xv6-cs450/ide.c

147 lines
2.9 KiB
C
Raw Normal View History

2006-09-06 19:50:20 +02:00
// Simple PIO-based (non-DMA) IDE driver code.
2006-06-16 22:29:25 +02:00
#include "types.h"
#include "param.h"
#include "mmu.h"
#include "proc.h"
#include "defs.h"
#include "x86.h"
#include "traps.h"
2006-07-17 07:00:25 +02:00
#include "spinlock.h"
2007-08-24 21:32:36 +02:00
#include "buf.h"
2006-06-16 22:29:25 +02:00
2006-09-06 19:54:29 +02:00
#define IDE_BSY 0x80
#define IDE_DRDY 0x40
#define IDE_DF 0x20
#define IDE_ERR 0x01
#define IDE_CMD_READ 0x20
#define IDE_CMD_WRITE 0x30
2006-06-16 22:29:25 +02:00
2007-08-24 21:32:36 +02:00
// ide_queue points to the buf now being read/written to the disk.
// ide_queue->qnext points to the next buf to be processed.
2007-08-24 21:52:49 +02:00
// You must hold ide_lock while manipulating queue.
2006-09-07 16:28:12 +02:00
2006-09-07 17:29:54 +02:00
static struct spinlock ide_lock;
2007-08-24 21:32:36 +02:00
static struct buf *ide_queue;
2006-09-07 16:28:12 +02:00
2006-09-07 17:29:54 +02:00
static int disk_1_present;
2007-08-24 21:32:36 +02:00
static void ide_start_request();
2006-08-30 20:55:06 +02:00
2006-09-07 17:29:54 +02:00
// Wait for IDE disk to become ready.
2006-06-16 22:29:25 +02:00
static int
ide_wait_ready(int check_error)
{
int r;
2006-06-16 22:29:25 +02:00
2007-08-25 00:17:41 +02:00
while(((r = inb(0x1f7)) & IDE_BSY) || !(r & IDE_DRDY))
2006-09-06 19:50:20 +02:00
;
2006-09-06 19:27:19 +02:00
if(check_error && (r & (IDE_DF|IDE_ERR)) != 0)
return -1;
return 0;
2006-06-16 22:29:25 +02:00
}
void
ide_init(void)
{
2007-08-25 00:17:41 +02:00
int i;
initlock(&ide_lock, "ide");
2006-09-07 17:29:54 +02:00
irq_enable(IRQ_IDE);
ioapic_enable(IRQ_IDE, ncpu - 1);
ide_wait_ready(0);
2007-08-25 00:17:41 +02:00
// 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;
}
}
// Switch back to disk 0.
outb(0x1f6, 0xE0 | (0<<4));
}
2007-08-25 00:17:41 +02:00
// Start the request for b. Caller must hold ide_lock.
static void
ide_start_request(struct buf *b)
2006-06-16 22:29:25 +02:00
{
2007-08-25 00:17:41 +02:00
if(b == 0)
panic("ide_start_request");
2006-06-16 22:29:25 +02:00
ide_wait_ready(0);
2007-08-25 00:17:41 +02:00
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);
}
2006-06-16 22:29:25 +02:00
}
2007-08-25 00:17:41 +02:00
// Interrupt handler.
2006-09-08 16:33:27 +02:00
void
ide_intr(void)
{
2007-08-25 00:17:41 +02:00
struct buf *b;
2006-09-08 16:33:27 +02:00
acquire(&ide_lock);
2007-08-25 00:17:41 +02:00
if((b = ide_queue) == 0){
2007-08-24 21:32:36 +02:00
cprintf("stray ide interrupt\n");
2007-08-25 00:17:41 +02:00
release(&ide_lock);
return;
2007-08-24 21:32:36 +02:00
}
2006-09-08 16:33:27 +02:00
2007-08-25 00:17:41 +02:00
// 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);
2006-07-10 21:06:48 +02:00
}
2007-08-25 00:17:41 +02:00
//PAGEBREAK!
// Queue a disk operation and wait for it to finish.
2006-09-07 17:29:54 +02:00
void
2007-08-24 21:32:36 +02:00
ide_rw(struct buf *b)
2006-06-16 22:29:25 +02:00
{
2007-08-24 21:32:36 +02:00
struct buf **pp;
2007-08-25 00:17:41 +02:00
if(!(b->flags & B_BUSY))
panic("ide_rw: buf not busy");
if(b->dev != 0 && !disk_1_present)
2006-08-30 20:55:06 +02:00
panic("ide disk 1 not present");
2006-09-07 17:29:54 +02:00
acquire(&ide_lock);
2006-09-06 19:27:19 +02:00
2007-08-25 00:17:41 +02:00
// Append b to ide_queue.
2007-08-24 21:32:36 +02:00
b->done = 0;
b->qnext = 0;
2007-08-25 00:17:41 +02:00
for(pp=&ide_queue; *pp; pp=&(*pp)->qnext)
;
2007-08-24 21:32:36 +02:00
*pp = b;
2007-08-25 00:17:41 +02:00
// Start disk if necessary.
2007-08-24 21:32:36 +02:00
if(ide_queue == b)
2007-08-25 00:17:41 +02:00
ide_start_request(b);
2007-08-24 21:32:36 +02:00
2007-08-25 00:17:41 +02:00
// Wait for request to finish.
2007-08-24 21:32:36 +02:00
while(!b->done)
sleep(b, &ide_lock);
2006-09-07 17:29:54 +02:00
release(&ide_lock);
2006-06-16 22:29:25 +02:00
}