interrupts.c

嵌入式ARM的一些源代码

/*
 * (C) Copyright 2000
 * Wolfgang Denk, DENX Software Engineering, [e-mail].
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 *
 * Hacked for MPC8260 by [e-mail], 22-Oct-00
 */

#include <ppcboot.h>
#include <command.h>
#include <mpc8260.h>
#include <mpc8260_irq.h>
#include <asm/processor.h>

/****************************************************************************/

#define	DECREMENTER_TICK	1000	/* 1 ms tick */
unsigned decrementer_count;		/* count val for 1e6/HZ microseconds */

struct irq_action {
    interrupt_handler_t *handler;
    void *arg;
    ulong count;
};

static struct irq_action irq_handlers[NR_IRQS];

static ulong ppc_cached_irq_mask[NR_MASK_WORDS];

/****************************************************************************/
/* this section was ripped out of arch/ppc/kernel/ppc8260_pic.c in the	    */
/* Linux/PPC 2.4.x source. There was no copyright notice in that file.	    */

/* The 8260 internal interrupt controller.  It is usually
 * the only interrupt controller.
 * There are two 32-bit registers (high/low) for up to 64
 * possible interrupts.
 *
 * Now, the fun starts.....Interrupt Numbers DO NOT MAP
 * in a simple arithmetic fashion to mask or pending registers.
 * That is, interrupt 4 does not map to bit position 4.
 * We create two tables, indexed by vector number, to indicate
 * which register to use and which bit in the register to use.
 */
static	u_char	irq_to_siureg[] = {
	1, 1, 1, 1, 1, 1, 1, 1,
	1, 1, 1, 1, 1, 1, 1, 1,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0,
	1, 1, 1, 1, 1, 1, 1, 1,
	1, 1, 1, 1, 1, 1, 1, 1,
	0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0
};

static	u_char	irq_to_siubit[] = {
	31, 16, 17, 18, 19, 20, 21, 22,
	23, 24, 25, 26, 27, 28, 29, 30,
	29, 30, 16, 17, 18, 19, 20, 21,
	22, 23, 24, 25, 26, 27, 28, 31,
	 0,  1,  2,  3,  4,  5,  6,  7,
	 8,  9, 10, 11, 12, 13, 14, 15,
	15, 14, 13, 12, 11, 10,  9,  8,
	 7,  6,  5,  4,  3,  2,  1,  0
};

static void
m8260_mask_irq(unsigned int irq_nr)
{
    volatile immap_t *immr = (immap_t *)CFG_IMMR;
    int	bit, word;
    volatile uint *simr;

    bit = irq_to_siubit[irq_nr];
    word = irq_to_siureg[irq_nr];

    simr = &(immr->im_intctl.ic_simrh);
    ppc_cached_irq_mask[word] &= ~(1 << (31 - bit));
    simr[word] = ppc_cached_irq_mask[word];
}

static void
m8260_unmask_irq(unsigned int irq_nr)
{
    volatile immap_t *immr = (immap_t *)CFG_IMMR;
    int bit, word;
    volatile uint *simr;

    bit = irq_to_siubit[irq_nr];
    word = irq_to_siureg[irq_nr];

    simr = &(immr->im_intctl.ic_simrh);
    ppc_cached_irq_mask[word] |= (1 << (31 - bit));
    simr[word] = ppc_cached_irq_mask[word];
}

static void
m8260_mask_and_ack(unsigned int irq_nr)
{
    volatile immap_t *immr = (immap_t *)CFG_IMMR;
    int bit, word;
    volatile uint *simr, *sipnr;

    bit = irq_to_siubit[irq_nr];
    word = irq_to_siureg[irq_nr];

    simr = &(immr->im_intctl.ic_simrh);
    sipnr = &(immr->im_intctl.ic_sipnrh);
    ppc_cached_irq_mask[word] &= ~(1 << (31 - bit));
    simr[word] = ppc_cached_irq_mask[word];
    sipnr[word] = 1 << (31 - bit);
}

static int
m8260_get_irq(struct pt_regs *regs)
{
    volatile immap_t *immr = (immap_t *)CFG_IMMR;
    int irq;
    unsigned long bits;

    /* For MPC8260, read the SIVEC register and shift the bits down
     * to get the irq number.         */
    bits = immr->im_intctl.ic_sivec;
    irq = bits >> 26;
    return irq;
}

/* end of code ripped out of arch/ppc/kernel/ppc8260_pic.c		    */
/****************************************************************************/

static __inline__ unsigned long
get_msr(void)
{
    unsigned long msr;

    __asm__ __volatile__ ("mfmsr %0" : "=r" (msr) : );
    return msr;
}

static __inline__ void
set_msr(unsigned long msr)
{
    __asm__ __volatile__ ("mtmsr %0" : : "r" (msr)); 
}

static __inline__ unsigned long
get_dec(void)
{
    unsigned long val;

    __asm__ __volatile__ ("mfdec %0" : "=r" (val) : );
    return val;
}

static __inline__ void
set_dec(unsigned long val)
{
    __asm__ __volatile__ ("mtdec %0" : : "r" (val)); 
}

void
enable_interrupts(void)
{
    set_msr(get_msr() | MSR_EE);
}

/* returns flag if MSR_EE was set before */
int
disable_interrupts(void)
{
    ulong msr = get_msr();

    set_msr(msr & ~MSR_EE);
    return ((msr & MSR_EE) != 0);
}

/****************************************************************************/

void
interrupt_init(bd_t *bd)
{
    volatile immap_t *immr = (immap_t *)CFG_IMMR;
    ulong freq;

#if defined(CFG_CLKS_IN_HZ)
    freq = bd->bi_intfreq / 4;
#else
    freq = (bd->bi_intfreq * 1000000) / 4;
#endif
    decrementer_count = freq / DECREMENTER_TICK;

    /* Initialize the default interrupt mapping priorities */
    immr->im_intctl.ic_sicr = 0;
    immr->im_intctl.ic_siprr = 0x05309770;
    immr->im_intctl.ic_scprrh = 0x05309770;
    immr->im_intctl.ic_scprrl = 0x05309770;

    /* disable all interrupts and clear all pending bits */
    immr->im_intctl.ic_simrh = ppc_cached_irq_mask[0] = 0;
    immr->im_intctl.ic_simrl = ppc_cached_irq_mask[1] = 0;
    immr->im_intctl.ic_sipnrh = 0xffffffff;
    immr->im_intctl.ic_sipnrl = 0xffffffff;

    set_dec (decrementer_count);

    set_msr (get_msr() | MSR_EE);
}

/****************************************************************************/

/*
 * Handle external interrupts
 */
void
external_interrupt(struct pt_regs *regs)
{
    int	irq, unmask = 1;

    irq = m8260_get_irq(regs);

    m8260_mask_and_ack(irq);

    set_msr (get_msr() | MSR_EE);

    if (irq_handlers[irq].handler != NULL)
	(*irq_handlers[irq].handler)(irq_handlers[irq].arg);
    else {
	printf ("\nBogus External Interrupt IRQ %d\n", irq);
	/*
	 * turn off the bogus interrupt, otherwise it
	 * might repeat forever
	 */
	unmask = 0;
    }

    if (unmask) m8260_unmask_irq(irq);
}

/****************************************************************************/

/*
 * Install and free an interrupt handler.
 */

void
irq_install_handler(int irq, interrupt_handler_t *handler, void *arg)
{
    if (irq < 0 || irq >= NR_IRQS) {
	printf("irq_install_handler: bad irq number %d\n", irq);
	return;
    }

    if (irq_handlers[irq].handler != NULL)
	printf("irq_install_handler: 0x%08lx replacing 0x%08lx\n",
	    (ulong)handler, (ulong)irq_handlers[irq].handler);

    irq_handlers[irq].handler = handler;
    irq_handlers[irq].arg     = arg;

    m8260_unmask_irq(irq);
}

void
irq_free_handler(int irq)
{
    if (irq < 0 || irq >= NR_IRQS) {
	printf("irq_free_handler: bad irq number %d\n", irq);
	return;
    }

    m8260_mask_irq(irq);

    irq_handlers[irq].handler = NULL;
    irq_handlers[irq].arg     = NULL;
}

/****************************************************************************/

volatile ulong timestamp = 0;

/*
 * timer_interrupt - gets called when the decrementer overflows,
 * with interrupts disabled.
 * Trivial implementation - no need to be really accurate.
 */
void
timer_interrupt(struct pt_regs *regs)
{
#if defined(CONFIG_WATCHDOG)
    volatile immap_t *immr = (immap_t *)CFG_IMMR;
#endif /* CONFIG_WATCHDOG */

    /* Restore Decrementer Count */
    set_dec (decrementer_count);

    timestamp++;

#if defined(CONFIG_WATCHDOG) || defined(CFG_CMA_LCD_HEARTBEAT)

    if ((timestamp % 1000) == 0) {
#if defined(CFG_CMA_LCD_HEARTBEAT)
	extern void lcd_heartbeat(void);

	lcd_heartbeat();
#endif /* CFG_CMA_LCD_HEARTBEAT */

#if defined(CONFIG_WATCHDOG)
	reset_8260_watchdog(immr);
#endif /* CONFIG_WATCHDOG */
    }

#endif /* CONFIG_WATCHDOG || CFG_CMA_LCD_HEARTBEAT */
}

/****************************************************************************/

void
reset_timer(void)
{
    timestamp = 0;
}

ulong
get_timer(ulong base)
{
    return (timestamp - base);
}

void
set_timer(ulong t)
{
    timestamp = t;
}

/****************************************************************************/

#if (CONFIG_COMMANDS & CFG_CMD_IRQ)

/* ripped this out of ppc4xx/interrupts.c */

/*******************************************************************************
*
* irqinfo - print information about PCI devices
*
*/
void
do_irqinfo(cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char *argv[])
{
    int irq, re_enable;

    re_enable = disable_interrupts();

    printf("\nInterrupt-Information:\n");
    printf("  Nr  Routine   Arg       Count\n");

    for (irq = 0; irq < 32; irq++)
	if (irq_handlers[irq].handler != NULL)
	    printf("  %02d  %08lx  %08lx  %ld\n", irq,
		(ulong)irq_handlers[irq].handler,
		(ulong)irq_handlers[irq].arg,
		irq_handlers[irq].count);

    if (re_enable) enable_interrupts();
}

#endif  /* CONFIG_COMMANDS & CFG_CMD_IRQ */