/* SPDX-License-Identifier: GPL-2.0 */
/*
 *    tape device driver for 3490E tapes.
 *
 *  S390 and zSeries version
 *    Copyright IBM Corp. 2001, 2009
 *    Author(s): Carsten Otte <cotte@de.ibm.com>
 *               Tuan Ngo-Anh <ngoanh@de.ibm.com>
 *               Martin Schwidefsky <schwidefsky@de.ibm.com>
 *               Stefan Bader <shbader@de.ibm.com>
 */

#ifndef _TAPE_H
#define _TAPE_H

#include <asm/ccwdev.h>
#include <asm/debug.h>
#include <asm/idals.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mtio.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>

struct gendisk;

/*
 * Define DBF_LIKE_HELL for lots of messages in the debug feature.
 */
#define DBF_LIKE_HELL
#ifdef  DBF_LIKE_HELL
#define DBF_LH(level, str, ...) \
do { \
        debug_sprintf_event(TAPE_DBF_AREA, level, str, ## __VA_ARGS__); \
} while (0)
#else
#define DBF_LH(level, str, ...) do {} while(0)
#endif

/*
 * macros s390 debug feature (dbf)
 */
#define DBF_EVENT(d_level, d_str...) \
do { \
        debug_sprintf_event(TAPE_DBF_AREA, d_level, d_str); \
} while (0)

#define DBF_EXCEPTION(d_level, d_str...) \
do { \
        debug_sprintf_exception(TAPE_DBF_AREA, d_level, d_str); \
} while (0)

#define TAPE_VERSION_MAJOR 2
#define TAPE_VERSION_MINOR 0
#define TAPE_MAGIC "tape"

#define TAPE_MINORS_PER_DEV 2       /* two minors per device */
#define TAPEBLOCK_HSEC_SIZE     2048
#define TAPEBLOCK_HSEC_S2B      2
#define TAPEBLOCK_RETRIES       5

enum tape_medium_state {
        MS_UNKNOWN,
        MS_LOADED,
        MS_UNLOADED,
        MS_SIZE
};

enum tape_state {
        TS_UNUSED=0,
        TS_IN_USE,
        TS_BLKUSE,
        TS_INIT,
        TS_NOT_OPER,
        TS_SIZE
};

enum tape_op {
        TO_BLOCK,       /* Block read */
        TO_BSB,         /* Backward space block */
        TO_BSF,         /* Backward space filemark */
        TO_DSE,         /* Data security erase */
        TO_FSB,         /* Forward space block */
        TO_FSF,         /* Forward space filemark */
        TO_LBL,         /* Locate block label */
        TO_NOP,         /* No operation */
        TO_RBA,         /* Read backward */
        TO_RBI,         /* Read block information */
        TO_RFO,         /* Read forward */
        TO_REW,         /* Rewind tape */
        TO_RUN,         /* Rewind and unload tape */
        TO_WRI,         /* Write block */
        TO_WTM,         /* Write tape mark */
        TO_MSEN,        /* Medium sense */
        TO_LOAD,        /* Load tape */
        TO_READ_CONFIG, /* Read configuration data */
        TO_READ_ATTMSG, /* Read attention message */
        TO_DIS,         /* Tape display */
        TO_ASSIGN,      /* Assign tape to channel path */
        TO_UNASSIGN,    /* Unassign tape from channel path */
        TO_RDC,         /* Read device characteristics */
        TO_SIZE,        /* #entries in tape_op_t */
};

/* Forward declaration */
struct tape_device;

/* tape_request->status can be: */
enum tape_request_status {
        TAPE_REQUEST_INIT,      /* request is ready to be processed */
        TAPE_REQUEST_QUEUED,    /* request is queued to be processed */
        TAPE_REQUEST_IN_IO,     /* request is currently in IO */
        TAPE_REQUEST_DONE,      /* request is completed. */
        TAPE_REQUEST_CANCEL,    /* request should be canceled. */
        TAPE_REQUEST_LONG_BUSY, /* request has to be restarted after long busy */
};

/* Tape CCW request */
struct tape_request {
        struct list_head list;          /* list head for request queueing. */
        struct tape_device *device;     /* tape device of this request */
        struct ccw1 *cpaddr;            /* address of the channel program. */
        void *cpdata;                   /* pointer to ccw data. */
        enum tape_request_status status;/* status of this request */
        int options;                    /* options for execution. */
        int retries;                    /* retry counter for error recovery. */
        int rescnt;                     /* residual count from devstat. */
        struct timer_list timer;        /* timer for std_assign_timeout(). */
        struct irb irb;                 /* device status */

        /* Callback for delivering final status. */
        void (*callback)(struct tape_request *, void *);
        void *callback_data;

        enum tape_op op;
        int rc;
};

/* Function type for magnetic tape commands */
typedef int (*tape_mtop_fn)(struct tape_device *, int);

/* Size of the array containing the mtops for a discipline */
#define TAPE_NR_MTOPS (MTMKPART+1)

/* Tape Discipline */
struct tape_discipline {
        struct module *owner;
        int  (*setup_device)(struct tape_device *);
        void (*cleanup_device)(struct tape_device *);
        int (*irq)(struct tape_device *, struct tape_request *, struct irb *);
        struct tape_request *(*read_block)(struct tape_device *);
        struct tape_request *(*write_block)(struct tape_device *);
        void (*process_eov)(struct tape_device*);
        /* Array of tape commands with TAPE_NR_MTOPS entries */
        tape_mtop_fn *mtop_array;
};

/*
 * The discipline irq function either returns an error code (<0) which
 * means that the request has failed with an error or one of the following:
 */
#define TAPE_IO_SUCCESS         0       /* request successful */
#define TAPE_IO_PENDING         1       /* request still running */
#define TAPE_IO_RETRY           2       /* retry to current request */
#define TAPE_IO_STOP            3       /* stop the running request */
#define TAPE_IO_LONG_BUSY       4       /* delay the running request */

/* Char Frontend Data */
struct tape_char_data {
        struct idal_buffer **ibs;       /* idal buffer array for user char data */
        int block_size;                 /*   of size block_size. */
};

/* Tape Info */
struct tape_device {
        /* entry in tape_device_list */
        struct list_head                node;

        int                             cdev_id;
        struct ccw_device *             cdev;
        struct tape_class_device *      nt;
        struct tape_class_device *      rt;

        /* Device mutex to serialize tape commands. */
        struct mutex                    mutex;

        /* Device discipline information. */
        struct tape_discipline *        discipline;

        /* Generic status flags */
        long                            tape_generic_status;

        /* Device state information. */
        wait_queue_head_t               state_change_wq;
        enum tape_state                 tape_state;
        enum tape_medium_state          medium_state;
        unsigned char *                 modeset_byte;

        /* Reference count. */
        atomic_t                        ref_count;

        /* Request queue. */
        struct list_head                req_queue;

        /* Request wait queue. */
        wait_queue_head_t               wait_queue;

        /* Each tape device has (currently) two minor numbers. */
        int                             first_minor;

        /* Number of tapemarks required for correct termination. */
        int                             required_tapemarks;

        /* Block ID of the BOF */
        unsigned int                    bof;

        /* Character device frontend data */
        struct tape_char_data           char_data;

        /* Function to start or stop the next request later. */
        struct delayed_work             tape_dnr;

        /* Timer for long busy */
        struct timer_list               lb_timeout;

};

/* Externals from tape_core.c */
extern struct tape_request *tape_alloc_request(int cplength, int datasize);
extern void tape_free_request(struct tape_request *);
extern int tape_check_idalbuffer(struct tape_device *device, size_t size);
extern int tape_do_io(struct tape_device *, struct tape_request *);
extern int tape_do_io_async(struct tape_device *, struct tape_request *);
extern int tape_do_io_interruptible(struct tape_device *, struct tape_request *);
extern int tape_cancel_io(struct tape_device *, struct tape_request *);

static inline int
tape_do_io_free(struct tape_device *device, struct tape_request *request)
{
        int rc;

        rc = tape_do_io(device, request);
        tape_free_request(request);
        return rc;
}

static inline void
tape_do_io_async_free(struct tape_device *device, struct tape_request *request)
{
        request->callback = (void *) tape_free_request;
        request->callback_data = NULL;
        tape_do_io_async(device, request);
}

extern int tape_open(struct tape_device *);
extern int tape_release(struct tape_device *);
extern int tape_mtop(struct tape_device *, int, int);
extern void tape_state_set(struct tape_device *, enum tape_state);

extern int tape_generic_online(struct tape_device *, struct tape_discipline *);
extern int tape_generic_offline(struct ccw_device *);

/* Externals from tape_devmap.c */
extern int tape_generic_probe(struct ccw_device *);
extern void tape_generic_remove(struct ccw_device *);

extern struct tape_device *tape_find_device(int devindex);
extern struct tape_device *tape_get_device(struct tape_device *);
extern void tape_put_device(struct tape_device *);

/* Externals from tape_char.c */
extern int tapechar_init(void);
extern void tapechar_exit(void);
extern int  tapechar_setup_device(struct tape_device *);
extern void tapechar_cleanup_device(struct tape_device *);

/* Externals from tape_3490.c */
extern int tape_3490_init(void);
extern void tape_3490_exit(void);

/* tape initialisation functions */
#ifdef CONFIG_PROC_FS
extern void tape_proc_init (void);
extern void tape_proc_cleanup (void);
#else
static inline void tape_proc_init (void) {;}
static inline void tape_proc_cleanup (void) {;}
#endif

/* a function for dumping device sense info */
extern void tape_dump_sense_dbf(struct tape_device *, struct tape_request *,
                                struct irb *);

/* functions for handling the status of a device */
extern void tape_med_state_set(struct tape_device *, enum tape_medium_state);

/* The debug area */
extern debug_info_t *TAPE_DBF_AREA;

/* functions for building ccws */
static inline struct ccw1 *
tape_ccw_cc(struct ccw1 *ccw, __u8 cmd_code, __u16 memsize, void *cda)
{
        ccw->cmd_code = cmd_code;
        ccw->flags = CCW_FLAG_CC;
        ccw->count = memsize;
        ccw->cda = 0;
        if (cda)
                ccw->cda = virt_to_dma32(cda);
        return ccw + 1;
}

static inline struct ccw1 *
tape_ccw_end(struct ccw1 *ccw, __u8 cmd_code, __u16 memsize, void *cda)
{
        ccw->cmd_code = cmd_code;
        ccw->flags = 0;
        ccw->count = memsize;
        ccw->cda = 0;
        if (cda)
                ccw->cda = virt_to_dma32(cda);
        return ccw + 1;
}

static inline struct ccw1 *
tape_ccw_cmd(struct ccw1 *ccw, __u8 cmd_code)
{
        ccw->cmd_code = cmd_code;
        ccw->flags = 0;
        ccw->count = 0;
        ccw->cda = virt_to_dma32(&ccw->cmd_code);
        return ccw + 1;
}

static inline struct ccw1 *
tape_ccw_repeat(struct ccw1 *ccw, __u8 cmd_code, int count)
{
        while (count-- > 0) {
                ccw->cmd_code = cmd_code;
                ccw->flags = CCW_FLAG_CC;
                ccw->count = 0;
                ccw->cda = virt_to_dma32(&ccw->cmd_code);
                ccw++;
        }
        return ccw;
}

static inline struct ccw1 *
tape_ccw_dc_idal(struct ccw1 *ccw, __u8 cmd_code, struct idal_buffer *idal)
{
        ccw->cmd_code = cmd_code;
        ccw->flags    = CCW_FLAG_DC;
        idal_buffer_set_cda(idal, ccw);
        return ccw + 1;
}

static inline struct ccw1 *
tape_ccw_cc_idal(struct ccw1 *ccw, __u8 cmd_code, struct idal_buffer *idal)
{
        ccw->cmd_code = cmd_code;
        ccw->flags    = CCW_FLAG_CC;
        idal_buffer_set_cda(idal, ccw);
        return ccw + 1;
}

static inline struct ccw1 *
tape_ccw_end_idal(struct ccw1 *ccw, __u8 cmd_code, struct idal_buffer *idal)
{
        ccw->cmd_code = cmd_code;
        ccw->flags    = 0;
        idal_buffer_set_cda(idal, ccw);
        return ccw + 1;
}

/* Global vars */
extern const char *tape_state_verbose[];
extern const char *tape_op_verbose[];

#endif /* for ifdef tape.h */