hd.c

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/*
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 * This is the low-level hd interrupt support. It traverses the
 * request-list, using interrupts to jump between functions. As
 * all the functions are called within interrupts, we may not
 * sleep. Special care is recommended.
 *
 *  modified by Drew Eckhardt to check nr of hd's from the CMOS.
 *
 *  Thanks to Branko Lankester, [email protected], who found a bug
 *  in the early extended-partition checks and added DM partitions
 *
 *  IRQ-unmask, drive-id, multiple-mode, support for ">16 heads",
 *  and general streamlining by Mark Lord.
 *
 *  Removed 99% of above. Use Mark's ide driver for those options.
 *  This is now a lightweight ST-506 driver. (Paul Gortmaker)
 *
 *  Modified 1995 Russell King for ARM processor.
 *
 *  Bugfix: max_sectors must be <= 255 or the wheels tend to come
 *  off in a hurry once you queue things up - Paul G. 02/2001
 */

/* Uncomment the following if you want verbose error reports. */
/* #define VERBOSE_ERRORS */

#include <linux/blkdev.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/interrupt.h>
#include <linux/timer.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/genhd.h>
#include <linux/string.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/blkpg.h>
#include <linux/ata.h>
#include <linux/hdreg.h>

#define HD_IRQ 14

#define REALLY_SLOW_IO
#include <asm/io.h>
#include <asm/uaccess.h>

#ifdef __arm__
#undef  HD_IRQ
#endif
#include <asm/irq.h>
#ifdef __arm__
#define HD_IRQ IRQ_HARDDISK
#endif

/* Hd controller regster ports */

#define HD_DATA     0x1f0       /* _CTL when writing */
#define HD_ERROR    0x1f1       /* see err-bits */
#define HD_NSECTOR  0x1f2       /* nr of sectors to read/write */
#define HD_SECTOR   0x1f3       /* starting sector */
#define HD_LCYL     0x1f4       /* starting cylinder */
#define HD_HCYL     0x1f5       /* high byte of starting cyl */
#define HD_CURRENT  0x1f6       /* 101dhhhh , d=drive, hhhh=head */
#define HD_STATUS   0x1f7       /* see status-bits */
#define HD_FEATURE  HD_ERROR    /* same io address, read=error, write=feature */
#define HD_PRECOMP  HD_FEATURE  /* obsolete use of this port - predates IDE */
#define HD_COMMAND  HD_STATUS   /* same io address, read=status, write=cmd */

#define HD_CMD      0x3f6       /* used for resets */
#define HD_ALTSTATUS    0x3f6       /* same as HD_STATUS but doesn't clear irq */

/* Bits of HD_STATUS */
#define ERR_STAT        0x01
#define INDEX_STAT      0x02
#define ECC_STAT        0x04    /* Corrected error */
#define DRQ_STAT        0x08
#define SEEK_STAT       0x10
#define SERVICE_STAT        SEEK_STAT
#define WRERR_STAT      0x20
#define READY_STAT      0x40
#define BUSY_STAT       0x80

/* Bits for HD_ERROR */
#define MARK_ERR        0x01    /* Bad address mark */
#define TRK0_ERR        0x02    /* couldn't find track 0 */
#define ABRT_ERR        0x04    /* Command aborted */
#define MCR_ERR         0x08    /* media change request */
#define ID_ERR          0x10    /* ID field not found */
#define MC_ERR          0x20    /* media changed */
#define ECC_ERR         0x40    /* Uncorrectable ECC error */
#define BBD_ERR         0x80    /* pre-EIDE meaning:  block marked bad */
#define ICRC_ERR        0x80    /* new meaning:  CRC error during transfer */

static DEFINE_SPINLOCK(hd_lock);
static struct request_queue *hd_queue;
static struct request *hd_req;

#define TIMEOUT_VALUE   (6*HZ)
#define HD_DELAY    0

#define MAX_ERRORS     16   /* Max read/write errors/sector */
#define RESET_FREQ      8   /* Reset controller every 8th retry */
#define RECAL_FREQ      4   /* Recalibrate every 4th retry */
#define MAX_HD      2

#define STAT_OK     (READY_STAT|SEEK_STAT)
#define OK_STATUS(s)    (((s)&(STAT_OK|(BUSY_STAT|WRERR_STAT|ERR_STAT)))==STAT_OK)

static void recal_intr(void);
static void bad_rw_intr(void);

static int reset;
static int hd_error;

/*
 *  This struct defines the HD's and their types.
 */
struct hd_i_struct {
    unsigned int head, sect, cyl, wpcom, lzone, ctl;
    int unit;
    int recalibrate;
    int special_op;
};

#ifdef HD_TYPE
static struct hd_i_struct hd_info[] = { HD_TYPE };
static int NR_HD = ARRAY_SIZE(hd_info);
#else
static struct hd_i_struct hd_info[MAX_HD];
static int NR_HD;
#endif

static struct gendisk *hd_gendisk[MAX_HD];

static struct timer_list device_timer;

#define TIMEOUT_VALUE (6*HZ)

#define SET_TIMER                           \
    do {                                \
        mod_timer(&device_timer, jiffies + TIMEOUT_VALUE);  \
    } while (0)

static void (*do_hd)(void) = NULL;
#define SET_HANDLER(x) \
if ((do_hd = (x)) != NULL) \
    SET_TIMER; \
else \
    del_timer(&device_timer);


#if (HD_DELAY > 0)

#include <linux/i8253.h>

unsigned long last_req;

unsigned long read_timer(void)
{
    unsigned long t, flags;
    int i;

    raw_spin_lock_irqsave(&i8253_lock, flags);
    t = jiffies * 11932;
    outb_p(0, 0x43);
    i = inb_p(0x40);
    i |= inb(0x40) << 8;
    raw_spin_unlock_irqrestore(&i8253_lock, flags);
    return(t - i);
}
#endif

static void __init hd_setup(char *str, int *ints)
{
    int hdind = 0;

    if (ints[0] != 3)
        return;
    if (hd_info[0].head != 0)
        hdind = 1;
    hd_info[hdind].head = ints[2];
    hd_info[hdind].sect = ints[3];
    hd_info[hdind].cyl = ints[1];
    hd_info[hdind].wpcom = 0;
    hd_info[hdind].lzone = ints[1];
    hd_info[hdind].ctl = (ints[2] > 8 ? 8 : 0);
    NR_HD = hdind+1;
}

static bool hd_end_request(int err, unsigned int bytes)
{
    if (__blk_end_request(hd_req, err, bytes))
        return true;
    hd_req = NULL;
    return false;
}

static bool hd_end_request_cur(int err)
{
    return hd_end_request(err, blk_rq_cur_bytes(hd_req));
}

static void dump_status(const char *msg, unsigned int stat)
{
    char *name = "hd?";
    if (hd_req)
        name = hd_req->rq_disk->disk_name;

#ifdef VERBOSE_ERRORS
    printk("%s: %s: status=0x%02x { ", name, msg, stat & 0xff);
    if (stat & BUSY_STAT)   printk("Busy ");
    if (stat & READY_STAT)  printk("DriveReady ");
    if (stat & WRERR_STAT)  printk("WriteFault ");
    if (stat & SEEK_STAT)   printk("SeekComplete ");
    if (stat & DRQ_STAT)    printk("DataRequest ");
    if (stat & ECC_STAT)    printk("CorrectedError ");
    if (stat & INDEX_STAT)  printk("Index ");
    if (stat & ERR_STAT)    printk("Error ");
    printk("}\n");
    if ((stat & ERR_STAT) == 0) {
        hd_error = 0;
    } else {
        hd_error = inb(HD_ERROR);
        printk("%s: %s: error=0x%02x { ", name, msg, hd_error & 0xff);
        if (hd_error & BBD_ERR)     printk("BadSector ");
        if (hd_error & ECC_ERR)     printk("UncorrectableError ");
        if (hd_error & ID_ERR)      printk("SectorIdNotFound ");
        if (hd_error & ABRT_ERR)    printk("DriveStatusError ");
        if (hd_error & TRK0_ERR)    printk("TrackZeroNotFound ");
        if (hd_error & MARK_ERR)    printk("AddrMarkNotFound ");
        printk("}");
        if (hd_error & (BBD_ERR|ECC_ERR|ID_ERR|MARK_ERR)) {
            printk(", CHS=%d/%d/%d", (inb(HD_HCYL)<<8) + inb(HD_LCYL),
                inb(HD_CURRENT) & 0xf, inb(HD_SECTOR));
            if (hd_req)
                printk(", sector=%ld", blk_rq_pos(hd_req));
        }
        printk("\n");
    }
#else
    printk("%s: %s: status=0x%02x.\n", name, msg, stat & 0xff);
    if ((stat & ERR_STAT) == 0) {
        hd_error = 0;
    } else {
        hd_error = inb(HD_ERROR);
        printk("%s: %s: error=0x%02x.\n", name, msg, hd_error & 0xff);
    }
#endif
}

static void check_status(void)
{
    int i = inb_p(HD_STATUS);

    if (!OK_STATUS(i)) {
        dump_status("check_status", i);
        bad_rw_intr();
    }
}

static int controller_busy(void)
{
    int retries = 100000;
    unsigned char status;

    do {
        status = inb_p(HD_STATUS);
    } while ((status & BUSY_STAT) && --retries);
    return status;
}

static int status_ok(void)
{
    unsigned char status = inb_p(HD_STATUS);

    if (status & BUSY_STAT)
        return 1;   /* Ancient, but does it make sense??? */
    if (status & WRERR_STAT)
        return 0;
    if (!(status & READY_STAT))
        return 0;
    if (!(status & SEEK_STAT))
        return 0;
    return 1;
}

static int controller_ready(unsigned int drive, unsigned int head)
{
    int retry = 100;

    do {
        if (controller_busy() & BUSY_STAT)
            return 0;
        outb_p(0xA0 | (drive<<4) | head, HD_CURRENT);
        if (status_ok())
            return 1;
    } while (--retry);
    return 0;
}

static void hd_out(struct hd_i_struct *disk,
           unsigned int nsect,
           unsigned int sect,
           unsigned int head,
           unsigned int cyl,
           unsigned int cmd,
           void (*intr_addr)(void))
{
    unsigned short port;

#if (HD_DELAY > 0)
    while (read_timer() - last_req < HD_DELAY)
        /* nothing */;
#endif
    if (reset)
        return;
    if (!controller_ready(disk->unit, head)) {
        reset = 1;
        return;
    }
    SET_HANDLER(intr_addr);
    outb_p(disk->ctl, HD_CMD);
    port = HD_DATA;
    outb_p(disk->wpcom >> 2, ++port);
    outb_p(nsect, ++port);
    outb_p(sect, ++port);
    outb_p(cyl, ++port);
    outb_p(cyl >> 8, ++port);
    outb_p(0xA0 | (disk->unit << 4) | head, ++port);
    outb_p(cmd, ++port);
}

static void hd_request (void);

static int drive_busy(void)
{
    unsigned int i;
    unsigned char c;

    for (i = 0; i < 500000 ; i++) {
        c = inb_p(HD_STATUS);
        if ((c & (BUSY_STAT | READY_STAT | SEEK_STAT)) == STAT_OK)
            return 0;
    }
    dump_status("reset timed out", c);
    return 1;
}

static void reset_controller(void)
{
    int i;

    outb_p(4, HD_CMD);
    for (i = 0; i < 1000; i++) barrier();
    outb_p(hd_info[0].ctl & 0x0f, HD_CMD);
    for (i = 0; i < 1000; i++) barrier();
    if (drive_busy())
        printk("hd: controller still busy\n");
    else if ((hd_error = inb(HD_ERROR)) != 1)
        printk("hd: controller reset failed: %02x\n", hd_error);
}

static void reset_hd(void)
{
    static int i;

repeat:
    if (reset) {
        reset = 0;
        i = -1;
        reset_controller();
    } else {
        check_status();
        if (reset)
            goto repeat;
    }
    if (++i < NR_HD) {
        struct hd_i_struct *disk = &hd_info[i];
        disk->special_op = disk->recalibrate = 1;
        hd_out(disk, disk->sect, disk->sect, disk->head-1,
            disk->cyl, ATA_CMD_INIT_DEV_PARAMS, &reset_hd);
        if (reset)
            goto repeat;
    } else
        hd_request();
}

/*
 * Ok, don't know what to do with the unexpected interrupts: on some machines
 * doing a reset and a retry seems to result in an eternal loop. Right now I
 * ignore it, and just set the timeout.
 *
 * On laptops (and "green" PCs), an unexpected interrupt occurs whenever the
 * drive enters "idle", "standby", or "sleep" mode, so if the status looks
 * "good", we just ignore the interrupt completely.
 */
static void unexpected_hd_interrupt(void)
{
    unsigned int stat = inb_p(HD_STATUS);

    if (stat & (BUSY_STAT|DRQ_STAT|ECC_STAT|ERR_STAT)) {
        dump_status("unexpected interrupt", stat);
        SET_TIMER;
    }
}

/*
 * bad_rw_intr() now tries to be a bit smarter and does things
 * according to the error returned by the controller.
 * -Mika Liljeberg ([email protected])
 */
static void bad_rw_intr(void)
{
    struct request *req = hd_req;

    if (req != NULL) {
        struct hd_i_struct *disk = req->rq_disk->private_data;
        if (++req->errors >= MAX_ERRORS || (hd_error & BBD_ERR)) {
            hd_end_request_cur(-EIO);
            disk->special_op = disk->recalibrate = 1;
        } else if (req->errors % RESET_FREQ == 0)
            reset = 1;
        else if ((hd_error & TRK0_ERR) || req->errors % RECAL_FREQ == 0)
            disk->special_op = disk->recalibrate = 1;
        /* Otherwise just retry */
    }
}

static inline int wait_DRQ(void)
{
    int retries;
    int stat;

    for (retries = 0; retries < 100000; retries++) {
        stat = inb_p(HD_STATUS);
        if (stat & DRQ_STAT)
            return 0;
    }
    dump_status("wait_DRQ", stat);
    return -1;
}

static void read_intr(void)
{
    struct request *req;
    int i, retries = 100000;

    do {
        i = (unsigned) inb_p(HD_STATUS);
        if (i & BUSY_STAT)
            continue;
        if (!OK_STATUS(i))
            break;
        if (i & DRQ_STAT)
            goto ok_to_read;
    } while (--retries > 0);
    dump_status("read_intr", i);
    bad_rw_intr();
    hd_request();
    return;

ok_to_read:
    req = hd_req;
    insw(HD_DATA, req->buffer, 256);
#ifdef DEBUG
    printk("%s: read: sector %ld, remaining = %u, buffer=%p\n",
           req->rq_disk->disk_name, blk_rq_pos(req) + 1,
           blk_rq_sectors(req) - 1, req->buffer+512);
#endif
    if (hd_end_request(0, 512)) {
        SET_HANDLER(&read_intr);
        return;
    }

    (void) inb_p(HD_STATUS);
#if (HD_DELAY > 0)
    last_req = read_timer();
#endif
    hd_request();
}

static void write_intr(void)
{
    struct request *req = hd_req;
    int i;
    int retries = 100000;

    do {
        i = (unsigned) inb_p(HD_STATUS);
        if (i & BUSY_STAT)
            continue;
        if (!OK_STATUS(i))
            break;
        if ((blk_rq_sectors(req) <= 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:
    if (hd_end_request(0, 512)) {
        SET_HANDLER(&write_intr);
        outsw(HD_DATA, req->buffer, 256);
        return;
    }

#if (HD_DELAY > 0)
    last_req = read_timer();
#endif
    hd_request();
}

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(unsigned long dummy)
{
    char *name;

    do_hd = NULL;

    if (!hd_req)
        return;

    spin_lock_irq(hd_queue->queue_lock);
    reset = 1;
    name = hd_req->rq_disk->disk_name;
    printk("%s: timeout\n", name);
    if (++hd_req->errors >= MAX_ERRORS) {
#ifdef DEBUG
        printk("%s: too many errors\n", name);
#endif
        hd_end_request_cur(-EIO);
    }
    hd_request();
    spin_unlock_irq(hd_queue->queue_lock);
}

static int do_special_op(struct hd_i_struct *disk, struct request *req)
{
    if (disk->recalibrate) {
        disk->recalibrate = 0;
        hd_out(disk, disk->sect, 0, 0, 0, ATA_CMD_RESTORE, &recal_intr);
        return reset;
    }
    if (disk->head > 16) {
        printk("%s: cannot handle device with more than 16 heads - giving up\n", req->rq_disk->disk_name);
        hd_end_request_cur(-EIO);
    }
    disk->special_op = 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. The IDE driver has support to unmask
 * interrupts for non-broken hardware, so use that driver if required.
 */
static void hd_request(void)
{
    unsigned int block, nsect, sec, track, head, cyl;
    struct hd_i_struct *disk;
    struct request *req;

    if (do_hd)
        return;
repeat:
    del_timer(&device_timer);

    if (!hd_req) {
        hd_req = blk_fetch_request(hd_queue);
        if (!hd_req) {
            do_hd = NULL;
            return;
        }
    }
    req = hd_req;

    if (reset) {
        reset_hd();
        return;
    }
    disk = req->rq_disk->private_data;
    block = blk_rq_pos(req);
    nsect = blk_rq_sectors(req);
    if (block >= get_capacity(req->rq_disk) ||
        ((block+nsect) > get_capacity(req->rq_disk))) {
        printk("%s: bad access: block=%d, count=%d\n",
            req->rq_disk->disk_name, block, nsect);
        hd_end_request_cur(-EIO);
        goto repeat;
    }

    if (disk->special_op) {
        if (do_special_op(disk, req))
            goto repeat;
        return;
    }
    sec   = block % disk->sect + 1;
    track = block / disk->sect;
    head  = track % disk->head;
    cyl   = track / disk->head;
#ifdef DEBUG
    printk("%s: %sing: CHS=%d/%d/%d, sectors=%d, buffer=%p\n",
        req->rq_disk->disk_name,
        req_data_dir(req) == READ ? "read" : "writ",
        cyl, head, sec, nsect, req->buffer);
#endif
    if (req->cmd_type == REQ_TYPE_FS) {
        switch (rq_data_dir(req)) {
        case READ:
            hd_out(disk, nsect, sec, head, cyl, ATA_CMD_PIO_READ,
                &read_intr);
            if (reset)
                goto repeat;
            break;
        case WRITE:
            hd_out(disk, nsect, sec, head, cyl, ATA_CMD_PIO_WRITE,
                &write_intr);
            if (reset)
                goto repeat;
            if (wait_DRQ()) {
                bad_rw_intr();
                goto repeat;
            }
            outsw(HD_DATA, req->buffer, 256);
            break;
        default:
            printk("unknown hd-command\n");
            hd_end_request_cur(-EIO);
            break;
        }
    }
}

static void do_hd_request(struct request_queue *q)
{
    hd_request();
}

static int hd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
    struct hd_i_struct *disk = bdev->bd_disk->private_data;

    geo->heads = disk->head;
    geo->sectors = disk->sect;
    geo->cylinders = disk->cyl;
    return 0;
}

/*
 * Releasing a block device means we sync() it, so that it can safely
 * be forgotten about...
 */

static irqreturn_t hd_interrupt(int irq, void *dev_id)
{
    void (*handler)(void) = do_hd;

    spin_lock(hd_queue->queue_lock);

    do_hd = NULL;
    del_timer(&device_timer);
    if (!handler)
        handler = unexpected_hd_interrupt;
    handler();

    spin_unlock(hd_queue->queue_lock);

    return IRQ_HANDLED;
}

static const struct block_device_operations hd_fops = {
    .getgeo =   hd_getgeo,
};

/*
 * This is the hard disk IRQ description. The IRQF_DISABLED 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 int __init hd_init(void)
{
    int drive;

    if (register_blkdev(HD_MAJOR, "hd"))
        return -1;

    hd_queue = blk_init_queue(do_hd_request, &hd_lock);
    if (!hd_queue) {
        unregister_blkdev(HD_MAJOR, "hd");
        return -ENOMEM;
    }

    blk_queue_max_hw_sectors(hd_queue, 255);
    init_timer(&device_timer);
    device_timer.function = hd_times_out;
    blk_queue_logical_block_size(hd_queue, 512);

    if (!NR_HD) {
        /*
         * We don't know anything about the drive.  This means
         * that you *MUST* specify the drive parameters to the
         * kernel yourself.
         *
         * If we were on an i386, we used to read this info from
         * the BIOS or CMOS.  This doesn't work all that well,
         * since this assumes that this is a primary or secondary
         * drive, and if we're using this legacy driver, it's
         * probably an auxiliary controller added to recover
         * legacy data off an ST-506 drive.  Either way, it's
         * definitely safest to have the user explicitly specify
         * the information.
         */
        printk("hd: no drives specified - use hd=cyl,head,sectors"
            " on kernel command line\n");
        goto out;
    }

    for (drive = 0 ; drive < NR_HD ; drive++) {
        struct gendisk *disk = alloc_disk(64);
        struct hd_i_struct *p = &hd_info[drive];
        if (!disk)
            goto Enomem;
        disk->major = HD_MAJOR;
        disk->first_minor = drive << 6;
        disk->fops = &hd_fops;
        sprintf(disk->disk_name, "hd%c", 'a'+drive);
        disk->private_data = p;
        set_capacity(disk, p->head * p->sect * p->cyl);
        disk->queue = hd_queue;
        p->unit = drive;
        hd_gendisk[drive] = disk;
        printk("%s: %luMB, CHS=%d/%d/%d\n",
            disk->disk_name, (unsigned long)get_capacity(disk)/2048,
            p->cyl, p->head, p->sect);
    }

    if (request_irq(HD_IRQ, hd_interrupt, IRQF_DISABLED, "hd", NULL)) {
        printk("hd: unable to get IRQ%d for the hard disk driver\n",
            HD_IRQ);
        goto out1;
    }
    if (!request_region(HD_DATA, 8, "hd")) {
        printk(KERN_WARNING "hd: port 0x%x busy\n", HD_DATA);
        goto out2;
    }
    if (!request_region(HD_CMD, 1, "hd(cmd)")) {
        printk(KERN_WARNING "hd: port 0x%x busy\n", HD_CMD);
        goto out3;
    }

    /* Let them fly */
    for (drive = 0; drive < NR_HD; drive++)
        add_disk(hd_gendisk[drive]);

    return 0;

out3:
    release_region(HD_DATA, 8);
out2:
    free_irq(HD_IRQ, NULL);
out1:
    for (drive = 0; drive < NR_HD; drive++)
        put_disk(hd_gendisk[drive]);
    NR_HD = 0;
out:
    del_timer(&device_timer);
    unregister_blkdev(HD_MAJOR, "hd");
    blk_cleanup_queue(hd_queue);
    return -1;
Enomem:
    while (drive--)
        put_disk(hd_gendisk[drive]);
    goto out;
}

static int __init parse_hd_setup(char *line)
{
    int ints[6];

    (void) get_options(line, ARRAY_SIZE(ints), ints);
    hd_setup(NULL, ints);

    return 1;
}
__setup("hd=", parse_hd_setup);

late_initcall(hd_init);