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1/* SPDX-License-Identifier: GPL-2.0-only */2/*3 * Copyright (C) 2002 Russell King4 *5 * Commonly used functions by the ARM SCSI-II drivers.6 */7 8#include <linux/scatterlist.h>9 10#define BELT_AND_BRACES11 12struct arm_cmd_priv {13 struct scsi_pointer scsi_pointer;14};15 16static inline struct scsi_pointer *arm_scsi_pointer(struct scsi_cmnd *cmd)17{18 struct arm_cmd_priv *acmd = scsi_cmd_priv(cmd);19 20 return &acmd->scsi_pointer;21}22 23/*24 * The scatter-gather list handling. This contains all25 * the yucky stuff that needs to be fixed properly.26 */27 28/*29 * copy_SCp_to_sg() Assumes contiguous allocation at @sg of at-most @max30 * entries of uninitialized memory. SCp is from scsi-ml and has a valid31 * (possibly chained) sg-list32 */33static inline int copy_SCp_to_sg(struct scatterlist *sg, struct scsi_pointer *SCp, int max)34{35 int bufs = SCp->buffers_residual;36 37 /* FIXME: It should be easy for drivers to loop on copy_SCp_to_sg().38 * and to remove this BUG_ON. Use min() in-its-place39 */40 BUG_ON(bufs + 1 > max);41 42 sg_set_buf(sg, SCp->ptr, SCp->this_residual);43 44 if (bufs) {45 struct scatterlist *src_sg;46 unsigned i;47 48 for_each_sg(sg_next(SCp->buffer), src_sg, bufs, i)49 *(++sg) = *src_sg;50 sg_mark_end(sg);51 }52 53 return bufs + 1;54}55 56static inline int next_SCp(struct scsi_pointer *SCp)57{58 int ret = SCp->buffers_residual;59 if (ret) {60 SCp->buffer = sg_next(SCp->buffer);61 SCp->buffers_residual--;62 SCp->ptr = sg_virt(SCp->buffer);63 SCp->this_residual = SCp->buffer->length;64 } else {65 SCp->ptr = NULL;66 SCp->this_residual = 0;67 }68 return ret;69}70 71static inline unsigned char get_next_SCp_byte(struct scsi_pointer *SCp)72{73 char c = *SCp->ptr;74 75 SCp->ptr += 1;76 SCp->this_residual -= 1;77 78 return c;79}80 81static inline void put_next_SCp_byte(struct scsi_pointer *SCp, unsigned char c)82{83 *SCp->ptr = c;84 SCp->ptr += 1;85 SCp->this_residual -= 1;86}87 88static inline void init_SCp(struct scsi_cmnd *SCpnt)89{90 struct scsi_pointer *scsi_pointer = arm_scsi_pointer(SCpnt);91 92 memset(scsi_pointer, 0, sizeof(struct scsi_pointer));93 94 if (scsi_bufflen(SCpnt)) {95 unsigned long len = 0;96 97 scsi_pointer->buffer = scsi_sglist(SCpnt);98 scsi_pointer->buffers_residual = scsi_sg_count(SCpnt) - 1;99 scsi_pointer->ptr = sg_virt(scsi_pointer->buffer);100 scsi_pointer->this_residual = scsi_pointer->buffer->length;101 scsi_pointer->phase = scsi_bufflen(SCpnt);102 103#ifdef BELT_AND_BRACES104 { /*105 * Calculate correct buffer length. Some commands106 * come in with the wrong scsi_bufflen.107 */108 struct scatterlist *sg;109 unsigned i, sg_count = scsi_sg_count(SCpnt);110 111 scsi_for_each_sg(SCpnt, sg, sg_count, i)112 len += sg->length;113 114 if (scsi_bufflen(SCpnt) != len) {115 printk(KERN_WARNING116 "scsi%d.%c: bad request buffer "117 "length %d, should be %ld\n",118 SCpnt->device->host->host_no,119 '0' + SCpnt->device->id,120 scsi_bufflen(SCpnt), len);121 /*122 * FIXME: Totaly naive fixup. We should abort123 * with error124 */125 scsi_pointer->phase =126 min_t(unsigned long, len,127 scsi_bufflen(SCpnt));128 }129 }130#endif131 } else {132 scsi_pointer->ptr = NULL;133 scsi_pointer->this_residual = 0;134 scsi_pointer->phase = 0;135 }136}137