (*ptr) = 1; \ + \ + switch (sizeof(*ptr)) { \ + case 1: \ + *(ptr) = virtio_cread8(vdev, \ + offsetof(structname, member)); \ + break; \ + case 2: \ + *(ptr) = virtio_cread16(vdev, \ + offsetof(structname, member)); \ + break; \ + case 4: \ + *(ptr) = virtio_cread32(vdev, \ + offsetof(structname, member)); \ + break; \ + case 8: \ + *(ptr) = virtio_cread64(vdev, \ + offsetof(structname, member)); \ + break; \ + default: \ + BUG(); \ + } \ + } while(0) + +/* Config space accessors. */ +#define virtio_cwrite(vdev, structname, member, ptr) \ + do { \ + /* Must match the member's type, and be integer */ \ + if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \ + BUG_ON((*ptr) == 1); \ + \ + switch (sizeof(*ptr)) { \ + case 1: \ + virtio_cwrite8(vdev, \ + offsetof(structname, member), \ + *(ptr)); \ + break; \ + case 2: \ + virtio_cwrite16(vdev, \ + offsetof(structname, member), \ + *(ptr)); \ + break; \ + case 4: \ + virtio_cwrite32(vdev, \ + offsetof(structname, member), \ + *(ptr)); \ + break; \ + case 8: \ + virtio_cwrite64(vdev, \ + offsetof(structname, member), \ + *(ptr)); \ + break; \ + default: \ + BUG(); \ + } \ + } while(0) + +/* Read @count fields, @bytes each. */ +static inline void __virtio_cread_many(struct virtio_device *vdev, + unsigned int offset, + void *buf, size_t count, size_t bytes) +{ + u32 old, gen = vdev->config->generation ? + vdev->config->generation(vdev) : 0; + int i; + + do { + old = gen; + + for (i = 0; i < count; i++) + vdev->config->get(vdev, offset + bytes * i, + buf + i * bytes, bytes); + + gen = vdev->config->generation ? + vdev->config->generation(vdev) : 0; + } while (gen != old); +} + +static inline void virtio_cread_bytes(struct virtio_device *vdev, + unsigned int offset, + void *buf, size_t len) +{ + __virtio_cread_many(vdev, offset, buf, len, 1); +} + +static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset) +{ + u8 ret; + vdev->config->get(vdev, offset, &ret, sizeof(ret)); + return ret; +} + +static inline void virtio_cwrite8(struct virtio_device *vdev, + unsigned int offset, u8 val) +{ + vdev->config->set(vdev, offset, &val, sizeof(val)); +} + +static inline u16 virtio_cread16(struct virtio_device *vdev, + unsigned int offset) +{ + u16 ret; + vdev->config->get(vdev, offset, &ret, sizeof(ret)); + return virtio16_to_cpu(vdev, (__force __virtio16)ret); +} + +static inline void virtio_cwrite16(struct virtio_device *vdev, + unsigned int offset, u16 val) +{ + val = (__force u16)cpu_to_virtio16(vdev, val); + vdev->config->set(vdev, offset, &val, sizeof(val)); +} + +static inline u32 virtio_cread32(struct virtio_device *vdev, + unsigned int offset) +{ + u32 ret; + vdev->config->get(vdev, offset, &ret, sizeof(ret)); + return virtio32_to_cpu(vdev, (__force __virtio32)ret); +} + +static inline void virtio_cwrite32(struct virtio_device *vdev, + unsigned int offset, u32 val) +{ + val = (__force u32)cpu_to_virtio32(vdev, val); + vdev->config->set(vdev, offset, &val, sizeof(val)); +} + +static inline u64 virtio_cread64(struct virtio_device *vdev, + unsigned int offset) +{ + u64 ret; + __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret)); + return virtio64_to_cpu(vdev, (__force __virtio64)ret); +} + +static inline void virtio_cwrite64(struct virtio_device *vdev, + unsigned int offset, u64 val) +{ + val = (__force u64)cpu_to_virtio64(vdev, val); + vdev->config->set(vdev, offset, &val, sizeof(val)); +} + +/* Conditional config space accessors. */ +#define virtio_cread_feature(vdev, fbit, structname, member, ptr) \ + ({ \ + int _r = 0; \ + if (!virtio_has_feature(vdev, fbit)) \ + _r = -ENOENT; \ + else \ + virtio_cread((vdev), structname, member, ptr); \ + _r; \ + }) + +#endif /* _LINUX_VIRTIO_CONFIG_H */ |