drivers/scsi/arm/arm_scsi.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  *  Copyright (C) 2002 Russell King
   4  *
   5  *  Commonly used functions by the ARM SCSI-II drivers.
   6  */
   7
   8 #include <linux/scatterlist.h>
   9
  10 #define BELT_AND_BRACES
  11
  12 struct arm_cmd_priv {
  13         struct scsi_pointer scsi_pointer;
  14 };
  15
  16 static inline struct scsi_pointer *arm_scsi_pointer(struct scsi_cmnd *cmd)
  17 {
  18         struct arm_cmd_priv *acmd = scsi_cmd_priv(cmd);
  19
  20         return &acmd->scsi_pointer;
  21 }
  22
  23 /*
  24  * The scatter-gather list handling.  This contains all
  25  * the yucky stuff that needs to be fixed properly.
  26  */
  27
  28 /*
  29  * copy_SCp_to_sg() Assumes contiguous allocation at @sg of at-most @max
  30  * entries of uninitialized memory. SCp is from scsi-ml and has a valid
  31  * (possibly chained) sg-list
  32  */
  33 static inline int copy_SCp_to_sg(struct scatterlist *sg, struct scsi_pointer *SCp, int max)
  34 {
  35         int bufs = SCp->buffers_residual;
  36
  37         /* FIXME: It should be easy for drivers to loop on copy_SCp_to_sg().
  38          * and to remove this BUG_ON. Use min() in-its-place
  39          */
  40         BUG_ON(bufs + 1 > max);
  41
  42         sg_set_buf(sg, SCp->ptr, SCp->this_residual);
  43
  44         if (bufs) {
  45                 struct scatterlist *src_sg;
  46                 unsigned i;
  47
  48                 for_each_sg(sg_next(SCp->buffer), src_sg, bufs, i)
  49                         *(++sg) = *src_sg;
  50                 sg_mark_end(sg);
  51         }
  52
  53         return bufs + 1;
  54 }
  55
  56 static inline int next_SCp(struct scsi_pointer *SCp)
  57 {
  58         int ret = SCp->buffers_residual;
  59         if (ret) {
  60                 SCp->buffer = sg_next(SCp->buffer);
  61                 SCp->buffers_residual--;
  62                 SCp->ptr = sg_virt(SCp->buffer);
  63                 SCp->this_residual = SCp->buffer->length;
  64         } else {
  65                 SCp->ptr = NULL;
  66                 SCp->this_residual = 0;
  67         }
  68         return ret;
  69 }
  70
  71 static inline unsigned char get_next_SCp_byte(struct scsi_pointer *SCp)
  72 {
  73         char c = *SCp->ptr;
  74
  75         SCp->ptr += 1;
  76         SCp->this_residual -= 1;
  77
  78         return c;
  79 }
  80
  81 static inline void put_next_SCp_byte(struct scsi_pointer *SCp, unsigned char c)
  82 {
  83         *SCp->ptr = c;
  84         SCp->ptr += 1;
  85         SCp->this_residual -= 1;
  86 }
  87
  88 static inline void init_SCp(struct scsi_cmnd *SCpnt)
  89 {
  90         struct scsi_pointer *scsi_pointer = arm_scsi_pointer(SCpnt);
  91
  92         memset(scsi_pointer, 0, sizeof(struct scsi_pointer));
  93
  94         if (scsi_bufflen(SCpnt)) {
  95                 unsigned long len = 0;
  96
  97                 scsi_pointer->buffer = scsi_sglist(SCpnt);
  98                 scsi_pointer->buffers_residual = scsi_sg_count(SCpnt) - 1;
  99                 scsi_pointer->ptr = sg_virt(scsi_pointer->buffer);
 100                 scsi_pointer->this_residual = scsi_pointer->buffer->length;
 101                 scsi_pointer->phase = scsi_bufflen(SCpnt);
 102
 103 #ifdef BELT_AND_BRACES
 104                 {       /*
 105                          * Calculate correct buffer length.  Some commands
 106                          * come in with the wrong scsi_bufflen.
 107                          */
 108                         struct scatterlist *sg;
 109                         unsigned i, sg_count = scsi_sg_count(SCpnt);
 110
 111                         scsi_for_each_sg(SCpnt, sg, sg_count, i)
 112                                 len += sg->length;
 113
 114                         if (scsi_bufflen(SCpnt) != len) {
 115                                 printk(KERN_WARNING
 116                                        "scsi%d.%c: bad request buffer "
 117                                        "length %d, should be %ld\n",
 118                                         SCpnt->device->host->host_no,
 119                                         '0' + SCpnt->device->id,
 120                                         scsi_bufflen(SCpnt), len);
 121                                 /*
 122                                  * FIXME: Totaly naive fixup. We should abort
 123                                  * with error
 124                                  */
 125                                 scsi_pointer->phase =
 126                                         min_t(unsigned long, len,
 127                                               scsi_bufflen(SCpnt));
 128                         }
 129                 }
 130 #endif
 131         } else {
 132                 scsi_pointer->ptr = NULL;
 133                 scsi_pointer->this_residual = 0;
 134                 scsi_pointer->phase = 0;
 135         }
 136 }