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 */
21static 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
35static 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
52static 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
62static 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
69static 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		SCpnt->SCp.phase = SCpnt->request_bufflen;
84
85#ifdef BELT_AND_BRACES
86		/*
87		 * Calculate correct buffer length.  Some commands
88		 * come in with the wrong request_bufflen.
89		 */
90		for (buf = 0; buf <= SCpnt->SCp.buffers_residual; buf++)
91			len += SCpnt->SCp.buffer[buf].length;
92
93		if (SCpnt->request_bufflen != len)
94			printk(KERN_WARNING "scsi%d.%c: bad request buffer "
95			       "length %d, should be %ld\n", SCpnt->device->host->host_no,
96			       '0' + SCpnt->device->id, SCpnt->request_bufflen, len);
97		SCpnt->request_bufflen = len;
98#endif
99	} else {
100		SCpnt->SCp.ptr = (unsigned char *)SCpnt->request_buffer;
101		SCpnt->SCp.this_residual = SCpnt->request_bufflen;
102		SCpnt->SCp.phase = SCpnt->request_bufflen;
103	}
104
105	/*
106	 * If the upper SCSI layers pass a buffer, but zero length,
107	 * we aren't interested in the buffer pointer.
108	 */
109	if (SCpnt->SCp.this_residual == 0 && SCpnt->SCp.ptr) {
110		SCpnt->SCp.ptr = NULL;
111	}
112}
113