irq.c

来自「优龙2410linux2.6.8内核源代码」· C语言 代码 · 共 220 行

/* $Id: irq.c,v 1.1 2002/12/11 15:42:02 starvik Exp $
 *
 *	linux/arch/cris/kernel/irq.c
 *
 *      Copyright (c) 2000-2002 Axis Communications AB
 *
 *      Authors: Bjorn Wesen ([e-mail])
 *
 *      This file contains the interrupt vectors and some 
 *      helper functions
 *
 */

#include <asm/irq.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/config.h>

irqvectptr irq_shortcuts[NR_IRQS]; /* vector of shortcut jumps after the irq prologue */

/* don't use set_int_vector, it bypasses the linux interrupt handlers. it is
 * global just so that the kernel gdb can use it.
 */

void
set_int_vector(int n, irqvectptr addr, irqvectptr saddr)
{
	/* remember the shortcut entry point, after the prologue */

	irq_shortcuts[n] = saddr;

	etrax_irv->v[n + 0x20] = (irqvectptr)addr;
}

/* the breakpoint vector is obviously not made just like the normal irq handlers
 * but needs to contain _code_ to jump to addr.
 *
 * the BREAK n instruction jumps to IBR + n * 8
 */

void
set_break_vector(int n, irqvectptr addr)
{
	unsigned short *jinstr = (unsigned short *)&etrax_irv->v[n*2];
	unsigned long *jaddr = (unsigned long *)(jinstr + 1);

	/* if you don't know what this does, do not touch it! */
	
	*jinstr = 0x0d3f;
	*jaddr = (unsigned long)addr;

	/* 00000026 <clrlop+1a> 3f0d82000000     jump  0x82 */
}

/*
 * This builds up the IRQ handler stubs using some ugly macros in irq.h
 *
 * These macros create the low-level assembly IRQ routines that do all
 * the operations that are needed. They are also written to be fast - and to
 * disable interrupts as little as humanly possible.
 *
 */

/* IRQ0 and 1 are special traps */
void hwbreakpoint(void);
void IRQ1_interrupt(void);
BUILD_TIMER_IRQ(2, 0x04)       /* the timer interrupt is somewhat special */
BUILD_IRQ(3, 0x08)
BUILD_IRQ(4, 0x10)
BUILD_IRQ(5, 0x20)
BUILD_IRQ(6, 0x40)
BUILD_IRQ(7, 0x80)
BUILD_IRQ(8, 0x100)
BUILD_IRQ(9, 0x200)
BUILD_IRQ(10, 0x400)
BUILD_IRQ(11, 0x800)
BUILD_IRQ(12, 0x1000)
BUILD_IRQ(13, 0x2000)
void mmu_bus_fault(void);      /* IRQ 14 is the bus fault interrupt */
void multiple_interrupt(void); /* IRQ 15 is the multiple IRQ interrupt */
BUILD_IRQ(16, 0x10000)
BUILD_IRQ(17, 0x20000)
BUILD_IRQ(18, 0x40000)
BUILD_IRQ(19, 0x80000)
BUILD_IRQ(20, 0x100000)
BUILD_IRQ(21, 0x200000)
BUILD_IRQ(22, 0x400000)
BUILD_IRQ(23, 0x800000)
BUILD_IRQ(24, 0x1000000)
BUILD_IRQ(25, 0x2000000)
/* IRQ 26-30 are reserved */
BUILD_IRQ(31, 0x80000000)
 
/*
 * Pointers to the low-level handlers 
 */

static void (*interrupt[NR_IRQS])(void) = {
	NULL, NULL, IRQ2_interrupt, IRQ3_interrupt,
	IRQ4_interrupt, IRQ5_interrupt, IRQ6_interrupt, IRQ7_interrupt,
	IRQ8_interrupt, IRQ9_interrupt, IRQ10_interrupt, IRQ11_interrupt,
	IRQ12_interrupt, IRQ13_interrupt, NULL, NULL,	
	IRQ16_interrupt, IRQ17_interrupt, IRQ18_interrupt, IRQ19_interrupt,	
	IRQ20_interrupt, IRQ21_interrupt, IRQ22_interrupt, IRQ23_interrupt,	
	IRQ24_interrupt, IRQ25_interrupt, NULL, NULL, NULL, NULL, NULL,
	IRQ31_interrupt
};

static void (*sinterrupt[NR_IRQS])(void) = {
	NULL, NULL, sIRQ2_interrupt, sIRQ3_interrupt,
	sIRQ4_interrupt, sIRQ5_interrupt, sIRQ6_interrupt, sIRQ7_interrupt,
	sIRQ8_interrupt, sIRQ9_interrupt, sIRQ10_interrupt, sIRQ11_interrupt,
	sIRQ12_interrupt, sIRQ13_interrupt, NULL, NULL,	
	sIRQ16_interrupt, sIRQ17_interrupt, sIRQ18_interrupt, sIRQ19_interrupt,	
	sIRQ20_interrupt, sIRQ21_interrupt, sIRQ22_interrupt, sIRQ23_interrupt,	
	sIRQ24_interrupt, sIRQ25_interrupt, NULL, NULL, NULL, NULL, NULL,
	sIRQ31_interrupt
};

static void (*bad_interrupt[NR_IRQS])(void) = {
        NULL, NULL,
	NULL, bad_IRQ3_interrupt,
	bad_IRQ4_interrupt, bad_IRQ5_interrupt,
	bad_IRQ6_interrupt, bad_IRQ7_interrupt,
	bad_IRQ8_interrupt, bad_IRQ9_interrupt,
	bad_IRQ10_interrupt, bad_IRQ11_interrupt,
	bad_IRQ12_interrupt, bad_IRQ13_interrupt,
	NULL, NULL,
	bad_IRQ16_interrupt, bad_IRQ17_interrupt,
	bad_IRQ18_interrupt, bad_IRQ19_interrupt,
	bad_IRQ20_interrupt, bad_IRQ21_interrupt,
	bad_IRQ22_interrupt, bad_IRQ23_interrupt,
	bad_IRQ24_interrupt, bad_IRQ25_interrupt,
	NULL, NULL, NULL, NULL, NULL,
	bad_IRQ31_interrupt
};

void arch_setup_irq(int irq)
{
  set_int_vector(irq, interrupt[irq], sinterrupt[irq]);
}

void arch_free_irq(int irq)
{
  set_int_vector(irq, bad_interrupt[irq], 0);
}

void weird_irq(void);
void system_call(void);  /* from entry.S */
void do_sigtrap(void); /* from entry.S */
void gdb_handle_breakpoint(void); /* from entry.S */

/* init_IRQ() is called by start_kernel and is responsible for fixing IRQ masks and
   setting the irq vector table to point to bad_interrupt ptrs.
*/

void __init
init_IRQ(void)
{
	int i;

	/* clear all interrupt masks */

#ifndef CONFIG_SVINTO_SIM
	*R_IRQ_MASK0_CLR = 0xffffffff;
	*R_IRQ_MASK1_CLR = 0xffffffff;
	*R_IRQ_MASK2_CLR = 0xffffffff;
#endif

	*R_VECT_MASK_CLR = 0xffffffff;

	/* clear the shortcut entry points */

	for(i = 0; i < NR_IRQS; i++)
		irq_shortcuts[i] = NULL;
        
        for (i = 0; i < 256; i++)
               etrax_irv->v[i] = weird_irq;

        /* the entries in the break vector contain actual code to be
           executed by the associated break handler, rather than just a jump
           address. therefore we need to setup a default breakpoint handler
           for all breakpoints */

	for (i = 0; i < 16; i++)
                set_break_vector(i, do_sigtrap);
        
	/* set all etrax irq's to the bad handlers */
	for (i = 2; i < NR_IRQS; i++)
		set_int_vector(i, bad_interrupt[i], 0);
        
	/* except IRQ 15 which is the multiple-IRQ handler on Etrax100 */

	set_int_vector(15, multiple_interrupt, 0);
	
	/* 0 and 1 which are special breakpoint/NMI traps */

	set_int_vector(0, hwbreakpoint, 0);
	set_int_vector(1, IRQ1_interrupt, 0);

	/* and irq 14 which is the mmu bus fault handler */

	set_int_vector(14, mmu_bus_fault, 0);

	/* setup the system-call trap, which is reached by BREAK 13 */

	set_break_vector(13, system_call);

        /* setup a breakpoint handler for debugging used for both user and
           kernel mode debugging  (which is why it is not inside an ifdef
           CONFIG_ETRAX_KGDB) */
        set_break_vector(8, gdb_handle_breakpoint);

#ifdef CONFIG_ETRAX_KGDB
	/* setup kgdb if its enabled, and break into the debugger */
	kgdb_init();
	breakpoint();
#endif
}