scsi_cmnd.h

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#ifndef _SCSI_SCSI_CMND_H
#define _SCSI_SCSI_CMND_H

#include <linux/dma-mapping.h>
#include <linux/blkdev.h>
#include <linux/list.h>
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/scatterlist.h>

struct Scsi_Host;
struct scsi_device;
struct scsi_driver;

/*
 * MAX_COMMAND_SIZE is:
 * The longest fixed-length SCSI CDB as per the SCSI standard.
 * fixed-length means: commands that their size can be determined
 * by their opcode and the CDB does not carry a length specifier, (unlike
 * the VARIABLE_LENGTH_CMD(0x7f) command). This is actually not exactly
 * true and the SCSI standard also defines extended commands and
 * vendor specific commands that can be bigger than 16 bytes. The kernel
 * will support these using the same infrastructure used for VARLEN CDB's.
 * So in effect MAX_COMMAND_SIZE means the maximum size command scsi-ml
 * supports without specifying a cmd_len by ULD's
 */
#define MAX_COMMAND_SIZE 16
#if (MAX_COMMAND_SIZE > BLK_MAX_CDB)
# error MAX_COMMAND_SIZE can not be bigger than BLK_MAX_CDB
#endif

struct scsi_data_buffer {
    struct sg_table table;
    unsigned length;
    int resid;
};

/* embedded in scsi_cmnd */
struct scsi_pointer {
    char *ptr;      /* data pointer */
    int this_residual;  /* left in this buffer */
    struct scatterlist *buffer; /* which buffer */
    int buffers_residual;   /* how many buffers left */

        dma_addr_t dma_handle;

    volatile int Status;
    volatile int Message;
    volatile int have_data_in;
    volatile int sent_command;
    volatile int phase;
};

struct scsi_cmnd {
    struct scsi_device *device;
    struct list_head list;  /* scsi_cmnd participates in queue lists */
    struct list_head eh_entry; /* entry for the host eh_cmd_q */
    int eh_eflags;      /* Used by error handlr */

    /*
     * A SCSI Command is assigned a nonzero serial_number before passed
     * to the driver's queue command function.  The serial_number is
     * cleared when scsi_done is entered indicating that the command
     * has been completed.  It is a bug for LLDDs to use this number
     * for purposes other than printk (and even that is only useful
     * for debugging).
     */
    unsigned long serial_number;

    /*
     * This is set to jiffies as it was when the command was first
     * allocated.  It is used to time how long the command has
     * been outstanding
     */
    unsigned long jiffies_at_alloc;

    int retries;
    int allowed;

    unsigned char prot_op;
    unsigned char prot_type;

    unsigned short cmd_len;
    enum dma_data_direction sc_data_direction;

    /* These elements define the operation we are about to perform */
    unsigned char *cmnd;


    /* These elements define the operation we ultimately want to perform */
    struct scsi_data_buffer sdb;
    struct scsi_data_buffer *prot_sdb;

    unsigned underflow; /* Return error if less than
                   this amount is transferred */

    unsigned transfersize;  /* How much we are guaranteed to
                   transfer with each SCSI transfer
                   (ie, between disconnect / 
                   reconnects.   Probably == sector
                   size */

    struct request *request;    /* The command we are
                       working on */

#define SCSI_SENSE_BUFFERSIZE   96
    unsigned char *sense_buffer;
                /* obtained by REQUEST SENSE when
                 * CHECK CONDITION is received on original
                 * command (auto-sense) */

    /* Low-level done function - can be used by low-level driver to point
     *        to completion function.  Not used by mid/upper level code. */
    void (*scsi_done) (struct scsi_cmnd *);

    /*
     * The following fields can be written to by the host specific code. 
     * Everything else should be left alone. 
     */
    struct scsi_pointer SCp;    /* Scratchpad used by some host adapters */

    unsigned char *host_scribble;   /* The host adapter is allowed to
                     * call scsi_malloc and get some memory
                     * and hang it here.  The host adapter
                     * is also expected to call scsi_free
                     * to release this memory.  (The memory
                     * obtained by scsi_malloc is guaranteed
                     * to be at an address < 16Mb). */

    int result;     /* Status code from lower level driver */

    unsigned char tag;  /* SCSI-II queued command tag */
};

/* make sure not to use it with REQ_TYPE_BLOCK_PC commands */
static inline struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
{
    return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
}

extern struct scsi_cmnd *scsi_get_command(struct scsi_device *, gfp_t);
extern struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *, gfp_t);
extern void scsi_put_command(struct scsi_cmnd *);
extern void __scsi_put_command(struct Scsi_Host *, struct scsi_cmnd *,
                   struct device *);
extern void scsi_finish_command(struct scsi_cmnd *cmd);

extern void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
                 size_t *offset, size_t *len);
extern void scsi_kunmap_atomic_sg(void *virt);

extern int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask);
extern void scsi_release_buffers(struct scsi_cmnd *cmd);

extern int scsi_dma_map(struct scsi_cmnd *cmd);
extern void scsi_dma_unmap(struct scsi_cmnd *cmd);

struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask);
void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd);

static inline unsigned scsi_sg_count(struct scsi_cmnd *cmd)
{
    return cmd->sdb.table.nents;
}

static inline struct scatterlist *scsi_sglist(struct scsi_cmnd *cmd)
{
    return cmd->sdb.table.sgl;
}

static inline unsigned scsi_bufflen(struct scsi_cmnd *cmd)
{
    return cmd->sdb.length;
}

static inline void scsi_set_resid(struct scsi_cmnd *cmd, int resid)
{
    cmd->sdb.resid = resid;
}

static inline int scsi_get_resid(struct scsi_cmnd *cmd)
{
    return cmd->sdb.resid;
}

#define scsi_for_each_sg(cmd, sg, nseg, __i)            \
    for_each_sg(scsi_sglist(cmd), sg, nseg, __i)

static inline int scsi_bidi_cmnd(struct scsi_cmnd *cmd)
{
    return blk_bidi_rq(cmd->request) &&
        (cmd->request->next_rq->special != NULL);
}

static inline struct scsi_data_buffer *scsi_in(struct scsi_cmnd *cmd)
{
    return scsi_bidi_cmnd(cmd) ?
        cmd->request->next_rq->special : &cmd->sdb;
}

static inline struct scsi_data_buffer *scsi_out(struct scsi_cmnd *cmd)
{
    return &cmd->sdb;
}

static inline int scsi_sg_copy_from_buffer(struct scsi_cmnd *cmd,
                       void *buf, int buflen)
{
    return sg_copy_from_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
                   buf, buflen);
}

static inline int scsi_sg_copy_to_buffer(struct scsi_cmnd *cmd,
                     void *buf, int buflen)
{
    return sg_copy_to_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
                 buf, buflen);
}

/*
 * The operations below are hints that tell the controller driver how
 * to handle I/Os with DIF or similar types of protection information.
 */
enum scsi_prot_operations {
    /* Normal I/O */
    SCSI_PROT_NORMAL = 0,

    /* OS-HBA: Protected, HBA-Target: Unprotected */
    SCSI_PROT_READ_INSERT,
    SCSI_PROT_WRITE_STRIP,

    /* OS-HBA: Unprotected, HBA-Target: Protected */
    SCSI_PROT_READ_STRIP,
    SCSI_PROT_WRITE_INSERT,

    /* OS-HBA: Protected, HBA-Target: Protected */
    SCSI_PROT_READ_PASS,
    SCSI_PROT_WRITE_PASS,
};

static inline void scsi_set_prot_op(struct scsi_cmnd *scmd, unsigned char op)
{
    scmd->prot_op = op;
}

static inline unsigned char scsi_get_prot_op(struct scsi_cmnd *scmd)
{
    return scmd->prot_op;
}

/*
 * The controller usually does not know anything about the target it
 * is communicating with.  However, when DIX is enabled the controller
 * must be know target type so it can verify the protection
 * information passed along with the I/O.
 */
enum scsi_prot_target_type {
    SCSI_PROT_DIF_TYPE0 = 0,
    SCSI_PROT_DIF_TYPE1,
    SCSI_PROT_DIF_TYPE2,
    SCSI_PROT_DIF_TYPE3,
};

static inline void scsi_set_prot_type(struct scsi_cmnd *scmd, unsigned char type)
{
    scmd->prot_type = type;
}

static inline unsigned char scsi_get_prot_type(struct scsi_cmnd *scmd)
{
    return scmd->prot_type;
}

static inline sector_t scsi_get_lba(struct scsi_cmnd *scmd)
{
    return blk_rq_pos(scmd->request);
}

static inline unsigned scsi_prot_sg_count(struct scsi_cmnd *cmd)
{
    return cmd->prot_sdb ? cmd->prot_sdb->table.nents : 0;
}

static inline struct scatterlist *scsi_prot_sglist(struct scsi_cmnd *cmd)
{
    return cmd->prot_sdb ? cmd->prot_sdb->table.sgl : NULL;
}

static inline struct scsi_data_buffer *scsi_prot(struct scsi_cmnd *cmd)
{
    return cmd->prot_sdb;
}

#define scsi_for_each_prot_sg(cmd, sg, nseg, __i)       \
    for_each_sg(scsi_prot_sglist(cmd), sg, nseg, __i)

static inline void set_msg_byte(struct scsi_cmnd *cmd, char status)
{
    cmd->result = (cmd->result & 0xffff00ff) | (status << 8);
}

static inline void set_host_byte(struct scsi_cmnd *cmd, char status)
{
    cmd->result = (cmd->result & 0xff00ffff) | (status << 16);
}

static inline void set_driver_byte(struct scsi_cmnd *cmd, char status)
{
    cmd->result = (cmd->result & 0x00ffffff) | (status << 24);
}

#endif /* _SCSI_SCSI_CMND_H */