hd.c

arm平台上的uclinux系统全部源代码

				}
#if (HD_DELAY > 0)
				last_req = read_timer();
#endif
				if (CURRENT)
					hd_request();
				return;
			}
		}
	}
	dump_status("multwrite_intr", i);
	bad_rw_intr();
	hd_request();
}

static void write_intr(void)
{
	int i;
	int retries = 100000;

	if (unmask_intr[DEVICE_NR(WCURRENT.rq_dev)])
		sti();
	do {
		i = (unsigned) inb_p(HD_STATUS);
		if (i & BUSY_STAT)
			continue;
		if (!OK_STATUS(i))
			break;
		if ((CURRENT->nr_sectors <= 1) || (i & DRQ_STAT))
			goto ok_to_write;
	} while (--retries > 0);
	dump_status("write_intr", i);
	bad_rw_intr();
	hd_request();
	return;
ok_to_write:
	CURRENT->sector++;
	i = --CURRENT->nr_sectors;
	--CURRENT->current_nr_sectors;
	CURRENT->buffer += 512;
	if (!i || (CURRENT->bh && !SUBSECTOR(i)))
		end_request(1);
	if (i > 0) {
		SET_INTR(&write_intr);
		outsw(HD_DATA,CURRENT->buffer,256);
		sti();
	} else {
#if (HD_DELAY > 0)
		last_req = read_timer();
#endif
		hd_request();
	}
	return;
}

static void recal_intr(void)
{
	check_status();
#if (HD_DELAY > 0)
	last_req = read_timer();
#endif
	hd_request();
}

/*
 * This is another of the error-routines I don't know what to do with. The
 * best idea seems to just set reset, and start all over again.
 */
static void hd_times_out(void)
{
	unsigned int dev;

	DEVICE_INTR = NULL;
	if (!CURRENT)
		return;
	disable_irq(HD_IRQ);
	sti();
	reset = 1;
	dev = DEVICE_NR(CURRENT->rq_dev);
	printk("hd%c: timeout\n", dev+'a');
	if (++CURRENT->errors >= MAX_ERRORS) {
#ifdef DEBUG
		printk("hd%c: too many errors\n", dev+'a');
#endif
		end_request(0);
	}
	cli();
	hd_request();
	enable_irq(HD_IRQ);
}

int do_special_op (unsigned int dev)
{
	if (recalibrate[dev]) {
		recalibrate[dev] = 0;
		hd_out(dev,hd_info[dev].sect,0,0,0,WIN_RESTORE,&recal_intr);
		return reset;
	}
	if (!identified[dev]) {
		identified[dev]  = 1;
		unmask_intr[dev] = DEFAULT_UNMASK_INTR;
		mult_req[dev]    = DEFAULT_MULT_COUNT;
		hd_out(dev,0,0,0,0,WIN_IDENTIFY,&identify_intr);
		return reset;
	}
	if (mult_req[dev] != mult_count[dev]) {
		hd_out(dev,mult_req[dev],0,0,0,WIN_SETMULT,&set_multmode_intr);
		return reset;
	}
	if (hd_info[dev].head > 16) {
		printk ("hd%c: cannot handle device with more than 16 heads - giving up\n", dev+'a');
		end_request(0);
	}
	special_op[dev] = 0;
	return 1;
}

/*
 * The driver enables interrupts as much as possible.  In order to do this,
 * (a) the device-interrupt is disabled before entering hd_request(),
 * and (b) the timeout-interrupt is disabled before the sti().
 *
 * Interrupts are still masked (by default) whenever we are exchanging
 * data/cmds with a drive, because some drives seem to have very poor
 * tolerance for latency during I/O.  For devices which don't suffer from
 * that problem (most don't), the unmask_intr[] flag can be set to unmask
 * other interrupts during data/cmd transfers (by defining DEFAULT_UNMASK_INTR
 * to 1, or by using "hdparm -u1 /dev/hd?" from the shell).
 */
static void hd_request(void)
{
	unsigned int dev, block, nsect, sec, track, head, cyl;

	if (CURRENT && CURRENT->rq_status == RQ_INACTIVE) return;
	if (DEVICE_INTR)
		return;
repeat:
	timer_active &= ~(1<<HD_TIMER);
	sti();
	INIT_REQUEST;
	if (reset) {
		cli();
		reset_hd();
		return;
	}
	dev = MINOR(CURRENT->rq_dev);
	block = CURRENT->sector;
	nsect = CURRENT->nr_sectors;
	if (dev >= (NR_HD<<6) || block >= hd[dev].nr_sects || ((block+nsect) > hd[dev].nr_sects)) {
#ifdef DEBUG
		if (dev >= (NR_HD<<6))
			printk("hd: bad minor number: device=%s\n",
			       kdevname(CURRENT->rq_dev));
		else
			printk("hd%c: bad access: block=%d, count=%d\n",
				(MINOR(CURRENT->rq_dev)>>6)+'a', block, nsect);
#endif
		end_request(0);
		goto repeat;
	}
	block += hd[dev].start_sect;
	dev >>= 6;
	if (special_op[dev]) {
		if (do_special_op(dev))
			goto repeat;
		return;
	}
	sec   = block % hd_info[dev].sect + 1;
	track = block / hd_info[dev].sect;
	head  = track % hd_info[dev].head;
	cyl   = track / hd_info[dev].head;
#ifdef DEBUG
	printk("hd%c: %sing: CHS=%d/%d/%d, sectors=%d, buffer=0x%08lx\n",
		dev+'a', (CURRENT->cmd == READ)?"read":"writ",
		cyl, head, sec, nsect, (unsigned long) CURRENT->buffer);
#endif
	if (!unmask_intr[dev])
		cli();
	if (CURRENT->cmd == READ) {
		unsigned int cmd = mult_count[dev] > 1 ? WIN_MULTREAD : WIN_READ;
		hd_out(dev,nsect,sec,head,cyl,cmd,&read_intr);
		if (reset)
			goto repeat;
		return;
	}
	if (CURRENT->cmd == WRITE) {
		if (mult_count[dev])
			hd_out(dev,nsect,sec,head,cyl,WIN_MULTWRITE,&multwrite_intr);
		else
			hd_out(dev,nsect,sec,head,cyl,WIN_WRITE,&write_intr);
		if (reset)
			goto repeat;
		if (wait_DRQ()) {
			bad_rw_intr();
			goto repeat;
		}
		if (mult_count[dev]) {
			WCURRENT = *CURRENT;
			multwrite(dev);
		} else
			outsw(HD_DATA,CURRENT->buffer,256);
		return;
	}
	panic("unknown hd-command");
}

static void do_hd_request (void)
{
	disable_irq(HD_IRQ);
	hd_request();
	enable_irq(HD_IRQ);
}

static int hd_ioctl(struct inode * inode, struct file * file,
	unsigned int cmd, unsigned long arg)
{
	struct hd_geometry *loc = (struct hd_geometry *) arg;
	int dev, err;
	unsigned long flags;

	if ((!inode) || !(inode->i_rdev))
		return -EINVAL;
	dev = DEVICE_NR(inode->i_rdev);
	if (dev >= NR_HD)
		return -EINVAL;
	switch (cmd) {
		case HDIO_GETGEO:
			if (!loc)  return -EINVAL;
			err = verify_area(VERIFY_WRITE, loc, sizeof(*loc));
			if (err)
				return err;
			put_user(bios_info[dev].head,
				(char *) &loc->heads);
			put_user(bios_info[dev].sect,
				(char *) &loc->sectors);
			put_user(bios_info[dev].cyl,
				(short *) &loc->cylinders);
			put_user(hd[MINOR(inode->i_rdev)].start_sect,
				(long *) &loc->start);
			return 0;
		case BLKRASET:
			if(!suser())  return -EACCES;
			if(arg > 0xff) return -EINVAL;
			read_ahead[MAJOR(inode->i_rdev)] = arg;
			return 0;
		case BLKRAGET:
			if (!arg)  return -EINVAL;
			err = verify_area(VERIFY_WRITE, (long *) arg, sizeof(long));
			if (err)
				return err;
			put_user(read_ahead[MAJOR(inode->i_rdev)],(long *) arg);
			return 0;
         	case BLKGETSIZE:   /* Return device size */
			if (!arg)  return -EINVAL;
			err = verify_area(VERIFY_WRITE, (long *) arg, sizeof(long));
			if (err)
				return err;
			put_user(hd[MINOR(inode->i_rdev)].nr_sects, (long *) arg);
			return 0;
		case BLKFLSBUF:
			if(!suser())  return -EACCES;
			fsync_dev(inode->i_rdev);
			invalidate_buffers(inode->i_rdev);
			return 0;

		case BLKRRPART: /* Re-read partition tables */
			return revalidate_hddisk(inode->i_rdev, 1);

		case HDIO_SET_UNMASKINTR:
			if (!suser()) return -EACCES;
			if ((arg > 1) || (MINOR(inode->i_rdev) & 0x3F))
				return -EINVAL;
			unmask_intr[dev] = arg;
			return 0;

                case HDIO_GET_UNMASKINTR:
			if (!arg)  return -EINVAL;
			err = verify_area(VERIFY_WRITE, (long *) arg, sizeof(long));
			if (err)
				return err;
			put_user(unmask_intr[dev], (long *) arg);
			return 0;

                case HDIO_GET_MULTCOUNT:
			if (!arg)  return -EINVAL;
			err = verify_area(VERIFY_WRITE, (long *) arg, sizeof(long));
			if (err)
				return err;
			put_user(mult_count[dev], (long *) arg);
			return 0;

		case HDIO_SET_MULTCOUNT:
			if (!suser()) return -EACCES;
			if (MINOR(inode->i_rdev) & 0x3F) return -EINVAL;
			save_flags(flags);
			cli();	/* a prior request might still be in progress */
			if (arg > max_mult[dev])
				err = -EINVAL;	/* out of range for device */
			else if (mult_req[dev] != mult_count[dev]) {
				special_op[dev] = 1;
				err = -EBUSY;	/* busy, try again */
			} else {
				mult_req[dev] = arg;
				special_op[dev] = 1;
				err = 0;
			}
			restore_flags(flags);
			return err;

		case HDIO_GET_IDENTITY:
			if (!arg)  return -EINVAL;
			if (MINOR(inode->i_rdev) & 0x3F) return -EINVAL;
			if (hd_ident_info[dev] == NULL)  return -ENOMSG;
			err = verify_area(VERIFY_WRITE, (char *) arg, sizeof(struct hd_driveid));
			if (err)
				return err;
			memcpy_tofs((char *)arg, (char *) hd_ident_info[dev], sizeof(struct hd_driveid));
			return 0;

		RO_IOCTLS(inode->i_rdev,arg);
		default:
			return -EINVAL;
	}
}

static int hd_open(struct inode * inode, struct file * filp)
{
	int target;
	target =  DEVICE_NR(inode->i_rdev);

	if (target >= NR_HD)
		return -ENODEV;
	while (busy[target])
		sleep_on(&busy_wait);
	access_count[target]++;
	return 0;
}

/*
 * Releasing a block device means we sync() it, so that it can safely
 * be forgotten about...
 */
static void hd_release(struct inode * inode, struct file * file)
{
        int target;
	sync_dev(inode->i_rdev);

	target =  DEVICE_NR(inode->i_rdev);
	access_count[target]--;

}

static void hd_geninit(struct gendisk *);

static struct gendisk hd_gendisk = {
	MAJOR_NR,	/* Major number */	
	"hd",		/* Major name */
	6,		/* Bits to shift to get real from partition */
	1 << 6,		/* Number of partitions per real */
	MAX_HD,		/* maximum number of real */
	hd_geninit,	/* init function */
	hd,		/* hd struct */
	hd_sizes,	/* block sizes */
	0,		/* number */
	(void *) bios_info,	/* internal */
	NULL		/* next */
};
	
static void hd_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	void (*handler)(void) = DEVICE_INTR;

	DEVICE_INTR = NULL;
	timer_active &= ~(1<<HD_TIMER);
	if (!handler)
		handler = unexpected_hd_interrupt;
	handler();
	sti();
}

/*
 * Since we find out the physical drive geometry, we don't touch that.
 * We only alter the logical disk geometry that is passed to user programs.
 * [as per PC Linux].
 */
void hd_set_geometry (kdev_t dev, unsigned char secspertrack, unsigned char heads,
		unsigned long discsize, unsigned int secsize)
{
    int minor = MINOR(dev);
    int drv = minor >> 6;

    if (bios_info[drv].cyl == 1) {
	bios_info[drv].cyl = discsize / (secspertrack * heads * secsize);
	bios_info[drv].head = heads;
	bios_info[drv].wpcom = -1;
	bios_info[drv].ctl = 8;
	bios_info[drv].lzone = bios_info[drv].cyl - 1;
	bios_info[drv].sect = secspertrack;
    }
    hd[minor].start_sect = 0;
    hd[minor].nr_sects = discsize / secsize;
}

/*
 * This is the harddisk IRQ description. The SA_INTERRUPT in sa_flags
 * means we run the IRQ-handler with interrupts disabled: this is bad for
 * interrupt latency, but anything else has led to problems on some
 * machines...
 *
 * We enable interrupts in some of the routines after making sure it's
 * safe.
 */
static void hd_geninit(struct gendisk *ignored)
{
	int i;

	if (!NR_HD) {
		int drive;
		extern int number_ide_drives;
		/*
		 * Default settings
		 *
		 * If we don't know anything about the drive, then set it
		 * so that we have enough to read the boot sector of the
		 * ADFS drive.  This means that you *MUST* specify the
		 * drive parameters of *all* drives if you have one IDE
		 * drive that is not ADFS formatted.
		 */
		for (drive=0 ; drive<2 ; drive++) {
			bios_info[drive].cyl   = hd_info[drive].cyl = 1;
			bios_info[drive].head  = hd_info[drive].head = 1;
			bios_info[drive].wpcom = hd_info[drive].wpcom = -1;
			bios_info[drive].ctl   = hd_info[drive].ctl = 8;
			bios_info[drive].lzone = hd_info[drive].lzone = 1;
			bios_info[drive].sect  = hd_info[drive].sect = 17;
		}

		/*
		 * We only set this to the one that the host OS gave us
		 * if the user has not defined any types.
		 */
		NR_HD = number_ide_drives;
	}

	i = NR_HD;
	while (i-- > 0) {
		/*
		 * The newer E-IDE BIOSs handle drives larger than 1024
		 * cylinders by increasing the number of logical heads
		 * to keep the number of logical cylinders below the
		 * sacred INT13 limit of 1024 (10 bits).  If that is
		 * what's happening here, we'll find out and correct
		 * it later when "identifying" the drive.
		 */
		hd[i<<6].nr_sects = bios_info[i].head *
				bios_info[i].sect * bios_info[i].cyl;
		hd_ident_info[i] = (struct hd_driveid *) kmalloc(512,GFP_KERNEL);
		special_op[i] = 1;
	}
	if (NR_HD) {
		if (request_irq(HD_IRQ, hd_interrupt, SA_INTERRUPT, "hd", NULL)) {
			printk("hd: unable to get IRQ%d for the harddisk driver\n",HD_IRQ);
			NR_HD = 0;
		} else {
			request_region(HD_DATA, 8, "hd");
			request_region(HD_CMD, 1, "hd(cmd)");
		}
	}
	hd_gendisk.nr_real = NR_HD;

	for (i = 0; i < (MAX_HD << 6); i++) {
		hd_blocksizes[i] = 1024;
		hd_hardsectsizes[i] = 512;
	}
	blksize_size[MAJOR_NR] = hd_blocksizes;
	hardsect_size[MAJOR_NR] = hd_hardsectsizes;
}

static struct file_operations hd_fops = {
	NULL,			/* lseek - default */
	block_read,		/* read - general block-dev read */
	block_write,		/* write - general block-dev write */
	NULL,			/* readdir - bad */
	NULL,			/* select */
	hd_ioctl,		/* ioctl */
	NULL,			/* mmap */
	hd_open,		/* open */
	hd_release,		/* release */
	block_fsync		/* fsync */
};

int hd_init(void)
{
	if (register_blkdev(MAJOR_NR,"hd",&hd_fops)) {
		printk("hd: unable to get major %d for harddisk\n",MAJOR_NR);
		return -1;
	}
	blk_dev[MAJOR_NR].request_fn = DEVICE_REQUEST;
	read_ahead[MAJOR_NR] = 8;		/* 8 sector (4kB) read-ahead */
	hd_gendisk.next = gendisk_head;
	gendisk_head = &hd_gendisk;
	timer_table[HD_TIMER].fn = hd_times_out;
	return 0;
}

#define DEVICE_BUSY busy[target]
#define USAGE access_count[target]
#define CAPACITY (bios_info[target].head*bios_info[target].sect*bios_info[target].cyl)
/* We assume that the the bios parameters do not change, so the disk capacity
   will not change */
#undef MAYBE_REINIT
#define GENDISK_STRUCT hd_gendisk

/*
 * This routine is called to flush all partitions and partition tables
 * for a changed scsi disk, and then re-read the new partition table.
 * If we are revalidating a disk because of a media change, then we
 * enter with usage == 0.  If we are using an ioctl, we automatically have
 * usage == 1 (we need an open channel to use an ioctl :-), so this
 * is our limit.
 */
static int revalidate_hddisk(kdev_t dev, int maxusage)
{
	int target;
	struct gendisk * gdev;
	int max_p;
	int start;
	int i;
	long flags;

	target = DEVICE_NR(dev);
	gdev = &GENDISK_STRUCT;

	save_flags_cli (flags);
	if (DEVICE_BUSY || USAGE > maxusage) {
		restore_flags(flags);
		return -EBUSY;
	};
	DEVICE_BUSY = 1;
	restore_flags(flags);

	max_p = gdev->max_p;
	start = target << gdev->minor_shift;

	for (i=max_p - 1; i >=0 ; i--) {
		int minor = start + i;
		kdev_t devi = MKDEV(MAJOR_NR, minor);
		sync_dev(devi);
		invalidate_inodes(devi);
		invalidate_buffers(devi);
		gdev->part[minor].start_sect = 0;
		gdev->part[minor].nr_sects = 0;
	};

#ifdef MAYBE_REINIT
	MAYBE_REINIT;
#endif

	gdev->part[start].nr_sects = CAPACITY;
	resetup_one_dev(gdev, target);

	DEVICE_BUSY = 0;
	wake_up(&busy_wait);
	return 0;
}