1 /****************************************************************************
2 * drivers/bch/bchlib_write.c
3 *
4 * Licensed to the Apache Software Foundation (ASF) under one or more
5 * contributor license agreements. See the NOTICE file distributed with
6 * this work for additional information regarding copyright ownership. The
7 * ASF licenses this file to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance with the
9 * License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
16 * License for the specific language governing permissions and limitations
17 * under the License.
18 *
19 ****************************************************************************/
20
21 /****************************************************************************
22 * Included Files
23 ****************************************************************************/
24 #include <sys/types.h>
25 #include <stdint.h>
26 #include <stdbool.h>
27 #include <string.h>
28 #include <errno.h>
29 #include <assert.h>
30 #include "bch.h"
31
32 /****************************************************************************
33 * Public Functions
34 ****************************************************************************/
35
36 /****************************************************************************
37 * Name: bchlib_write
38 *
39 * Description:
40 * Write to the block device set-up by bchlib_setup as if it were a character
41 * device.
42 *
43 ****************************************************************************/
44
bchlib_write(void * handle,const char * buffer,loff_t offset,size_t len)45 ssize_t bchlib_write(void *handle, const char *buffer, loff_t offset, size_t len)
46 {
47 struct bchlib_s *bch = (struct bchlib_s *)handle;
48 size_t nsectors;
49 unsigned long long sector;
50 uint16_t sectoffset;
51 size_t nbytes;
52 size_t byteswritten;
53 int ret;
54
55 /* Get rid of this special case right away */
56
57 if (len < 1)
58 {
59 return 0;
60 }
61
62 /* Convert the file position into a sector number and offset. */
63
64 sector = offset / bch->sectsize;
65 sectoffset = offset - sector * bch->sectsize;
66
67 if (sector >= bch->nsectors)
68 {
69 return 0;
70 }
71
72 /* Write the initial partial sector */
73
74 byteswritten = 0;
75 if (sectoffset > 0)
76 {
77 /* Read the full sector into the sector buffer */
78
79 ret = bchlib_readsector(bch, sector + bch->sectstart);
80 if (ret < 0)
81 {
82 return byteswritten;
83 }
84
85 /* Copy the tail end of the sector from the user buffer */
86
87 if (sectoffset + len > bch->sectsize)
88 {
89 nbytes = bch->sectsize - sectoffset;
90 }
91 else
92 {
93 nbytes = len;
94 }
95
96 ret = LOS_CopyToKernel(&bch->buffer[sectoffset], nbytes, buffer, nbytes);
97 if (ret != EOK)
98 {
99 PRINTK("ERROR: bchlib_write failed: %d\n", ret);
100 return byteswritten;
101 }
102 bch->dirty = true;
103
104 /* Adjust pointers and counts */
105
106 sector++;
107
108 if (sector >= bch->nsectors)
109 {
110 return nbytes;
111 }
112
113 byteswritten = nbytes;
114 buffer += nbytes;
115 len -= nbytes;
116 }
117
118 /* Then write all of the full sectors following the partial sector
119 * directly from the user buffer.
120 */
121
122 if (len >= bch->sectsize)
123 {
124 nsectors = len / bch->sectsize;
125 if (sector + nsectors > bch->nsectors)
126 {
127 nsectors = bch->nsectors - sector;
128 }
129
130 /* Flush the dirty sector to keep the sector sequence */
131
132 ret = bchlib_flushsector(bch);
133 if (ret < 0)
134 {
135 PRINTK("ERROR: Flush failed: %d\n", ret);
136 return ret;
137 }
138
139 /* Write the contiguous sectors */
140
141 ret = los_disk_write(bch->disk->disk_id, (const void *)buffer,
142 sector + bch->sectstart, nsectors);
143 if (ret < 0)
144 {
145 PRINTK("ERROR: Write failed: %d\n", ret);
146 return byteswritten;
147 }
148
149 /* Adjust pointers and counts */
150
151 sector += nsectors;
152 nbytes = nsectors * bch->sectsize;
153 byteswritten += nbytes;
154
155 if (sector >= bch->nsectors)
156 {
157 return byteswritten;
158 }
159
160 buffer += nbytes;
161 len -= nbytes;
162 }
163
164 /* Then write any partial final sector */
165
166 if (len > 0)
167 {
168 /* Read the sector into the sector buffer */
169
170 ret = bchlib_readsector(bch, sector + bch->sectstart);
171 if (ret < 0)
172 {
173 return byteswritten;
174 }
175
176 /* Copy the head end of the sector from the user buffer */
177
178 ret = LOS_CopyToKernel(bch->buffer, len, buffer, len);
179 if (ret != EOK)
180 {
181 PRINTK("ERROR: bchlib_write failed: %d\n", ret);
182 return byteswritten;
183 }
184 bch->dirty = true;
185
186 /* Adjust counts */
187
188 byteswritten += len;
189 }
190
191 return byteswritten;
192 }
193
194