1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * linux/drivers/acorn/scsi/scsi.h
4 *
5 * Copyright (C) 2002 Russell King
6 *
7 * Commonly used scsi driver functions.
8 */
9
10 #include <linux/scatterlist.h>
11
12 #define BELT_AND_BRACES
13
14 /*
15 * The scatter-gather list handling. This contains all
16 * the yucky stuff that needs to be fixed properly.
17 */
18
19 /*
20 * copy_SCp_to_sg() Assumes contiguous allocation at @sg of at-most @max
21 * entries of uninitialized memory. SCp is from scsi-ml and has a valid
22 * (possibly chained) sg-list
23 */
copy_SCp_to_sg(struct scatterlist * sg,struct scsi_pointer * SCp,int max)24 static inline int copy_SCp_to_sg(struct scatterlist *sg, struct scsi_pointer *SCp, int max)
25 {
26 int bufs = SCp->buffers_residual;
27
28 /* FIXME: It should be easy for drivers to loop on copy_SCp_to_sg().
29 * and to remove this BUG_ON. Use min() in-its-place
30 */
31 BUG_ON(bufs + 1 > max);
32
33 sg_set_buf(sg, SCp->ptr, SCp->this_residual);
34
35 if (bufs) {
36 struct scatterlist *src_sg;
37 unsigned i;
38
39 for_each_sg(sg_next(SCp->buffer), src_sg, bufs, i)
40 *(++sg) = *src_sg;
41 sg_mark_end(sg);
42 }
43
44 return bufs + 1;
45 }
46
next_SCp(struct scsi_pointer * SCp)47 static inline int next_SCp(struct scsi_pointer *SCp)
48 {
49 int ret = SCp->buffers_residual;
50 if (ret) {
51 SCp->buffer = sg_next(SCp->buffer);
52 SCp->buffers_residual--;
53 SCp->ptr = sg_virt(SCp->buffer);
54 SCp->this_residual = SCp->buffer->length;
55 } else {
56 SCp->ptr = NULL;
57 SCp->this_residual = 0;
58 }
59 return ret;
60 }
61
get_next_SCp_byte(struct scsi_pointer * SCp)62 static inline unsigned char get_next_SCp_byte(struct scsi_pointer *SCp)
63 {
64 char c = *SCp->ptr;
65
66 SCp->ptr += 1;
67 SCp->this_residual -= 1;
68
69 return c;
70 }
71
put_next_SCp_byte(struct scsi_pointer * SCp,unsigned char c)72 static inline void put_next_SCp_byte(struct scsi_pointer *SCp, unsigned char c)
73 {
74 *SCp->ptr = c;
75 SCp->ptr += 1;
76 SCp->this_residual -= 1;
77 }
78
init_SCp(struct scsi_cmnd * SCpnt)79 static inline void init_SCp(struct scsi_cmnd *SCpnt)
80 {
81 memset(&SCpnt->SCp, 0, sizeof(struct scsi_pointer));
82
83 if (scsi_bufflen(SCpnt)) {
84 unsigned long len = 0;
85
86 SCpnt->SCp.buffer = scsi_sglist(SCpnt);
87 SCpnt->SCp.buffers_residual = scsi_sg_count(SCpnt) - 1;
88 SCpnt->SCp.ptr = sg_virt(SCpnt->SCp.buffer);
89 SCpnt->SCp.this_residual = SCpnt->SCp.buffer->length;
90 SCpnt->SCp.phase = scsi_bufflen(SCpnt);
91
92 #ifdef BELT_AND_BRACES
93 { /*
94 * Calculate correct buffer length. Some commands
95 * come in with the wrong scsi_bufflen.
96 */
97 struct scatterlist *sg;
98 unsigned i, sg_count = scsi_sg_count(SCpnt);
99
100 scsi_for_each_sg(SCpnt, sg, sg_count, i)
101 len += sg->length;
102
103 if (scsi_bufflen(SCpnt) != len) {
104 printk(KERN_WARNING
105 "scsi%d.%c: bad request buffer "
106 "length %d, should be %ld\n",
107 SCpnt->device->host->host_no,
108 '0' + SCpnt->device->id,
109 scsi_bufflen(SCpnt), len);
110 /*
111 * FIXME: Totaly naive fixup. We should abort
112 * with error
113 */
114 SCpnt->SCp.phase =
115 min_t(unsigned long, len,
116 scsi_bufflen(SCpnt));
117 }
118 }
119 #endif
120 } else {
121 SCpnt->SCp.ptr = NULL;
122 SCpnt->SCp.this_residual = 0;
123 SCpnt->SCp.phase = 0;
124 }
125 }
126
