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bast-irq.c

/* linux/arch/arm/mach-s3c2410/bast-irq.c
 *
 * Copyright (c) 2003,2005 Simtec Electronics
 *   Ben Dooks <ben@simtec.co.uk>
 *
 * http://www.simtec.co.uk/products/EB2410ITX/
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/


#include <linux/init.h>
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/sysdev.h>

#include <asm/mach-types.h>

#include <mach/hardware.h>
#include <asm/irq.h>
#include <asm/io.h>

#include <asm/mach/irq.h>

#include <mach/regs-irq.h>
#include <mach/bast-map.h>
#include <mach/bast-irq.h>

#include <asm/plat-s3c24xx/irq.h>

#if 0
#include <asm/debug-ll.h>
#endif

#define irqdbf(x...)
#define irqdbf2(x...)


/* handle PC104 ISA interrupts from the system CPLD */

/* table of ISA irq nos to the relevant mask... zero means
 * the irq is not implemented
*/
static unsigned char bast_pc104_irqmasks[] = {
      0,   /* 0 */
      0,   /* 1 */
      0,   /* 2 */
      1,   /* 3 */
      0,   /* 4 */
      2,   /* 5 */
      0,   /* 6 */
      4,   /* 7 */
      0,   /* 8 */
      0,   /* 9 */
      8,   /* 10 */
      0,   /* 11 */
      0,   /* 12 */
      0,   /* 13 */
      0,   /* 14 */
      0,   /* 15 */
};

static unsigned char bast_pc104_irqs[] = { 3, 5, 7, 10 };

static void
bast_pc104_mask(unsigned int irqno)
{
      unsigned long temp;

      temp = __raw_readb(BAST_VA_PC104_IRQMASK);
      temp &= ~bast_pc104_irqmasks[irqno];
      __raw_writeb(temp, BAST_VA_PC104_IRQMASK);
}

static void
bast_pc104_maskack(unsigned int irqno)
{
      struct irq_desc *desc = irq_desc + IRQ_ISA;

      bast_pc104_mask(irqno);
      desc->chip->ack(IRQ_ISA);
}

static void
bast_pc104_unmask(unsigned int irqno)
{
      unsigned long temp;

      temp = __raw_readb(BAST_VA_PC104_IRQMASK);
      temp |= bast_pc104_irqmasks[irqno];
      __raw_writeb(temp, BAST_VA_PC104_IRQMASK);
}

static struct irq_chip  bast_pc104_chip = {
      .mask      = bast_pc104_mask,
      .unmask          = bast_pc104_unmask,
      .ack       = bast_pc104_maskack
};

static void
bast_irq_pc104_demux(unsigned int irq,
                 struct irq_desc *desc)
{
      unsigned int stat;
      unsigned int irqno;
      int i;

      stat = __raw_readb(BAST_VA_PC104_IRQREQ) & 0xf;

      if (unlikely(stat == 0)) {
            /* ack if we get an irq with nothing (ie, startup) */

            desc = irq_desc + IRQ_ISA;
            desc->chip->ack(IRQ_ISA);
      } else {
            /* handle the IRQ */

            for (i = 0; stat != 0; i++, stat >>= 1) {
                  if (stat & 1) {
                        irqno = bast_pc104_irqs[i];
                        desc = irq_desc + irqno;
                        desc_handle_irq(irqno, desc);
                  }
            }
      }
}

static __init int bast_irq_init(void)
{
      unsigned int i;

      if (machine_is_bast()) {
            printk(KERN_INFO "BAST PC104 IRQ routing, (c) 2005 Simtec Electronics\n");

            /* zap all the IRQs */

            __raw_writeb(0x0, BAST_VA_PC104_IRQMASK);

            set_irq_chained_handler(IRQ_ISA, bast_irq_pc104_demux);

            /* register our IRQs */

            for (i = 0; i < 4; i++) {
                  unsigned int irqno = bast_pc104_irqs[i];

                  set_irq_chip(irqno, &bast_pc104_chip);
                  set_irq_handler(irqno, handle_level_irq);
                  set_irq_flags(irqno, IRQF_VALID);
            }
      }

      return 0;
}

arch_initcall(bast_irq_init);

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