You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
127 lines
2.7 KiB
127 lines
2.7 KiB
3 years ago
|
/*
|
||
|
|
* linux/kernel/blk_drv/ramdisk.c
|
||
|
|
*
|
||
|
|
* Written by Theodore Ts'o, 12/2/91
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <string.h>
|
||
|
|
|
||
|
|
#include <linux/config.h>
|
||
|
|
#include <linux/sched.h>
|
||
|
|
#include <linux/fs.h>
|
||
|
|
#include <linux/kernel.h>
|
||
|
|
#include <asm/system.h>
|
||
|
|
#include <asm/segment.h>
|
||
|
|
#include <asm/memory.h>
|
||
|
|
|
||
|
|
#define MAJOR_NR 1
|
||
|
|
#include "blk.h"
|
||
|
|
|
||
|
|
char *rd_start;
|
||
|
|
int rd_length = 0;
|
||
|
|
|
||
|
|
void do_rd_request(void)
|
||
|
|
{
|
||
|
|
int len;
|
||
|
|
char *addr;
|
||
|
|
|
||
|
|
INIT_REQUEST;
|
||
|
|
addr = rd_start + (CURRENT->sector << 9);
|
||
|
|
len = CURRENT->nr_sectors << 9;
|
||
|
|
if ((MINOR(CURRENT->dev) != 1) || (addr+len > rd_start+rd_length)) {
|
||
|
|
end_request(0);
|
||
|
|
goto repeat;
|
||
|
|
}
|
||
|
|
if (CURRENT-> cmd == WRITE) {
|
||
|
|
(void ) memcpy(addr,
|
||
|
|
CURRENT->buffer,
|
||
|
|
len);
|
||
|
|
} else if (CURRENT->cmd == READ) {
|
||
|
|
(void) memcpy(CURRENT->buffer,
|
||
|
|
addr,
|
||
|
|
len);
|
||
|
|
} else
|
||
|
|
panic("unknown ramdisk-command");
|
||
|
|
end_request(1);
|
||
|
|
goto repeat;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Returns amount of memory which needs to be reserved.
|
||
|
|
*/
|
||
|
|
long rd_init(long mem_start, int length)
|
||
|
|
{
|
||
|
|
int i;
|
||
|
|
char *cp;
|
||
|
|
|
||
|
|
blk_dev[MAJOR_NR].request_fn = DEVICE_REQUEST;
|
||
|
|
rd_start = (char *) mem_start;
|
||
|
|
rd_length = length;
|
||
|
|
cp = rd_start;
|
||
|
|
for (i=0; i < length; i++)
|
||
|
|
*cp++ = '\0';
|
||
|
|
return(length);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* If the root device is the ram disk, try to load it.
|
||
|
|
* In order to do this, the root device is originally set to the
|
||
|
|
* floppy, and we later change it to be ram disk.
|
||
|
|
*/
|
||
|
|
void rd_load(void)
|
||
|
|
{
|
||
|
|
struct buffer_head *bh;
|
||
|
|
struct super_block s;
|
||
|
|
int block = 256; /* Start at block 256 */
|
||
|
|
int i = 1;
|
||
|
|
int nblocks;
|
||
|
|
char *cp; /* Move pointer */
|
||
|
|
|
||
|
|
if (!rd_length)
|
||
|
|
return;
|
||
|
|
printk("Ram disk: %d bytes, starting at 0x%x\n", rd_length,
|
||
|
|
(int) rd_start);
|
||
|
|
if (MAJOR(ROOT_DEV) != 2)
|
||
|
|
return;
|
||
|
|
bh = breada(ROOT_DEV,block+1,block,block+2,-1);
|
||
|
|
if (!bh) {
|
||
|
|
printk("Disk error while looking for ramdisk!\n");
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
__asm__ volatile ("cld"); /* by wyj */
|
||
|
|
*((struct d_super_block *) &s) = *((struct d_super_block *) bh->b_data);
|
||
|
|
brelse(bh);
|
||
|
|
if (s.s_magic != SUPER_MAGIC)
|
||
|
|
/* No ram disk image present, assume normal floppy boot */
|
||
|
|
return;
|
||
|
|
nblocks = s.s_nzones << s.s_log_zone_size;
|
||
|
|
if (nblocks > (rd_length >> BLOCK_SIZE_BITS)) {
|
||
|
|
printk("Ram disk image too big! (%d blocks, %d avail)\n",
|
||
|
|
nblocks, rd_length >> BLOCK_SIZE_BITS);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
printk("Loading %d bytes into ram disk... 0000k",
|
||
|
|
nblocks << BLOCK_SIZE_BITS);
|
||
|
|
cp = rd_start;
|
||
|
|
while (nblocks) {
|
||
|
|
if (nblocks > 2)
|
||
|
|
bh = breada(ROOT_DEV, block, block+1, block+2, -1);
|
||
|
|
else
|
||
|
|
bh = bread(ROOT_DEV, block);
|
||
|
|
if (!bh) {
|
||
|
|
printk("I/O error on block %d, aborting load\n",
|
||
|
|
block);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
(void) memcpy(cp, bh->b_data, BLOCK_SIZE);
|
||
|
|
brelse(bh);
|
||
|
|
printk("\010\010\010\010\010%4dk",i);
|
||
|
|
cp += BLOCK_SIZE;
|
||
|
|
block++;
|
||
|
|
nblocks--;
|
||
|
|
i++;
|
||
|
|
}
|
||
|
|
printk("\010\010\010\010\010done \n");
|
||
|
|
ROOT_DEV=0x0101;
|
||
|
|
}
|