drivers/scsi/arm/scsi.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  *  linux/drivers/acorn/scsi/scsi.h
   4  *
   5  *  Copyright (C) 2002 Russell King
   6  *
   7  *  Commonly used scsi driver functions.
   8  */
   9
  10 #include <linux/scatterlist.h>
  11
  12 #define BELT_AND_BRACES
  13
  14 /*
  15  * The scatter-gather list handling.  This contains all
  16  * the yucky stuff that needs to be fixed properly.
  17  */
  18
  19 /*
  20  * copy_SCp_to_sg() Assumes contiguous allocation at @sg of at-most @max
  21  * entries of uninitialized memory. SCp is from scsi-ml and has a valid
  22  * (possibly chained) sg-list
  23  */
  24 static inline int copy_SCp_to_sg(struct scatterlist *sg, struct scsi_pointer *SCp, int max)
  25 {
  26         int bufs = SCp->buffers_residual;
  27
  28         /* FIXME: It should be easy for drivers to loop on copy_SCp_to_sg().
  29          * and to remove this BUG_ON. Use min() in-its-place
  30          */
  31         BUG_ON(bufs + 1 > max);
  32
  33         sg_set_buf(sg, SCp->ptr, SCp->this_residual);
  34
  35         if (bufs) {
  36                 struct scatterlist *src_sg;
  37                 unsigned i;
  38
  39                 for_each_sg(sg_next(SCp->buffer), src_sg, bufs, i)
  40                         *(++sg) = *src_sg;
  41                 sg_mark_end(sg);
  42         }
  43
  44         return bufs + 1;
  45 }
  46
  47 static inline int next_SCp(struct scsi_pointer *SCp)
  48 {
  49         int ret = SCp->buffers_residual;
  50         if (ret) {
  51                 SCp->buffer = sg_next(SCp->buffer);
  52                 SCp->buffers_residual--;
  53                 SCp->ptr = sg_virt(SCp->buffer);
  54                 SCp->this_residual = SCp->buffer->length;
  55         } else {
  56                 SCp->ptr = NULL;
  57                 SCp->this_residual = 0;
  58         }
  59         return ret;
  60 }
  61
  62 static inline unsigned char get_next_SCp_byte(struct scsi_pointer *SCp)
  63 {
  64         char c = *SCp->ptr;
  65
  66         SCp->ptr += 1;
  67         SCp->this_residual -= 1;
  68
  69         return c;
  70 }
  71
  72 static inline void put_next_SCp_byte(struct scsi_pointer *SCp, unsigned char c)
  73 {
  74         *SCp->ptr = c;
  75         SCp->ptr += 1;
  76         SCp->this_residual -= 1;
  77 }
  78
  79 static inline void init_SCp(struct scsi_cmnd *SCpnt)
  80 {
  81         memset(&SCpnt->SCp, 0, sizeof(struct scsi_pointer));
  82
  83         if (scsi_bufflen(SCpnt)) {
  84                 unsigned long len = 0;
  85
  86                 SCpnt->SCp.buffer = scsi_sglist(SCpnt);
  87                 SCpnt->SCp.buffers_residual = scsi_sg_count(SCpnt) - 1;
  88                 SCpnt->SCp.ptr = sg_virt(SCpnt->SCp.buffer);
  89                 SCpnt->SCp.this_residual = SCpnt->SCp.buffer->length;
  90                 SCpnt->SCp.phase = scsi_bufflen(SCpnt);
  91
  92 #ifdef BELT_AND_BRACES
  93                 {       /*
  94                          * Calculate correct buffer length.  Some commands
  95                          * come in with the wrong scsi_bufflen.
  96                          */
  97                         struct scatterlist *sg;
  98                         unsigned i, sg_count = scsi_sg_count(SCpnt);
  99
 100                         scsi_for_each_sg(SCpnt, sg, sg_count, i)
 101                                 len += sg->length;
 102
 103                         if (scsi_bufflen(SCpnt) != len) {
 104                                 printk(KERN_WARNING
 105                                        "scsi%d.%c: bad request buffer "
 106                                        "length %d, should be %ld\n",
 107                                         SCpnt->device->host->host_no,
 108                                         '0' + SCpnt->device->id,
 109                                         scsi_bufflen(SCpnt), len);
 110                                 /*
 111                                  * FIXME: Totaly naive fixup. We should abort
 112                                  * with error
 113                                  */
 114                                 SCpnt->SCp.phase =
 115                                         min_t(unsigned long, len,
 116                                               scsi_bufflen(SCpnt));
 117                         }
 118                 }
 119 #endif
 120         } else {
 121                 SCpnt->SCp.ptr = NULL;
 122                 SCpnt->SCp.this_residual = 0;
 123                 SCpnt->SCp.phase = 0;
 124         }
 125 }