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 /* simple interrupt prio table: prio(x) < prio(y) <=> x < y */
  23 #define irq2prio(i) (i)
  24 #define prio2irq(p) (p)
  25
  26 static void ns9xxx_mask_irq(unsigned int irq)
  27 {
  28         /* XXX: better use cpp symbols */
  29         int prio = irq2prio(irq);
  30         u32 ic = __raw_readl(SYS_IC(prio / 4));
  31         ic &= ~(1 << (7 + 8 * (3 - (prio & 3))));
  32         __raw_writel(ic, SYS_IC(prio / 4));
  33 }
  34
  35 static void ns9xxx_ack_irq(unsigned int irq)
  36 {
  37         __raw_writel(0, SYS_ISRADDR);
  38 }
  39
  40 static void ns9xxx_maskack_irq(unsigned int irq)
  41 {
  42         ns9xxx_mask_irq(irq);
  43         ns9xxx_ack_irq(irq);
  44 }
  45
  46 static void ns9xxx_unmask_irq(unsigned int irq)
  47 {
  48         /* XXX: better use cpp symbols */
  49         int prio = irq2prio(irq);
  50         u32 ic = __raw_readl(SYS_IC(prio / 4));
  51         ic |= 1 << (7 + 8 * (3 - (prio & 3)));
  52         __raw_writel(ic, SYS_IC(prio / 4));
  53 }
  54
  55 static struct irq_chip ns9xxx_chip = {
  56         .ack            = ns9xxx_ack_irq,
  57         .mask           = ns9xxx_mask_irq,
  58         .mask_ack       = ns9xxx_maskack_irq,
  59         .unmask         = ns9xxx_unmask_irq,
  60 };
  61
  62 #if 0
  63 #define handle_irq handle_level_irq
  64 #else
  65 static void handle_prio_irq(unsigned int irq, struct irq_desc *desc)
  66 {
  67         unsigned int cpu = smp_processor_id();
  68         struct irqaction *action;
  69         irqreturn_t action_ret;
  70
  71         spin_lock(&desc->lock);
  72
  73         BUG_ON(desc->status & IRQ_INPROGRESS);
  74
  75         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
  76         kstat_cpu(cpu).irqs[irq]++;
  77
  78         action = desc->action;
  79         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
  80                 goto out_mask;
  81
  82         desc->status |= IRQ_INPROGRESS;
  83         spin_unlock(&desc->lock);
  84
  85         action_ret = handle_IRQ_event(irq, action);
  86
  87         /* XXX: There is no direct way to access noirqdebug, so check
  88          * unconditionally for spurious irqs...
  89          * Maybe this function should go to kernel/irq/chip.c? */
  90         note_interrupt(irq, desc, action_ret);
  91
  92         spin_lock(&desc->lock);
  93         desc->status &= ~IRQ_INPROGRESS;
  94
  95         if (desc->status & IRQ_DISABLED)
  96 out_mask:
  97                 desc->chip->mask(irq);
  98
  99         /* ack unconditionally to unmask lower prio irqs */
 100         desc->chip->ack(irq);
 101
 102         spin_unlock(&desc->lock);
 103 }
 104 #define handle_irq handle_prio_irq
 105 #endif
 106
 107 void __init ns9xxx_init_irq(void)
 108 {
 109         int i;
 110
 111         /* disable all IRQs */
 112         for (i = 0; i < 8; ++i)
 113                 __raw_writel(prio2irq(4 * i) << 24 |
 114                                 prio2irq(4 * i + 1) << 16 |
 115                                 prio2irq(4 * i + 2) << 8 |
 116                                 prio2irq(4 * i + 3),
 117                                 SYS_IC(i));
 118
 119         for (i = 0; i < 32; ++i)
 120                 __raw_writel(prio2irq(i), SYS_IVA(i));
 121
 122         for (i = 0; i <= 31; ++i) {
 123                 set_irq_chip(i, &ns9xxx_chip);
 124                 set_irq_handler(i, handle_irq);
 125                 set_irq_flags(i, IRQF_VALID);
 126         }
 127 }