ide-disk.c

讲述linux的初始化过程

/*
 *  linux/drivers/ide/ide-disk.c	Version 1.10	June 9, 2000
 *
 *  Copyright (C) 1994-1998  Linus Torvalds & authors (see below)
 */

/*
 *  Mostly written by Mark Lord <[e-mail]>
 *                and Gadi Oxman <[e-mail]>
 *                and Andre Hedrick <[e-mail]>
 *
 * This is the IDE/ATA disk driver, as evolved from hd.c and ide.c.
 *
 * Version 1.00		move disk only code from ide.c to ide-disk.c
 *			support optional byte-swapping of all data
 * Version 1.01		fix previous byte-swapping code
 * Version 1.02		remove ", LBA" from drive identification msgs
 * Version 1.03		fix display of id->buf_size for big-endian
 * Version 1.04		add /proc configurable settings and S.M.A.R.T support
 * Version 1.05		add capacity support for ATA3 >= 8GB
 * Version 1.06		get boot-up messages to show full cyl count
 * Version 1.07		disable door-locking if it fails
 * Version 1.08		fixed CHS/LBA translations for ATA4 > 8GB,
 *			process of adding new ATA4 compliance.
 *			fixed problems in allowing fdisk to see
 *			the entire disk.
 * Version 1.09		added increment of rq->sector in ide_multwrite
 *			added UDMA 3/4 reporting
 * Version 1.10		request queue changes, Ultra DMA 100
 */

#define IDEDISK_VERSION	"1.10"

#undef REALLY_SLOW_IO		/* most systems can safely undef this */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/major.h>
#include <linux/errno.h>
#include <linux/genhd.h>
#include <linux/malloc.h>
#include <linux/delay.h>
#include <linux/ide.h>

#include <asm/byteorder.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/io.h>

#ifdef CONFIG_BLK_DEV_PDC4030
#define IS_PDC4030_DRIVE (HWIF(drive)->chipset == ide_pdc4030)
#else
#define IS_PDC4030_DRIVE (0)	/* auto-NULLs out pdc4030 code */
#endif

static void idedisk_bswap_data (void *buffer, int wcount)
{
	u16 *p = buffer;

	while (wcount--) {
		*p = *p << 8 | *p >> 8; p++;
		*p = *p << 8 | *p >> 8; p++;
	}
}

static inline void idedisk_input_data (ide_drive_t *drive, void *buffer, unsigned int wcount)
{
	ide_input_data(drive, buffer, wcount);
	if (drive->bswap)
		idedisk_bswap_data(buffer, wcount);
}

static inline void idedisk_output_data (ide_drive_t *drive, void *buffer, unsigned int wcount)
{
	if (drive->bswap) {
		idedisk_bswap_data(buffer, wcount);
		ide_output_data(drive, buffer, wcount);
		idedisk_bswap_data(buffer, wcount);
	} else
		ide_output_data(drive, buffer, wcount);
}

/*
 * lba_capacity_is_ok() performs a sanity check on the claimed "lba_capacity"
 * value for this drive (from its reported identification information).
 *
 * Returns:	1 if lba_capacity looks sensible
 *		0 otherwise
 *
 * It is called only once for each drive.
 */
static int lba_capacity_is_ok (struct hd_driveid *id)
{
	unsigned long lba_sects, chs_sects, head, tail;

	/*
	 * The ATA spec tells large drives to return
	 * C/H/S = 16383/16/63 independent of their size.
	 * Some drives can be jumpered to use 15 heads instead of 16.
	 * Some drives can be jumpered to use 4092 cyls instead of 16383.
	 */
	if ((id->cyls == 16383
	     || (id->cyls == 4092 && id->cur_cyls == 16383)) &&
	    id->sectors == 63 &&
	    (id->heads == 15 || id->heads == 16) &&
	    id->lba_capacity >= 16383*63*id->heads)
		return 1;

	lba_sects   = id->lba_capacity;
	chs_sects   = id->cyls * id->heads * id->sectors;

	/* perform a rough sanity check on lba_sects:  within 10% is OK */
	if ((lba_sects - chs_sects) < chs_sects/10)
		return 1;

	/* some drives have the word order reversed */
	head = ((lba_sects >> 16) & 0xffff);
	tail = (lba_sects & 0xffff);
	lba_sects = (head | (tail << 16));
	if ((lba_sects - chs_sects) < chs_sects/10) {
		id->lba_capacity = lba_sects;
		return 1;	/* lba_capacity is (now) good */
	}

	return 0;	/* lba_capacity value may be bad */
}

/*
 * read_intr() is the handler for disk read/multread interrupts
 */
static ide_startstop_t read_intr (ide_drive_t *drive)
{
	byte stat;
	int i;
	unsigned int msect, nsect;
	struct request *rq;

	/* new way for dealing with premature shared PCI interrupts */
	if (!OK_STAT(stat=GET_STAT(),DATA_READY,BAD_R_STAT)) {
		if (stat & (ERR_STAT|DRQ_STAT)) {
			return ide_error(drive, "read_intr", stat);
		}
		/* no data yet, so wait for another interrupt */
		ide_set_handler(drive, &read_intr, WAIT_CMD, NULL);
		return ide_started;
	}
	msect = drive->mult_count;
	
read_next:
	rq = HWGROUP(drive)->rq;
	if (msect) {
		if ((nsect = rq->current_nr_sectors) > msect)
			nsect = msect;
		msect -= nsect;
	} else
		nsect = 1;
	idedisk_input_data(drive, rq->buffer, nsect * SECTOR_WORDS);
#ifdef DEBUG
	printk("%s:  read: sectors(%ld-%ld), buffer=0x%08lx, remaining=%ld\n",
		drive->name, rq->sector, rq->sector+nsect-1,
		(unsigned long) rq->buffer+(nsect<<9), rq->nr_sectors-nsect);
#endif
	rq->sector += nsect;
	rq->buffer += nsect<<9;
	rq->errors = 0;
	i = (rq->nr_sectors -= nsect);
	if (((long)(rq->current_nr_sectors -= nsect)) <= 0)
		ide_end_request(1, HWGROUP(drive));
	if (i > 0) {
		if (msect)
			goto read_next;
		ide_set_handler (drive, &read_intr, WAIT_CMD, NULL);
                return ide_started;
	}
        return ide_stopped;
}

/*
 * write_intr() is the handler for disk write interrupts
 */
static ide_startstop_t write_intr (ide_drive_t *drive)
{
	byte stat;
	int i;
	ide_hwgroup_t *hwgroup = HWGROUP(drive);
	struct request *rq = hwgroup->rq;

	if (!OK_STAT(stat=GET_STAT(),DRIVE_READY,drive->bad_wstat)) {
		printk("%s: write_intr error1: nr_sectors=%ld, stat=0x%02x\n", drive->name, rq->nr_sectors, stat);
        } else {
#ifdef DEBUG
		printk("%s: write: sector %ld, buffer=0x%08lx, remaining=%ld\n",
			drive->name, rq->sector, (unsigned long) rq->buffer,
			rq->nr_sectors-1);
#endif
		if ((rq->nr_sectors == 1) ^ ((stat & DRQ_STAT) != 0)) {
			rq->sector++;
			rq->buffer += 512;
			rq->errors = 0;
			i = --rq->nr_sectors;
			--rq->current_nr_sectors;
			if (((long)rq->current_nr_sectors) <= 0)
				ide_end_request(1, hwgroup);
			if (i > 0) {
				idedisk_output_data (drive, rq->buffer, SECTOR_WORDS);
				ide_set_handler (drive, &write_intr, WAIT_CMD, NULL);
                                return ide_started;
			}
                        return ide_stopped;
		}
		return ide_stopped;	/* the original code did this here (?) */
	}
	return ide_error(drive, "write_intr", stat);
}

/*
 * ide_multwrite() transfers a block of up to mcount sectors of data
 * to a drive as part of a disk multiple-sector write operation.
 *
 * Returns 0 if successful;  returns 1 if request had to be aborted due to corrupted buffer list.
 */
int ide_multwrite (ide_drive_t *drive, unsigned int mcount)
{
 	ide_hwgroup_t	*hwgroup= HWGROUP(drive);

	/*
	 *	This may look a bit odd, but remember wrq is a copy of the
	 *	request not the original. The pointers are real however so the
	 *	bh's are not copies. Remember that or bad stuff will happen
	 *
	 *	At the point we are called the drive has asked us for the
	 *	data, and its our job to feed it, walking across bh boundaries
	 *	if need be.
	 */

 	struct request	*rq = &hwgroup->wrq;

  	do {
 		unsigned long flags;
  		unsigned int nsect = rq->current_nr_sectors;
		if (nsect > mcount)
			nsect = mcount;
		mcount -= nsect;

		idedisk_output_data(drive, rq->buffer, nsect<<7);
#ifdef DEBUG
		printk("%s: multwrite: sector %ld, buffer=0x%08lx, count=%d, remaining=%ld\n",
			drive->name, rq->sector, (unsigned long) rq->buffer,
			nsect, rq->nr_sectors - nsect);
#endif
		spin_lock_irqsave(&io_request_lock, flags);	/* Is this really necessary? */
#ifdef CONFIG_BLK_DEV_PDC4030
		rq->sector += nsect;
#endif
		if (((long)(rq->nr_sectors -= nsect)) <= 0) {
#ifdef DEBUG
			printk("%s: multwrite: count=%d, current=%ld\n",
				drive->name, nsect, rq->nr_sectors);
#endif
			spin_unlock_irqrestore(&io_request_lock, flags);
			break;
		}
		if ((rq->current_nr_sectors -= nsect) == 0) {
			if ((rq->bh = rq->bh->b_reqnext) != NULL) {
				rq->current_nr_sectors = rq->bh->b_size>>9;
				rq->buffer             = rq->bh->b_data;
			} else {
				spin_unlock_irqrestore(&io_request_lock, flags);
				printk("%s: buffer list corrupted (%ld, %ld, %d)\n",
					drive->name, rq->current_nr_sectors,
					rq->nr_sectors, nsect);
				ide_end_request(0, hwgroup);
				return 1;
			}
		} else {
			/* Fix the pointer.. we ate data */
			rq->buffer += nsect << 9;
		}
                spin_unlock_irqrestore(&io_request_lock, flags);
	} while (mcount);
        return 0;
}

/*
 * multwrite_intr() is the handler for disk multwrite interrupts
 */
static ide_startstop_t multwrite_intr (ide_drive_t *drive)
{
	byte stat;
	int i;
	ide_hwgroup_t *hwgroup = HWGROUP(drive);
	struct request *rq = &hwgroup->wrq;

	if (OK_STAT(stat=GET_STAT(),DRIVE_READY,drive->bad_wstat)) {
		if (stat & DRQ_STAT) {
			/*
			 *	The drive wants data. Remember rq is the copy
			 *	of the request
			 */
			if (rq->nr_sectors) {
				if (ide_multwrite(drive, drive->mult_count))
					return ide_stopped;
				ide_set_handler (drive, &multwrite_intr, WAIT_CMD, NULL);
				return ide_started;
			}
		} else {
			/*
			 *	If the copy has all the blocks completed then
			 *	we can end the original request.
			 */
			if (!rq->nr_sectors) {	/* all done? */
				rq = hwgroup->rq;
				for (i = rq->nr_sectors; i > 0;){
					i -= rq->current_nr_sectors;
					ide_end_request(1, hwgroup);
				}
				return ide_stopped;
			}
		}
		return ide_stopped;	/* the original code did this here (?) */
	}
	return ide_error(drive, "multwrite_intr", stat);
}

/*
 * set_multmode_intr() is invoked on completion of a WIN_SETMULT cmd.
 */
static ide_startstop_t set_multmode_intr (ide_drive_t *drive)
{
	byte stat;

	if (OK_STAT(stat=GET_STAT(),READY_STAT,BAD_STAT)) {
		drive->mult_count = drive->mult_req;
	} else {
		drive->mult_req = drive->mult_count = 0;
		drive->special.b.recalibrate = 1;
		(void) ide_dump_status(drive, "set_multmode", stat);
	}
	return ide_stopped;
}

/*
 * set_geometry_intr() is invoked on completion of a WIN_SPECIFY cmd.
 */
static ide_startstop_t set_geometry_intr (ide_drive_t *drive)
{
	byte stat;

	if (OK_STAT(stat=GET_STAT(),READY_STAT,BAD_STAT))
		return ide_stopped;

	if (stat & (ERR_STAT|DRQ_STAT))
		return ide_error(drive, "set_geometry_intr", stat);

	ide_set_handler(drive, &set_geometry_intr, WAIT_CMD, NULL);
	return ide_started;	
}

/*
 * recal_intr() is invoked on completion of a WIN_RESTORE (recalibrate) cmd.
 */
static ide_startstop_t recal_intr (ide_drive_t *drive)
{
	byte stat = GET_STAT();

	if (!OK_STAT(stat,READY_STAT,BAD_STAT))
		return ide_error(drive, "recal_intr", stat);
	return ide_stopped;
}

/*
 * do_rw_disk() issues READ and WRITE commands to a disk,
 * using LBA if supported, or CHS otherwise, to address sectors.
 * It also takes care of issuing special DRIVE_CMDs.
 */
static ide_startstop_t do_rw_disk (ide_drive_t *drive, struct request *rq, unsigned long block)
{
	if (IDE_CONTROL_REG)
		OUT_BYTE(drive->ctl,IDE_CONTROL_REG);
	OUT_BYTE(rq->nr_sectors,IDE_NSECTOR_REG);
#ifdef CONFIG_BLK_DEV_PDC4030
	if (drive->select.b.lba || IS_PDC4030_DRIVE) {
#else /* !CONFIG_BLK_DEV_PDC4030 */
	if (drive->select.b.lba) {
#endif /* CONFIG_BLK_DEV_PDC4030 */
#ifdef DEBUG
		printk("%s: %sing: LBAsect=%ld, sectors=%ld, buffer=0x%08lx\n",
			drive->name, (rq->cmd==READ)?"read":"writ",
			block, rq->nr_sectors, (unsigned long) rq->buffer);
#endif
		OUT_BYTE(block,IDE_SECTOR_REG);
		OUT_BYTE(block>>=8,IDE_LCYL_REG);
		OUT_BYTE(block>>=8,IDE_HCYL_REG);
		OUT_BYTE(((block>>8)&0x0f)|drive->select.all,IDE_SELECT_REG);
	} else {
		unsigned int sect,head,cyl,track;
		track = block / drive->sect;
		sect  = block % drive->sect + 1;
		OUT_BYTE(sect,IDE_SECTOR_REG);
		head  = track % drive->head;
		cyl   = track / drive->head;
		OUT_BYTE(cyl,IDE_LCYL_REG);
		OUT_BYTE(cyl>>8,IDE_HCYL_REG);
		OUT_BYTE(head|drive->select.all,IDE_SELECT_REG);
#ifdef DEBUG
		printk("%s: %sing: CHS=%d/%d/%d, sectors=%ld, buffer=0x%08lx\n",
			drive->name, (rq->cmd==READ)?"read":"writ", cyl,
			head, sect, rq->nr_sectors, (unsigned long) rq->buffer);
#endif
	}
#ifdef CONFIG_BLK_DEV_PDC4030
	if (IS_PDC4030_DRIVE) {
		extern ide_startstop_t do_pdc4030_io(ide_drive_t *, struct request *);
		return do_pdc4030_io (drive, rq);
	}
#endif /* CONFIG_BLK_DEV_PDC4030 */
	if (rq->cmd == READ) {
#ifdef CONFIG_BLK_DEV_IDEDMA
		if (drive->using_dma && !(HWIF(drive)->dmaproc(ide_dma_read, drive)))
			return ide_started;
#endif /* CONFIG_BLK_DEV_IDEDMA */
		ide_set_handler(drive, &read_intr, WAIT_CMD, NULL);
		OUT_BYTE(drive->mult_count ? WIN_MULTREAD : WIN_READ, IDE_COMMAND_REG);
		return ide_started;
	}
	if (rq->cmd == WRITE) {
		ide_startstop_t startstop;
#ifdef CONFIG_BLK_DEV_IDEDMA
		if (drive->using_dma && !(HWIF(drive)->dmaproc(ide_dma_write, drive)))
			return ide_started;
#endif /* CONFIG_BLK_DEV_IDEDMA */
		OUT_BYTE(drive->mult_count ? WIN_MULTWRITE : WIN_WRITE, IDE_COMMAND_REG);
		if (ide_wait_stat(&startstop, drive, DATA_READY, drive->bad_wstat, WAIT_DRQ)) {
			printk(KERN_ERR "%s: no DRQ after issuing %s\n", drive->name,
				drive->mult_count ? "MULTWRITE" : "WRITE");
			return startstop;
		}
		if (!drive->unmask)
			__cli();	/* local CPU only */
		if (drive->mult_count) {
			ide_hwgroup_t *hwgroup = HWGROUP(drive);
			/*
			 * Ugh.. this part looks ugly because we MUST set up
			 * the interrupt handler before outputting the first block