arch/arm/mach-ns9xxx/irq.c

   1 /*
   2  * arch/arm/mach-ns9xxx/irq.c
   3  *
   4  * Copyright (C) 2006,2007 by Digi International Inc.
   5  * All rights reserved.
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License version 2 as published by
   9  * the Free Software Foundation.
  10  */
  11 #include <linux/interrupt.h>
  12 #include <asm/mach/irq.h>
  13 #include <asm/mach-types.h>
  14 #include <asm/arch-ns9xxx/regs-sys.h>
  15 #include <asm/arch-ns9xxx/irqs.h>
  16 #include <asm/arch-ns9xxx/board.h>
  17
  18 #include "generic.h"
  19
  20 static void ns9xxx_ack_irq_timer(unsigned int irq)
  21 {
  22         u32 tc = SYS_TC(irq - IRQ_TIMER0);
  23
  24         /*
  25          * If the timer is programmed to halt on terminal count, the
  26          * timer must be disabled before clearing the interrupt.
  27          */
  28         if (REGGET(tc, SYS_TCx, REN) == 0) {
  29                 REGSET(tc, SYS_TCx, TEN, DIS);
  30                 SYS_TC(irq - IRQ_TIMER0) = tc;
  31         }
  32
  33         REGSET(tc, SYS_TCx, INTC, SET);
  34         SYS_TC(irq - IRQ_TIMER0) = tc;
  35
  36         REGSET(tc, SYS_TCx, INTC, UNSET);
  37         SYS_TC(irq - IRQ_TIMER0) = tc;
  38 }
  39
  40 static void (*ns9xxx_ack_irq_functions[NR_IRQS])(unsigned int) = {
  41         [IRQ_TIMER0] = ns9xxx_ack_irq_timer,
  42         [IRQ_TIMER1] = ns9xxx_ack_irq_timer,
  43         [IRQ_TIMER2] = ns9xxx_ack_irq_timer,
  44         [IRQ_TIMER3] = ns9xxx_ack_irq_timer,
  45 };
  46
  47 static void ns9xxx_mask_irq(unsigned int irq)
  48 {
  49         /* XXX: better use cpp symbols */
  50         SYS_IC(irq / 4) &= ~(1 << (7 + 8 * (3 - (irq & 3))));
  51 }
  52
  53 static void ns9xxx_ack_irq(unsigned int irq)
  54 {
  55         if (!ns9xxx_ack_irq_functions[irq]) {
  56                 printk(KERN_ERR "no ack function for irq %u\n", irq);
  57                 BUG();
  58         }
  59
  60         ns9xxx_ack_irq_functions[irq](irq);
  61         SYS_ISRADDR = 0;
  62 }
  63
  64 static void ns9xxx_maskack_irq(unsigned int irq)
  65 {
  66         ns9xxx_mask_irq(irq);
  67         ns9xxx_ack_irq(irq);
  68 }
  69
  70 static void ns9xxx_unmask_irq(unsigned int irq)
  71 {
  72         /* XXX: better use cpp symbols */
  73         SYS_IC(irq / 4) |= 1 << (7 + 8 * (3 - (irq & 3)));
  74 }
  75
  76 static struct irq_chip ns9xxx_chip = {
  77         .ack            = ns9xxx_ack_irq,
  78         .mask           = ns9xxx_mask_irq,
  79         .mask_ack       = ns9xxx_maskack_irq,
  80         .unmask         = ns9xxx_unmask_irq,
  81 };
  82
  83 void __init ns9xxx_init_irq(void)
  84 {
  85         int i;
  86
  87         /* disable all IRQs */
  88         for (i = 0; i < 8; ++i)
  89                 SYS_IC(i) = (4 * i) << 24 | (4 * i + 1) << 16 |
  90                         (4 * i + 2) << 8 | (4 * i + 3);
  91
  92         /* simple interrupt prio table:
  93          * prio(x) < prio(y) <=> x < y
  94          */
  95         for (i = 0; i < 32; ++i)
  96                 SYS_IVA(i) = i;
  97
  98         for (i = IRQ_WATCHDOG; i <= IRQ_EXT3; ++i) {
  99                 set_irq_chip(i, &ns9xxx_chip);
 100                 set_irq_handler(i, handle_level_irq);
 101                 set_irq_flags(i, IRQF_VALID);
 102         }
 103 }