release/src-rt-6.x.4708/linux/linux-2.6.36/arch/mips/loongson/lemote-2f/irq.c

   1 /*
   2  * Copyright (C) 2007 Lemote Inc.
   3  * Author: Fuxin Zhang, zhangfx@lemote.com
   4  *
   5  *  This program is free software; you can redistribute  it and/or modify it
   6  *  under  the terms of  the GNU General  Public License as published by the
   7  *  Free Software Foundation;  either version 2 of the  License, or (at your
   8  *  option) any later version.
   9  */
  10
  11 #include <linux/interrupt.h>
  12 #include <linux/module.h>
  13
  14 #include <asm/irq_cpu.h>
  15 #include <asm/i8259.h>
  16 #include <asm/mipsregs.h>
  17
  18 #include <loongson.h>
  19 #include <machine.h>
  20
  21 #define LOONGSON_TIMER_IRQ      (MIPS_CPU_IRQ_BASE + 7) /* cpu timer */
  22 #define LOONGSON_NORTH_BRIDGE_IRQ       (MIPS_CPU_IRQ_BASE + 6) /* bonito */
  23 #define LOONGSON_UART_IRQ       (MIPS_CPU_IRQ_BASE + 3) /* cpu serial port */
  24 #define LOONGSON_SOUTH_BRIDGE_IRQ       (MIPS_CPU_IRQ_BASE + 2) /* i8259 */
  25
  26 #define LOONGSON_INT_BIT_INT0           (1 << 11)
  27 #define LOONGSON_INT_BIT_INT1           (1 << 12)
  28
  29 /*
  30  * The generic i8259_irq() make the kernel hang on booting.  Since we cannot
  31  * get the irq via the IRR directly, we access the ISR instead.
  32  */
  33 int mach_i8259_irq(void)
  34 {
  35         int irq, isr;
  36
  37         irq = -1;
  38
  39         if ((LOONGSON_INTISR & LOONGSON_INTEN) & LOONGSON_INT_BIT_INT0) {
  40                 raw_spin_lock(&i8259A_lock);
  41                 isr = inb(PIC_MASTER_CMD) &
  42                         ~inb(PIC_MASTER_IMR) & ~(1 << PIC_CASCADE_IR);
  43                 if (!isr)
  44                         isr = (inb(PIC_SLAVE_CMD) & ~inb(PIC_SLAVE_IMR)) << 8;
  45                 irq = ffs(isr) - 1;
  46                 if (unlikely(irq == 7)) {
  47                         /*
  48                          * This may be a spurious interrupt.
  49                          *
  50                          * Read the interrupt status register (ISR). If the most
  51                          * significant bit is not set then there is no valid
  52                          * interrupt.
  53                          */
  54                         outb(0x0B, PIC_MASTER_ISR);     /* ISR register */
  55                         if (~inb(PIC_MASTER_ISR) & 0x80)
  56                                 irq = -1;
  57                 }
  58                 raw_spin_unlock(&i8259A_lock);
  59         }
  60
  61         return irq;
  62 }
  63 EXPORT_SYMBOL(mach_i8259_irq);
  64
  65 static void i8259_irqdispatch(void)
  66 {
  67         int irq;
  68
  69         irq = mach_i8259_irq();
  70         if (irq >= 0)
  71                 do_IRQ(irq);
  72         else
  73                 spurious_interrupt();
  74 }
  75
  76 void mach_irq_dispatch(unsigned int pending)
  77 {
  78         if (pending & CAUSEF_IP7)
  79                 do_IRQ(LOONGSON_TIMER_IRQ);
  80         else if (pending & CAUSEF_IP6) {        /* North Bridge, Perf counter */
  81                 do_perfcnt_IRQ();
  82                 bonito_irqdispatch();
  83         } else if (pending & CAUSEF_IP3)        /* CPU UART */
  84                 do_IRQ(LOONGSON_UART_IRQ);
  85         else if (pending & CAUSEF_IP2)  /* South Bridge */
  86                 i8259_irqdispatch();
  87         else
  88                 spurious_interrupt();
  89 }
  90
  91 static irqreturn_t ip6_action(int cpl, void *dev_id)
  92 {
  93         return IRQ_HANDLED;
  94 }
  95
  96 struct irqaction ip6_irqaction = {
  97         .handler = ip6_action,
  98         .name = "cascade",
  99         .flags = IRQF_SHARED,
 100 };
 101
 102 struct irqaction cascade_irqaction = {
 103         .handler = no_action,
 104         .name = "cascade",
 105 };
 106
 107 void __init mach_init_irq(void)
 108 {
 109         /* init all controller
 110          *   0-15         ------> i8259 interrupt
 111          *   16-23        ------> mips cpu interrupt
 112          *   32-63        ------> bonito irq
 113          */
 114
 115         /* setup cs5536 as high level trigger */
 116         LOONGSON_INTPOL = LOONGSON_INT_BIT_INT0 | LOONGSON_INT_BIT_INT1;
 117         LOONGSON_INTEDGE &= ~(LOONGSON_INT_BIT_INT0 | LOONGSON_INT_BIT_INT1);
 118
 119         /* Sets the first-level interrupt dispatcher. */
 120         mips_cpu_irq_init();
 121         init_i8259_irqs();
 122         bonito_irq_init();
 123
 124         /* setup north bridge irq (bonito) */
 125         setup_irq(LOONGSON_NORTH_BRIDGE_IRQ, &ip6_irqaction);
 126         /* setup source bridge irq (i8259) */
 127         setup_irq(LOONGSON_SOUTH_BRIDGE_IRQ, &cascade_irqaction);
 128 }