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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 static inline int copy_SCp_to_sg(struct scatterlist *sg, struct scsi_pointer *SCp, int max)
  22 {
  23         int bufs = SCp->buffers_residual;
  24
  25         BUG_ON(bufs + 1 > max);
  26
  27         sg_set_buf(sg, SCp->ptr, SCp->this_residual);
  28
  29         if (bufs)
  30                 memcpy(sg + 1, SCp->buffer + 1,
  31                        sizeof(struct scatterlist) * bufs);
  32         return bufs + 1;
  33 }
  34
  35 static inline int next_SCp(struct scsi_pointer *SCp)
  36 {
  37         int ret = SCp->buffers_residual;
  38         if (ret) {
  39                 SCp->buffer++;
  40                 SCp->buffers_residual--;
  41                 SCp->ptr = (char *)
  42                          (page_address(SCp->buffer->page) +
  43                           SCp->buffer->offset);
  44                 SCp->this_residual = SCp->buffer->length;
  45         } else {
  46                 SCp->ptr = NULL;
  47                 SCp->this_residual = 0;
  48         }
  49         return ret;
  50 }
  51
  52 static inline unsigned char get_next_SCp_byte(struct scsi_pointer *SCp)
  53 {
  54         char c = *SCp->ptr;
  55
  56         SCp->ptr += 1;
  57         SCp->this_residual -= 1;
  58
  59         return c;
  60 }
  61
  62 static inline void put_next_SCp_byte(struct scsi_pointer *SCp, unsigned char c)
  63 {
  64         *SCp->ptr = c;
  65         SCp->ptr += 1;
  66         SCp->this_residual -= 1;
  67 }
  68
  69 static inline void init_SCp(struct scsi_cmnd *SCpnt)
  70 {
  71         memset(&SCpnt->SCp, 0, sizeof(struct scsi_pointer));
  72
  73         if (SCpnt->use_sg) {
  74                 unsigned long len = 0;
  75                 int buf;
  76
  77                 SCpnt->SCp.buffer = (struct scatterlist *) SCpnt->request_buffer;
  78                 SCpnt->SCp.buffers_residual = SCpnt->use_sg - 1;
  79                 SCpnt->SCp.ptr = (char *)
  80                          (page_address(SCpnt->SCp.buffer->page) +
  81                           SCpnt->SCp.buffer->offset);
  82                 SCpnt->SCp.this_residual = SCpnt->SCp.buffer->length;
  83
  84 #ifdef BELT_AND_BRACES
  85                 /*
  86                  * Calculate correct buffer length.  Some commands
  87                  * come in with the wrong request_bufflen.
  88                  */
  89                 for (buf = 0; buf <= SCpnt->SCp.buffers_residual; buf++)
  90                         len += SCpnt->SCp.buffer[buf].length;
  91
  92                 if (SCpnt->request_bufflen != len)
  93                         printk(KERN_WARNING "scsi%d.%c: bad request buffer "
  94                                "length %d, should be %ld\n", SCpnt->device->host->host_no,
  95                                '0' + SCpnt->device->id, SCpnt->request_bufflen, len);
  96                 SCpnt->request_bufflen = len;
  97 #endif
  98         } else {
  99                 SCpnt->SCp.ptr = (unsigned char *)SCpnt->request_buffer;
 100                 SCpnt->SCp.this_residual = SCpnt->request_bufflen;
 101         }
 102
 103         /*
 104          * If the upper SCSI layers pass a buffer, but zero length,
 105          * we aren't interested in the buffer pointer.
 106          */
 107         if (SCpnt->SCp.this_residual == 0 && SCpnt->SCp.ptr) {
 108 #if 0 //def BELT_AND_BRACES
 109                 printk(KERN_WARNING "scsi%d.%c: zero length buffer passed for "
 110                        "command ", SCpnt->host->host_no, '0' + SCpnt->target);
 111                 __scsi_print_command(SCpnt->cmnd);
 112 #endif
 113                 SCpnt->SCp.ptr = NULL;
 114         }
 115 }