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root/include/linux/pktcdvd.h

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/*
 * Copyright (C) 2000 Jens Axboe <axboe@suse.de>
 * Copyright (C) 2001-2004 Peter Osterlund <petero2@telia.com>
 *
 * May be copied or modified under the terms of the GNU General Public
 * License.  See linux/COPYING for more information.
 *
 * Packet writing layer for ATAPI and SCSI CD-R, CD-RW, DVD-R, and
 * DVD-RW devices.
 *
 */
#ifndef __PKTCDVD_H
#define __PKTCDVD_H

#include <linux/types.h>

/*
 * 1 for normal debug messages, 2 is very verbose. 0 to turn it off.
 */
#define PACKET_DEBUG            1

#define MAX_WRITERS             8

#define PKT_RB_POOL_SIZE        512

/*
 * How long we should hold a non-full packet before starting data gathering.
 */
#define PACKET_WAIT_TIME        (HZ * 5 / 1000)

/*
 * use drive write caching -- we need deferred error handling to be
 * able to sucessfully recover with this option (drive will return good
 * status as soon as the cdb is validated).
 */
#if defined(CONFIG_CDROM_PKTCDVD_WCACHE)
#define USE_WCACHING            1
#else
#define USE_WCACHING            0
#endif

/*
 * No user-servicable parts beyond this point ->
 */

/*
 * device types
 */
#define PACKET_CDR              1
#define PACKET_CDRW             2
#define PACKET_DVDR             3
#define PACKET_DVDRW            4

/*
 * flags
 */
#define PACKET_WRITABLE         1       /* pd is writable */
#define PACKET_NWA_VALID        2       /* next writable address valid */
#define PACKET_LRA_VALID        3       /* last recorded address valid */
#define PACKET_MERGE_SEGS       4       /* perform segment merging to keep */
                                        /* underlying cdrom device happy */

/*
 * Disc status -- from READ_DISC_INFO
 */
#define PACKET_DISC_EMPTY       0
#define PACKET_DISC_INCOMPLETE  1
#define PACKET_DISC_COMPLETE    2
#define PACKET_DISC_OTHER       3

/*
 * write type, and corresponding data block type
 */
#define PACKET_MODE1            1
#define PACKET_MODE2            2
#define PACKET_BLOCK_MODE1      8
#define PACKET_BLOCK_MODE2      10

/*
 * Last session/border status
 */
#define PACKET_SESSION_EMPTY            0
#define PACKET_SESSION_INCOMPLETE       1
#define PACKET_SESSION_RESERVED         2
#define PACKET_SESSION_COMPLETE         3

#define PACKET_MCN                      "4a656e734178626f65323030300000"

#undef PACKET_USE_LS

#define PKT_CTRL_CMD_SETUP      0
#define PKT_CTRL_CMD_TEARDOWN   1
#define PKT_CTRL_CMD_STATUS     2

struct pkt_ctrl_command {
        __u32 command;                          /* in: Setup, teardown, status */
        __u32 dev_index;                        /* in/out: Device index */
        __u32 dev;                              /* in/out: Device nr for cdrw device */
        __u32 pkt_dev;                          /* in/out: Device nr for packet device */
        __u32 num_devices;                      /* out: Largest device index + 1 */
        __u32 padding;                          /* Not used */
};

/*
 * packet ioctls
 */
#define PACKET_IOCTL_MAGIC      ('X')
#define PACKET_CTRL_CMD         _IOWR(PACKET_IOCTL_MAGIC, 1, struct pkt_ctrl_command)

#ifdef __KERNEL__
#include <linux/blkdev.h>
#include <linux/completion.h>
#include <linux/cdrom.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>

/* default bio write queue congestion marks */
#define PKT_WRITE_CONGESTION_ON    10000
#define PKT_WRITE_CONGESTION_OFF   9000


struct packet_settings
{
        __u32                   size;           /* packet size in (512 byte) sectors */
        __u8                    fp;             /* fixed packets */
        __u8                    link_loss;      /* the rest is specified
                                                 * as per Mt Fuji */
        __u8                    write_type;
        __u8                    track_mode;
        __u8                    block_mode;
};

/*
 * Very crude stats for now
 */
struct packet_stats
{
        unsigned long           pkt_started;
        unsigned long           pkt_ended;
        unsigned long           secs_w;
        unsigned long           secs_rg;
        unsigned long           secs_r;
};

struct packet_cdrw
{
        struct list_head        pkt_free_list;
        struct list_head        pkt_active_list;
        spinlock_t              active_list_lock; /* Serialize access to pkt_active_list */
        struct task_struct      *thread;
        atomic_t                pending_bios;
};

/*
 * Switch to high speed reading after reading this many kilobytes
 * with no interspersed writes.
 */
#define HI_SPEED_SWITCH 512

struct packet_iosched
{
        atomic_t                attention;      /* Set to non-zero when queue processing is needed */
        int                     writing;        /* Non-zero when writing, zero when reading */
        spinlock_t              lock;           /* Protecting read/write queue manipulations */
        struct bio              *read_queue;
        struct bio              *read_queue_tail;
        struct bio              *write_queue;
        struct bio              *write_queue_tail;
        sector_t                last_write;     /* The sector where the last write ended */
        int                     successive_reads;
};

/*
 * 32 buffers of 2048 bytes
 */
#if (PAGE_SIZE % CD_FRAMESIZE) != 0
#error "PAGE_SIZE must be a multiple of CD_FRAMESIZE"
#endif
#define PACKET_MAX_SIZE         128
#define FRAMES_PER_PAGE         (PAGE_SIZE / CD_FRAMESIZE)
#define PACKET_MAX_SECTORS      (PACKET_MAX_SIZE * CD_FRAMESIZE >> 9)

enum packet_data_state {
        PACKET_IDLE_STATE,                      /* Not used at the moment */
        PACKET_WAITING_STATE,                   /* Waiting for more bios to arrive, so */
                                                /* we don't have to do as much */
                                                /* data gathering */
        PACKET_READ_WAIT_STATE,                 /* Waiting for reads to fill in holes */
        PACKET_WRITE_WAIT_STATE,                /* Waiting for the write to complete */
        PACKET_RECOVERY_STATE,                  /* Recover after read/write errors */
        PACKET_FINISHED_STATE,                  /* After write has finished */

        PACKET_NUM_STATES                       /* Number of possible states */
};

/*
 * Information needed for writing a single packet
 */
struct pktcdvd_device;

struct packet_data
{
        struct list_head        list;

        spinlock_t              lock;           /* Lock protecting state transitions and */
                                                /* orig_bios list */

        struct bio              *orig_bios;     /* Original bios passed to pkt_make_request */
        struct bio              *orig_bios_tail;/* that will be handled by this packet */
        int                     write_size;     /* Total size of all bios in the orig_bios */
                                                /* list, measured in number of frames */

        struct bio              *w_bio;         /* The bio we will send to the real CD */
                                                /* device once we have all data for the */
                                                /* packet we are going to write */
        sector_t                sector;         /* First sector in this packet */
        int                     frames;         /* Number of frames in this packet */

        enum packet_data_state  state;          /* Current state */
        atomic_t                run_sm;         /* Incremented whenever the state */
                                                /* machine needs to be run */
        long                    sleep_time;     /* Set this to non-zero to make the state */
                                                /* machine run after this many jiffies. */

        atomic_t                io_wait;        /* Number of pending IO operations */
        atomic_t                io_errors;      /* Number of read/write errors during IO */

        struct bio              *r_bios[PACKET_MAX_SIZE]; /* bios to use during data gathering */
        struct page             *pages[PACKET_MAX_SIZE / FRAMES_PER_PAGE];

        int                     cache_valid;    /* If non-zero, the data for the zone defined */
                                                /* by the sector variable is completely cached */
                                                /* in the pages[] vector. */

        int                     id;             /* ID number for debugging */
        struct pktcdvd_device   *pd;
};

struct pkt_rb_node {
        struct rb_node          rb_node;
        struct bio              *bio;
};

struct packet_stacked_data
{
        struct bio              *bio;           /* Original read request bio */
        struct pktcdvd_device   *pd;
};
#define PSD_POOL_SIZE           64

struct pktcdvd_kobj
{
        struct kobject          kobj;
        struct pktcdvd_device   *pd;
};
#define to_pktcdvdkobj(_k) \
  ((struct pktcdvd_kobj*)container_of(_k,struct pktcdvd_kobj,kobj))

struct pktcdvd_device
{
        struct block_device     *bdev;          /* dev attached */
        dev_t                   pkt_dev;        /* our dev */
        char                    name[20];
        struct packet_settings  settings;
        struct packet_stats     stats;
        int                     refcnt;         /* Open count */
        int                     write_speed;    /* current write speed, kB/s */
        int                     read_speed;     /* current read speed, kB/s */
        unsigned long           offset;         /* start offset */
        __u8                    mode_offset;    /* 0 / 8 */
        __u8                    type;
        unsigned long           flags;
        __u16                   mmc3_profile;
        __u32                   nwa;            /* next writable address */
        __u32                   lra;            /* last recorded address */
        struct packet_cdrw      cdrw;
        wait_queue_head_t       wqueue;

        spinlock_t              lock;           /* Serialize access to bio_queue */
        struct rb_root          bio_queue;      /* Work queue of bios we need to handle */
        int                     bio_queue_size; /* Number of nodes in bio_queue */
        sector_t                current_sector; /* Keep track of where the elevator is */
        atomic_t                scan_queue;     /* Set to non-zero when pkt_handle_queue */
                                                /* needs to be run. */
        mempool_t               *rb_pool;       /* mempool for pkt_rb_node allocations */

        struct packet_iosched   iosched;
        struct gendisk          *disk;

        int                     write_congestion_off;
        int                     write_congestion_on;

        struct device           *dev;           /* sysfs pktcdvd[0-7] dev */
        struct pktcdvd_kobj     *kobj_stat;     /* sysfs pktcdvd[0-7]/stat/     */
        struct pktcdvd_kobj     *kobj_wqueue;   /* sysfs pktcdvd[0-7]/write_queue/ */

        struct dentry           *dfs_d_root;    /* debugfs: devname directory */
        struct dentry           *dfs_f_info;    /* debugfs: info file */
};

#endif /* __KERNEL__ */

#endif /* __PKTCDVD_H */

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