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core.c

/*
 *  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.h>

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

#include <asm/mach/time.h>

#define IRQ_MASK        0xfe000000  /* read */
#define IRQ_MSET        0xfe000000  /* write */
#define IRQ_STAT        0xff000000  /* read */
#define IRQ_MCLR        0xff000000  /* write */

static void ebsa110_mask_irq(unsigned int irq)
{
      __raw_writeb(1 << irq, IRQ_MCLR);
}

static void ebsa110_unmask_irq(unsigned int irq)
{
      __raw_writeb(1 << irq, IRQ_MSET);
}

static struct irq_chip ebsa110_irq_chip = {
      .ack  = ebsa110_mask_irq,
      .mask = ebsa110_mask_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++) {
            set_irq_chip(irq, &ebsa110_irq_chip);
            set_irq_handler(irq, handle_level_irq);
            set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
      }
}

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


#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 unsigned long 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;
}

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_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
      .handler    = ebsa110_timer_interrupt,
};

/*
 * Set up timer interrupt.
 */
static void __init ebsa110_timer_init(void)
{
      /*
       * 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 sys_timer ebsa110_timer = {
      .init       = ebsa110_timer_init,
      .offset           = ebsa110_gettimeoffset,
};

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,
};

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

arch_initcall(ebsa110_init);

MACHINE_START(EBSA110, "EBSA110")
      /* Maintainer: Russell King */
      .phys_io    = 0xe0000000,
      .io_pg_offst      = ((0xe0000000) >> 18) & 0xfffc,
      .boot_params      = 0x00000400,
      .reserve_lp0      = 1,
      .reserve_lp2      = 1,
      .soft_reboot      = 1,
      .map_io           = ebsa110_map_io,
      .init_irq   = ebsa110_init_irq,
      .timer            = &ebsa110_timer,
MACHINE_END

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