minor cleanups

This commit is contained in:
rsc 2007-08-24 22:17:41 +00:00
parent cb30c81860
commit d7b44dbcfc

130
ide.c
View file

@ -26,20 +26,16 @@ static struct spinlock ide_lock;
static struct buf *ide_queue;
static int disk_1_present;
static int ide_probe_disk1(void);
static void ide_start_request();
//PAGEBREAK: 10
// Wait for IDE disk to become ready.
static int
ide_wait_ready(int check_error)
{
int r;
while(((r = inb(0x1F7)) & (IDE_BSY|IDE_DRDY)) != IDE_DRDY)
while(((r = inb(0x1f7)) & IDE_BSY) || !(r & IDE_DRDY))
;
if(check_error && (r & (IDE_DF|IDE_ERR)) != 0)
return -1;
return 0;
@ -48,105 +44,103 @@ ide_wait_ready(int check_error)
void
ide_init(void)
{
int i;
initlock(&ide_lock, "ide");
irq_enable(IRQ_IDE);
ioapic_enable(IRQ_IDE, ncpu - 1);
ide_wait_ready(0);
disk_1_present = ide_probe_disk1();
// Check if disk 1 is present
outb(0x1f6, 0xE0 | (1<<4));
for(i=0; i<1000; i++){
if(inb(0x1f7) != 0){
disk_1_present = 1;
break;
}
}
// Probe to see if disk 1 exists (we assume disk 0 exists).
static int
ide_probe_disk1(void)
// Switch back to disk 0.
outb(0x1f6, 0xE0 | (0<<4));
}
// Start the request for b. Caller must hold ide_lock.
static void
ide_start_request(struct buf *b)
{
int r, x;
if(b == 0)
panic("ide_start_request");
// wait for Device 0 to be ready
ide_wait_ready(0);
// switch to Device 1
outb(0x1F6, 0xE0 | (1<<4));
// check for Device 1 to be ready for a while
for(x = 0; x < 1000 && (r = inb(0x1F7)) == 0; x++)
;
// switch back to Device 0
outb(0x1F6, 0xE0 | (0<<4));
return x < 1000;
outb(0x3f6, 0); // generate interrupt
outb(0x1f2, 1); // number of sectors
outb(0x1f3, b->sector & 0xff);
outb(0x1f4, (b->sector >> 8) & 0xff);
outb(0x1f5, (b->sector >> 16) & 0xff);
outb(0x1f6, 0xE0 | ((b->dev&1)<<4) | ((b->sector>>24)&0x0f));
if(b->flags & B_WRITE){
outb(0x1f7, IDE_CMD_WRITE);
outsl(0x1f0, b->data, 512/4);
}else{
outb(0x1f7, IDE_CMD_READ);
}
}
// Interrupt handler - wake up the request that just finished.
// Interrupt handler.
void
ide_intr(void)
{
struct buf *b;
acquire(&ide_lock);
if(ide_queue){
if((ide_queue->flags & B_WRITE) == 0)
if(ide_wait_ready(1) >= 0)
insl(0x1F0, ide_queue->data, 512/4);
ide_queue->done = 1;
wakeup(ide_queue);
ide_queue = ide_queue->qnext;
ide_start_request();
} else {
if((b = ide_queue) == 0){
cprintf("stray ide interrupt\n");
release(&ide_lock);
return;
}
// Read data if needed.
if((b->flags & B_WRITE) == 0 && ide_wait_ready(1) >= 0)
insl(0x1f0, b->data, 512/4);
// Wake process waiting for this buf.
b->done = 1;
wakeup(b);
// Start disk on next buf in queue.
if((ide_queue = b->qnext) != 0)
ide_start_request(ide_queue);
release(&ide_lock);
}
// Start the next request in the queue.
// Caller must hold ide_lock.
static void
ide_start_request (void)
{
if(ide_queue){
ide_wait_ready(0);
outb(0x3f6, 0); // generate interrupt
outb(0x1F2, 1); // number of sectors
outb(0x1F3, ide_queue->sector & 0xFF);
outb(0x1F4, (ide_queue->sector >> 8) & 0xFF);
outb(0x1F5, (ide_queue->sector >> 16) & 0xFF);
outb(0x1F6, 0xE0 |
((ide_queue->dev & 1)<<4) |
((ide_queue->sector>>24)&0x0F));
if(ide_queue->flags & B_WRITE){
outb(0x1F7, IDE_CMD_WRITE);
outsl(0x1F0, ide_queue->data, 512/4);
} else {
outb(0x1F7, IDE_CMD_READ);
}
}
}
//PAGEBREAK: 30
// Queue up a disk operation and wait for it to finish.
// b must have B_BUSY set.
//PAGEBREAK!
// Queue a disk operation and wait for it to finish.
void
ide_rw(struct buf *b)
{
struct buf **pp;
if((b->dev & 0xff) && !disk_1_present)
if(!(b->flags & B_BUSY))
panic("ide_rw: buf not busy");
if(b->dev != 0 && !disk_1_present)
panic("ide disk 1 not present");
acquire(&ide_lock);
// Append b to ide_queue.
b->done = 0;
b->qnext = 0;
// append b to ide_queue
pp = &ide_queue;
while(*pp)
pp = &(*pp)->qnext;
for(pp=&ide_queue; *pp; pp=&(*pp)->qnext)
;
*pp = b;
// Start disk if necessary.
if(ide_queue == b)
ide_start_request();
ide_start_request(b);
// Wait for request to finish.
while(!b->done)
sleep(b, &ide_lock);
release(&ide_lock);
}