1 /*
2 * Copyright (c) 2009 Travis Geiselbrecht
3 *
4 * Use of this source code is governed by a MIT-style
5 * license that can be found in the LICENSE file or at
6 * https://opensource.org/licenses/MIT
7 */
8 #include <lk/debug.h>
9 #include <lk/trace.h>
10 #include <string.h>
11 #include <stdlib.h>
12 #include <lib/bio.h>
13
14 #define LOCAL_TRACE 0
15
16 #define BLOCKSIZE 512
17
18 typedef struct mem_bdev {
19 bdev_t dev; // base device
20
21 void *ptr;
22 } mem_bdev_t;
23
mem_bdev_read(bdev_t * bdev,void * buf,off_t offset,size_t len)24 static ssize_t mem_bdev_read(bdev_t *bdev, void *buf, off_t offset, size_t len) {
25 mem_bdev_t *mem = (mem_bdev_t *)bdev;
26
27 LTRACEF("bdev %s, buf %p, offset %lld, len %zu\n", bdev->name, buf, offset, len);
28
29 memcpy(buf, (uint8_t *)mem->ptr + offset, len);
30
31 return len;
32 }
33
mem_bdev_read_block(struct bdev * bdev,void * buf,bnum_t block,uint count)34 static ssize_t mem_bdev_read_block(struct bdev *bdev, void *buf, bnum_t block, uint count) {
35 mem_bdev_t *mem = (mem_bdev_t *)bdev;
36
37 LTRACEF("bdev %s, buf %p, block %u, count %u\n", bdev->name, buf, block, count);
38
39 memcpy(buf, (uint8_t *)mem->ptr + block * BLOCKSIZE, count * BLOCKSIZE);
40
41 return count * BLOCKSIZE;
42 }
43
mem_bdev_write(bdev_t * bdev,const void * buf,off_t offset,size_t len)44 static ssize_t mem_bdev_write(bdev_t *bdev, const void *buf, off_t offset, size_t len) {
45 mem_bdev_t *mem = (mem_bdev_t *)bdev;
46
47 LTRACEF("bdev %s, buf %p, offset %lld, len %zu\n", bdev->name, buf, offset, len);
48
49 memcpy((uint8_t *)mem->ptr + offset, buf, len);
50
51 return len;
52 }
53
mem_bdev_write_block(struct bdev * bdev,const void * buf,bnum_t block,uint count)54 static ssize_t mem_bdev_write_block(struct bdev *bdev, const void *buf, bnum_t block, uint count) {
55 mem_bdev_t *mem = (mem_bdev_t *)bdev;
56
57 LTRACEF("bdev %s, buf %p, block %u, count %u\n", bdev->name, buf, block, count);
58
59 memcpy((uint8_t *)mem->ptr + block * BLOCKSIZE, buf, count * BLOCKSIZE);
60
61 return count * BLOCKSIZE;
62 }
63
create_membdev(const char * name,void * ptr,size_t len)64 int create_membdev(const char *name, void *ptr, size_t len) {
65 mem_bdev_t *mem = malloc(sizeof(mem_bdev_t));
66
67 /* set up the base device */
68 bio_initialize_bdev(&mem->dev, name, BLOCKSIZE, len / BLOCKSIZE, 0, NULL,
69 BIO_FLAGS_NONE);
70
71 /* our bits */
72 mem->ptr = ptr;
73 mem->dev.read = mem_bdev_read;
74 mem->dev.read_block = mem_bdev_read_block;
75 mem->dev.write = mem_bdev_write;
76 mem->dev.write_block = mem_bdev_write_block;
77
78 /* register it */
79 bio_register_device(&mem->dev);
80
81 return 0;
82 }
83
84