linux/include/scsi/scsi_cmnd.h
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   1#ifndef _SCSI_SCSI_CMND_H
   2#define _SCSI_SCSI_CMND_H
   3
   4#include <linux/dma-mapping.h>
   5#include <linux/blkdev.h>
   6#include <linux/list.h>
   7#include <linux/types.h>
   8#include <linux/timer.h>
   9#include <linux/scatterlist.h>
  10
  11struct Scsi_Host;
  12struct scsi_device;
  13
  14/*
  15 * MAX_COMMAND_SIZE is:
  16 * The longest fixed-length SCSI CDB as per the SCSI standard.
  17 * fixed-length means: commands that their size can be determined
  18 * by their opcode and the CDB does not carry a length specifier, (unlike
  19 * the VARIABLE_LENGTH_CMD(0x7f) command). This is actually not exactly
  20 * true and the SCSI standard also defines extended commands and
  21 * vendor specific commands that can be bigger than 16 bytes. The kernel
  22 * will support these using the same infrastructure used for VARLEN CDB's.
  23 * So in effect MAX_COMMAND_SIZE means the maximum size command scsi-ml
  24 * supports without specifying a cmd_len by ULD's
  25 */
  26#define MAX_COMMAND_SIZE 16
  27#if (MAX_COMMAND_SIZE > BLK_MAX_CDB)
  28# error MAX_COMMAND_SIZE can not be bigger than BLK_MAX_CDB
  29#endif
  30
  31struct scsi_data_buffer {
  32        struct sg_table table;
  33        unsigned length;
  34        int resid;
  35};
  36
  37/* embedded in scsi_cmnd */
  38struct scsi_pointer {
  39        char *ptr;              /* data pointer */
  40        int this_residual;      /* left in this buffer */
  41        struct scatterlist *buffer;     /* which buffer */
  42        int buffers_residual;   /* how many buffers left */
  43
  44        dma_addr_t dma_handle;
  45
  46        volatile int Status;
  47        volatile int Message;
  48        volatile int have_data_in;
  49        volatile int sent_command;
  50        volatile int phase;
  51};
  52
  53struct scsi_cmnd {
  54        struct scsi_device *device;
  55        struct list_head list;  /* scsi_cmnd participates in queue lists */
  56        struct list_head eh_entry; /* entry for the host eh_cmd_q */
  57        int eh_eflags;          /* Used by error handlr */
  58
  59        /*
  60         * A SCSI Command is assigned a nonzero serial_number before passed
  61         * to the driver's queue command function.  The serial_number is
  62         * cleared when scsi_done is entered indicating that the command
  63         * has been completed.  It is a bug for LLDDs to use this number
  64         * for purposes other than printk (and even that is only useful
  65         * for debugging).
  66         */
  67        unsigned long serial_number;
  68
  69        /*
  70         * This is set to jiffies as it was when the command was first
  71         * allocated.  It is used to time how long the command has
  72         * been outstanding
  73         */
  74        unsigned long jiffies_at_alloc;
  75
  76        int retries;
  77        int allowed;
  78
  79        unsigned char prot_op;
  80        unsigned char prot_type;
  81
  82        unsigned short cmd_len;
  83        enum dma_data_direction sc_data_direction;
  84
  85        /* These elements define the operation we are about to perform */
  86        unsigned char *cmnd;
  87
  88
  89        /* These elements define the operation we ultimately want to perform */
  90        struct scsi_data_buffer sdb;
  91        struct scsi_data_buffer *prot_sdb;
  92
  93        unsigned underflow;     /* Return error if less than
  94                                   this amount is transferred */
  95
  96        unsigned transfersize;  /* How much we are guaranteed to
  97                                   transfer with each SCSI transfer
  98                                   (ie, between disconnect / 
  99                                   reconnects.   Probably == sector
 100                                   size */
 101
 102        struct request *request;        /* The command we are
 103                                           working on */
 104
 105#define SCSI_SENSE_BUFFERSIZE   96
 106        unsigned char *sense_buffer;
 107                                /* obtained by REQUEST SENSE when
 108                                 * CHECK CONDITION is received on original
 109                                 * command (auto-sense) */
 110
 111        /* Low-level done function - can be used by low-level driver to point
 112         *        to completion function.  Not used by mid/upper level code. */
 113        void (*scsi_done) (struct scsi_cmnd *);
 114
 115        /*
 116         * The following fields can be written to by the host specific code. 
 117         * Everything else should be left alone. 
 118         */
 119        struct scsi_pointer SCp;        /* Scratchpad used by some host adapters */
 120
 121        unsigned char *host_scribble;   /* The host adapter is allowed to
 122                                         * call scsi_malloc and get some memory
 123                                         * and hang it here.  The host adapter
 124                                         * is also expected to call scsi_free
 125                                         * to release this memory.  (The memory
 126                                         * obtained by scsi_malloc is guaranteed
 127                                         * to be at an address < 16Mb). */
 128
 129        int result;             /* Status code from lower level driver */
 130
 131        unsigned char tag;      /* SCSI-II queued command tag */
 132};
 133
 134extern struct scsi_cmnd *scsi_get_command(struct scsi_device *, gfp_t);
 135extern struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *, gfp_t);
 136extern void scsi_put_command(struct scsi_cmnd *);
 137extern void __scsi_put_command(struct Scsi_Host *, struct scsi_cmnd *,
 138                               struct device *);
 139extern void scsi_finish_command(struct scsi_cmnd *cmd);
 140
 141extern void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
 142                                 size_t *offset, size_t *len);
 143extern void scsi_kunmap_atomic_sg(void *virt);
 144
 145extern int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask);
 146extern void scsi_release_buffers(struct scsi_cmnd *cmd);
 147
 148extern int scsi_dma_map(struct scsi_cmnd *cmd);
 149extern void scsi_dma_unmap(struct scsi_cmnd *cmd);
 150
 151struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask);
 152void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd);
 153
 154static inline unsigned scsi_sg_count(struct scsi_cmnd *cmd)
 155{
 156        return cmd->sdb.table.nents;
 157}
 158
 159static inline struct scatterlist *scsi_sglist(struct scsi_cmnd *cmd)
 160{
 161        return cmd->sdb.table.sgl;
 162}
 163
 164static inline unsigned scsi_bufflen(struct scsi_cmnd *cmd)
 165{
 166        return cmd->sdb.length;
 167}
 168
 169static inline void scsi_set_resid(struct scsi_cmnd *cmd, int resid)
 170{
 171        cmd->sdb.resid = resid;
 172}
 173
 174static inline int scsi_get_resid(struct scsi_cmnd *cmd)
 175{
 176        return cmd->sdb.resid;
 177}
 178
 179#define scsi_for_each_sg(cmd, sg, nseg, __i)                    \
 180        for_each_sg(scsi_sglist(cmd), sg, nseg, __i)
 181
 182static inline int scsi_bidi_cmnd(struct scsi_cmnd *cmd)
 183{
 184        return blk_bidi_rq(cmd->request) &&
 185                (cmd->request->next_rq->special != NULL);
 186}
 187
 188static inline struct scsi_data_buffer *scsi_in(struct scsi_cmnd *cmd)
 189{
 190        return scsi_bidi_cmnd(cmd) ?
 191                cmd->request->next_rq->special : &cmd->sdb;
 192}
 193
 194static inline struct scsi_data_buffer *scsi_out(struct scsi_cmnd *cmd)
 195{
 196        return &cmd->sdb;
 197}
 198
 199static inline int scsi_sg_copy_from_buffer(struct scsi_cmnd *cmd,
 200                                           void *buf, int buflen)
 201{
 202        return sg_copy_from_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
 203                                   buf, buflen);
 204}
 205
 206static inline int scsi_sg_copy_to_buffer(struct scsi_cmnd *cmd,
 207                                         void *buf, int buflen)
 208{
 209        return sg_copy_to_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
 210                                 buf, buflen);
 211}
 212
 213/*
 214 * The operations below are hints that tell the controller driver how
 215 * to handle I/Os with DIF or similar types of protection information.
 216 */
 217enum scsi_prot_operations {
 218        /* Normal I/O */
 219        SCSI_PROT_NORMAL = 0,
 220
 221        /* OS-HBA: Protected, HBA-Target: Unprotected */
 222        SCSI_PROT_READ_INSERT,
 223        SCSI_PROT_WRITE_STRIP,
 224
 225        /* OS-HBA: Unprotected, HBA-Target: Protected */
 226        SCSI_PROT_READ_STRIP,
 227        SCSI_PROT_WRITE_INSERT,
 228
 229        /* OS-HBA: Protected, HBA-Target: Protected */
 230        SCSI_PROT_READ_PASS,
 231        SCSI_PROT_WRITE_PASS,
 232};
 233
 234static inline void scsi_set_prot_op(struct scsi_cmnd *scmd, unsigned char op)
 235{
 236        scmd->prot_op = op;
 237}
 238
 239static inline unsigned char scsi_get_prot_op(struct scsi_cmnd *scmd)
 240{
 241        return scmd->prot_op;
 242}
 243
 244/*
 245 * The controller usually does not know anything about the target it
 246 * is communicating with.  However, when DIX is enabled the controller
 247 * must be know target type so it can verify the protection
 248 * information passed along with the I/O.
 249 */
 250enum scsi_prot_target_type {
 251        SCSI_PROT_DIF_TYPE0 = 0,
 252        SCSI_PROT_DIF_TYPE1,
 253        SCSI_PROT_DIF_TYPE2,
 254        SCSI_PROT_DIF_TYPE3,
 255};
 256
 257static inline void scsi_set_prot_type(struct scsi_cmnd *scmd, unsigned char type)
 258{
 259        scmd->prot_type = type;
 260}
 261
 262static inline unsigned char scsi_get_prot_type(struct scsi_cmnd *scmd)
 263{
 264        return scmd->prot_type;
 265}
 266
 267static inline sector_t scsi_get_lba(struct scsi_cmnd *scmd)
 268{
 269        return blk_rq_pos(scmd->request);
 270}
 271
 272static inline unsigned scsi_prot_sg_count(struct scsi_cmnd *cmd)
 273{
 274        return cmd->prot_sdb ? cmd->prot_sdb->table.nents : 0;
 275}
 276
 277static inline struct scatterlist *scsi_prot_sglist(struct scsi_cmnd *cmd)
 278{
 279        return cmd->prot_sdb ? cmd->prot_sdb->table.sgl : NULL;
 280}
 281
 282static inline struct scsi_data_buffer *scsi_prot(struct scsi_cmnd *cmd)
 283{
 284        return cmd->prot_sdb;
 285}
 286
 287#define scsi_for_each_prot_sg(cmd, sg, nseg, __i)               \
 288        for_each_sg(scsi_prot_sglist(cmd), sg, nseg, __i)
 289
 290static inline void set_msg_byte(struct scsi_cmnd *cmd, char status)
 291{
 292        cmd->result |= status << 8;
 293}
 294
 295static inline void set_host_byte(struct scsi_cmnd *cmd, char status)
 296{
 297        cmd->result |= status << 16;
 298}
 299
 300static inline void set_driver_byte(struct scsi_cmnd *cmd, char status)
 301{
 302        cmd->result |= status << 24;
 303}
 304
 305#endif /* _SCSI_SCSI_CMND_H */
 306
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