Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
branch: master
Fetching contributors…

Cannot retrieve contributors at this time

151 lines (123 sloc) 3.193 kb
// Simple PIO-based (non-DMA) IDE driver code.
#include "types.h"
#include "defs.h"
#include "param.h"
#include "mmu.h"
#include "proc.h"
#include "x86.h"
#include "traps.h"
#include "spinlock.h"
#include "buf.h"
#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
// ide_queue points to the buf now being read/written to the disk.
// ide_queue->qnext points to the next buf to be processed.
// You must hold ide_lock while manipulating queue.
static struct spinlock ide_lock;
static struct buf *ide_queue;
static int disk_1_present;
static void ide_start_request();
// Wait for IDE disk to become ready.
static int
ide_wait_ready(int check_error)
{
int r;
while(((r = inb(0x1f7)) & IDE_BSY) || !(r & IDE_DRDY))
;
if(check_error && (r & (IDE_DF|IDE_ERR)) != 0)
return -1;
return 0;
}
void
ide_init(void)
{
int i;
initlock(&ide_lock, "ide");
pic_enable(IRQ_IDE);
ioapic_enable(IRQ_IDE, ncpu - 1);
ide_wait_ready(0);
// 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));
}
// Start the request for b. Caller must hold ide_lock.
static void
ide_start_request(struct buf *b)
{
if(b == 0)
panic("ide_start_request");
ide_wait_ready(0);
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_DIRTY){
outb(0x1f7, IDE_CMD_WRITE);
outsl(0x1f0, b->data, 512/4);
} else {
outb(0x1f7, IDE_CMD_READ);
}
}
// Interrupt handler.
void
ide_intr(void)
{
struct buf *b;
acquire(&ide_lock);
if((b = ide_queue) == 0){
release(&ide_lock);
return;
}
// Read data if needed.
if(!(b->flags & B_DIRTY) && ide_wait_ready(1) >= 0)
insl(0x1f0, b->data, 512/4);
// Wake process waiting for this buf.
b->flags |= B_VALID;
b->flags &= ~B_DIRTY;
wakeup(b);
// Start disk on next buf in queue.
if((ide_queue = b->qnext) != 0)
ide_start_request(ide_queue);
release(&ide_lock);
}
// Sync buf with disk.
// If B_DIRTY is set, write buf to disk, clear B_DIRTY, set B_VALID.
// Else if B_VALID is not set, read buf from disk, set B_VALID.
void
ide_rw(struct buf *b)
{
struct buf **pp;
if(!(b->flags & B_BUSY))
panic("ide_rw: buf not busy");
if((b->flags & (B_VALID|B_DIRTY)) == B_VALID)
panic("ide_rw: nothing to do");
if(b->dev != 0 && !disk_1_present)
panic("ide disk 1 not present");
acquire(&ide_lock);
// Append b to ide_queue.
b->qnext = 0;
for(pp=&ide_queue; *pp; pp=&(*pp)->qnext)
;
*pp = b;
// Start disk if necessary.
if(ide_queue == b)
ide_start_request(b);
// Wait for request to finish.
// Assuming will not sleep too long: ignore cp->killed.
while((b->flags & (B_VALID|B_DIRTY)) != B_VALID)
sleep(b, &ide_lock);
release(&ide_lock);
}
Jump to Line
Something went wrong with that request. Please try again.