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[linux-2.6/linux-mips.git] / drivers / ide / probe.c

/**** vi:set ts=8 sts=8 sw=8:************************************************
 *
 *  Copyright (C) 1994-1998  Linus Torvalds & authors (see below)
 *
 *  Mostly written by Mark Lord <mlord@pobox.com>
 *                and Gadi Oxman <gadio@netvision.net.il>
 *                and Andre Hedrick <andre@linux-ide.org>
 *
 *  See linux/MAINTAINERS for address of current maintainer.
 *
 */

/*
 * This is roughly the code related to device detection and
 * device id handling.
 */

#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/slab.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/pci.h>
#include <linux/hdreg.h>
#include <linux/ide.h>

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

extern struct ata_device * get_info_ptr(kdev_t);

/*
 * This is called from the partition-table code in pt/msdos.c
 * to invent a translated geometry.
 *
 * This is suppressed if the user specifies an explicit geometry.
 *
 * The ptheads parameter is either 0 or tells about the number of
 * heads shown by the end of the first nonempty partition.
 * If this is either 16, 32, 64, 128, 240 or 255 we'll believe it.
 *
 * The xparm parameter has the following meaning:
 *       0 = convert to CHS with fewer than 1024 cyls
 *           using the same method as Ontrack DiskManager.
 *       1 = same as "0", plus offset everything by 63 sectors.
 *      -1 = similar to "0", plus redirect sector 0 to sector 1.
 *       2 = convert to a CHS geometry with "ptheads" heads.
 *
 * Returns 0 if the translation was not possible, if the device was not
 * an IDE disk drive, or if a geometry was "forced" on the commandline.
 * Returns 1 if the geometry translation was successful.
 */
int ide_xlate_1024(kdev_t i_rdev, int xparm, int ptheads, const char *msg)
{
        struct ata_device *drive;
        const char *msg1 = "";
        int heads = 0;
        int c, h, s;
        int transl = 1;         /* try translation */
        int ret = 0;

        drive = get_info_ptr(i_rdev);
        if (!drive)
                return 0;

        /* There used to be code here that assigned drive->id->CHS to
         * drive->CHS and that to drive->bios_CHS. However, some disks have
         * id->C/H/S = 4092/16/63 but are larger than 2.1 GB.  In such cases
         * that code was wrong.  Moreover, there seems to be no reason to do
         * any of these things.
         *
         * Please note that recent RedHat changes to the disk utils are bogous
         * and will report spurious errors.
         */

        /* translate? */
        if (drive->forced_geom)
                transl = 0;

        /* does ptheads look reasonable? */
        if (ptheads == 32 || ptheads == 64 || ptheads == 128 ||
            ptheads == 240 || ptheads == 255)
                heads = ptheads;

        if (xparm == 2) {
                if (!heads ||
                   (drive->bios_head >= heads && drive->bios_sect == 63))
                        transl = 0;
        }
        if (xparm == -1) {
                if (drive->bios_head > 16)
                        transl = 0;     /* we already have a translation */
        }

        if (transl) {
                static const u8 dm_head_vals[] = {4, 8, 16, 32, 64, 128, 255, 0};
                const u8 *headp = dm_head_vals;
                unsigned long total;

                /*
                 * If heads is nonzero: find a translation with this many heads
                 * and S=63.  Otherwise: find out how OnTrack Disk Manager
                 * would translate the disk.
                 *
                 * The specs say: take geometry as obtained from Identify,
                 * compute total capacity C*H*S from that, and truncate to
                 * 1024*255*63. Now take S=63, H the first in the sequence 4,
                 * 8, 16, 32, 64, 128, 255 such that 63*H*1024 >= total.
                 * [Please tell aeb@cwi.nl in case this computes a geometry
                 * different from what OnTrack uses.]
                 */

                total = ata_capacity(drive);

                s = 63;

                if (heads) {
                        h = heads;
                        c = total / (63 * heads);
                } else {
                        while (63 * headp[0] * 1024 < total && headp[1] != 0)
                                headp++;
                        h = headp[0];
                        c = total / (63 * headp[0]);
                }

                drive->bios_cyl = c;
                drive->bios_head = h;
                drive->bios_sect = s;
                ret = 1;
        }

        drive->part[0].nr_sects = ata_capacity(drive);

        if (ret)
                printk("%s%s [%d/%d/%d]", msg, msg1,
                       drive->bios_cyl, drive->bios_head, drive->bios_sect);
        return ret;
}

/*
 * Drive ID data come as little endian, it needs to be converted on big endian
 * machines.
 */
void ata_fix_driveid(struct hd_driveid *id)
{
#ifndef __LITTLE_ENDIAN
# ifdef __BIG_ENDIAN
        int i;
        u16 *stringcast;

        id->config         = __le16_to_cpu(id->config);
        id->cyls           = __le16_to_cpu(id->cyls);
        id->reserved2      = __le16_to_cpu(id->reserved2);
        id->heads          = __le16_to_cpu(id->heads);
        id->track_bytes    = __le16_to_cpu(id->track_bytes);
        id->sector_bytes   = __le16_to_cpu(id->sector_bytes);
        id->sectors        = __le16_to_cpu(id->sectors);
        id->vendor0        = __le16_to_cpu(id->vendor0);
        id->vendor1        = __le16_to_cpu(id->vendor1);
        id->vendor2        = __le16_to_cpu(id->vendor2);
        stringcast = (u16 *)&id->serial_no[0];
        for (i = 0; i < (20/2); i++)
                stringcast[i] = __le16_to_cpu(stringcast[i]);
        id->buf_type       = __le16_to_cpu(id->buf_type);
        id->buf_size       = __le16_to_cpu(id->buf_size);
        id->ecc_bytes      = __le16_to_cpu(id->ecc_bytes);
        stringcast = (u16 *)&id->fw_rev[0];
        for (i = 0; i < (8/2); i++)
                stringcast[i] = __le16_to_cpu(stringcast[i]);
        stringcast = (u16 *)&id->model[0];
        for (i = 0; i < (40/2); i++)
                stringcast[i] = __le16_to_cpu(stringcast[i]);
        id->dword_io       = __le16_to_cpu(id->dword_io);
        id->reserved50     = __le16_to_cpu(id->reserved50);
        id->field_valid    = __le16_to_cpu(id->field_valid);
        id->cur_cyls       = __le16_to_cpu(id->cur_cyls);
        id->cur_heads      = __le16_to_cpu(id->cur_heads);
        id->cur_sectors    = __le16_to_cpu(id->cur_sectors);
        id->cur_capacity0  = __le16_to_cpu(id->cur_capacity0);
        id->cur_capacity1  = __le16_to_cpu(id->cur_capacity1);
        id->lba_capacity   = __le32_to_cpu(id->lba_capacity);
        id->dma_1word      = __le16_to_cpu(id->dma_1word);
        id->dma_mword      = __le16_to_cpu(id->dma_mword);
        id->eide_pio_modes = __le16_to_cpu(id->eide_pio_modes);
        id->eide_dma_min   = __le16_to_cpu(id->eide_dma_min);
        id->eide_dma_time  = __le16_to_cpu(id->eide_dma_time);
        id->eide_pio       = __le16_to_cpu(id->eide_pio);
        id->eide_pio_iordy = __le16_to_cpu(id->eide_pio_iordy);
        for (i = 0; i < 2; ++i)
                id->words69_70[i] = __le16_to_cpu(id->words69_70[i]);
        for (i = 0; i < 4; ++i)
                id->words71_74[i] = __le16_to_cpu(id->words71_74[i]);
        id->queue_depth    = __le16_to_cpu(id->queue_depth);
        for (i = 0; i < 4; ++i)
                id->words76_79[i] = __le16_to_cpu(id->words76_79[i]);
        id->major_rev_num  = __le16_to_cpu(id->major_rev_num);
        id->minor_rev_num  = __le16_to_cpu(id->minor_rev_num);
        id->command_set_1  = __le16_to_cpu(id->command_set_1);
        id->command_set_2  = __le16_to_cpu(id->command_set_2);
        id->cfsse          = __le16_to_cpu(id->cfsse);
        id->cfs_enable_1   = __le16_to_cpu(id->cfs_enable_1);
        id->cfs_enable_2   = __le16_to_cpu(id->cfs_enable_2);
        id->csf_default    = __le16_to_cpu(id->csf_default);
        id->dma_ultra      = __le16_to_cpu(id->dma_ultra);
        id->word89         = __le16_to_cpu(id->word89);
        id->word90         = __le16_to_cpu(id->word90);
        id->CurAPMvalues   = __le16_to_cpu(id->CurAPMvalues);
        id->word92         = __le16_to_cpu(id->word92);
        id->hw_config      = __le16_to_cpu(id->hw_config);
        id->acoustic       = __le16_to_cpu(id->acoustic);
        for (i = 0; i < 5; i++)
                id->words95_99[i]  = __le16_to_cpu(id->words95_99[i]);
        id->lba_capacity_2 = __le64_to_cpu(id->lba_capacity_2);
        for (i = 0; i < 22; i++)
                id->words104_125[i]   = __le16_to_cpu(id->words104_125[i]);
        id->last_lun       = __le16_to_cpu(id->last_lun);
        id->word127        = __le16_to_cpu(id->word127);
        id->dlf            = __le16_to_cpu(id->dlf);
        id->csfo           = __le16_to_cpu(id->csfo);
        for (i = 0; i < 26; i++)
                id->words130_155[i] = __le16_to_cpu(id->words130_155[i]);
        id->word156        = __le16_to_cpu(id->word156);
        for (i = 0; i < 3; i++)
                id->words157_159[i] = __le16_to_cpu(id->words157_159[i]);
        id->cfa_power      = __le16_to_cpu(id->cfa_power);
        for (i = 0; i < 14; i++)
                id->words161_175[i] = __le16_to_cpu(id->words161_175[i]);
        for (i = 0; i < 31; i++)
                id->words176_205[i] = __le16_to_cpu(id->words176_205[i]);
        for (i = 0; i < 48; i++)
                id->words206_254[i] = __le16_to_cpu(id->words206_254[i]);
        id->integrity_word  = __le16_to_cpu(id->integrity_word);
# else
#  error "Please fix <asm/byteorder.h>"
# endif
#endif
}

void ide_fixstring(char *s, const int bytecount, const int byteswap)
{
        char *p = s;
        char *end = &s[bytecount & ~1]; /* bytecount must be even */

        if (byteswap) {
                /* convert from big-endian to host byte order */
                for (p = end ; p != s;) {
                        unsigned short *pp = (unsigned short *) (p -= 2);
                        *pp = ntohs(*pp);
                }
        }

        /* strip leading blanks */
        while (s != end && *s == ' ')
                ++s;

        /* compress internal blanks and strip trailing blanks */
        while (s != end && *s) {
                if (*s++ != ' ' || (s != end && *s && *s != ' '))
                        *p++ = *(s-1);
        }

        /* wipe out trailing garbage */
        while (p != end)
                *p++ = '\0';
}

/*
 *  All hosts that use the 80c ribbon must use this!
 */
int eighty_ninty_three(struct ata_device *drive)
{
        return ((drive->channel->udma_four) &&
#ifndef CONFIG_IDEDMA_IVB
                (drive->id->hw_config & 0x4000) &&
#endif
                (drive->id->hw_config & 0x6000)) ? 1 : 0;
}

/* FIXME: Channel lock should be held.
 */
int ide_config_drive_speed(struct ata_device *drive, u8 speed)
{
        struct ata_channel *ch = drive->channel;
        int ret;

#if defined(CONFIG_BLK_DEV_IDEDMA) && !defined(__CRIS__)
        u8 unit = (drive->select.b.unit & 0x01);
        outb(inb(ch->dma_base + 2) & ~(1 << (5 + unit)), ch->dma_base + 2);
#endif

        /*
         * Select the drive, and issue the SETFEATURES command.
         */
        disable_irq(ch->irq);   /* disable_irq_nosync ?? */
        udelay(1);
        ata_select(drive, 0);
        ata_mask(drive);
        udelay(1);
        ata_irq_enable(drive, 0);
        OUT_BYTE(speed, IDE_NSECTOR_REG);
        OUT_BYTE(SETFEATURES_XFER, IDE_FEATURE_REG);
        OUT_BYTE(WIN_SETFEATURES, IDE_COMMAND_REG);
        if (drive->quirk_list == 2)
                ata_irq_enable(drive, 1);
        udelay(1);
        ret = ata_status_poll(drive, 0, BUSY_STAT, WAIT_CMD, NULL);
        ata_mask(drive);
        enable_irq(ch->irq);

        if (ret != ATA_OP_READY) {
                ata_dump(drive, NULL, "set drive speed");
                return 1;
        }

        drive->id->dma_ultra &= ~0xFF00;
        drive->id->dma_mword &= ~0x0F00;
        drive->id->dma_1word &= ~0x0F00;

#if defined(CONFIG_BLK_DEV_IDEDMA) && !defined(__CRIS__)
        if (speed > XFER_PIO_4) {
                outb(inb(ch->dma_base + 2)|(1 << (5 + unit)), ch->dma_base + 2);
        } else {
                outb(inb(ch->dma_base + 2) & ~(1 << (5 + unit)), ch->dma_base + 2);
        }
#endif

        switch(speed) {
                case XFER_UDMA_7:   drive->id->dma_ultra |= 0x8080; break;
                case XFER_UDMA_6:   drive->id->dma_ultra |= 0x4040; break;
                case XFER_UDMA_5:   drive->id->dma_ultra |= 0x2020; break;
                case XFER_UDMA_4:   drive->id->dma_ultra |= 0x1010; break;
                case XFER_UDMA_3:   drive->id->dma_ultra |= 0x0808; break;
                case XFER_UDMA_2:   drive->id->dma_ultra |= 0x0404; break;
                case XFER_UDMA_1:   drive->id->dma_ultra |= 0x0202; break;
                case XFER_UDMA_0:   drive->id->dma_ultra |= 0x0101; break;
                case XFER_MW_DMA_2: drive->id->dma_mword |= 0x0404; break;
                case XFER_MW_DMA_1: drive->id->dma_mword |= 0x0202; break;
                case XFER_MW_DMA_0: drive->id->dma_mword |= 0x0101; break;
                case XFER_SW_DMA_2: drive->id->dma_1word |= 0x0404; break;
                case XFER_SW_DMA_1: drive->id->dma_1word |= 0x0202; break;
                case XFER_SW_DMA_0: drive->id->dma_1word |= 0x0101; break;
                default: break;
        }

        drive->current_speed = speed;

        return 0;
}

static inline void do_identify(struct ata_device *drive, u8 cmd)
{
        int bswap = 1;
        struct hd_driveid *id;

        id = drive->id = kmalloc (SECTOR_WORDS*4, GFP_ATOMIC);  /* called with interrupts disabled! */
        if (!id) {
                printk(KERN_WARNING "(ide-probe::do_identify) Out of memory.\n");
                goto err_kmalloc;
        }

        /* Read 512 bytes of id info.
         *
         * Please note that it is well known that some *very* old drives are
         * able to provide only 256 of them, since this was the amount read by
         * DOS.
         *
         * However let's try to get away with this...
         */

        ata_read(drive, id, SECTOR_WORDS);
        local_irq_enable();
        ata_fix_driveid(id);

        if (id->word156 == 0x4d42) {
                printk("%s: drive->id->word156 == 0x%04x \n", drive->name, drive->id->word156);
        }

        if (!drive->forced_lun)
                drive->last_lun = id->last_lun & 0x7;
#if defined (CONFIG_SCSI_EATA_DMA) || defined (CONFIG_SCSI_EATA_PIO) || defined (CONFIG_SCSI_EATA)
        /*
         * EATA SCSI controllers do a hardware ATA emulation:
         * Ignore them if there is a driver for them available.
         */
        if ((id->model[0] == 'P' && id->model[1] == 'M')
         || (id->model[0] == 'S' && id->model[1] == 'K')) {
                printk("%s: EATA SCSI HBA %.10s\n", drive->name, id->model);
                goto err_misc;
        }
#endif

        /*
         *  WIN_IDENTIFY returns little-endian info,
         *  WIN_PIDENTIFY *usually* returns little-endian info.
         */
        if (cmd == WIN_PIDENTIFY) {
                if ((id->model[0] == 'N' && id->model[1] == 'E') /* NEC */
                 || (id->model[0] == 'F' && id->model[1] == 'X') /* Mitsumi */
                 || (id->model[0] == 'P' && id->model[1] == 'i'))/* Pioneer */
                        bswap ^= 1;     /* Vertos drives may still be weird */
        }
        ide_fixstring(id->model,     sizeof(id->model),     bswap);
        ide_fixstring(id->fw_rev,    sizeof(id->fw_rev),    bswap);
        ide_fixstring(id->serial_no, sizeof(id->serial_no), bswap);

        if (strstr(id->model, "E X A B Y T E N E S T"))
                goto err_misc;

        id->model[sizeof(id->model)-1] = '\0';  /* we depend on this a lot! */
        printk("%s: %s, ", drive->name, id->model);
        drive->present = 1;

        /*
         * Check for an ATAPI device:
         */
        if (cmd == WIN_PIDENTIFY) {
                u8 type = (id->config >> 8) & 0x1f;
                printk("ATAPI ");
#ifdef CONFIG_BLK_DEV_PDC4030
                if (drive->channel->unit == 1 && drive->channel->chipset == ide_pdc4030) {
                        printk(" -- not supported on 2nd Promise port\n");
                        goto err_misc;
                }
#endif
                switch (type) {
                        case ATA_FLOPPY:
                                if (!strstr(id->model, "CD-ROM")) {
                                        if (!strstr(id->model, "oppy") && !strstr(id->model, "poyp") && !strstr(id->model, "ZIP"))
                                                printk("cdrom or floppy?, assuming ");
                                        if (drive->type != ATA_ROM) {
                                                printk ("FLOPPY");
                                                break;
                                        }
                                }
                                type = ATA_ROM; /* Early cdrom models used zero */
                        case ATA_ROM:
                                drive->removable = 1;
#ifdef CONFIG_PPC
                                /* kludge for Apple PowerBook internal zip */
                                if (!strstr(id->model, "CD-ROM") && strstr(id->model, "ZIP")) {
                                        printk ("FLOPPY");
                                        type = ATA_FLOPPY;
                                        break;
                                }
#endif
                                printk ("CD/DVD-ROM");
                                break;
                        case ATA_TAPE:
                                printk ("TAPE");
                                break;
                        case ATA_MOD:
                                printk ("OPTICAL");
                                drive->removable = 1;
                                break;
                        default:
                                printk("UNKNOWN (type %d)", type);
                                break;
                }
                printk (" drive\n");
                drive->type = type;
                return;
        }

        /*
         * Not an ATAPI device: looks like a "regular" hard disk:
         */
        if (id->config & (1<<7))
                drive->removable = 1;

        /*
         * FIXME: This is just plain ugly or plain unnecessary.
         *
         * Prevent long system lockup probing later for non-existant slave
         * drive if the hwif is actually a flash memory card of some variety:
         */

        if (drive_is_flashcard(drive)) {
                struct ata_device *mate = &drive->channel->drives[1 ^ drive->select.b.unit];
                if (!mate->ata_flash) {
                        mate->present = 0;
                        mate->noprobe = 1;
                }
        }
        drive->type = ATA_DISK;
        printk("DISK drive\n");

        /* Initialize our quirk list. */
        if (drive->channel->quirkproc)
                drive->quirk_list = drive->channel->quirkproc(drive);

        /* Initialize queue depth settings */
        drive->queue_depth = 1;
#ifdef CONFIG_BLK_DEV_IDE_TCQ_DEPTH
        drive->queue_depth = CONFIG_BLK_DEV_IDE_TCQ_DEPTH;
#else
        drive->queue_depth = drive->id->queue_depth + 1;
#endif
        if (drive->queue_depth < 1 || drive->queue_depth > IDE_MAX_TAG)
                drive->queue_depth = IDE_MAX_TAG;

        return;

err_misc:
        kfree(id);
err_kmalloc:
        drive->present = 0;

        return;
}

/*
 * Sends an ATA(PI) IDENTIFY request to a drive and wait for a response.  It
 * also monitor irqs while this is happening, in hope of automatically
 * determining which one is being used by the interface.
 *
 * Returns:     0  device was identified
 *              1  device timed-out (no response to identify request)
 *              2  device aborted the command (refused to identify itself)
 */
static int identify(struct ata_device *drive, u8 cmd)
{
        struct ata_channel *ch = drive->channel;
        int rc = 1;
        int autoprobe = 0;
        unsigned long cookie = 0;
        ide_ioreg_t hd_status;
        unsigned long timeout;


        /* FIXME: perhaps we should be just using allways the status register,
         * since it should simplify the code significantly.
         */
        if (ch->io_ports[IDE_CONTROL_OFFSET]) {
                u8 s;
                u8 a;

                if (!drive->channel->irq) {
                        autoprobe = 1;
                        cookie = probe_irq_on();
                        ata_irq_enable(drive, 1);       /* enable device irq */
                }

                /* take a deep breath */
                mdelay(50);
                a = IN_BYTE(ch->io_ports[IDE_ALTSTATUS_OFFSET]);
                s = IN_BYTE(ch->io_ports[IDE_STATUS_OFFSET]);
                if ((a ^ s) & ~INDEX_STAT) {
                        printk("%s: probing with STATUS(0x%02x) instead of ALTSTATUS(0x%02x)\n", drive->name, s, a);
                        hd_status = ch->io_ports[IDE_STATUS_OFFSET];    /* ancient Seagate drives, broken interfaces */
                } else {
                        hd_status = ch->io_ports[IDE_ALTSTATUS_OFFSET]; /* use non-intrusive polling */
                }
        } else {
                mdelay(50);
                hd_status = ch->io_ports[IDE_STATUS_OFFSET];
        }

        /* set features register for atapi identify command to be sure of reply */
        if ((cmd == WIN_PIDENTIFY))
                OUT_BYTE(0,IDE_FEATURE_REG);    /* disable dma & overlap */

#if CONFIG_BLK_DEV_PDC4030
        if (drive->channel->chipset == ide_pdc4030) {
                /* DC4030 hosted drives need their own identify... */
                extern int pdc4030_identify(struct ata_device *);

                if (pdc4030_identify(drive))
                        goto out;
        } else
#endif
                OUT_BYTE(cmd, IDE_COMMAND_REG);         /* ask drive for ID */
        timeout = ((cmd == WIN_IDENTIFY) ? WAIT_WORSTCASE : WAIT_PIDENTIFY) / 2;
        timeout += jiffies;
        do {
                if (time_after(jiffies, timeout))
                        goto out;       /* drive timed-out */
                mdelay(50);             /* give drive a breather */
        } while (IN_BYTE(hd_status) & BUSY_STAT);

        mdelay(50);             /* wait for IRQ and DRQ_STAT */

        if (ata_status(drive, DRQ_STAT, BAD_R_STAT)) {
                unsigned long flags;

                local_irq_save(flags);          /* some systems need this */
                do_identify(drive, cmd);        /* drive returned ID */
                rc = 0;                         /* drive responded with ID */
                ata_status(drive, 0, 0);        /* clear drive IRQ */
                local_irq_restore(flags);       /* local CPU only */
        } else
                rc = 2;                 /* drive refused ID */

out:
        if (autoprobe) {
                int irq;

                ata_irq_enable(drive, 0);       /* mask device irq */
                ata_status(drive, 0, 0);        /* clear drive IRQ */
                udelay(5);
                irq = probe_irq_off(cookie);
                if (!drive->channel->irq) {
                        if (irq > 0)
                                drive->channel->irq = irq;
                        else    /* Mmmm.. multiple IRQs.. don't know which was ours */
                                printk("%s: IRQ probe failed (0x%lx)\n", drive->name, cookie);
                }
        }

        return rc;
}


/*
 * This has the difficult job of finding a drive if it exists, without getting
 * hung up if it doesn't exist, without trampling on ethernet cards, and
 * without leaving any IRQs dangling to haunt us later.
 *
 * If a drive is "known" to exist (from CMOS or kernel parameters), but does
 * not respond right away, the probe will "hang in there" for the maximum wait
 * time (about 30 seconds), otherwise it will exit much more quickly.
 *
 * Returns:     0  device was identified
 *              1  device timed-out (no response to identify request)
 *              2  device aborted the command (refused to identify itself)
 *              3  bad status from device (possible for ATAPI drives)
 *              4  probe was not attempted because failure was obvious
 */
static int do_probe(struct ata_device *drive, u8 cmd)
{
        int rc;
        struct ata_channel *ch = drive->channel;
        u8 select;

        if (drive->present) {   /* avoid waiting for inappropriate probes */
                if ((drive->type != ATA_DISK) && (cmd == WIN_IDENTIFY))
                        return 4;
        }
#ifdef DEBUG
        printk("probing for %s: present=%d, type=%02x, probetype=%s\n",
                drive->name, drive->present, drive->type,
                (cmd == WIN_IDENTIFY) ? "ATA" : "ATAPI");
#endif
        mdelay(50);     /* needed for some systems (e.g. crw9624 as drive0 with disk as slave) */
        ata_select(drive, 50000);
        select = IN_BYTE(IDE_SELECT_REG);
        if (select != drive->select.all && !drive->present) {
                if (drive->select.b.unit != 0) {
                        ata_select(&ch->drives[0], 50000);      /* exit with drive0 selected */
                }
                return 3;    /* no i/f present: mmm.. this should be a 4 -ml */
        }

        if (ata_status(drive, READY_STAT, BUSY_STAT) || drive->present || cmd == WIN_PIDENTIFY) {
                if ((rc = identify(drive,cmd)))   /* send cmd and wait */
                        rc = identify(drive,cmd); /* failed: try again */
                if (rc == 1 && cmd == WIN_PIDENTIFY && drive->autotune != 2) {
                        unsigned long timeout;
                        printk("%s: no response (status = 0x%02x), resetting drive\n",
                                        drive->name, drive->status);
                        mdelay(50);
                        OUT_BYTE(drive->select.all, IDE_SELECT_REG);
                        mdelay(50);
                        OUT_BYTE(WIN_SRST, IDE_COMMAND_REG);
                        timeout = jiffies;
                        while (!ata_status(drive, 0, BUSY_STAT) && time_before(jiffies, timeout + WAIT_WORSTCASE))
                                mdelay(50);
                        rc = identify(drive, cmd);
                }
                if (rc == 1)
                        printk("%s: no response (status = 0x%02x)\n",
                                        drive->name, drive->status);
                ata_status(drive, 0, 0);        /* ensure drive irq is clear */
        } else
                rc = 3;                         /* not present or maybe ATAPI */

        if (drive->select.b.unit != 0) {
                ata_select(&ch->drives[0], 50000);      /* exit with drive0 selected */
                ata_status(drive, 0, 0);                /* ensure drive irq is clear */
        }

        return rc;
}

/*
 * Probe for drivers on a channel.
 *
 * This routine only knows how to look for drive units 0 and 1 on an interface,
 * so any setting of MAX_DRIVES > 2 won't work here.
 */
static void channel_probe(struct ata_channel *ch)
{
        unsigned int i;
        unsigned long flags;
        int error;

        if (ch->noprobe)
                return;

        ch->straight8 = 0;

        local_save_flags(flags);
        local_irq_enable();     /* needed for jiffies and irq probing */

        /*
         * Check for the presence of a channel by probing for drives on it.
         */
        for (i = 0; i < MAX_DRIVES; ++i) {
                struct ata_device *drive = &ch->drives[i];

                if (drive->noprobe)     /* don't look for this one */
                        continue;

                if (do_probe(drive, WIN_IDENTIFY) >= 2) { /* if !(success||timed-out) */
                        do_probe(drive, WIN_PIDENTIFY); /* look for ATAPI device */
                }

                /* Special handling of EXABYTE controller cards. */
                if (drive->id && strstr(drive->id->model, "E X A B Y T E N E S T")) {
                        unsigned long timeout;

                        printk("%s: enabling %s -- ", drive->channel->name, drive->id->model);
                        ata_select(drive, 50000);
                        OUT_BYTE(EXABYTE_ENABLE_NEST, IDE_COMMAND_REG);
                        timeout = jiffies + WAIT_WORSTCASE;
                        do {
                                if (time_after(jiffies, timeout)) {
                                        printk("failed (timeout)\n");
                                        return;
                                }
                                mdelay(50);
                        } while (!ata_status(drive, 0, BUSY_STAT));
                        mdelay(50);
                        if (!ata_status(drive, 0, BAD_STAT))
                                printk("failed (status = 0x%02x)\n", drive->status);
                        else
                                printk("success\n");

                        if (do_probe(drive, WIN_IDENTIFY) >= 2) { /* if !(success||timed-out) */
                                do_probe(drive, WIN_PIDENTIFY); /* look for ATAPI device */
                }
                }

                if (!drive->present)
                        continue;       /* drive not found */

                if (!drive->id) {       /* identification failed? */
                        if (drive->type == ATA_DISK)
                                printk ("%s: pre-ATA drive, CHS=%d/%d/%d\n",
                                                drive->name, drive->cyl, drive->head, drive->sect);
                        else if (drive->type == ATA_ROM)
                                printk("%s: ATAPI cdrom (?)\n", drive->name);
                        else
                                drive->present = 0;     /* nuke it */
                }

                /* drive found, there is a channel it is attached too. */
                if (drive->present)
                        ch->present = 1;
        }

        if (!ch->present)
                goto not_found;

        error = 0;

        if (((unsigned long)ch->io_ports[IDE_DATA_OFFSET] | 7) ==
                        ((unsigned long)ch->io_ports[IDE_STATUS_OFFSET])) {
                error += !request_region(ch->io_ports[IDE_DATA_OFFSET], 8, ch->name);
                ch->straight8 = 1;
        } else {
                for (i = 0; i < 8; i++)
                        error += !request_region(ch->io_ports[i], 1, ch->name);
        }
        if (ch->io_ports[IDE_CONTROL_OFFSET])
                error += !request_region(ch->io_ports[IDE_CONTROL_OFFSET], 1, ch->name);
#if defined(CONFIG_AMIGA) || defined(CONFIG_MAC)
        if (ch->io_ports[IDE_IRQ_OFFSET])
                error += !request_region(ch->io_ports[IDE_IRQ_OFFSET], 1, ch->name);
#endif

        /* Some neccessary register area was already used. Skip this device.
         */

        if (
#if CONFIG_BLK_DEV_PDC4030
                        (ch->chipset != ide_pdc4030 || ch->unit == 0) &&
#endif
                        error) {

                /* FIXME: We should be dealing properly with partial IO region
                 * allocations here.
                 */

                ch->present = 0;
                printk("%s: error: ports already in use!\n", ch->name);
        }

        if (!ch->present)
                goto not_found;

        /* Register this hardware interface within the global device tree.
         *
         * FIXME: This should be handled as a pci subdevice in a generic way.
         */
        sprintf(ch->dev.bus_id, "ata@%02x", ch->unit);
        strcpy(ch->dev.name, "ATA/ATAPI Host-Channel");
        ch->dev.driver_data = ch;
#ifdef CONFIG_PCI
        if (ch->pci_dev)
                ch->dev.parent = &ch->pci_dev->dev;
        else
#endif
                ch->dev.parent = NULL; /* Would like to do = &device_legacy */

        device_register(&ch->dev);

        if (ch->reset)
                ata_reset(ch);

        local_irq_restore(flags);

        /*
         * Now setup the PIO transfer modes of the drives on this channel.
         */
        for (i = 0; i < MAX_DRIVES; ++i) {
                struct ata_device *drive = &ch->drives[i];

                if (drive->present && (drive->autotune == 1)) {
                        if (drive->channel->tuneproc)
                                drive->channel->tuneproc(drive, 255);   /* auto-tune PIO mode */
                }
        }

        return;

not_found:
        local_irq_restore(flags);
}

/*
 * This routine sets up the irq for an ide interface, and creates a new hwgroup
 * for the irq/channel if none was previously assigned.
 *
 * Much of the code is for correctly detecting/handling irq sharing and irq
 * serialization situations.  This is somewhat complex because it handles
 * static as well as dynamic (PCMCIA) IDE interfaces.
 *
 * The SA_INTERRUPT in sa_flags means ata_irq_request() is always entered with
 * interrupts completely disabled.  This can be bad for interrupt latency, but
 * anything else has led to problems on some machines.  We re-enable interrupts
 * as much as we can safely do in most places.
 */
static int init_irq(struct ata_channel *ch)
{
        unsigned long flags;
        int i;
        spinlock_t *lock;
        spinlock_t *new_lock;
        unsigned long *active;
        unsigned long *new_active;
        struct ata_channel *match = NULL;

        /* Spare allocation before sleep. */
        new_lock = kmalloc(sizeof(*lock), GFP_KERNEL);
        new_active = kmalloc(sizeof(*active), GFP_KERNEL);
        *new_active = 0L;

        spin_lock_irqsave(&ide_lock, flags);
        ch->lock = NULL;

#if MAX_HWIFS > 1
        /*
         * Group up with any other channels that share our irq(s).
         */
        for (i = 0; i < MAX_HWIFS; ++i) {
                struct ata_channel *h = &ide_hwifs[i];

                /* scan only initialized channels */
                if (!h->lock)
                        continue;

                if (ch->irq != h->irq)
                        continue;

                ch->sharing_irq = h->sharing_irq = 1;

                if (ch->chipset != ide_pci || h->chipset != ide_pci ||
                     ch->serialized || h->serialized) {
                        if (match && match->lock && match->lock != h->lock)
                                printk("%s: potential irq problem with %s and %s\n", ch->name, h->name, match->name);
                        /* don't undo a prior perfect match */
                        if (!match || match->irq != ch->irq)
                                match = h;
                }
        }
#endif
        /*
         * If we are still without a lock group, then form a new one
         */
        if (!match) {
                lock = new_lock;
                active = new_active;
                if (!lock) {
                        spin_unlock_irqrestore(&ide_lock, flags);

                        return 1;
                }
                spin_lock_init(lock);
        } else {
                lock = match->lock;
                active = match->active;
                if(new_lock)
                        kfree(new_lock);
        }

        /*
         * Allocate the irq, if not already obtained for another channel
         */
        if (!match || match->irq != ch->irq) {
                struct ata_device tmp;
#ifdef CONFIG_IDEPCI_SHARE_IRQ
                int sa = IDE_CHIPSET_IS_PCI(ch->chipset) ? SA_SHIRQ : SA_INTERRUPT;
#else
                int sa = IDE_CHIPSET_IS_PCI(ch->chipset) ? SA_INTERRUPT|SA_SHIRQ : SA_INTERRUPT;
#endif

                /* Enable interrupts triggered by the drive.  We use a shallow
                 * device structure, just to use the generic function very
                 * early.
                 */
                tmp.channel = ch;
                ata_irq_enable(&tmp, 1);

                if (request_irq(ch->irq, &ata_irq_request, sa, ch->name, ch)) {
                        if (!match) {
                                kfree(lock);
                                kfree(active);
                        }

                        spin_unlock_irqrestore(&ide_lock, flags);

                        return 1;
                }
        }

        /*
         * Everything is okay. Tag us as member of this lock group.
         */
        ch->lock = lock;
        ch->active = active;

        init_timer(&ch->timer);
        ch->timer.function = &ide_timer_expiry;
        ch->timer.data = (unsigned long) ch;

        for (i = 0; i < MAX_DRIVES; ++i) {
                struct ata_device *drive = &ch->drives[i];
                request_queue_t *q;
                int max_sectors = 255;

                if (!drive->present)
                        continue;

                if (!ch->drive)
                        ch->drive = drive;

                /*
                 * Init the per device request queue.
                 */

                q = &drive->queue;
                q->queuedata = drive;
                blk_init_queue(q, do_ide_request, drive->channel->lock);
                blk_queue_segment_boundary(q, ch->seg_boundary_mask);
                blk_queue_max_segment_size(q, ch->max_segment_size);

                /* ATA can do up to 128K per request, pdc4030 needs smaller
                 * limit. */
#ifdef CONFIG_BLK_DEV_PDC4030
                if (drive->channel->chipset == ide_pdc4030)
                        max_sectors = 127;
#endif
                blk_queue_max_sectors(q, max_sectors);

                /* ATA DMA can do PRD_ENTRIES number of segments. */
                blk_queue_max_hw_segments(q, PRD_ENTRIES);

                /* FIXME: This is a driver limit and could be eliminated. */
                blk_queue_max_phys_segments(q, PRD_ENTRIES);
        }
        spin_unlock_irqrestore(&ide_lock, flags);

#if !defined(__mc68000__) && !defined(CONFIG_APUS) && !defined(__sparc__)
        printk("%s at 0x%03x-0x%03x,0x%03x on irq %d", ch->name,
                ch->io_ports[IDE_DATA_OFFSET],
                ch->io_ports[IDE_DATA_OFFSET]+7,
                ch->io_ports[IDE_CONTROL_OFFSET], ch->irq);
#elif defined(__sparc__)
        printk("%s at 0x%03lx-0x%03lx,0x%03lx on irq %s", ch->name,
                ch->io_ports[IDE_DATA_OFFSET],
                ch->io_ports[IDE_DATA_OFFSET]+7,
                ch->io_ports[IDE_CONTROL_OFFSET], __irq_itoa(ch->irq));
#else
        printk("%s at %p on irq 0x%08x", ch->name,
                ch->io_ports[IDE_DATA_OFFSET], ch->irq);
#endif
        if (match)
                printk(" (%sed with %s)",
                        ch->sharing_irq ? "shar" : "serializ", match->name);
        printk("\n");

        return 0;
}

/*
 * Returns the queue which corresponds to a given device.
 *
 * FIXME: this should take struct block_device * as argument in future.
 */
static request_queue_t *ata_get_queue(kdev_t dev)
{
        struct ata_channel *ch = (struct ata_channel *)blk_dev[major(dev)].data;

        /* FIXME: ALLERT: This discriminates between master and slave! */
        return &ch->drives[DEVICE_NR(dev) & 1].queue;
}

/* Number of minor numbers we consume par channel. */
#define ATA_MINORS      (MAX_DRIVES * (1 << PARTN_BITS))

static void channel_init(struct ata_channel *ch)
{
        struct gendisk *gd;
        struct hd_struct *part;
        devfs_handle_t *de_arr;
        char *flags;
        unsigned int unit;
        extern devfs_handle_t ide_devfs_handle;
        char *names;

        if (!ch->present)
                return;

        /* we set it back to 1 if all is ok below */
        ch->present = 0;

        if (!ch->irq) {
                if (!(ch->irq = ide_default_irq(ch->io_ports[IDE_DATA_OFFSET]))) {
                        printk("%s: DISABLED, NO IRQ\n", ch->name);

                        return;
                }
        }
#ifdef CONFIG_BLK_DEV_HD

        /* The first "legacy"  HD gets distinguished by the IRQ it is attached
         * to and the IO port it takes.
         */

        if (ch->irq == 14 && ch->io_ports[IDE_DATA_OFFSET] != 0x1f0) {
                printk("%s: CANNOT SHARE IRQ WITH OLD HARDDISK DRIVER (hd.c)\n", ch->name);

                return;
        }
#endif

        if (register_blkdev(ch->major, ch->name, ide_fops)) {
                printk("%s: UNABLE TO GET MAJOR NUMBER %d\n", ch->name, ch->major);

                return;
        }

        if (init_irq(ch)) {
                int irq = ch->irq;
                /*
                 * It failed to initialise. Find the default IRQ for
                 * this port and try that.
                 */
                if (!(ch->irq = ide_default_irq(ch->io_ports[IDE_DATA_OFFSET]))) {
                        printk(KERN_INFO "%s: disabled; unable to get IRQ %d.\n", ch->name, irq);
                        (void) unregister_blkdev (ch->major, ch->name);

                        return;
                }
                if (init_irq(ch)) {
                        printk(KERN_INFO "%s: probed IRQ %d and default IRQ %d failed.\n",
                                ch->name, irq, ch->irq);
                        (void) unregister_blkdev(ch->major, ch->name);

                        return;
                }
                printk(KERN_INFO "%s: probed IRQ %d failed, using default.\n", ch->name, ch->irq);
        }

        /* Initialize partition and global device data.
         */

        gd = kmalloc (MAX_DRIVES * sizeof(struct gendisk), GFP_KERNEL);
        if (!gd)
                goto err_kmalloc_gd;

        memset(gd, 0, MAX_DRIVES * sizeof(struct gendisk));

        part = kmalloc(ATA_MINORS * sizeof(struct hd_struct), GFP_KERNEL);
        if (!part)
                goto err_kmalloc_gd_part;
        memset(part, 0, ATA_MINORS * sizeof(struct hd_struct));

        de_arr = kmalloc (sizeof(devfs_handle_t) * MAX_DRIVES, GFP_KERNEL);
        if (!de_arr)
                goto err_kmalloc_gd_de_arr;
        memset(de_arr, 0, sizeof(devfs_handle_t) * MAX_DRIVES);

        flags = kmalloc (sizeof(char) * MAX_DRIVES, GFP_KERNEL);
        if (!flags)
                goto err_kmalloc_gd_flags;
        memset(flags, 0, sizeof(char) * MAX_DRIVES);

        names = kmalloc (4 * MAX_DRIVES, GFP_KERNEL);
        if (!names)
                goto err_kmalloc_gd_names;
        memset(names, 0, 4 * MAX_DRIVES);

        for (unit = 0; unit < MAX_DRIVES; ++unit) {
                gd[unit].part = part + (unit << PARTN_BITS);
                gd[unit].de_arr = de_arr + unit;
                gd[unit].flags = flags + unit;
                ch->drives[unit].part = gd[unit].part;
                gd[unit].major  = ch->major;
                gd[unit].first_minor = unit << PARTN_BITS;
                sprintf(names + 4*unit, "hd%c", 'a'+ch->index*MAX_DRIVES+unit);
                gd[unit].major_name = names + 4*unit;
                gd[unit].minor_shift = PARTN_BITS;
                gd[unit].nr_real = 1;
                gd[unit].fops = ide_fops;
                ch->gd[unit] = gd + unit;
                add_gendisk(gd + unit);
        }

        for (unit = 0; unit < MAX_DRIVES; ++unit) {
                char name[80];

                ch->drives[unit].dn = ((ch->unit ? 2 : 0) + unit);
                sprintf(name, "host%d/bus%d/target%d/lun%d",
                        ch->index, ch->unit, unit, ch->drives[unit].lun);
                if (ch->drives[unit].present)
                        ch->drives[unit].de = devfs_mk_dir(ide_devfs_handle, name, NULL);
        }

        blk_dev[ch->major].data = ch;
        blk_dev[ch->major].queue = ata_get_queue;

        /* All went well, flag this channel entry as valid again. */
        ch->present = 1;

        return;

err_kmalloc_gd_names:
        kfree(names);
err_kmalloc_gd_flags:
        kfree(de_arr);
err_kmalloc_gd_de_arr:
        kfree(part);
err_kmalloc_gd_part:
        kfree(gd);
err_kmalloc_gd:
        printk(KERN_CRIT "(%s) Out of memory\n", __FUNCTION__);
}

/*
 * FIXME: consider moving this to main.c, since this is the only place where
 * it's used.
 *
 * Probe only for drives on channes which are not already present.
 */
int ideprobe_init(void)
{
        unsigned int i;
        int probe[MAX_HWIFS];

        for (i = 0; i < MAX_HWIFS; ++i)
                probe[i] = !ide_hwifs[i].present;

        /*
         * Probe for drives in the usual way.. CMOS/BIOS, then poke at ports
         */
        for (i = 0; i < MAX_HWIFS; ++i) {
                if (!probe[i])
                        continue;
                channel_probe(&ide_hwifs[i]);
        }
        for (i = 0; i < MAX_HWIFS; ++i) {
                if (!probe[i])
                        continue;
                channel_init(&ide_hwifs[i]);
        }
        return 0;
}

EXPORT_SYMBOL(ata_fix_driveid);
EXPORT_SYMBOL(ide_fixstring);
EXPORT_SYMBOL(eighty_ninty_three);
EXPORT_SYMBOL(ide_config_drive_speed);