/* 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 dma;	/* DMA-able 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_driver *driver;
  	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 restr_dma;
  	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 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? */
  	int block_size;
  	int min_block;
  	int max_block;
  	int recover_count;     /* From tape opening */
  	int recover_reg;       /* From last status call */
  
  #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
  	struct gendisk *disk;

  	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