/*
 *  Copyright (C) 1995-2000  Linus Torvalds & author (see below)
 */

/*
 *  HT-6560B EIDE-controller support
 *  To activate controller support use kernel parameter "ide0=ht6560b".
 *  Use hdparm utility to enable PIO mode support.
 *
 *  Author:    Mikko Ala-Fossi            <maf@iki.fi>
 *             Jan Evert van Grootheest   <j.e.van.grootheest@caiway.nl>
 *
 */

#define DRV_NAME        "ht6560b"
#define HT6560B_VERSION "v0.08"

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/ioport.h>
#include <linux/blkdev.h>
#include <linux/ide.h>
#include <linux/init.h>

#include <asm/io.h>

/* #define DEBUG */  /* remove comments for DEBUG messages */

/*
 * The special i/o-port that HT-6560B uses to configuration:
 *    bit0 (0x01): "1" selects secondary interface
 *    bit2 (0x04): "1" enables FIFO function
 *    bit5 (0x20): "1" enables prefetched data read function  (???)
 *
 * The special i/o-port that HT-6560A uses to configuration:
 *    bit0 (0x01): "1" selects secondary interface
 *    bit1 (0x02): "1" enables prefetched data read function
 *    bit2 (0x04): "0" enables multi-master system            (?)
 *    bit3 (0x08): "1" 3 cycle time, "0" 2 cycle time         (?)
 */
#define HT_CONFIG_PORT    0x3e6

static inline u8 HT_CONFIG(ide_drive_t *drive)
{
        return ((unsigned long)ide_get_drivedata(drive) & 0xff00) >> 8;
}

/*
 * FIFO + PREFETCH (both a/b-model)
 */
#define HT_CONFIG_DEFAULT 0x1c /* no prefetch */
/* #define HT_CONFIG_DEFAULT 0x3c */ /* with prefetch */
#define HT_SECONDARY_IF   0x01
#define HT_PREFETCH_MODE  0x20

/*
 * ht6560b Timing values:
 *
 * I reviewed some assembler source listings of htide drivers and found
 * out how they setup those cycle time interfacing values, as they at Holtek
 * call them. IDESETUP.COM that is supplied with the drivers figures out
 * optimal values and fetches those values to drivers. I found out that
 * they use Select register to fetch timings to the ide board right after
 * interface switching. After that it was quite easy to add code to
 * ht6560b.c.
 *
 * IDESETUP.COM gave me values 0x24, 0x45, 0xaa, 0xff that worked fine
 * for hda and hdc. But hdb needed higher values to work, so I guess
 * that sometimes it is necessary to give higher value than IDESETUP
 * gives.   [see cmd640.c for an extreme example of this. -ml]
 *
 * Perhaps I should explain something about these timing values:
 * The higher nibble of value is the Recovery Time  (rt) and the lower nibble
 * of the value is the Active Time  (at). Minimum value 2 is the fastest and
 * the maximum value 15 is the slowest. Default values should be 15 for both.
 * So 0x24 means 2 for rt and 4 for at. Each of the drives should have
 * both values, and IDESETUP gives automatically rt=15 st=15 for CDROMs or
 * similar. If value is too small there will be all sorts of failures.
 *
 * Timing byte consists of
 *      High nibble:  Recovery Cycle Time  (rt)
 *           The valid values range from 2 to 15. The default is 15.
 *
 *      Low nibble:   Active Cycle Time    (at)
 *           The valid values range from 2 to 15. The default is 15.
 *
 * You can obtain optimized timing values by running Holtek IDESETUP.COM
 * for DOS. DOS drivers get their timing values from command line, where
 * the first value is the Recovery Time and the second value is the
 * Active Time for each drive. Smaller value gives higher speed.
 * In case of failures you should probably fall back to a higher value.
 */
static inline u8 HT_TIMING(ide_drive_t *drive)
{
        return (unsigned long)ide_get_drivedata(drive) & 0x00ff;
}

#define HT_TIMING_DEFAULT 0xff

/*
 * This routine handles interface switching for the peculiar hardware design
 * on the F.G.I./Holtek HT-6560B VLB IDE interface.
 * The HT-6560B can only enable one IDE port at a time, and requires a
 * silly sequence (below) whenever we switch between primary and secondary.
 */

/*
 * This routine is invoked from ide.c to prepare for access to a given drive.
 */
static void ht6560b_dev_select(ide_drive_t *drive)
{
        ide_hwif_t *hwif = drive->hwif;
        unsigned long flags;
        static u8 current_select = 0;
        static u8 current_timing = 0;
        u8 select, timing;
        
        local_irq_save(flags);

        select = HT_CONFIG(drive);
        timing = HT_TIMING(drive);

        /*
         * Need to enforce prefetch sometimes because otherwise
         * it'll hang (hard).
         */
        if (drive->media != ide_disk ||
            (drive->dev_flags & IDE_DFLAG_PRESENT) == 0)
                select |= HT_PREFETCH_MODE;

        if (select != current_select || timing != current_timing) {
                current_select = select;
                current_timing = timing;
                (void)inb(HT_CONFIG_PORT);
                (void)inb(HT_CONFIG_PORT);
                (void)inb(HT_CONFIG_PORT);
                (void)inb(HT_CONFIG_PORT);
                outb(select, HT_CONFIG_PORT);
                /*
                 * Set timing for this drive:
                 */
                outb(timing, hwif->io_ports.device_addr);
                (void)inb(hwif->io_ports.status_addr);
#ifdef DEBUG
                printk("ht6560b: %s: select=%#x timing=%#x\n",
                        drive->name, select, timing);
#endif
        }
        local_irq_restore(flags);

        outb(drive->select | ATA_DEVICE_OBS, hwif->io_ports.device_addr);
}

/*
 * Autodetection and initialization of ht6560b
 */
static int __init try_to_init_ht6560b(void)
{
        u8 orig_value;
        int i;
        
        /* Autodetect ht6560b */
        if ((orig_value = inb(HT_CONFIG_PORT)) == 0xff)
                return 0;
        
        for (i=3;i>0;i--) {
                outb(0x00, HT_CONFIG_PORT);
                if (!( (~inb(HT_CONFIG_PORT)) & 0x3f )) {
                        outb(orig_value, HT_CONFIG_PORT);
                        return 0;
                }
        }
        outb(0x00, HT_CONFIG_PORT);
        if ((~inb(HT_CONFIG_PORT))& 0x3f) {
                outb(orig_value, HT_CONFIG_PORT);
                return 0;
        }
        /*
         * Ht6560b autodetected
         */
        outb(HT_CONFIG_DEFAULT, HT_CONFIG_PORT);
        outb(HT_TIMING_DEFAULT, 0x1f6); /* Select register */
        (void)inb(0x1f7);               /* Status register */

        printk("ht6560b " HT6560B_VERSION
               ": chipset detected and initialized"
#ifdef DEBUG
               " with debug enabled"
#endif
               "\n"
                );
        return 1;
}

static u8 ht_pio2timings(ide_drive_t *drive, const u8 pio)
{
        int active_time, recovery_time;
        int active_cycles, recovery_cycles;
        int bus_speed = ide_vlb_clk ? ide_vlb_clk : 50;

        if (pio) {
                unsigned int cycle_time;
                struct ide_timing *t = ide_timing_find_mode(XFER_PIO_0 + pio);

                cycle_time = ide_pio_cycle_time(drive, pio);

                /*
                 *  Just like opti621.c we try to calculate the
                 *  actual cycle time for recovery and activity
                 *  according system bus speed.
                 */
                active_time = t->active;
                recovery_time = cycle_time - active_time - t->setup;
                /*
                 *  Cycle times should be Vesa bus cycles
                 */
                active_cycles   = (active_time   * bus_speed + 999) / 1000;
                recovery_cycles = (recovery_time * bus_speed + 999) / 1000;
                /*
                 *  Upper and lower limits
                 */
                if (active_cycles   < 2)  active_cycles   = 2;
                if (recovery_cycles < 2)  recovery_cycles = 2;
                if (active_cycles   > 15) active_cycles   = 15;
                if (recovery_cycles > 15) recovery_cycles = 0;  /* 0==16 */
                
#ifdef DEBUG
                printk("ht6560b: drive %s setting pio=%d recovery=%d (%dns) active=%d (%dns)\n", drive->name, pio, recovery_cycles, recovery_time, active_cycles, active_time);
#endif
                
                return (u8)((recovery_cycles << 4) | active_cycles);
        } else {
                
#ifdef DEBUG
                printk("ht6560b: drive %s setting pio=0\n", drive->name);
#endif
                
                return HT_TIMING_DEFAULT;    /* default setting */
        }
}

static DEFINE_SPINLOCK(ht6560b_lock);

/*
 *  Enable/Disable so called prefetch mode
 */
static void ht_set_prefetch(ide_drive_t *drive, u8 state)
{
        unsigned long flags, config;
        int t = HT_PREFETCH_MODE << 8;

        spin_lock_irqsave(&ht6560b_lock, flags);

        config = (unsigned long)ide_get_drivedata(drive);

        /*
         *  Prefetch mode and unmask irq seems to conflict
         */
        if (state) {
                config |= t;   /* enable prefetch mode */
                drive->dev_flags |= IDE_DFLAG_NO_UNMASK;
                drive->dev_flags &= ~IDE_DFLAG_UNMASK;
        } else {
                config &= ~t;  /* disable prefetch mode */
                drive->dev_flags &= ~IDE_DFLAG_NO_UNMASK;
        }

        ide_set_drivedata(drive, (void *)config);

        spin_unlock_irqrestore(&ht6560b_lock, flags);

#ifdef DEBUG
        printk("ht6560b: drive %s prefetch mode %sabled\n", drive->name, (state ? "en" : "dis"));
#endif
}

static void ht6560b_set_pio_mode(ide_hwif_t *hwif, ide_drive_t *drive)
{
        unsigned long flags, config;
        const u8 pio = drive->pio_mode - XFER_PIO_0;
        u8 timing;
        
        switch (pio) {
        case 8:         /* set prefetch off */
        case 9:         /* set prefetch on */
                ht_set_prefetch(drive, pio & 1);
                return;
        }

        timing = ht_pio2timings(drive, pio);

        spin_lock_irqsave(&ht6560b_lock, flags);
        config = (unsigned long)ide_get_drivedata(drive);
        config &= 0xff00;
        config |= timing;
        ide_set_drivedata(drive, (void *)config);
        spin_unlock_irqrestore(&ht6560b_lock, flags);

#ifdef DEBUG
        printk("ht6560b: drive %s tuned to pio mode %#x timing=%#x\n", drive->name, pio, timing);
#endif
}

static void __init ht6560b_init_dev(ide_drive_t *drive)
{
        ide_hwif_t *hwif = drive->hwif;
        /* Setting default configurations for drives. */
        int t = (HT_CONFIG_DEFAULT << 8) | HT_TIMING_DEFAULT;

        if (hwif->channel)
                t |= (HT_SECONDARY_IF << 8);

        ide_set_drivedata(drive, (void *)t);
}

static bool probe_ht6560b;

module_param_named(probe, probe_ht6560b, bool, 0);
MODULE_PARM_DESC(probe, "probe for HT6560B chipset");

static const struct ide_tp_ops ht6560b_tp_ops = {
        .exec_command           = ide_exec_command,
        .read_status            = ide_read_status,
        .read_altstatus         = ide_read_altstatus,
        .write_devctl           = ide_write_devctl,

        .dev_select             = ht6560b_dev_select,
        .tf_load                = ide_tf_load,
        .tf_read                = ide_tf_read,

        .input_data             = ide_input_data,
        .output_data            = ide_output_data,
};

static const struct ide_port_ops ht6560b_port_ops = {
        .init_dev               = ht6560b_init_dev,
        .set_pio_mode           = ht6560b_set_pio_mode,
};

static const struct ide_port_info ht6560b_port_info __initconst = {
        .name                   = DRV_NAME,
        .chipset                = ide_ht6560b,
        .tp_ops                 = &ht6560b_tp_ops,
        .port_ops               = &ht6560b_port_ops,
        .host_flags             = IDE_HFLAG_SERIALIZE | /* is this needed? */
                                  IDE_HFLAG_NO_DMA |
                                  IDE_HFLAG_ABUSE_PREFETCH,
        .pio_mask               = ATA_PIO4,
};

static int __init ht6560b_init(void)
{
        if (probe_ht6560b == 0)
                return -ENODEV;

        if (!request_region(HT_CONFIG_PORT, 1, DRV_NAME)) {
                printk(KERN_NOTICE "%s: HT_CONFIG_PORT not found\n",
                        __func__);
                return -ENODEV;
        }

        if (!try_to_init_ht6560b()) {
                printk(KERN_NOTICE "%s: HBA not found\n", __func__);
                goto release_region;
        }

        return ide_legacy_device_add(&ht6560b_port_info, 0);

release_region:
        release_region(HT_CONFIG_PORT, 1);
        return -ENODEV;
}

module_init(ht6560b_init);

MODULE_AUTHOR("See Local File");
MODULE_DESCRIPTION("HT-6560B EIDE-controller support");
MODULE_LICENSE("GPL");