Annotation of prex-old/dev/gen/ramdisk.c, Revision 1.1.1.1.2.1
1.1 nbrk 1: /*-
2: * Copyright (c) 2006, Kohsuke Ohtani
3: * All rights reserved.
4: *
5: * Redistribution and use in source and binary forms, with or without
6: * modification, are permitted provided that the following conditions
7: * are met:
8: * 1. Redistributions of source code must retain the above copyright
9: * notice, this list of conditions and the following disclaimer.
10: * 2. Redistributions in binary form must reproduce the above copyright
11: * notice, this list of conditions and the following disclaimer in the
12: * documentation and/or other materials provided with the distribution.
13: * 3. Neither the name of the author nor the names of any co-contributors
14: * may be used to endorse or promote products derived from this software
15: * without specific prior written permission.
16: *
17: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20: * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27: * SUCH DAMAGE.
28: */
29:
30: /*
31: * ramdisk.c - RAM disk driver
32: */
33:
34: #include <driver.h>
35:
36: /* #define DEBUG_RAMDISK 1 */
37:
38: #ifdef DEBUG_RAMDISK
1.1.1.1.2.1! nbrk 39: #define DPRINTF(a) printf a
1.1 nbrk 40: #else
1.1.1.1.2.1! nbrk 41: #define DPRINTF(a)
1.1 nbrk 42: #endif
43:
44: /* Block size */
45: #define BSIZE 512
46:
1.1.1.1.2.1! nbrk 47: static int ramdisk_read(device_t, char *, size_t *, int);
! 48: static int ramdisk_write(device_t, char *, size_t *, int);
1.1 nbrk 49: static int ramdisk_init(void);
50:
51: /*
52: * Driver structure
53: */
54: struct driver ramdisk_drv = {
55: /* name */ "RAM disk",
56: /* order */ 6,
57: /* init */ ramdisk_init,
58: };
59:
1.1.1.1.2.1! nbrk 60: /*
! 61: * Device I/O table
! 62: */
1.1 nbrk 63: static struct devio ramdisk_io = {
64: /* open */ NULL,
65: /* close */ NULL,
66: /* read */ ramdisk_read,
67: /* write */ ramdisk_write,
68: /* ioctl */ NULL,
69: /* event */ NULL,
70: };
71:
72: static device_t ramdisk_dev; /* Device object */
73:
74: static char *img_start;
75: static size_t img_size;
76:
77: static int
78: ramdisk_read(device_t dev, char *buf, size_t *nbyte, int blkno)
79: {
80: void *kbuf;
81: size_t nr_read;
82:
1.1.1.1.2.1! nbrk 83: DPRINTF(("ramdisk_read: buf=%x nbyte=%d blkno=%x\n",
! 84: buf, *nbyte, blkno));
1.1 nbrk 85:
86: /* Check overrun */
87: if ((size_t)blkno * BSIZE > img_size) {
1.1.1.1.2.1! nbrk 88: DPRINTF(("ramdisk_read: overrun!\n"));
1.1 nbrk 89: return EIO;
90: }
91: nr_read = *nbyte;
92: if ((size_t)blkno * BSIZE + nr_read > img_size)
93: nr_read = img_size - blkno * BSIZE;
94:
95: /* Translate buffer address to kernel address */
96: kbuf = kmem_map(buf, nr_read);
97: if (kbuf == NULL)
98: return EFAULT;
99:
100: /* Copy data */
101: memcpy(kbuf, img_start + blkno * BSIZE, nr_read);
102: *nbyte = nr_read;
103: return 0;
104: }
105:
106: static int
107: ramdisk_write(device_t dev, char *buf, size_t *nbyte, int blkno)
108: {
109: void *kbuf;
110: size_t nr_write;
111:
1.1.1.1.2.1! nbrk 112: DPRINTF(("ramdisk_write: buf=%x nbyte=%d blkno=%x\n",
! 113: buf, *nbyte, blkno));
1.1 nbrk 114:
115: /* Check overrun */
116: if ((size_t)blkno * BSIZE > img_size)
117: return EIO;
118: nr_write = *nbyte;
119: if ((size_t)blkno * BSIZE + nr_write > img_size)
120: nr_write = img_size - blkno * BSIZE;
121:
122: /* Translate buffer address to kernel address */
123: kbuf = kmem_map(buf, nr_write);
124: if (kbuf == NULL)
125: return EFAULT;
126:
127: /* Copy data */
128: memcpy(img_start + blkno * BSIZE, kbuf, nr_write);
129: *nbyte = nr_write;
130: return 0;
131: }
132:
133: /*
134: * Initialize
135: */
136: static int
137: ramdisk_init(void)
138: {
139: struct boot_info *boot_info;
140: struct mem_map *rd;
141:
142: machine_bootinfo(&boot_info);
143: rd = (struct mem_map *)&boot_info->ram_disk;
144: img_start = (char *)phys_to_virt((void *)rd->start);
145: img_size = rd->size;
146: if (img_size == 0)
147: return -1;
1.1.1.1.2.1! nbrk 148: #ifdef DEBUG
! 149: printf("RAM disk at 0x%08x (%dK bytes)\n", img_start, img_size/1024);
! 150: #endif
1.1 nbrk 151: /* Create device object */
152: ramdisk_dev = device_create(&ramdisk_io, "ram0", DF_BLK);
153: ASSERT(ramdisk_dev);
154: return 0;
155: }
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