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 <linux/kernel_stat.h>
  13 #include <asm/io.h>
  14 #include <asm/mach/irq.h>
  15 #include <asm/mach-types.h>
  16 #include <asm/arch-ns9xxx/regs-sys-common.h>
  17 #include <asm/arch-ns9xxx/irqs.h>
  18 #include <asm/arch-ns9xxx/board.h>
  19
  20 #include "generic.h"
  21
  22 static void ns9xxx_mask_irq(unsigned int irq)
  23 {
  24         /* XXX: better use cpp symbols */
  25         u32 ic = __raw_readl(SYS_IC(irq / 4));
  26         ic &= ~(1 << (7 + 8 * (3 - (irq & 3))));
  27         __raw_writel(ic, SYS_IC(irq / 4));
  28 }
  29
  30 static void ns9xxx_ack_irq(unsigned int irq)
  31 {
  32         __raw_writel(0, SYS_ISRADDR);
  33 }
  34
  35 static void ns9xxx_maskack_irq(unsigned int irq)
  36 {
  37         ns9xxx_mask_irq(irq);
  38         ns9xxx_ack_irq(irq);
  39 }
  40
  41 static void ns9xxx_unmask_irq(unsigned int irq)
  42 {
  43         /* XXX: better use cpp symbols */
  44         u32 ic = __raw_readl(SYS_IC(irq / 4));
  45         ic |= 1 << (7 + 8 * (3 - (irq & 3)));
  46         __raw_writel(ic, SYS_IC(irq / 4));
  47 }
  48
  49 static struct irq_chip ns9xxx_chip = {
  50         .ack            = ns9xxx_ack_irq,
  51         .mask           = ns9xxx_mask_irq,
  52         .mask_ack       = ns9xxx_maskack_irq,
  53         .unmask         = ns9xxx_unmask_irq,
  54 };
  55
  56 #if 0
  57 #define handle_irq handle_level_irq
  58 #else
  59 static void handle_prio_irq(unsigned int irq, struct irq_desc *desc)
  60 {
  61         unsigned int cpu = smp_processor_id();
  62         struct irqaction *action;
  63         irqreturn_t action_ret;
  64
  65         spin_lock(&desc->lock);
  66
  67         BUG_ON(desc->status & IRQ_INPROGRESS);
  68
  69         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
  70         kstat_cpu(cpu).irqs[irq]++;
  71
  72         action = desc->action;
  73         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
  74                 goto out_mask;
  75
  76         desc->status |= IRQ_INPROGRESS;
  77         spin_unlock(&desc->lock);
  78
  79         action_ret = handle_IRQ_event(irq, action);
  80
  81         /* XXX: There is no direct way to access noirqdebug, so check
  82          * unconditionally for spurious irqs...
  83          * Maybe this function should go to kernel/irq/chip.c? */
  84         note_interrupt(irq, desc, action_ret);
  85
  86         spin_lock(&desc->lock);
  87         desc->status &= ~IRQ_INPROGRESS;
  88
  89         if (desc->status & IRQ_DISABLED)
  90 out_mask:
  91                 desc->chip->mask(irq);
  92
  93         /* ack unconditionally to unmask lower prio irqs */
  94         desc->chip->ack(irq);
  95
  96         spin_unlock(&desc->lock);
  97 }
  98 #define handle_irq handle_prio_irq
  99 #endif
 100
 101 void __init ns9xxx_init_irq(void)
 102 {
 103         int i;
 104
 105         /* disable all IRQs */
 106         for (i = 0; i < 8; ++i)
 107                 __raw_writel((4 * i) << 24 | (4 * i + 1) << 16 |
 108                                 (4 * i + 2) << 8 | (4 * i + 3), SYS_IC(i));
 109
 110         /* simple interrupt prio table:
 111          * prio(x) < prio(y) <=> x < y
 112          */
 113         for (i = 0; i < 32; ++i)
 114                 __raw_writel(i, SYS_IVA(i));
 115
 116         for (i = 0; i <= 31; ++i) {
 117                 set_irq_chip(i, &ns9xxx_chip);
 118                 set_irq_handler(i, handle_irq);
 119                 set_irq_flags(i, IRQF_VALID);
 120         }
 121 }