1 /* SPDX-License-Identifier: GPL-2.0-only */
3 * linux/drivers/acorn/scsi/scsi.h
5 * Copyright (C) 2002 Russell King
7 * Commonly used scsi driver functions.
10 #include <linux/scatterlist.h>
12 #define BELT_AND_BRACES
15 * The scatter-gather list handling. This contains all
16 * the yucky stuff that needs to be fixed properly.
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
24 static inline int copy_SCp_to_sg(struct scatterlist *sg, struct scsi_pointer *SCp, int max)
26 int bufs = SCp->buffers_residual;
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
31 BUG_ON(bufs + 1 > max);
33 sg_set_buf(sg, SCp->ptr, SCp->this_residual);
36 struct scatterlist *src_sg;
39 for_each_sg(sg_next(SCp->buffer), src_sg, bufs, i)
47 static inline int next_SCp(struct scsi_pointer *SCp)
49 int ret = SCp->buffers_residual;
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;
57 SCp->this_residual = 0;
62 static inline unsigned char get_next_SCp_byte(struct scsi_pointer *SCp)
67 SCp->this_residual -= 1;
72 static inline void put_next_SCp_byte(struct scsi_pointer *SCp, unsigned char c)
76 SCp->this_residual -= 1;
79 static inline void init_SCp(struct scsi_cmnd *SCpnt)
81 memset(&SCpnt->SCp, 0, sizeof(struct scsi_pointer));
83 if (scsi_bufflen(SCpnt)) {
84 unsigned long len = 0;
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);
92 #ifdef BELT_AND_BRACES
94 * Calculate correct buffer length. Some commands
95 * come in with the wrong scsi_bufflen.
97 struct scatterlist *sg;
98 unsigned i, sg_count = scsi_sg_count(SCpnt);
100 scsi_for_each_sg(SCpnt, sg, sg_count, i)
103 if (scsi_bufflen(SCpnt) != len) {
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);
111 * FIXME: Totaly naive fixup. We should abort
115 min_t(unsigned long, len,
116 scsi_bufflen(SCpnt));
121 SCpnt->SCp.ptr = NULL;
122 SCpnt->SCp.this_residual = 0;
123 SCpnt->SCp.phase = 0;