release/src-rt-6.x.4708/linux/linux-2.6.36/arch/mips/kernel/irq_cpu.c

   1 /*
   2  * Copyright 2001 MontaVista Software Inc.
   3  * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
   4  *
   5  * Copyright (C) 2001 Ralf Baechle
   6  * Copyright (C) 2005  MIPS Technologies, Inc.  All rights reserved.
   7  *      Author: Maciej W. Rozycki <macro@mips.com>
   8  *
   9  * This file define the irq handler for MIPS CPU interrupts.
  10  *
  11  * This program is free software; you can redistribute  it and/or modify it
  12  * under  the terms of  the GNU General  Public License as published by the
  13  * Free Software Foundation;  either version 2 of the  License, or (at your
  14  * option) any later version.
  15  */
  16
  17 /*
  18  * Almost all MIPS CPUs define 8 interrupt sources.  They are typically
  19  * level triggered (i.e., cannot be cleared from CPU; must be cleared from
  20  * device).  The first two are software interrupts which we don't really
  21  * use or support.  The last one is usually the CPU timer interrupt if
  22  * counter register is present or, for CPUs with an external FPU, by
  23  * convention it's the FPU exception interrupt.
  24  *
  25  * Don't even think about using this on SMP.  You have been warned.
  26  *
  27  * This file exports one global function:
  28  *      void mips_cpu_irq_init(void);
  29  */
  30 #include <linux/init.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/kernel.h>
  33
  34 #include <asm/irq_cpu.h>
  35 #include <asm/mipsregs.h>
  36 #include <asm/mipsmtregs.h>
  37 #include <asm/system.h>
  38
  39 static inline void unmask_mips_irq(unsigned int irq)
  40 {
  41         set_c0_status(0x100 << (irq - MIPS_CPU_IRQ_BASE));
  42         irq_enable_hazard();
  43 }
  44
  45 static inline void mask_mips_irq(unsigned int irq)
  46 {
  47         clear_c0_status(0x100 << (irq - MIPS_CPU_IRQ_BASE));
  48         irq_disable_hazard();
  49 }
  50
  51 static struct irq_chip mips_cpu_irq_controller = {
  52         .name           = "MIPS",
  53         .ack            = mask_mips_irq,
  54         .mask           = mask_mips_irq,
  55         .mask_ack       = mask_mips_irq,
  56         .unmask         = unmask_mips_irq,
  57         .eoi            = unmask_mips_irq,
  58 };
  59
  60 /*
  61  * Basically the same as above but taking care of all the MT stuff
  62  */
  63
  64 #define unmask_mips_mt_irq      unmask_mips_irq
  65 #define mask_mips_mt_irq        mask_mips_irq
  66
  67 static unsigned int mips_mt_cpu_irq_startup(unsigned int irq)
  68 {
  69         unsigned int vpflags = dvpe();
  70
  71         clear_c0_cause(0x100 << (irq - MIPS_CPU_IRQ_BASE));
  72         evpe(vpflags);
  73         unmask_mips_mt_irq(irq);
  74
  75         return 0;
  76 }
  77
  78 /*
  79  * While we ack the interrupt interrupts are disabled and thus we don't need
  80  * to deal with concurrency issues.  Same for mips_cpu_irq_end.
  81  */
  82 static void mips_mt_cpu_irq_ack(unsigned int irq)
  83 {
  84         unsigned int vpflags = dvpe();
  85         clear_c0_cause(0x100 << (irq - MIPS_CPU_IRQ_BASE));
  86         evpe(vpflags);
  87         mask_mips_mt_irq(irq);
  88 }
  89
  90 static struct irq_chip mips_mt_cpu_irq_controller = {
  91         .name           = "MIPS",
  92         .startup        = mips_mt_cpu_irq_startup,
  93         .ack            = mips_mt_cpu_irq_ack,
  94         .mask           = mask_mips_mt_irq,
  95         .mask_ack       = mips_mt_cpu_irq_ack,
  96         .unmask         = unmask_mips_mt_irq,
  97         .eoi            = unmask_mips_mt_irq,
  98 };
  99
 100 void __init mips_cpu_irq_init(void)
 101 {
 102         int irq_base = MIPS_CPU_IRQ_BASE;
 103         int i;
 104
 105         /* Mask interrupts. */
 106         clear_c0_status(ST0_IM);
 107         clear_c0_cause(CAUSEF_IP);
 108
 109         /*
 110          * Only MT is using the software interrupts currently, so we just
 111          * leave them uninitialized for other processors.
 112          */
 113         if (cpu_has_mipsmt)
 114                 for (i = irq_base; i < irq_base + 2; i++)
 115                         set_irq_chip_and_handler(i, &mips_mt_cpu_irq_controller,
 116                                                  handle_percpu_irq);
 117
 118         for (i = irq_base + 2; i < irq_base + 8; i++)
 119                 set_irq_chip_and_handler(i, &mips_cpu_irq_controller,
 120                                          handle_percpu_irq);
 121 }