/*
 *  linux/arch/arm/mach-ebsa110/core.c
 *
 *  Copyright (C) 1998-2001 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *  Extra MM routines for the EBSA-110 architecture
 */
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/serial_8250.h>
#include <linux/init.h>
#include <linux/io.h>

#include <mach/hardware.h>
#include <asm/irq.h>
#include <asm/setup.h>
#include <asm/mach-types.h>
#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/system_misc.h>

#include <asm/mach/arch.h>
#include <asm/mach/irq.h>
#include <asm/mach/map.h>

#include <asm/mach/time.h>

#include "core.h"

static void ebsa110_mask_irq(struct irq_data *d)
{
        __raw_writeb(1 << d->irq, IRQ_MCLR);
}

static void ebsa110_unmask_irq(struct irq_data *d)
{
        __raw_writeb(1 << d->irq, IRQ_MSET);
}

static struct irq_chip ebsa110_irq_chip = {
        .irq_ack        = ebsa110_mask_irq,
        .irq_mask       = ebsa110_mask_irq,
        .irq_unmask     = ebsa110_unmask_irq,
};
 
static void __init ebsa110_init_irq(void)
{
        unsigned long flags;
        unsigned int irq;

        local_irq_save(flags);
        __raw_writeb(0xff, IRQ_MCLR);
        __raw_writeb(0x55, IRQ_MSET);
        __raw_writeb(0x00, IRQ_MSET);
        if (__raw_readb(IRQ_MASK) != 0x55)
                while (1);
        __raw_writeb(0xff, IRQ_MCLR);   /* clear all interrupt enables */
        local_irq_restore(flags);

        for (irq = 0; irq < NR_IRQS; irq++) {
                irq_set_chip_and_handler(irq, &ebsa110_irq_chip,
                                         handle_level_irq);
                irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
        }
}

static struct map_desc ebsa110_io_desc[] __initdata = {
        /*
         * sparse external-decode ISAIO space
         */
        {       /* IRQ_STAT/IRQ_MCLR */
                .virtual        = (unsigned long)IRQ_STAT,
                .pfn            = __phys_to_pfn(TRICK4_PHYS),
                .length         = TRICK4_SIZE,
                .type           = MT_DEVICE
        }, {    /* IRQ_MASK/IRQ_MSET */
                .virtual        = (unsigned long)IRQ_MASK,
                .pfn            = __phys_to_pfn(TRICK3_PHYS),
                .length         = TRICK3_SIZE,
                .type           = MT_DEVICE
        }, {    /* SOFT_BASE */
                .virtual        = (unsigned long)SOFT_BASE,
                .pfn            = __phys_to_pfn(TRICK1_PHYS),
                .length         = TRICK1_SIZE,
                .type           = MT_DEVICE
        }, {    /* PIT_BASE */
                .virtual        = (unsigned long)PIT_BASE,
                .pfn            = __phys_to_pfn(TRICK0_PHYS),
                .length         = TRICK0_SIZE,
                .type           = MT_DEVICE
        },

        /*
         * self-decode ISAIO space
         */
        {
                .virtual        = ISAIO_BASE,
                .pfn            = __phys_to_pfn(ISAIO_PHYS),
                .length         = ISAIO_SIZE,
                .type           = MT_DEVICE
        }, {
                .virtual        = ISAMEM_BASE,
                .pfn            = __phys_to_pfn(ISAMEM_PHYS),
                .length         = ISAMEM_SIZE,
                .type           = MT_DEVICE
        }
};

static void __init ebsa110_map_io(void)
{
        iotable_init(ebsa110_io_desc, ARRAY_SIZE(ebsa110_io_desc));
}

static void __iomem *ebsa110_ioremap_caller(phys_addr_t cookie, size_t size,
                                            unsigned int flags, void *caller)
{
        return (void __iomem *)cookie;
}

static void ebsa110_iounmap(volatile void __iomem *io_addr)
{}

static void __init ebsa110_init_early(void)
{
        arch_ioremap_caller = ebsa110_ioremap_caller;
        arch_iounmap = ebsa110_iounmap;
}

#define PIT_CTRL                (PIT_BASE + 0x0d)
#define PIT_T2                  (PIT_BASE + 0x09)
#define PIT_T1                  (PIT_BASE + 0x05)
#define PIT_T0                  (PIT_BASE + 0x01)

/*
 * This is the rate at which your MCLK signal toggles (in Hz)
 * This was measured on a 10 digit frequency counter sampling
 * over 1 second.
 */
#define MCLK    47894000

/*
 * This is the rate at which the PIT timers get clocked
 */
#define CLKBY7  (MCLK / 7)

/*
 * This is the counter value.  We tick at 200Hz on this platform.
 */
#define COUNT   ((CLKBY7 + (HZ / 2)) / HZ)

/*
 * Get the time offset from the system PIT.  Note that if we have missed an
 * interrupt, then the PIT counter will roll over (ie, be negative).
 * This actually works out to be convenient.
 */
static u32 ebsa110_gettimeoffset(void)
{
        unsigned long offset, count;

        __raw_writeb(0x40, PIT_CTRL);
        count = __raw_readb(PIT_T1);
        count |= __raw_readb(PIT_T1) << 8;

        /*
         * If count > COUNT, make the number negative.
         */
        if (count > COUNT)
                count |= 0xffff0000;

        offset = COUNT;
        offset -= count;

        /*
         * `offset' is in units of timer counts.  Convert
         * offset to units of microseconds.
         */
        offset = offset * (1000000 / HZ) / COUNT;

        return offset * 1000;
}

static irqreturn_t
ebsa110_timer_interrupt(int irq, void *dev_id)
{
        u32 count;

        /* latch and read timer 1 */
        __raw_writeb(0x40, PIT_CTRL);
        count = __raw_readb(PIT_T1);
        count |= __raw_readb(PIT_T1) << 8;

        count += COUNT;

        __raw_writeb(count & 0xff, PIT_T1);
        __raw_writeb(count >> 8, PIT_T1);

        timer_tick();

        return IRQ_HANDLED;
}

static struct irqaction ebsa110_timer_irq = {
        .name           = "EBSA110 Timer Tick",
        .flags          = IRQF_TIMER | IRQF_IRQPOLL,
        .handler        = ebsa110_timer_interrupt,
};

/*
 * Set up timer interrupt.
 */
void __init ebsa110_timer_init(void)
{
        arch_gettimeoffset = ebsa110_gettimeoffset;

        /*
         * Timer 1, mode 2, LSB/MSB
         */
        __raw_writeb(0x70, PIT_CTRL);
        __raw_writeb(COUNT & 0xff, PIT_T1);
        __raw_writeb(COUNT >> 8, PIT_T1);

        setup_irq(IRQ_EBSA110_TIMER0, &ebsa110_timer_irq);
}

static struct plat_serial8250_port serial_platform_data[] = {
        {
                .iobase         = 0x3f8,
                .irq            = 1,
                .uartclk        = 1843200,
                .regshift       = 0,
                .iotype         = UPIO_PORT,
                .flags          = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,
        },
        {
                .iobase         = 0x2f8,
                .irq            = 2,
                .uartclk        = 1843200,
                .regshift       = 0,
                .iotype         = UPIO_PORT,
                .flags          = UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,
        },
        { },
};

static struct platform_device serial_device = {
        .name                   = "serial8250",
        .id                     = PLAT8250_DEV_PLATFORM,
        .dev                    = {
                .platform_data  = serial_platform_data,
        },
};

static struct resource am79c961_resources[] = {
        {
                .start          = 0x220,
                .end            = 0x238,
                .flags          = IORESOURCE_IO,
        }, {
                .start          = IRQ_EBSA110_ETHERNET,
                .end            = IRQ_EBSA110_ETHERNET,
                .flags          = IORESOURCE_IRQ,
        },
};

static struct platform_device am79c961_device = {
        .name                   = "am79c961",
        .id                     = -1,
        .num_resources          = ARRAY_SIZE(am79c961_resources),
        .resource               = am79c961_resources,
};

static struct platform_device *ebsa110_devices[] = {
        &serial_device,
        &am79c961_device,
};

/*
 * EBSA110 idling methodology:
 *
 * We can not execute the "wait for interrupt" instruction since that
 * will stop our MCLK signal (which provides the clock for the glue
 * logic, and therefore the timer interrupt).
 *
 * Instead, we spin, polling the IRQ_STAT register for the occurrence
 * of any interrupt with core clock down to the memory clock.
 */
static void ebsa110_idle(void)
{
        const char *irq_stat = (char *)0xff000000;

        /* disable clock switching */
        asm volatile ("mcr p15, 0, ip, c15, c2, 2" : : : "cc");

        /* wait for an interrupt to occur */
        while (!*irq_stat);

        /* enable clock switching */
        asm volatile ("mcr p15, 0, ip, c15, c1, 2" : : : "cc");
}

static int __init ebsa110_init(void)
{
        arm_pm_idle = ebsa110_idle;
        return platform_add_devices(ebsa110_devices, ARRAY_SIZE(ebsa110_devices));
}

arch_initcall(ebsa110_init);

static void ebsa110_restart(enum reboot_mode mode, const char *cmd)
{
        soft_restart(0x80000000);
}

MACHINE_START(EBSA110, "EBSA110")
        /* Maintainer: Russell King */
        .atag_offset    = 0x400,
        .reserve_lp0    = 1,
        .reserve_lp2    = 1,
        .map_io         = ebsa110_map_io,
        .init_early     = ebsa110_init_early,
        .init_irq       = ebsa110_init_irq,
        .init_time      = ebsa110_timer_init,
        .restart        = ebsa110_restart,
MACHINE_END