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 <linux/io.h>
  14 #include <asm/mach/irq.h>
  15 #include <mach/regs-sys-common.h>
  16 #include <mach/irqs.h>
  17 #include <mach/board.h>
  18
  19 #include "generic.h"
  20
  21 /* simple interrupt prio table: prio(x) < prio(y) <=> x < y */
  22 #define irq2prio(i) (i)
  23 #define prio2irq(p) (p)
  24
  25 static void ns9xxx_mask_irq(unsigned int irq)
  26 {
  27         /* XXX: better use cpp symbols */
  28         int prio = irq2prio(irq);
  29         u32 ic = __raw_readl(SYS_IC(prio / 4));
  30         ic &= ~(1 << (7 + 8 * (3 - (prio & 3))));
  31         __raw_writel(ic, SYS_IC(prio / 4));
  32 }
  33
  34 static void ns9xxx_ack_irq(unsigned int irq)
  35 {
  36         __raw_writel(0, SYS_ISRADDR);
  37 }
  38
  39 static void ns9xxx_maskack_irq(unsigned int irq)
  40 {
  41         ns9xxx_mask_irq(irq);
  42         ns9xxx_ack_irq(irq);
  43 }
  44
  45 static void ns9xxx_unmask_irq(unsigned int irq)
  46 {
  47         /* XXX: better use cpp symbols */
  48         int prio = irq2prio(irq);
  49         u32 ic = __raw_readl(SYS_IC(prio / 4));
  50         ic |= 1 << (7 + 8 * (3 - (prio & 3)));
  51         __raw_writel(ic, SYS_IC(prio / 4));
  52 }
  53
  54 static struct irq_chip ns9xxx_chip = {
  55         .ack            = ns9xxx_ack_irq,
  56         .mask           = ns9xxx_mask_irq,
  57         .mask_ack       = ns9xxx_maskack_irq,
  58         .unmask         = ns9xxx_unmask_irq,
  59 };
  60
  61 #if 0
  62 #define handle_irq handle_level_irq
  63 #else
  64 static void handle_prio_irq(unsigned int irq, struct irq_desc *desc)
  65 {
  66         unsigned int cpu = smp_processor_id();
  67         struct irqaction *action;
  68         irqreturn_t action_ret;
  69
  70         spin_lock(&desc->lock);
  71
  72         BUG_ON(desc->status & IRQ_INPROGRESS);
  73
  74         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
  75         kstat_cpu(cpu).irqs[irq]++;
  76
  77         action = desc->action;
  78         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
  79                 goto out_mask;
  80
  81         desc->status |= IRQ_INPROGRESS;
  82         spin_unlock(&desc->lock);
  83
  84         action_ret = handle_IRQ_event(irq, action);
  85
  86         /* XXX: There is no direct way to access noirqdebug, so check
  87          * unconditionally for spurious irqs...
  88          * Maybe this function should go to kernel/irq/chip.c? */
  89         note_interrupt(irq, desc, action_ret);
  90
  91         spin_lock(&desc->lock);
  92         desc->status &= ~IRQ_INPROGRESS;
  93
  94         if (desc->status & IRQ_DISABLED)
  95 out_mask:
  96                 desc->chip->mask(irq);
  97
  98         /* ack unconditionally to unmask lower prio irqs */
  99         desc->chip->ack(irq);
 100
 101         spin_unlock(&desc->lock);
 102 }
 103 #define handle_irq handle_prio_irq
 104 #endif
 105
 106 void __init ns9xxx_init_irq(void)
 107 {
 108         int i;
 109
 110         /* disable all IRQs */
 111         for (i = 0; i < 8; ++i)
 112                 __raw_writel(prio2irq(4 * i) << 24 |
 113                                 prio2irq(4 * i + 1) << 16 |
 114                                 prio2irq(4 * i + 2) << 8 |
 115                                 prio2irq(4 * i + 3),
 116                                 SYS_IC(i));
 117
 118         for (i = 0; i < 32; ++i)
 119                 __raw_writel(prio2irq(i), SYS_IVA(i));
 120
 121         for (i = 0; i <= 31; ++i) {
 122                 set_irq_chip(i, &ns9xxx_chip);
 123                 set_irq_handler(i, handle_irq);
 124                 set_irq_flags(i, IRQF_VALID);
 125         }
 126 }