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 */
27 static 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
50 static 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
65 static 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
75 static 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
82 static 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 '' + 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
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