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 */
 27static 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
 50static 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
 65static 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
 75static 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
 82static 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}