* add p cc

[mascara-docs.git] / i386 / linux / linux-0.99 / drivers / block / hd.c

/*
 *  linux/kernel/hd.c
 *
 *  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, lankeste@fwi.uva.nl, who found a bug
 *  in the early extended-partition checks and added DM partitions
 */


#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/hdreg.h>
#include <linux/genhd.h>
#include <linux/config.h>

#define REALLY_SLOW_IO
#include <asm/system.h>
#include <asm/io.h>
#include <asm/segment.h>

#define MAJOR_NR HD_MAJOR
#include "blk.h"

#define HD_IRQ 14

static int revalidate_hddisk(int, int);

static inline unsigned char CMOS_READ(unsigned char addr)
{
        outb_p(addr,0x70);
        return inb_p(0x71);
}

#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

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

static char recalibrate[ MAX_HD ] = { 0, };
static int access_count[MAX_HD] = {0, };
static char busy[MAX_HD] = {0, };
static struct wait_queue * busy_wait = NULL;

static int reset = 0;
static int hd_error = 0;

#if (HD_DELAY > 0)
unsigned long last_req, read_timer();
#endif

/*
 *  This struct defines the HD's and their types.
 */
struct hd_i_struct {
        unsigned int head,sect,cyl,wpcom,lzone,ctl;
        };
#ifdef HD_TYPE
struct hd_i_struct hd_info[] = { HD_TYPE };
static int NR_HD = ((sizeof (hd_info))/(sizeof (struct hd_i_struct)));
#else
struct hd_i_struct hd_info[] = { {0,0,0,0,0,0},{0,0,0,0,0,0} };
static int NR_HD = 0;
#endif

static struct hd_struct hd[MAX_HD<<6]={{0,0},};
static int hd_sizes[MAX_HD<<6] = {0, };
static int hd_blocksizes[MAX_HD<<6] = {0, };

#if (HD_DELAY > 0)
unsigned long read_timer(void)
{
        unsigned long t;
        int i;

        cli();
        t = jiffies * 11932;
        outb_p(0, 0x43);
        i = inb_p(0x40);
        i |= inb(0x40) << 8;
        sti();
        return(t - i);
}
#endif

void 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 int win_result(void)
{
        int i=inb_p(HD_STATUS);

        if ((i & (BUSY_STAT | READY_STAT | WRERR_STAT | SEEK_STAT | ERR_STAT))
                == (READY_STAT | SEEK_STAT)) {
                hd_error = 0;
                return 0; /* ok */
        }
        printk("HD: win_result: status = 0x%02x\n",i);
        if (i&1) {
                hd_error = inb(HD_ERROR);
                printk("HD: win_result: error = 0x%02x\n",hd_error);
        }       
        return 1;
}

static int controller_busy(void);
static int status_ok(void);

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

        if (status & BUSY_STAT)
                return 1;
        if (status & WRERR_STAT)
                return 0;
        if (!(status & READY_STAT))
                return 0;
        if (!(status & SEEK_STAT))
                return 0;
        return 1;
}

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 void hd_out(unsigned int drive,unsigned int nsect,unsigned int sect,
                unsigned int head,unsigned int cyl,unsigned int cmd,
                void (*intr_addr)(void))
{
        unsigned short port;

        if (drive>1 || head>15)
                panic("Trying to write bad sector");
#if (HD_DELAY > 0)
        while (read_timer() - last_req < HD_DELAY)
                /* nothing */;
#endif
        if (reset)
                return;
        if (!controller_ready(drive, head)) {
                reset = 1;
                return;
        }
        SET_INTR(intr_addr);
        outb_p(hd_info[drive].ctl,HD_CMD);
        port=HD_DATA;
        outb_p(hd_info[drive].wpcom>>2,++port);
        outb_p(nsect,++port);
        outb_p(sect,++port);
        outb_p(cyl,++port);
        outb_p(cyl>>8,++port);
        outb_p(0xA0|(drive<<4)|head,++port);
        outb_p(cmd,++port);
}

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

        for (i = 0; i < 500000 ; i++) {
                c = inb_p(HD_STATUS);
                c &= (BUSY_STAT | READY_STAT | SEEK_STAT);
                if (c == (READY_STAT | SEEK_STAT))
                        return 0;
        }
        printk("HD controller times out, status = 0x%02x\n",c);
        return 1;
}

static void reset_controller(void)
{
        int     i;

        printk(KERN_DEBUG "HD-controller reset\n");
        outb_p(4,HD_CMD);
        for(i = 0; i < 1000; i++) nop();
        outb(hd_info[0].ctl & 0x0f ,HD_CMD);
        if (drive_busy())
                printk("HD-controller still busy\n");
        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 if (win_result()) {
                bad_rw_intr();
                if (reset)
                        goto repeat;
        }
        i++;
        if (i < NR_HD) {
                hd_out(i,hd_info[i].sect,hd_info[i].sect,hd_info[i].head-1,
                        hd_info[i].cyl,WIN_SPECIFY,&reset_hd);
                if (reset)
                        goto repeat;
        } else
                do_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.
 */
void unexpected_hd_interrupt(void)
{
        sti();
        printk(KERN_DEBUG "Unexpected HD interrupt\n");
        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 (liljeber@cs.Helsinki.FI)
 */
static void bad_rw_intr(void)
{
        int dev;

        if (!CURRENT)
                return;
        dev = MINOR(CURRENT->dev) >> 6;
        if (++CURRENT->errors >= MAX_ERRORS || (hd_error & BBD_ERR)) {
                end_request(0);
                recalibrate[dev] = 1;
        } else if (CURRENT->errors % RESET_FREQ == 0)
                reset = 1;
        else if ((hd_error & TRK0_ERR) || CURRENT->errors % RECAL_FREQ == 0)
                recalibrate[dev] = 1;
        /* Otherwise just retry */
}

static inline int wait_DRQ(void)
{
        int retries = 100000;

        while (--retries > 0)
                if (inb_p(HD_STATUS) & DRQ_STAT)
                        return 0;
        return -1;
}

#define STAT_MASK (BUSY_STAT | READY_STAT | WRERR_STAT | SEEK_STAT | ERR_STAT)
#define STAT_OK (READY_STAT | SEEK_STAT)

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

        do {
                i = (unsigned) inb_p(HD_STATUS);
                if (i & BUSY_STAT)
                        continue;
                if ((i & STAT_MASK) != STAT_OK)
                        break;
                if (i & DRQ_STAT)
                        goto ok_to_read;
        } while (--retries > 0);
        sti();
        printk("HD: read_intr: status = 0x%02x\n",i);
        if (i & ERR_STAT) {
                hd_error = (unsigned) inb(HD_ERROR);
                printk("HD: read_intr: error = 0x%02x\n",hd_error);
        }
        bad_rw_intr();
        cli();
        do_hd_request();
        return;
ok_to_read:
        insw(HD_DATA,CURRENT->buffer,256);
        CURRENT->errors = 0;
        CURRENT->buffer += 512;
        CURRENT->sector++;
        i = --CURRENT->nr_sectors;
        --CURRENT->current_nr_sectors;
#ifdef DEBUG
        printk("hd%d : sector = %d, %d remaining to buffer = %08x\n",
                MINOR(CURRENT->dev), CURRENT->sector, i, CURRENT-> 
                buffer);
#endif
        if (!i || (CURRENT->bh && !SUBSECTOR(i)))
                end_request(1);
        if (i > 0) {
                SET_INTR(&read_intr);
                sti();
                return;
        }
        (void) inb_p(HD_STATUS);
#if (HD_DELAY > 0)
        last_req = read_timer();
#endif
        do_hd_request();
        return;
}

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

        do {
                i = (unsigned) inb_p(HD_STATUS);
                if (i & BUSY_STAT)
                        continue;
                if ((i & STAT_MASK) != STAT_OK)
                        break;
                if ((CURRENT->nr_sectors <= 1) || (i & DRQ_STAT))
                        goto ok_to_write;
        } while (--retries > 0);
        sti();
        printk("HD: write_intr: status = 0x%02x\n",i);
        if (i & ERR_STAT) {
                hd_error = (unsigned) inb(HD_ERROR);
                printk("HD: write_intr: error = 0x%02x\n",hd_error);
        }
        bad_rw_intr();
        cli();
        do_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
                do_hd_request();
        }
        return;
}

static void recal_intr(void)
{
        if (win_result())
                bad_rw_intr();
        do_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)
{
        DEVICE_INTR = NULL;
        sti();
        reset = 1;
        if (!CURRENT)
                return;
        printk(KERN_DEBUG "HD timeout\n");
        cli();
        if (++CURRENT->errors >= MAX_ERRORS) {
#ifdef DEBUG
                printk("hd : too many errors.\n");
#endif
                end_request(0);
        }

        do_hd_request();
}

/*
 * The driver has been modified to enable interrupts a bit more: in order to
 * do this we first (a) disable the timeout-interrupt and (b) clear the
 * device-interrupt. This way the interrupts won't mess with out code (the
 * worst that can happen is that an unexpected HD-interrupt comes in and
 * sets the "reset" variable and starts the timer)
 */
static void do_hd_request(void)
{
        unsigned int block,dev;
        unsigned int sec,head,cyl,track;
        unsigned int nsect;

        if (CURRENT && CURRENT->dev < 0) return;

        if (DEVICE_INTR)
                return;
repeat:
        timer_active &= ~(1<<HD_TIMER);
        sti();
        INIT_REQUEST;
        dev = MINOR(CURRENT->dev);
        block = CURRENT->sector;
        nsect = CURRENT->nr_sectors;
        if (dev >= (NR_HD<<6) || block >= hd[dev].nr_sects) {
#ifdef DEBUG
                printk("hd%d : attempted read for sector %d past end of device at sector %d.\n",
                        block, hd[dev].nr_sects);
#endif
                end_request(0);
                goto repeat;
        }
        block += hd[dev].start_sect;
        dev >>= 6;
        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%d : cyl = %d, head = %d, sector = %d, buffer = %08x\n",
                dev, cyl, head, sec, CURRENT->buffer);
#endif
        cli();
        if (reset) {
                int i;

                for (i=0; i < NR_HD; i++)
                        recalibrate[i] = 1;
                reset_hd();
                sti();
                return;
        }
        if (recalibrate[dev]) {
                recalibrate[dev] = 0;
                hd_out(dev,hd_info[dev].sect,0,0,0,WIN_RESTORE,&recal_intr);
                if (reset)
                        goto repeat;
                sti();
                return;
        }       
        if (CURRENT->cmd == WRITE) {
                hd_out(dev,nsect,sec,head,cyl,WIN_WRITE,&write_intr);
                if (reset)
                        goto repeat;
                if (wait_DRQ()) {
                        printk("HD: do_hd_request: no DRQ\n");
                        bad_rw_intr();
                        goto repeat;
                }
                outsw(HD_DATA,CURRENT->buffer,256);
                sti();
                return;
        }
        if (CURRENT->cmd == READ) {
                hd_out(dev,nsect,sec,head,cyl,WIN_READ,&read_intr);
                if (reset)
                        goto repeat;
                sti();
                return;
        }
        panic("unknown hd-command");
}

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;

        if (!inode)
                return -EINVAL;
        dev = MINOR(inode->i_rdev) >> 6;
        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_fs_byte(hd_info[dev].head,
                                (char *) &loc->heads);
                        put_fs_byte(hd_info[dev].sect,
                                (char *) &loc->sectors);
                        put_fs_word(hd_info[dev].cyl,
                                (short *) &loc->cylinders);
                        put_fs_long(hd[MINOR(inode->i_rdev)].start_sect,
                                (long *) &loc->start);
                        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_fs_long(hd[MINOR(inode->i_rdev)].nr_sects,
                                (long *) arg);
                        return 0;
                case BLKFLSBUF:
                        if(!suser())  return -EACCES;
                        if(!inode->i_rdev) return -EINVAL;
                        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);
                RO_IOCTLS(inode->i_rdev,arg);
                default:
                        return -EINVAL;
        }
}

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

        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(MINOR(inode->i_rdev));
        access_count[target]--;

}

static void hd_geninit(void);

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 *) hd_info,       /* internal */
        NULL            /* next */
};
        
static void hd_interrupt(int unused)
{
        void (*handler)(void) = DEVICE_INTR;

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

/*
 * 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 struct sigaction hd_sigaction = {
        hd_interrupt,
        0,
        SA_INTERRUPT,
        NULL
};

static void hd_geninit(void)
{
        int drive, i;
        extern struct drive_info drive_info;
        unsigned char *BIOS = (unsigned char *) &drive_info;
        int cmos_disks;

        if (!NR_HD) {      
                for (drive=0 ; drive<2 ; drive++) {
                        hd_info[drive].cyl = *(unsigned short *) BIOS;
                        hd_info[drive].head = *(2+BIOS);
                        hd_info[drive].wpcom = *(unsigned short *) (5+BIOS);
                        hd_info[drive].ctl = *(8+BIOS);
                        hd_info[drive].lzone = *(unsigned short *) (12+BIOS);
                        hd_info[drive].sect = *(14+BIOS);
                        BIOS += 16;
                }

        /*
                We querry CMOS about hard disks : it could be that 
                we have a SCSI/ESDI/etc controller that is BIOS
                compatable with ST-506, and thus showing up in our
                BIOS table, but not register compatable, and therefore
                not present in CMOS.

                Furthurmore, we will assume that our ST-506 drives
                <if any> are the primary drives in the system, and 
                the ones reflected as drive 1 or 2.

                The first drive is stored in the high nibble of CMOS
                byte 0x12, the second in the low nibble.  This will be
                either a 4 bit drive type or 0xf indicating use byte 0x19 
                for an 8 bit type, drive 1, 0x1a for drive 2 in CMOS.

                Needless to say, a non-zero value means we have 
                an AT controller hard disk for that drive.

                
        */

                if ((cmos_disks = CMOS_READ(0x12)) & 0xf0)
                        if (cmos_disks & 0x0f)
                                NR_HD = 2;
                        else
                                NR_HD = 1;
        }
        i = NR_HD;
        while (i-- > 0) {
                hd[i<<6].nr_sects = 0;
                if (hd_info[i].head > 16) {
                        printk("hd.c: ST-506 interface disk with more than 16 heads detected,\n");
                        printk("  probably due to non-standard sector translation. Giving up.\n");
                        printk("  (disk %d: cyl=%d, sect=%d, head=%d)\n", i,
                                hd_info[i].cyl,
                                hd_info[i].sect,
                                hd_info[i].head);
                        if (i+1 == NR_HD)
                                NR_HD--;
                        continue;
                }
                hd[i<<6].nr_sects = hd_info[i].head*
                                hd_info[i].sect*hd_info[i].cyl;
        }
        if (NR_HD) {
                if (irqaction(HD_IRQ,&hd_sigaction)) {
                        printk("hd.c: unable to get IRQ%d for the harddisk driver\n",HD_IRQ);
                        NR_HD = 0;
                }
        }
        hd_gendisk.nr_real = NR_HD;

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

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 */
};

unsigned long hd_init(unsigned long mem_start, unsigned long mem_end)
{
        if (register_blkdev(MAJOR_NR,"hd",&hd_fops)) {
                printk("Unable to get major %d for harddisk\n",MAJOR_NR);
                return mem_start;
        }
        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 mem_start;
}

#define DEVICE_BUSY busy[target]
#define USAGE access_count[target]
#define CAPACITY (hd_info[target].head*hd_info[target].sect*hd_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(int dev, int maxusage)
{
        int target, major;
        struct gendisk * gdev;
        int max_p;
        int start;
        int i;

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

        cli();
        if (DEVICE_BUSY || USAGE > maxusage) {
                sti();
                return -EBUSY;
        };
        DEVICE_BUSY = 1;
        sti();

        max_p = gdev->max_p;
        start = target << gdev->minor_shift;
        major = MAJOR_NR << 8;

        for (i=max_p - 1; i >=0 ; i--) {
                sync_dev(major | start | i);
                invalidate_inodes(major | start | i);
                invalidate_buffers(major | start | i);
                gdev->part[start+i].start_sect = 0;
                gdev->part[start+i].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;
}