Annotation of prex-old/dev/gen/ramdisk.c, Revision 1.1
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
! 39: #define rd_printf(fmt, args...) printk("%s: " fmt, __FUNCTION__ , ## args)
! 40: #else
! 41: #define rd_printf(fmt...) do {} while (0)
! 42: #endif
! 43:
! 44: /* Block size */
! 45: #define BSIZE 512
! 46:
! 47: static int ramdisk_read(device_t dev, char *buf, size_t *nbyte, int blkno);
! 48: static int ramdisk_write(device_t dev, char *buf, size_t *nbyte, int blkno);
! 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:
! 60: static struct devio ramdisk_io = {
! 61: /* open */ NULL,
! 62: /* close */ NULL,
! 63: /* read */ ramdisk_read,
! 64: /* write */ ramdisk_write,
! 65: /* ioctl */ NULL,
! 66: /* event */ NULL,
! 67: };
! 68:
! 69: static device_t ramdisk_dev; /* Device object */
! 70:
! 71: static char *img_start;
! 72: static size_t img_size;
! 73:
! 74: static int
! 75: ramdisk_read(device_t dev, char *buf, size_t *nbyte, int blkno)
! 76: {
! 77: void *kbuf;
! 78: size_t nr_read;
! 79:
! 80: rd_printf("read buf=%x nbyte=%d blkno=%x\n", buf, *nbyte, blkno);
! 81:
! 82: /* Check overrun */
! 83: if ((size_t)blkno * BSIZE > img_size) {
! 84: rd_printf("Overrun!\n");
! 85: return EIO;
! 86: }
! 87: nr_read = *nbyte;
! 88: if ((size_t)blkno * BSIZE + nr_read > img_size)
! 89: nr_read = img_size - blkno * BSIZE;
! 90:
! 91: /* Translate buffer address to kernel address */
! 92: kbuf = kmem_map(buf, nr_read);
! 93: if (kbuf == NULL)
! 94: return EFAULT;
! 95:
! 96: /* Copy data */
! 97: memcpy(kbuf, img_start + blkno * BSIZE, nr_read);
! 98: *nbyte = nr_read;
! 99: return 0;
! 100: }
! 101:
! 102: /*
! 103: * Data written to this device is discarded.
! 104: */
! 105: static int
! 106: ramdisk_write(device_t dev, char *buf, size_t *nbyte, int blkno)
! 107: {
! 108: void *kbuf;
! 109: size_t nr_write;
! 110:
! 111: rd_printf("write buf=%x nbyte=%d blkno=%x\n", buf, *nbyte, blkno);
! 112:
! 113: /* Check overrun */
! 114: if ((size_t)blkno * BSIZE > img_size)
! 115: return EIO;
! 116: nr_write = *nbyte;
! 117: if ((size_t)blkno * BSIZE + nr_write > img_size)
! 118: nr_write = img_size - blkno * BSIZE;
! 119:
! 120: /* Translate buffer address to kernel address */
! 121: kbuf = kmem_map(buf, nr_write);
! 122: if (kbuf == NULL)
! 123: return EFAULT;
! 124:
! 125: /* Copy data */
! 126: memcpy(img_start + blkno * BSIZE, kbuf, nr_write);
! 127: *nbyte = nr_write;
! 128: return 0;
! 129: }
! 130:
! 131: /*
! 132: * Initialize
! 133: */
! 134: static int
! 135: ramdisk_init(void)
! 136: {
! 137: struct boot_info *boot_info;
! 138: struct mem_map *rd;
! 139:
! 140: machine_bootinfo(&boot_info);
! 141: rd = (struct mem_map *)&boot_info->ram_disk;
! 142: img_start = (char *)phys_to_virt((void *)rd->start);
! 143: img_size = rd->size;
! 144: if (img_size == 0)
! 145: return -1;
! 146: printk("RAM disk at 0x%08x (%dK bytes)\n", img_start, img_size/1024);
! 147:
! 148: /* Create device object */
! 149: ramdisk_dev = device_create(&ramdisk_io, "ram0", DF_BLK);
! 150: ASSERT(ramdisk_dev);
! 151: return 0;
! 152: }
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