interrupts.c

/*
 * (C) Copyright 2000-2002
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * 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
 */

#include <common.h>
#include <watchdog.h>
#include <mpc8xx.h>
#include <mpc8xx_irq.h>
#include <asm/processor.h>
#include <commproc.h>

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

unsigned decrementer_count;		/* count value for 1e6/HZ microseconds */

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

/*
 * CPM interrupt vector functions.
 */
struct	cpm_action {
	 interrupt_handler_t *handler;
	 void *arg;
};

static struct cpm_action cpm_vecs[CPMVEC_NR];

static void cpm_interrupt_init (void);
static void cpm_interrupt(int irq, struct pt_regs * regs);

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

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);
}

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

int interrupt_init(void)
{
	volatile immap_t *immr = (immap_t *)CFG_IMMR;

	decrementer_count = get_tbclk() / CFG_HZ;

	cpm_interrupt_init();

	/* disable all interrupts except for the CPM interrupt */
	immr->im_siu_conf.sc_simask = 1 << (31-CPM_INTERRUPT);

	set_dec (decrementer_count);

	set_msr (get_msr() | MSR_EE);

	return (0);
}

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

/*
 * Handle external interrupts
 */
void external_interrupt(struct pt_regs *regs)
{
	volatile immap_t *immr = (immap_t *)CFG_IMMR;
	int	irq;
	ulong	simask, newmask;
	ulong	vec, v_bit;

	/*
	 * read the SIVEC register and shift the bits down
	 * to get the irq number
	 */
	vec = immr->im_siu_conf.sc_sivec;
	irq = vec >> 26;
	v_bit = 0x80000000UL >> irq;

	/*
	 * Read Interrupt Mask Register and Mask Interrupts
	 */
	simask = immr->im_siu_conf.sc_simask;
	newmask = simask & (~(0xFFFF0000 >> irq));
	immr->im_siu_conf.sc_simask = newmask;

	if (!(irq & 0x1)) {			/* External Interrupt ?		*/
		ulong siel;
		/*
		 * Read Interrupt Edge/Level Register
		 */
		siel = immr->im_siu_conf.sc_siel;

		if (siel & v_bit) {		/* edge triggered interrupt ?	*/
			/*
			 * Rewrite SIPEND Register to clear interrupt
			 */
			immr->im_siu_conf.sc_sipend = v_bit;
		}
	}

	switch (irq) {
	case CPM_INTERRUPT:
		cpm_interrupt (irq, regs);
		break;
	default:
		printf ("\nBogus External Interrupt IRQ %d Vector %ld\n",
			irq, vec);
		/* turn off the bogus interrupt to avoid it from now */
		simask &= ~v_bit;
		break;
	}

	/*
	 * Re-Enable old Interrupt Mask
	 */
	immr->im_siu_conf.sc_simask = simask;
}

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

/*
 * CPM interrupt handler
 */
static void
cpm_interrupt(int irq, struct pt_regs * regs)
{
	volatile immap_t *immr = (immap_t *)CFG_IMMR;
	uint	vec;

	/*
	 * Get the vector by setting the ACK bit
	 * and then reading the register.
	 */
	immr->im_cpic.cpic_civr = 1;
	vec = immr->im_cpic.cpic_civr;
	vec >>= 11;

	if (cpm_vecs[vec].handler != NULL) {
		(*cpm_vecs[vec].handler)(cpm_vecs[vec].arg);
	} else {
		immr->im_cpic.cpic_cimr &= ~(1 << vec);
		printf ("Masking bogus CPM interrupt vector 0x%x\n", vec);
	}
	/*
	 * After servicing the interrupt, we have to remove the status indicator.
	 */
	immr->im_cpic.cpic_cisr |= (1 << vec);
}

/*
 * The CPM can generate the error interrupt when there is a race
 * condition between generating and masking interrupts. All we have
 * to do is ACK it and return. This is a no-op function so we don't
 * need any special tests in the interrupt handler.
 */
static void
cpm_error_interrupt (void *dummy)
{
}

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

/*
 * Install and free a CPM interrupt handler.
 */

void
irq_install_handler(int vec, interrupt_handler_t *handler, void *arg)
{
	volatile immap_t *immr = (immap_t *)CFG_IMMR;

	if (cpm_vecs[vec].handler != NULL) {
		printf ("CPM interrupt 0x%x replacing 0x%x\n",
			(uint)handler, (uint)cpm_vecs[vec].handler);
	}
	cpm_vecs[vec].handler = handler;
	cpm_vecs[vec].arg     = arg;
	immr->im_cpic.cpic_cimr |= (1 << vec);
#if 0
	printf ("Install CPM interrupt for vector %d ==> %p\n", vec, handler);
#endif
}

void
irq_free_handler(int vec)
{
	volatile immap_t *immr = (immap_t *)CFG_IMMR;
#if 0
	printf ("Free CPM interrupt for vector %d ==> %p\n",
		vec, cpm_vecs[vec].handler);
#endif
	immr->im_cpic.cpic_cimr &= ~(1 << vec);
	cpm_vecs[vec].handler = NULL;
	cpm_vecs[vec].arg     = NULL;
}

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

static void
cpm_interrupt_init (void)
{
	volatile immap_t *immr = (immap_t *)CFG_IMMR;

	/*
	 * Initialize the CPM interrupt controller.
	 */

	immr->im_cpic.cpic_cicr =
		( CICR_SCD_SCC4 |
		  CICR_SCC_SCC3 |
		  CICR_SCB_SCC2 |
		  CICR_SCA_SCC1 ) | ((CPM_INTERRUPT/2) << 13) | CICR_HP_MASK;

	immr->im_cpic.cpic_cimr = 0;

	/*
	 * Install the error handler.
	 */
	irq_install_handler(CPMVEC_ERROR, cpm_error_interrupt, NULL);

	immr->im_cpic.cpic_cicr |= CICR_IEN;
}

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

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)
{
	volatile immap_t *immr = (immap_t *)CFG_IMMR;
#ifdef CONFIG_STATUS_LED
    	extern void status_led_tick (ulong);
#endif
#if 0
	printf ("*** Timer Interrupt *** ");
#endif
	/* Reset Timer Expired and Timers Interrupt Status */
	immr->im_clkrstk.cark_plprcrk = KAPWR_KEY;
	__asm__("nop");
	immr->im_clkrst.car_plprcr |= PLPRCR_TEXPS | PLPRCR_TMIST;
	/* Restore Decrementer Count */
	set_dec (decrementer_count);

	timestamp++;

#ifdef CONFIG_STATUS_LED
	status_led_tick (timestamp);
#endif	/* CONFIG_STATUS_LED */

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


	/*
	 * The shortest watchdog period of all boards (except LWMON)
	 * is approx. 1 sec, thus re-trigger watchdog at least
	 * every 500 ms = CFG_HZ / 2
	 */
#ifndef CONFIG_LWMON
	if ((timestamp % (CFG_HZ / 2)) == 0) {
#else
	if ((timestamp % (CFG_HZ / 20)) == 0) {
#endif

#if defined(CFG_CMA_LCD_HEARTBEAT)
		extern void lcd_heartbeat(void);
		lcd_heartbeat();
#endif /* CFG_CMA_LCD_HEARTBEAT */

#if defined(CONFIG_WATCHDOG)
		reset_8xx_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;
}

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