include/scsi/scsi_cmnd.h

   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
  11 struct Scsi_Host;
  12 struct 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
  31 struct scsi_data_buffer {
  32         struct sg_table table;
  33         unsigned length;
  34         int resid;
  35 };
  36
  37 /* embedded in scsi_cmnd */
  38 struct 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
  53 struct 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         int timeout_per_command;
  79
  80         unsigned short cmd_len;
  81         enum dma_data_direction sc_data_direction;
  82
  83         /* These elements define the operation we are about to perform */
  84         unsigned char *cmnd;
  85
  86         struct timer_list eh_timeout;   /* Used to time out the command. */
  87
  88         /* These elements define the operation we ultimately want to perform */
  89         struct scsi_data_buffer sdb;
  90         unsigned underflow;     /* Return error if less than
  91                                    this amount is transferred */
  92
  93         unsigned transfersize;  /* How much we are guaranteed to
  94                                    transfer with each SCSI transfer
  95                                    (ie, between disconnect /
  96                                    reconnects.   Probably == sector
  97                                    size */
  98
  99         struct request *request;        /* The command we are
 100                                            working on */
 101
 102 #define SCSI_SENSE_BUFFERSIZE   96
 103         unsigned char *sense_buffer;
 104                                 /* obtained by REQUEST SENSE when
 105                                  * CHECK CONDITION is received on original
 106                                  * command (auto-sense) */
 107
 108         /* Low-level done function - can be used by low-level driver to point
 109          *        to completion function.  Not used by mid/upper level code. */
 110         void (*scsi_done) (struct scsi_cmnd *);
 111
 112         /*
 113          * The following fields can be written to by the host specific code.
 114          * Everything else should be left alone.
 115          */
 116         struct scsi_pointer SCp;        /* Scratchpad used by some host adapters */
 117
 118         unsigned char *host_scribble;   /* The host adapter is allowed to
 119                                          * call scsi_malloc and get some memory
 120                                          * and hang it here.  The host adapter
 121                                          * is also expected to call scsi_free
 122                                          * to release this memory.  (The memory
 123                                          * obtained by scsi_malloc is guaranteed
 124                                          * to be at an address < 16Mb). */
 125
 126         int result;             /* Status code from lower level driver */
 127
 128         unsigned char tag;      /* SCSI-II queued command tag */
 129 };
 130
 131 extern struct scsi_cmnd *scsi_get_command(struct scsi_device *, gfp_t);
 132 extern struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *, gfp_t);
 133 extern void scsi_put_command(struct scsi_cmnd *);
 134 extern void __scsi_put_command(struct Scsi_Host *, struct scsi_cmnd *,
 135                                struct device *);
 136 extern void scsi_finish_command(struct scsi_cmnd *cmd);
 137 extern void scsi_req_abort_cmd(struct scsi_cmnd *cmd);
 138
 139 extern void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
 140                                  size_t *offset, size_t *len);
 141 extern void scsi_kunmap_atomic_sg(void *virt);
 142
 143 extern int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask);
 144 extern void scsi_release_buffers(struct scsi_cmnd *cmd);
 145
 146 extern int scsi_dma_map(struct scsi_cmnd *cmd);
 147 extern void scsi_dma_unmap(struct scsi_cmnd *cmd);
 148
 149 struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask);
 150 void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd);
 151
 152 static inline unsigned scsi_sg_count(struct scsi_cmnd *cmd)
 153 {
 154         return cmd->sdb.table.nents;
 155 }
 156
 157 static inline struct scatterlist *scsi_sglist(struct scsi_cmnd *cmd)
 158 {
 159         return cmd->sdb.table.sgl;
 160 }
 161
 162 static inline unsigned scsi_bufflen(struct scsi_cmnd *cmd)
 163 {
 164         return cmd->sdb.length;
 165 }
 166
 167 static inline void scsi_set_resid(struct scsi_cmnd *cmd, int resid)
 168 {
 169         cmd->sdb.resid = resid;
 170 }
 171
 172 static inline int scsi_get_resid(struct scsi_cmnd *cmd)
 173 {
 174         return cmd->sdb.resid;
 175 }
 176
 177 #define scsi_for_each_sg(cmd, sg, nseg, __i)                    \
 178         for_each_sg(scsi_sglist(cmd), sg, nseg, __i)
 179
 180 static inline int scsi_bidi_cmnd(struct scsi_cmnd *cmd)
 181 {
 182         return blk_bidi_rq(cmd->request) &&
 183                 (cmd->request->next_rq->special != NULL);
 184 }
 185
 186 static inline struct scsi_data_buffer *scsi_in(struct scsi_cmnd *cmd)
 187 {
 188         return scsi_bidi_cmnd(cmd) ?
 189                 cmd->request->next_rq->special : &cmd->sdb;
 190 }
 191
 192 static inline struct scsi_data_buffer *scsi_out(struct scsi_cmnd *cmd)
 193 {
 194         return &cmd->sdb;
 195 }
 196
 197 static inline int scsi_sg_copy_from_buffer(struct scsi_cmnd *cmd,
 198                                            void *buf, int buflen)
 199 {
 200         return sg_copy_from_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
 201                                    buf, buflen);
 202 }
 203
 204 static inline int scsi_sg_copy_to_buffer(struct scsi_cmnd *cmd,
 205                                          void *buf, int buflen)
 206 {
 207         return sg_copy_to_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
 208                                  buf, buflen);
 209 }
 210
 211 #endif /* _SCSI_SCSI_CMND_H */