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}
129