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   1 /*
   2  *  linux/drivers/acorn/scsi/scsi.h
   3  *
   4  *  Copyright (C) 2002 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  *  Commonly used scsi driver functions.
  11  */
  12
  13 #include <linux/scatterlist.h>
  14
  15 #define BELT_AND_BRACES
  16
  17 /*
  18  * The scatter-gather list handling.  This contains all
  19  * the yucky stuff that needs to be fixed properly.
  20  */
  21
  22 /*
  23  * copy_SCp_to_sg() Assumes contiguous allocation at @sg of at-most @max
  24  * entries of uninitialized memory. SCp is from scsi-ml and has a valid
  25  * (possibly chained) sg-list
  26  */
  27 static inline int copy_SCp_to_sg(struct scatterlist *sg, struct scsi_pointer *SCp, int max)
  28 {
  29         int bufs = SCp->buffers_residual;
  30
  31         /* FIXME: It should be easy for drivers to loop on copy_SCp_to_sg().
  32          * and to remove this BUG_ON. Use min() in-its-place
  33          */
  34         BUG_ON(bufs + 1 > max);
  35
  36         sg_set_buf(sg, SCp->ptr, SCp->this_residual);
  37
  38         if (bufs) {
  39                 struct scatterlist *src_sg;
  40                 unsigned i;
  41
  42                 for_each_sg(sg_next(SCp->buffer), src_sg, bufs, i)
  43                         *(++sg) = *src_sg;
  44                 sg_mark_end(sg);
  45         }
  46
  47         return bufs + 1;
  48 }
  49
  50 static inline int next_SCp(struct scsi_pointer *SCp)
  51 {
  52         int ret = SCp->buffers_residual;
  53         if (ret) {
  54                 SCp->buffer = sg_next(SCp->buffer);
  55                 SCp->buffers_residual--;
  56                 SCp->ptr = sg_virt(SCp->buffer);
  57                 SCp->this_residual = SCp->buffer->length;
  58         } else {
  59                 SCp->ptr = NULL;
  60                 SCp->this_residual = 0;
  61         }
  62         return ret;
  63 }
  64
  65 static inline unsigned char get_next_SCp_byte(struct scsi_pointer *SCp)
  66 {
  67         char c = *SCp->ptr;
  68
  69         SCp->ptr += 1;
  70         SCp->this_residual -= 1;
  71
  72         return c;
  73 }
  74
  75 static inline void put_next_SCp_byte(struct scsi_pointer *SCp, unsigned char c)
  76 {
  77         *SCp->ptr = c;
  78         SCp->ptr += 1;
  79         SCp->this_residual -= 1;
  80 }
  81
  82 static inline void init_SCp(struct scsi_cmnd *SCpnt)
  83 {
  84         memset(&SCpnt->SCp, 0, sizeof(struct scsi_pointer));
  85
  86         if (scsi_bufflen(SCpnt)) {
  87                 unsigned long len = 0;
  88
  89                 SCpnt->SCp.buffer = scsi_sglist(SCpnt);
  90                 SCpnt->SCp.buffers_residual = scsi_sg_count(SCpnt) - 1;
  91                 SCpnt->SCp.ptr = sg_virt(SCpnt->SCp.buffer);
  92                 SCpnt->SCp.this_residual = SCpnt->SCp.buffer->length;
  93                 SCpnt->SCp.phase = scsi_bufflen(SCpnt);
  94
  95 #ifdef BELT_AND_BRACES
  96                 {       /*
  97                          * Calculate correct buffer length.  Some commands
  98                          * come in with the wrong scsi_bufflen.
  99                          */
 100                         struct scatterlist *sg;
 101                         unsigned i, sg_count = scsi_sg_count(SCpnt);
 102
 103                         scsi_for_each_sg(SCpnt, sg, sg_count, i)
 104                                 len += sg->length;
 105
 106                         if (scsi_bufflen(SCpnt) != len) {
 107                                 printk(KERN_WARNING
 108                                        "scsi%d.%c: bad request buffer "
 109                                        "length %d, should be %ld\n",
 110                                         SCpnt->device->host->host_no,
 111                                         '0' + SCpnt->device->id,
 112                                         scsi_bufflen(SCpnt), len);
 113                                 /*
 114                                  * FIXME: Totaly naive fixup. We should abort
 115                                  * with error
 116                                  */
 117                                 SCpnt->SCp.phase =
 118                                         min_t(unsigned long, len,
 119                                               scsi_bufflen(SCpnt));
 120                         }
 121                 }
 122 #endif
 123         } else {
 124                 SCpnt->SCp.ptr = NULL;
 125                 SCpnt->SCp.this_residual = 0;
 126                 SCpnt->SCp.phase = 0;
 127         }
 128 }