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

#ifndef _ST_H
#define _ST_H

#include <linux/completion.h>
#include <linux/mutex.h>
#include <linux/kref.h>
#include <scsi/scsi_cmnd.h>

/* Descriptor for analyzed sense data */
struct st_cmdstatus {
        int midlevel_result;
        struct scsi_sense_hdr sense_hdr;
        int have_sense;
        int residual;
        u64 uremainder64;
        u8 flags;
        u8 remainder_valid;
        u8 fixed_format;
        u8 deferred;
};

struct scsi_tape;

/* scsi tape command */
struct st_request {
        unsigned char cmd[MAX_COMMAND_SIZE];
        unsigned char sense[SCSI_SENSE_BUFFERSIZE];
        int result;
        struct scsi_tape *stp;
        struct completion *waiting;
        struct bio *bio;
};

/* The tape buffer descriptor. */
struct st_buffer {
        unsigned char cleared;  /* internal buffer cleared after open? */
        unsigned short do_dio;  /* direct i/o set up? */
        int buffer_size;
        int buffer_blocks;
        int buffer_bytes;
        int read_pointer;
        int writing;
        int syscall_result;
        struct st_request *last_SRpnt;
        struct st_cmdstatus cmdstat;
        struct page **reserved_pages;
        int reserved_page_order;
        struct page **mapped_pages;
        struct rq_map_data map_data;
        unsigned char *b_data;
        unsigned short use_sg;  /* zero or max number of s/g segments for this adapter */
        unsigned short sg_segs;         /* number of segments in s/g list */
        unsigned short frp_segs;        /* number of buffer segments */
};

/* The tape mode definition */
struct st_modedef {
        unsigned char defined;
        unsigned char sysv;     /* SYS V semantics? */
        unsigned char do_async_writes;
        unsigned char do_buffer_writes;
        unsigned char do_read_ahead;
        unsigned char defaults_for_writes;
        unsigned char default_compression;      /* 0 = don't touch, etc */
        short default_density;  /* Forced density, -1 = no value */
        int default_blksize;    /* Forced blocksize, -1 = no value */
        struct scsi_tape *tape;
        struct device *devs[2];  /* Auto-rewind and non-rewind devices */
        struct cdev *cdevs[2];  /* Auto-rewind and non-rewind devices */
};

/* Number of modes can be changed by changing ST_NBR_MODE_BITS. The maximum
   number of modes is 16 (ST_NBR_MODE_BITS 4) */
#define ST_NBR_MODE_BITS 2
#define ST_NBR_MODES (1 << ST_NBR_MODE_BITS)
#define ST_MODE_SHIFT (7 - ST_NBR_MODE_BITS)
#define ST_MODE_MASK ((ST_NBR_MODES - 1) << ST_MODE_SHIFT)

#define ST_MAX_TAPES (1 << (20 - (ST_NBR_MODE_BITS + 1)))
#define ST_MAX_TAPE_ENTRIES  (ST_MAX_TAPES << (ST_NBR_MODE_BITS + 1))

/* The status related to each partition */
struct st_partstat {
        unsigned char rw;
        unsigned char eof;
        unsigned char at_sm;
        unsigned char last_block_valid;
        u32 last_block_visited;
        int drv_block;          /* The block where the drive head is */
        int drv_file;
};

/* Tape statistics */
struct scsi_tape_stats {
        atomic64_t read_byte_cnt;  /* bytes read */
        atomic64_t write_byte_cnt; /* bytes written */
        atomic64_t in_flight;      /* Number of I/Os in flight */
        atomic64_t read_cnt;       /* Count of read requests */
        atomic64_t write_cnt;      /* Count of write requests */
        atomic64_t other_cnt;      /* Count of other requests either
                                    * implicit or from user space
                                    * ioctl. */
        atomic64_t resid_cnt;      /* Count of resid_len > 0 */
        atomic64_t tot_read_time;  /* ktime spent completing reads */
        atomic64_t tot_write_time; /* ktime spent completing writes */
        atomic64_t tot_io_time;    /* ktime spent doing any I/O */
        ktime_t read_time;         /* holds ktime request was queued */
        ktime_t write_time;        /* holds ktime request was queued */
        ktime_t other_time;        /* holds ktime request was queued */
        atomic_t last_read_size;   /* Number of bytes issued for last read */
        atomic_t last_write_size;  /* Number of bytes issued for last write */
};

#define ST_NBR_PARTITIONS 4

/* The tape drive descriptor */
struct scsi_tape {
        struct scsi_device *device;
        struct mutex lock;      /* For serialization */
        struct completion wait; /* For SCSI commands */
        struct st_buffer *buffer;
        int index;

        /* Drive characteristics */
        unsigned char omit_blklims;
        unsigned char do_auto_lock;
        unsigned char can_bsr;
        unsigned char can_partitions;
        unsigned char two_fm;
        unsigned char fast_mteom;
        unsigned char immediate;
        unsigned char scsi2_logical;
        unsigned char default_drvbuffer;        /* 0xff = don't touch, value 3 bits */
        unsigned char cln_mode;                 /* 0 = none, otherwise sense byte nbr */
        unsigned char cln_sense_value;
        unsigned char cln_sense_mask;
        unsigned char use_pf;                   /* Set Page Format bit in all mode selects? */
        unsigned char try_dio;                  /* try direct i/o in general? */
        unsigned char try_dio_now;              /* try direct i/o before next close? */
        unsigned char c_algo;                   /* compression algorithm */
        unsigned char pos_unknown;                      /* after reset position unknown */
        unsigned char sili;                     /* use SILI when reading in variable b mode */
        unsigned char immediate_filemark;       /* write filemark immediately */
        int tape_type;
        int long_timeout;       /* timeout for commands known to take long time */

        /* Mode characteristics */
        struct st_modedef modes[ST_NBR_MODES];
        int current_mode;

        /* Status variables */
        int partition;
        int new_partition;
        int nbr_partitions;     /* zero until partition support enabled */
        struct st_partstat ps[ST_NBR_PARTITIONS];
        unsigned char dirty;
        unsigned char ready;
        unsigned char write_prot;
        unsigned char drv_write_prot;
        unsigned char in_use;
        unsigned char blksize_changed;
        unsigned char density_changed;
        unsigned char compression_changed;
        unsigned char drv_buffer;
        unsigned char density;
        unsigned char changed_density;
        unsigned char door_locked;
        unsigned char autorew_dev;   /* auto-rewind device */
        unsigned char rew_at_close;  /* rewind necessary at close */
        unsigned char inited;
        unsigned char cleaning_req;  /* cleaning requested? */
        unsigned char first_tur;     /* first TEST UNIT READY */
        int block_size;
        int changed_blksize;
        int min_block;
        int max_block;
        int recover_count;     /* From tape opening */
        int recover_reg;       /* From last status call */

        /* The saved values of midlevel counters */
        unsigned int new_media_ctr;
        unsigned int por_ctr;

#if DEBUG
        unsigned char write_pending;
        int nbr_finished;
        int nbr_waits;
        int nbr_requests;
        int nbr_dio;
        int nbr_pages;
        unsigned char last_cmnd[6];
        unsigned char last_sense[16];
#endif
        char name[DISK_NAME_LEN];
        struct kref     kref;
        struct scsi_tape_stats *stats;
};

/* Bit masks for use_pf */
#define USE_PF      1
#define PF_TESTED   2

/* Values of eof */
#define ST_NOEOF        0
#define ST_FM_HIT       1
#define ST_FM           2
#define ST_EOM_OK       3
#define ST_EOM_ERROR    4
#define ST_EOD_1        5
#define ST_EOD_2        6
#define ST_EOD          7
/* EOD hit while reading => ST_EOD_1 => return zero => ST_EOD_2 =>
   return zero => ST_EOD, return ENOSPC */
/* When writing: ST_EOM_OK == early warning found, write OK
                 ST_EOD_1  == allow trying new write after early warning
                 ST_EOM_ERROR == early warning found, not able to write all */

/* Values of rw */
#define ST_IDLE         0
#define ST_READING      1
#define ST_WRITING      2

/* Values of ready state */
#define ST_READY        0
#define ST_NOT_READY    1
#define ST_NO_TAPE      2

/* Values for door lock state */
#define ST_UNLOCKED     0
#define ST_LOCKED_EXPLICIT 1
#define ST_LOCKED_AUTO  2
#define ST_LOCK_FAILS   3

/* Positioning SCSI-commands for Tandberg, etc. drives */
#define QFA_REQUEST_BLOCK       0x02
#define QFA_SEEK_BLOCK          0x0c

/* Setting the binary options */
#define ST_DONT_TOUCH  0
#define ST_NO          1
#define ST_YES         2

#define EXTENDED_SENSE_START  18

/* Masks for some conditions in the sense data */
#define SENSE_FMK   0x80
#define SENSE_EOM   0x40
#define SENSE_ILI   0x20

#endif