arch/mips/loongson64/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/export.h>
  12 #include <linux/init.h>
  13 #include <linux/interrupt.h>
  14
  15 #include <asm/irq_cpu.h>
  16 #include <asm/i8259.h>
  17 #include <asm/mipsregs.h>
  18
  19 #include <loongson.h>
  20 #include <machine.h>
  21
  22 #define LOONGSON_TIMER_IRQ      (MIPS_CPU_IRQ_BASE + 7) /* cpu timer */
  23 #define LOONGSON_NORTH_BRIDGE_IRQ       (MIPS_CPU_IRQ_BASE + 6) /* bonito */
  24 #define LOONGSON_UART_IRQ       (MIPS_CPU_IRQ_BASE + 3) /* cpu serial port */
  25 #define LOONGSON_SOUTH_BRIDGE_IRQ       (MIPS_CPU_IRQ_BASE + 2) /* i8259 */
  26
  27 #define LOONGSON_INT_BIT_INT0           (1 << 11)
  28 #define LOONGSON_INT_BIT_INT1           (1 << 12)
  29
  30 /*
  31  * The generic i8259_irq() make the kernel hang on booting.  Since we cannot
  32  * get the irq via the IRR directly, we access the ISR instead.
  33  */
  34 int mach_i8259_irq(void)
  35 {
  36         int irq, isr;
  37
  38         irq = -1;
  39
  40         if ((LOONGSON_INTISR & LOONGSON_INTEN) & LOONGSON_INT_BIT_INT0) {
  41                 raw_spin_lock(&i8259A_lock);
  42                 isr = inb(PIC_MASTER_CMD) &
  43                         ~inb(PIC_MASTER_IMR) & ~(1 << PIC_CASCADE_IR);
  44                 if (!isr)
  45                         isr = (inb(PIC_SLAVE_CMD) & ~inb(PIC_SLAVE_IMR)) << 8;
  46                 irq = ffs(isr) - 1;
  47                 if (unlikely(irq == 7)) {
  48                         /*
  49                          * This may be a spurious interrupt.
  50                          *
  51                          * Read the interrupt status register (ISR). If the most
  52                          * significant bit is not set then there is no valid
  53                          * interrupt.
  54                          */
  55                         outb(0x0B, PIC_MASTER_ISR);     /* ISR register */
  56                         if (~inb(PIC_MASTER_ISR) & 0x80)
  57                                 irq = -1;
  58                 }
  59                 raw_spin_unlock(&i8259A_lock);
  60         }
  61
  62         return irq;
  63 }
  64 EXPORT_SYMBOL(mach_i8259_irq);
  65
  66 static void i8259_irqdispatch(void)
  67 {
  68         int irq;
  69
  70         irq = mach_i8259_irq();
  71         if (irq >= 0)
  72                 do_IRQ(irq);
  73         else
  74                 spurious_interrupt();
  75 }
  76
  77 void mach_irq_dispatch(unsigned int pending)
  78 {
  79         if (pending & CAUSEF_IP7)
  80                 do_IRQ(LOONGSON_TIMER_IRQ);
  81         else if (pending & CAUSEF_IP6) {        /* North Bridge, Perf counter */
  82                 do_perfcnt_IRQ();
  83                 bonito_irqdispatch();
  84         } else if (pending & CAUSEF_IP3)        /* CPU UART */
  85                 do_IRQ(LOONGSON_UART_IRQ);
  86         else if (pending & CAUSEF_IP2)  /* South Bridge */
  87                 i8259_irqdispatch();
  88         else
  89                 spurious_interrupt();
  90 }
  91
  92 static irqreturn_t ip6_action(int cpl, void *dev_id)
  93 {
  94         return IRQ_HANDLED;
  95 }
  96
  97 static struct irqaction ip6_irqaction = {
  98         .handler = ip6_action,
  99         .name = "cascade",
 100         .flags = IRQF_SHARED | IRQF_NO_THREAD,
 101 };
 102
 103 static struct irqaction cascade_irqaction = {
 104         .handler = no_action,
 105         .name = "cascade",
 106         .flags = IRQF_NO_THREAD,
 107 };
 108
 109 void __init mach_init_irq(void)
 110 {
 111         /* init all controller
 112          *   0-15         ------> i8259 interrupt
 113          *   16-23        ------> mips cpu interrupt
 114          *   32-63        ------> bonito irq
 115          */
 116
 117         /* setup cs5536 as high level trigger */
 118         LOONGSON_INTPOL = LOONGSON_INT_BIT_INT0 | LOONGSON_INT_BIT_INT1;
 119         LOONGSON_INTEDGE &= ~(LOONGSON_INT_BIT_INT0 | LOONGSON_INT_BIT_INT1);
 120
 121         /* Sets the first-level interrupt dispatcher. */
 122         mips_cpu_irq_init();
 123         init_i8259_irqs();
 124         bonito_irq_init();
 125
 126         /* setup north bridge irq (bonito) */
 127         setup_irq(LOONGSON_NORTH_BRIDGE_IRQ, &ip6_irqaction);
 128         /* setup source bridge irq (i8259) */
 129         setup_irq(LOONGSON_SOUTH_BRIDGE_IRQ, &cascade_irqaction);
 130 }