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irq.c

/*
 * linux/arch/arm/mach-omap2/irq.c
 *
 * Interrupt handler for OMAP2 boards.
 *
 * Copyright (C) 2005 Nokia Corporation
 * Author: Paul Mundt <paul.mundt@nokia.com>
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License. See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <mach/hardware.h>
#include <asm/mach/irq.h>


/* selected INTC register offsets */

#define INTC_REVISION         0x0000
#define INTC_SYSCONFIG        0x0010
#define INTC_SYSSTATUS        0x0014
#define INTC_CONTROL          0x0048
#define INTC_MIR_CLEAR0       0x0088
#define INTC_MIR_SET0         0x008c
#define INTC_PENDING_IRQ0     0x0098

/* Number of IRQ state bits in each MIR register */
#define IRQ_BITS_PER_REG      32

/*
 * OMAP2 has a number of different interrupt controllers, each interrupt
 * controller is identified as its own "bank". Register definitions are
 * fairly consistent for each bank, but not all registers are implemented
 * for each bank.. when in doubt, consult the TRM.
 */
static struct omap_irq_bank {
      void __iomem *base_reg;
      unsigned int nr_irqs;
} __attribute__ ((aligned(4))) irq_banks[] = {
      {
            /* MPU INTC */
            .base_reg   = 0,
            .nr_irqs    = 96,
      },
};

/* INTC bank register get/set */

static void intc_bank_write_reg(u32 val, struct omap_irq_bank *bank, u16 reg)
{
      __raw_writel(val, bank->base_reg + reg);
}

static u32 intc_bank_read_reg(struct omap_irq_bank *bank, u16 reg)
{
      return __raw_readl(bank->base_reg + reg);
}

/* XXX: FIQ and additional INTC support (only MPU at the moment) */
static void omap_ack_irq(unsigned int irq)
{
      intc_bank_write_reg(0x1, &irq_banks[0], INTC_CONTROL);
}

static void omap_mask_irq(unsigned int irq)
{
      int offset = irq & (~(IRQ_BITS_PER_REG - 1));

      irq &= (IRQ_BITS_PER_REG - 1);

      intc_bank_write_reg(1 << irq, &irq_banks[0], INTC_MIR_SET0 + offset);
}

static void omap_unmask_irq(unsigned int irq)
{
      int offset = irq & (~(IRQ_BITS_PER_REG - 1));

      irq &= (IRQ_BITS_PER_REG - 1);

      intc_bank_write_reg(1 << irq, &irq_banks[0], INTC_MIR_CLEAR0 + offset);
}

static void omap_mask_ack_irq(unsigned int irq)
{
      omap_mask_irq(irq);
      omap_ack_irq(irq);
}

static struct irq_chip omap_irq_chip = {
      .name = "INTC",
      .ack  = omap_mask_ack_irq,
      .mask = omap_mask_irq,
      .unmask     = omap_unmask_irq,
};

static void __init omap_irq_bank_init_one(struct omap_irq_bank *bank)
{
      unsigned long tmp;

      tmp = intc_bank_read_reg(bank, INTC_REVISION) & 0xff;
      printk(KERN_INFO "IRQ: Found an INTC at 0x%p "
                   "(revision %ld.%ld) with %d interrupts\n",
                   bank->base_reg, tmp >> 4, tmp & 0xf, bank->nr_irqs);

      tmp = intc_bank_read_reg(bank, INTC_SYSCONFIG);
      tmp |= 1 << 1;    /* soft reset */
      intc_bank_write_reg(tmp, bank, INTC_SYSCONFIG);

      while (!(intc_bank_read_reg(bank, INTC_SYSSTATUS) & 0x1))
            /* Wait for reset to complete */;

      /* Enable autoidle */
      intc_bank_write_reg(1 << 0, bank, INTC_SYSCONFIG);
}

void __init omap_init_irq(void)
{
      unsigned long nr_of_irqs = 0;
      unsigned int nr_banks = 0;
      int i;

      for (i = 0; i < ARRAY_SIZE(irq_banks); i++) {
            struct omap_irq_bank *bank = irq_banks + i;

            if (cpu_is_omap24xx())
                  bank->base_reg = OMAP2_IO_ADDRESS(OMAP24XX_IC_BASE);
            else if (cpu_is_omap34xx())
                  bank->base_reg = OMAP2_IO_ADDRESS(OMAP34XX_IC_BASE);

            omap_irq_bank_init_one(bank);

            nr_of_irqs += bank->nr_irqs;
            nr_banks++;
      }

      printk(KERN_INFO "Total of %ld interrupts on %d active controller%s\n",
             nr_of_irqs, nr_banks, nr_banks > 1 ? "s" : "");

      for (i = 0; i < nr_of_irqs; i++) {
            set_irq_chip(i, &omap_irq_chip);
            set_irq_handler(i, handle_level_irq);
            set_irq_flags(i, IRQF_VALID);
      }
}


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