os_kernel_lab/code/lab8/kern/fs/devs/dev_disk0.c
2012-08-22 12:32:13 +08:00

145 lines
3.8 KiB
C

#include <defs.h>
#include <mmu.h>
#include <sem.h>
#include <ide.h>
#include <inode.h>
#include <kmalloc.h>
#include <dev.h>
#include <vfs.h>
#include <iobuf.h>
#include <error.h>
#include <assert.h>
#define DISK0_BLKSIZE PGSIZE
#define DISK0_BUFSIZE (4 * DISK0_BLKSIZE)
#define DISK0_BLK_NSECT (DISK0_BLKSIZE / SECTSIZE)
static char *disk0_buffer;
static semaphore_t disk0_sem;
static void
lock_disk0(void) {
down(&(disk0_sem));
}
static void
unlock_disk0(void) {
up(&(disk0_sem));
}
static int
disk0_open(struct device *dev, uint32_t open_flags) {
return 0;
}
static int
disk0_close(struct device *dev) {
return 0;
}
static void
disk0_read_blks_nolock(uint32_t blkno, uint32_t nblks) {
int ret;
uint32_t sectno = blkno * DISK0_BLK_NSECT, nsecs = nblks * DISK0_BLK_NSECT;
if ((ret = ide_read_secs(DISK0_DEV_NO, sectno, disk0_buffer, nsecs)) != 0) {
panic("disk0: read blkno = %d (sectno = %d), nblks = %d (nsecs = %d): 0x%08x.\n",
blkno, sectno, nblks, nsecs, ret);
}
}
static void
disk0_write_blks_nolock(uint32_t blkno, uint32_t nblks) {
int ret;
uint32_t sectno = blkno * DISK0_BLK_NSECT, nsecs = nblks * DISK0_BLK_NSECT;
if ((ret = ide_write_secs(DISK0_DEV_NO, sectno, disk0_buffer, nsecs)) != 0) {
panic("disk0: write blkno = %d (sectno = %d), nblks = %d (nsecs = %d): 0x%08x.\n",
blkno, sectno, nblks, nsecs, ret);
}
}
static int
disk0_io(struct device *dev, struct iobuf *iob, bool write) {
off_t offset = iob->io_offset;
size_t resid = iob->io_resid;
uint32_t blkno = offset / DISK0_BLKSIZE;
uint32_t nblks = resid / DISK0_BLKSIZE;
/* don't allow I/O that isn't block-aligned */
if ((offset % DISK0_BLKSIZE) != 0 || (resid % DISK0_BLKSIZE) != 0) {
return -E_INVAL;
}
/* don't allow I/O past the end of disk0 */
if (blkno + nblks > dev->d_blocks) {
return -E_INVAL;
}
/* read/write nothing ? */
if (nblks == 0) {
return 0;
}
lock_disk0();
while (resid != 0) {
size_t copied, alen = DISK0_BUFSIZE;
if (write) {
iobuf_move(iob, disk0_buffer, alen, 0, &copied);
assert(copied != 0 && copied <= resid && copied % DISK0_BLKSIZE == 0);
nblks = copied / DISK0_BLKSIZE;
disk0_write_blks_nolock(blkno, nblks);
}
else {
if (alen > resid) {
alen = resid;
}
nblks = alen / DISK0_BLKSIZE;
disk0_read_blks_nolock(blkno, nblks);
iobuf_move(iob, disk0_buffer, alen, 1, &copied);
assert(copied == alen && copied % DISK0_BLKSIZE == 0);
}
resid -= copied, blkno += nblks;
}
unlock_disk0();
return 0;
}
static int
disk0_ioctl(struct device *dev, int op, void *data) {
return -E_UNIMP;
}
static void
disk0_device_init(struct device *dev) {
static_assert(DISK0_BLKSIZE % SECTSIZE == 0);
if (!ide_device_valid(DISK0_DEV_NO)) {
panic("disk0 device isn't available.\n");
}
dev->d_blocks = ide_device_size(DISK0_DEV_NO) / DISK0_BLK_NSECT;
dev->d_blocksize = DISK0_BLKSIZE;
dev->d_open = disk0_open;
dev->d_close = disk0_close;
dev->d_io = disk0_io;
dev->d_ioctl = disk0_ioctl;
sem_init(&(disk0_sem), 1);
static_assert(DISK0_BUFSIZE % DISK0_BLKSIZE == 0);
if ((disk0_buffer = kmalloc(DISK0_BUFSIZE)) == NULL) {
panic("disk0 alloc buffer failed.\n");
}
}
void
dev_init_disk0(void) {
struct inode *node;
if ((node = dev_create_inode()) == NULL) {
panic("disk0: dev_create_node.\n");
}
disk0_device_init(vop_info(node, device));
int ret;
if ((ret = vfs_add_dev("disk0", node, 1)) != 0) {
panic("disk0: vfs_add_dev: %e.\n", ret);
}
}