LXR linux/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 */
  24static 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
  47static 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
  62static 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
  72static 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
  79static 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}
 126