1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * Copyright (C) 2002 Russell King 4 * 5 * Commonly used functions by the ARM SCSI-II drivers. 6 */ 7 8 #include <linux/scatterlist.h> 9 10 #define BELT_AND_BRACES 11 12 struct arm_cmd_priv { 13 struct scsi_pointer scsi_pointer; 14 }; 15 16 static 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 all 25 * 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 @max 30 * entries of uninitialized memory. SCp is from scsi-ml and has a valid 31 * (possibly chained) sg-list 32 */ 33 static 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-place 39 */ 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 56 static 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 71 static 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 81 static 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 88 static 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_BRACES 104 { /* 105 * Calculate correct buffer length. Some commands 106 * 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_WARNING 116 "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 abort 123 * with error 124 */ 125 scsi_pointer->phase = 126 min_t(unsigned long, len, 127 scsi_bufflen(SCpnt)); 128 } 129 } 130 #endif 131 } else { 132 scsi_pointer->ptr = NULL; 133 scsi_pointer->this_residual = 0; 134 scsi_pointer->phase = 0; 135 } 136 } 137