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 #include <linux/blkdev.h>
  11
  12 struct Scsi_Host;
  13 struct scsi_device;
  14
  15 /*
  16  * MAX_COMMAND_SIZE is:
  17  * The longest fixed-length SCSI CDB as per the SCSI standard.
  18  * fixed-length means: commands that their size can be determined
  19  * by their opcode and the CDB does not carry a length specifier, (unlike
  20  * the VARIABLE_LENGTH_CMD(0x7f) command). This is actually not exactly
  21  * true and the SCSI standard also defines extended commands and
  22  * vendor specific commands that can be bigger than 16 bytes. The kernel
  23  * will support these using the same infrastructure used for VARLEN CDB's.
  24  * So in effect MAX_COMMAND_SIZE means the maximum size command scsi-ml
  25  * supports without specifying a cmd_len by ULD's
  26  */
  27 #define MAX_COMMAND_SIZE 16
  28 #if (MAX_COMMAND_SIZE > BLK_MAX_CDB)
  29 # error MAX_COMMAND_SIZE can not be bigger than BLK_MAX_CDB
  30 #endif
  31
  32 struct scsi_data_buffer {
  33         struct sg_table table;
  34         unsigned length;
  35         int resid;
  36 };
  37
  38 /* embedded in scsi_cmnd */
  39 struct scsi_pointer {
  40         char *ptr;              /* data pointer */
  41         int this_residual;      /* left in this buffer */
  42         struct scatterlist *buffer;     /* which buffer */
  43         int buffers_residual;   /* how many buffers left */
  44
  45         dma_addr_t dma_handle;
  46
  47         volatile int Status;
  48         volatile int Message;
  49         volatile int have_data_in;
  50         volatile int sent_command;
  51         volatile int phase;
  52 };
  53
  54 struct scsi_cmnd {
  55         struct scsi_device *device;
  56         struct list_head list;  /* scsi_cmnd participates in queue lists */
  57         struct list_head eh_entry; /* entry for the host eh_cmd_q */
  58         int eh_eflags;          /* Used by error handlr */
  59
  60         /*
  61          * A SCSI Command is assigned a nonzero serial_number before passed
  62          * to the driver's queue command function.  The serial_number is
  63          * cleared when scsi_done is entered indicating that the command
  64          * has been completed.  It is a bug for LLDDs to use this number
  65          * for purposes other than printk (and even that is only useful
  66          * for debugging).
  67          */
  68         unsigned long serial_number;
  69
  70         /*
  71          * This is set to jiffies as it was when the command was first
  72          * allocated.  It is used to time how long the command has
  73          * been outstanding
  74          */
  75         unsigned long jiffies_at_alloc;
  76
  77         int retries;
  78         int allowed;
  79         int timeout_per_command;
  80
  81         unsigned short cmd_len;
  82         enum dma_data_direction sc_data_direction;
  83
  84         /* These elements define the operation we are about to perform */
  85         unsigned char *cmnd;
  86
  87         struct timer_list eh_timeout;   /* Used to time out the command. */
  88
  89         /* These elements define the operation we ultimately want to perform */
  90         struct scsi_data_buffer sdb;
  91         unsigned underflow;     /* Return error if less than
  92                                    this amount is transferred */
  93
  94         unsigned transfersize;  /* How much we are guaranteed to
  95                                    transfer with each SCSI transfer
  96                                    (ie, between disconnect /
  97                                    reconnects.   Probably == sector
  98                                    size */
  99
 100         struct request *request;        /* The command we are
 101                                            working on */
 102
 103 #define SCSI_SENSE_BUFFERSIZE   96
 104         unsigned char *sense_buffer;
 105                                 /* obtained by REQUEST SENSE when
 106                                  * CHECK CONDITION is received on original
 107                                  * command (auto-sense) */
 108
 109         /* Low-level done function - can be used by low-level driver to point
 110          *        to completion function.  Not used by mid/upper level code. */
 111         void (*scsi_done) (struct scsi_cmnd *);
 112
 113         /*
 114          * The following fields can be written to by the host specific code.
 115          * Everything else should be left alone.
 116          */
 117         struct scsi_pointer SCp;        /* Scratchpad used by some host adapters */
 118
 119         unsigned char *host_scribble;   /* The host adapter is allowed to
 120                                          * call scsi_malloc and get some memory
 121                                          * and hang it here.  The host adapter
 122                                          * is also expected to call scsi_free
 123                                          * to release this memory.  (The memory
 124                                          * obtained by scsi_malloc is guaranteed
 125                                          * to be at an address < 16Mb). */
 126
 127         int result;             /* Status code from lower level driver */
 128
 129         unsigned char tag;      /* SCSI-II queued command tag */
 130 };
 131
 132 extern struct scsi_cmnd *scsi_get_command(struct scsi_device *, gfp_t);
 133 extern struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *, gfp_t);
 134 extern void scsi_put_command(struct scsi_cmnd *);
 135 extern void __scsi_put_command(struct Scsi_Host *, struct scsi_cmnd *,
 136                                struct device *);
 137 extern void scsi_finish_command(struct scsi_cmnd *cmd);
 138 extern void scsi_req_abort_cmd(struct scsi_cmnd *cmd);
 139
 140 extern void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
 141                                  size_t *offset, size_t *len);
 142 extern void scsi_kunmap_atomic_sg(void *virt);
 143
 144 extern int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask);
 145 extern void scsi_release_buffers(struct scsi_cmnd *cmd);
 146
 147 extern int scsi_dma_map(struct scsi_cmnd *cmd);
 148 extern void scsi_dma_unmap(struct scsi_cmnd *cmd);
 149
 150 struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask);
 151 void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd);
 152
 153 static inline unsigned scsi_sg_count(struct scsi_cmnd *cmd)
 154 {
 155         return cmd->sdb.table.nents;
 156 }
 157
 158 static inline struct scatterlist *scsi_sglist(struct scsi_cmnd *cmd)
 159 {
 160         return cmd->sdb.table.sgl;
 161 }
 162
 163 static inline unsigned scsi_bufflen(struct scsi_cmnd *cmd)
 164 {
 165         return cmd->sdb.length;
 166 }
 167
 168 static inline void scsi_set_resid(struct scsi_cmnd *cmd, int resid)
 169 {
 170         cmd->sdb.resid = resid;
 171 }
 172
 173 static inline int scsi_get_resid(struct scsi_cmnd *cmd)
 174 {
 175         return cmd->sdb.resid;
 176 }
 177
 178 #define scsi_for_each_sg(cmd, sg, nseg, __i)                    \
 179         for_each_sg(scsi_sglist(cmd), sg, nseg, __i)
 180
 181 static inline int scsi_bidi_cmnd(struct scsi_cmnd *cmd)
 182 {
 183         return blk_bidi_rq(cmd->request) &&
 184                 (cmd->request->next_rq->special != NULL);
 185 }
 186
 187 static inline struct scsi_data_buffer *scsi_in(struct scsi_cmnd *cmd)
 188 {
 189         return scsi_bidi_cmnd(cmd) ?
 190                 cmd->request->next_rq->special : &cmd->sdb;
 191 }
 192
 193 static inline struct scsi_data_buffer *scsi_out(struct scsi_cmnd *cmd)
 194 {
 195         return &cmd->sdb;
 196 }
 197
 198 static inline int scsi_sg_copy_from_buffer(struct scsi_cmnd *cmd,
 199                                            void *buf, int buflen)
 200 {
 201         return sg_copy_from_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
 202                                    buf, buflen);
 203 }
 204
 205 static inline int scsi_sg_copy_to_buffer(struct scsi_cmnd *cmd,
 206                                          void *buf, int buflen)
 207 {
 208         return sg_copy_to_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
 209                                  buf, buflen);
 210 }
 211
 212 #endif /* _SCSI_SCSI_CMND_H */