/* SPDX-License-Identifier: GPL-2.0-or-later */

#ifndef _ZCOMP_H_
#define _ZCOMP_H_

#include <linux/mutex.h>

#define ZCOMP_PARAM_NOT_SET     INT_MIN

struct deflate_params {
        s32 winbits;
};

/*
 * Immutable driver (backend) parameters. The driver may attach private
 * data to it (e.g. driver representation of the dictionary, etc.).
 *
 * This data is kept per-comp and is shared among execution contexts.
 */
struct zcomp_params {
        void *dict;
        size_t dict_sz;
        s32 level;
        union {
                struct deflate_params deflate;
        };

        void *drv_data;
};

/*
 * Run-time driver context - scratch buffers, etc. It is modified during
 * request execution (compression/decompression), cannot be shared, so
 * it's in per-CPU area.
 */
struct zcomp_ctx {
        void *context;
};

struct zcomp_strm {
        struct mutex lock;
        /* compression buffer */
        void *buffer;
        /* local copy of handle memory */
        void *local_copy;
        struct zcomp_ctx ctx;
};

struct zcomp_req {
        const unsigned char *src;
        const size_t src_len;

        unsigned char *dst;
        size_t dst_len;
};

struct zcomp_ops {
        int (*compress)(struct zcomp_params *params, struct zcomp_ctx *ctx,
                        struct zcomp_req *req);
        int (*decompress)(struct zcomp_params *params, struct zcomp_ctx *ctx,
                          struct zcomp_req *req);

        int (*create_ctx)(struct zcomp_params *params, struct zcomp_ctx *ctx);
        void (*destroy_ctx)(struct zcomp_ctx *ctx);

        int (*setup_params)(struct zcomp_params *params);
        void (*release_params)(struct zcomp_params *params);

        const char *name;
};

/* dynamic per-device compression frontend */
struct zcomp {
        struct zcomp_strm __percpu *stream;
        const struct zcomp_ops *ops;
        struct zcomp_params *params;
        struct hlist_node node;
};

int zcomp_cpu_up_prepare(unsigned int cpu, struct hlist_node *node);
int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node);
ssize_t zcomp_available_show(const char *comp, char *buf, ssize_t at);
bool zcomp_available_algorithm(const char *comp);

struct zcomp *zcomp_create(const char *alg, struct zcomp_params *params);
void zcomp_destroy(struct zcomp *comp);

struct zcomp_strm *zcomp_stream_get(struct zcomp *comp);
void zcomp_stream_put(struct zcomp_strm *zstrm);

int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
                   const void *src, unsigned int *dst_len);
int zcomp_decompress(struct zcomp *comp, struct zcomp_strm *zstrm,
                     const void *src, unsigned int src_len, void *dst);

#endif /* _ZCOMP_H_ */