/* SPDX-License-Identifier: GPL-2.0 */
#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>
#include <linux/gfp.h>
#include <linux/dma-mapping.h>
#include <linux/completion.h>
#include <linux/virtio_features.h>

struct module;

/**
 * struct virtqueue - a queue to register buffers for sending or receiving.
 * @list: the chain of virtqueues for this device
 * @callback: the function to call when buffers are consumed (can be NULL).
 * @name: the name of this virtqueue (mainly for debugging)
 * @vdev: the virtio device this queue was created for.
 * @priv: a pointer for the virtqueue implementation to use.
 * @index: the zero-based ordinal number for this queue.
 * @num_free: number of elements we expect to be able to fit.
 * @num_max: the maximum number of elements supported by the device.
 * @reset: vq is in reset state or not.
 *
 * A note on @num_free: with indirect buffers, each buffer needs one
 * element in the queue, otherwise a buffer will need one element per
 * sg element.
 */
struct virtqueue {
        struct list_head list;
        void (*callback)(struct virtqueue *vq);
        const char *name;
        struct virtio_device *vdev;
        unsigned int index;
        unsigned int num_free;
        unsigned int num_max;
        bool reset;
        void *priv;
};

struct vduse_vq_group;

union virtio_map {
        /* Device that performs DMA */
        struct device *dma_dev;
        /* VDUSE specific virtqueue group for doing map */
        struct vduse_vq_group *group;
};

int virtqueue_add_outbuf(struct virtqueue *vq,
                         struct scatterlist sg[], unsigned int num,
                         void *data,
                         gfp_t gfp);

int virtqueue_add_inbuf(struct virtqueue *vq,
                        struct scatterlist sg[], unsigned int num,
                        void *data,
                        gfp_t gfp);

int virtqueue_add_inbuf_cache_clean(struct virtqueue *vq,
                                    struct scatterlist sg[], unsigned int num,
                                    void *data,
                                    gfp_t gfp);

int virtqueue_add_inbuf_ctx(struct virtqueue *vq,
                            struct scatterlist sg[], unsigned int num,
                            void *data,
                            void *ctx,
                            gfp_t gfp);

int virtqueue_add_inbuf_premapped(struct virtqueue *vq,
                                  struct scatterlist *sg, unsigned int num,
                                  void *data,
                                  void *ctx,
                                  gfp_t gfp);

int virtqueue_add_outbuf_premapped(struct virtqueue *vq,
                                   struct scatterlist *sg, unsigned int num,
                                   void *data,
                                   gfp_t gfp);

int virtqueue_add_sgs(struct virtqueue *vq,
                      struct scatterlist *sgs[],
                      unsigned int out_sgs,
                      unsigned int in_sgs,
                      void *data,
                      gfp_t gfp);

struct device *virtqueue_dma_dev(struct virtqueue *vq);

bool virtqueue_kick(struct virtqueue *vq);

bool virtqueue_kick_prepare(struct virtqueue *vq);

bool virtqueue_notify(struct virtqueue *vq);

void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);

void *virtqueue_get_buf_ctx(struct virtqueue *vq, unsigned int *len,
                            void **ctx);

void virtqueue_disable_cb(struct virtqueue *vq);

bool virtqueue_enable_cb(struct virtqueue *vq);

unsigned virtqueue_enable_cb_prepare(struct virtqueue *vq);

bool virtqueue_poll(struct virtqueue *vq, unsigned);

bool virtqueue_enable_cb_delayed(struct virtqueue *vq);

void *virtqueue_detach_unused_buf(struct virtqueue *vq);

unsigned int virtqueue_get_vring_size(const struct virtqueue *vq);

bool virtqueue_is_broken(const struct virtqueue *vq);

const struct vring *virtqueue_get_vring(const struct virtqueue *vq);
dma_addr_t virtqueue_get_desc_addr(const struct virtqueue *vq);
dma_addr_t virtqueue_get_avail_addr(const struct virtqueue *vq);
dma_addr_t virtqueue_get_used_addr(const struct virtqueue *vq);

int virtqueue_resize(struct virtqueue *vq, u32 num,
                     void (*recycle)(struct virtqueue *vq, void *buf),
                     void (*recycle_done)(struct virtqueue *vq));
int virtqueue_reset(struct virtqueue *vq,
                    void (*recycle)(struct virtqueue *vq, void *buf),
                    void (*recycle_done)(struct virtqueue *vq));

struct virtio_admin_cmd {
        __le16 opcode;
        __le16 group_type;
        __le64 group_member_id;
        struct scatterlist *data_sg;
        struct scatterlist *result_sg;
        struct completion completion;
        u32 result_sg_size;
        int ret;
};

/**
 * struct virtio_device - representation of a device using virtio
 * @index: unique position on the virtio bus
 * @failed: saved value for VIRTIO_CONFIG_S_FAILED bit (for restore)
 * @config_core_enabled: configuration change reporting enabled by core
 * @config_driver_disabled: configuration change reporting disabled by
 *                          a driver
 * @config_change_pending: configuration change reported while disabled
 * @config_lock: protects configuration change reporting
 * @vqs_list_lock: protects @vqs.
 * @dev: underlying device.
 * @id: the device type identification (used to match it with a driver).
 * @config: the configuration ops for this device.
 * @vringh_config: configuration ops for host vrings.
 * @vqs: the list of virtqueues for this device.
 * @features: the 64 lower features supported by both driver and device.
 * @features_array: the full features space supported by both driver and
 *                  device.
 * @priv: private pointer for the driver's use.
 * @debugfs_dir: debugfs directory entry.
 * @debugfs_filter_features: features to be filtered set by debugfs.
 */
struct virtio_device {
        int index;
        bool failed;
        bool config_core_enabled;
        bool config_driver_disabled;
        bool config_change_pending;
        spinlock_t config_lock;
        spinlock_t vqs_list_lock;
        struct device dev;
        struct virtio_device_id id;
        const struct virtio_config_ops *config;
        const struct vringh_config_ops *vringh_config;
        const struct virtio_map_ops *map;
        struct list_head vqs;
        VIRTIO_DECLARE_FEATURES(features);
        void *priv;
        union virtio_map vmap;
#ifdef CONFIG_VIRTIO_DEBUG
        struct dentry *debugfs_dir;
        u64 debugfs_filter_features[VIRTIO_FEATURES_U64S];
#endif
};

#define dev_to_virtio(_dev)     container_of_const(_dev, struct virtio_device, dev)

void virtio_add_status(struct virtio_device *dev, unsigned int status);
int register_virtio_device(struct virtio_device *dev);
void unregister_virtio_device(struct virtio_device *dev);
bool is_virtio_device(struct device *dev);

void virtio_break_device(struct virtio_device *dev);
void __virtio_unbreak_device(struct virtio_device *dev);

void __virtqueue_break(struct virtqueue *_vq);
void __virtqueue_unbreak(struct virtqueue *_vq);

void virtio_config_changed(struct virtio_device *dev);

void virtio_config_driver_disable(struct virtio_device *dev);
void virtio_config_driver_enable(struct virtio_device *dev);

#ifdef CONFIG_PM_SLEEP
int virtio_device_freeze(struct virtio_device *dev);
int virtio_device_restore(struct virtio_device *dev);
#endif
void virtio_reset_device(struct virtio_device *dev);
int virtio_device_reset_prepare(struct virtio_device *dev);
int virtio_device_reset_done(struct virtio_device *dev);

size_t virtio_max_dma_size(const struct virtio_device *vdev);

#define virtio_device_for_each_vq(vdev, vq) \
        list_for_each_entry(vq, &(vdev)->vqs, list)

/**
 * struct virtio_driver - operations for a virtio I/O driver
 * @driver: underlying device driver (populate name).
 * @id_table: the ids serviced by this driver.
 * @feature_table: an array of feature numbers supported by this driver.
 * @feature_table_size: number of entries in the feature table array.
 * @feature_table_legacy: same as feature_table but when working in legacy mode.
 * @feature_table_size_legacy: number of entries in feature table legacy array.
 * @validate: the function to call to validate features and config space.
 *            Returns 0 or -errno.
 * @probe: the function to call when a device is found.  Returns 0 or -errno.
 * @scan: optional function to call after successful probe; intended
 *    for virtio-scsi to invoke a scan.
 * @remove: the function to call when a device is removed.
 * @config_changed: optional function to call when the device configuration
 *    changes; may be called in interrupt context.
 * @freeze: optional function to call during suspend/hibernation.
 * @restore: optional function to call on resume.
 * @reset_prepare: optional function to call when a transport specific reset
 *    occurs.
 * @reset_done: optional function to call after transport specific reset
 *    operation has finished.
 * @shutdown: synchronize with the device on shutdown. If provided, replaces
 *    the virtio core implementation.
 */
struct virtio_driver {
        struct device_driver driver;
        const struct virtio_device_id *id_table;
        const unsigned int *feature_table;
        unsigned int feature_table_size;
        const unsigned int *feature_table_legacy;
        unsigned int feature_table_size_legacy;
        int (*validate)(struct virtio_device *dev);
        int (*probe)(struct virtio_device *dev);
        void (*scan)(struct virtio_device *dev);
        void (*remove)(struct virtio_device *dev);
        void (*config_changed)(struct virtio_device *dev);
        int (*freeze)(struct virtio_device *dev);
        int (*restore)(struct virtio_device *dev);
        int (*reset_prepare)(struct virtio_device *dev);
        int (*reset_done)(struct virtio_device *dev);
        void (*shutdown)(struct virtio_device *dev);
};

#define drv_to_virtio(__drv)    container_of_const(__drv, struct virtio_driver, driver)

/* use a macro to avoid include chaining to get THIS_MODULE */
#define register_virtio_driver(drv) \
        __register_virtio_driver(drv, THIS_MODULE)
int __register_virtio_driver(struct virtio_driver *drv, struct module *owner);
void unregister_virtio_driver(struct virtio_driver *drv);

/* module_virtio_driver() - Helper macro for drivers that don't do
 * anything special in module init/exit.  This eliminates a lot of
 * boilerplate.  Each module may only use this macro once, and
 * calling it replaces module_init() and module_exit()
 */
#define module_virtio_driver(__virtio_driver) \
        module_driver(__virtio_driver, register_virtio_driver, \
                        unregister_virtio_driver)


void *virtqueue_map_alloc_coherent(struct virtio_device *vdev,
                                   union virtio_map mapping_token,
                                   size_t size, dma_addr_t *dma_handle,
                                   gfp_t gfp);

void virtqueue_map_free_coherent(struct virtio_device *vdev,
                                 union virtio_map mapping_token,
                                 size_t size, void *vaddr,
                                 dma_addr_t dma_handle);

dma_addr_t virtqueue_map_page_attrs(const struct virtqueue *_vq,
                                    struct page *page,
                                    unsigned long offset,
                                    size_t size,
                                    enum dma_data_direction dir,
                                    unsigned long attrs);

void virtqueue_unmap_page_attrs(const struct virtqueue *_vq,
                                dma_addr_t dma_handle,
                                size_t size, enum dma_data_direction dir,
                                unsigned long attrs);

dma_addr_t virtqueue_map_single_attrs(const struct virtqueue *_vq, void *ptr, size_t size,
                                          enum dma_data_direction dir, unsigned long attrs);
void virtqueue_unmap_single_attrs(const struct virtqueue *_vq, dma_addr_t addr,
                                      size_t size, enum dma_data_direction dir,
                                      unsigned long attrs);
int virtqueue_map_mapping_error(const struct virtqueue *_vq, dma_addr_t addr);

bool virtqueue_map_need_sync(const struct virtqueue *_vq, dma_addr_t addr);
void virtqueue_map_sync_single_range_for_cpu(const struct virtqueue *_vq, dma_addr_t addr,
                                             unsigned long offset, size_t size,
                                             enum dma_data_direction dir);
void virtqueue_map_sync_single_range_for_device(const struct virtqueue *_vq, dma_addr_t addr,
                                                unsigned long offset, size_t size,
                                                enum dma_data_direction dir);

#ifdef CONFIG_VIRTIO_DEBUG
void virtio_debug_device_init(struct virtio_device *dev);
void virtio_debug_device_exit(struct virtio_device *dev);
void virtio_debug_device_filter_features(struct virtio_device *dev);
void virtio_debug_init(void);
void virtio_debug_exit(void);
#else
static inline void virtio_debug_device_init(struct virtio_device *dev)
{
}

static inline void virtio_debug_device_exit(struct virtio_device *dev)
{
}

static inline void virtio_debug_device_filter_features(struct virtio_device *dev)
{
}

static inline void virtio_debug_init(void)
{
}

static inline void virtio_debug_exit(void)
{
}
#endif

#endif /* _LINUX_VIRTIO_H */