/* * linux/arch/arm/mach-iop310/time-iq80310.c * * Timer functions for IQ80310 onboard timer * * Author:  Nicolas Pitre * Copyright:   (C) 2001 MontaVista Software Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * */#include <linux/module.h>#include <linux/sched.h>#include <linux/kernel.h>#include <linux/interrupt.h>#include <linux/time.h>#include <linux/init.h>#include <linux/timex.h>#include <linux/smp.h>#include <asm/hardware.h>#include <asm/io.h>#include <asm/irq.h>#include <asm/uaccess.h>#include <asm/mach-types.h>#include <asm/mach/irq.h>static void iq80310_write_timer (u_long val){	volatile u_char *la0 = (volatile u_char *)IQ80310_TIMER_LA0;	volatile u_char *la1 = (volatile u_char *)IQ80310_TIMER_LA1;	volatile u_char *la2 = (volatile u_char *)IQ80310_TIMER_LA2;	*la0 = val;	*la1 = val >> 8;	*la2 = (val >> 16) & 0x3f;}static u_long iq80310_read_timer (void){	volatile u_char *la0 = (volatile u_char *)IQ80310_TIMER_LA0;	volatile u_char *la1 = (volatile u_char *)IQ80310_TIMER_LA1;	volatile u_char *la2 = (volatile u_char *)IQ80310_TIMER_LA2;	volatile u_char *la3 = (volatile u_char *)IQ80310_TIMER_LA3;	u_long b0, b1, b2, b3, val;	b0 = *la0; b1 = *la1; b2 = *la2; b3 = *la3;	b0 = (((b0 & 0x40) >> 1) | (b0 & 0x1f));	b1 = (((b1 & 0x40) >> 1) | (b1 & 0x1f));	b2 = (((b2 & 0x40) >> 1) | (b2 & 0x1f));	b3 = (b3 & 0x0f);	val = ((b0 << 0) | (b1 << 6) | (b2 << 12) | (b3 << 18));	return val;}/* * IRQs are disabled before entering here from do_gettimeofday(). * Note that the counter may wrap.  When it does, 'elapsed' will * be small, but we will have a pending interrupt. */static unsigned long iq80310_gettimeoffset (void){	unsigned long elapsed, usec;	unsigned int stat1, stat2;	stat1 = *(volatile u8 *)IQ80310_INT_STAT;	elapsed = iq80310_read_timer();	stat2 = *(volatile u8 *)IQ80310_INT_STAT;	/*	 * If an interrupt was pending before we read the timer,	 * we've already wrapped.  Factor this into the time.	 * If an interrupt was pending after we read the timer,	 * it may have wrapped between checking the interrupt	 * status and reading the timer.  Re-read the timer to	 * be sure its value is after the wrap.	 */	if (stat1 & 1)		elapsed += LATCH;	else if (stat2 & 1)		elapsed = LATCH + iq80310_read_timer();	/*	 * Now convert them to usec.	 */	usec = (unsigned long)(elapsed*tick)/LATCH;	return usec;}static void iq80310_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs){	volatile u_char *timer_en = (volatile u_char *)IQ80310_TIMER_EN;	/* clear timer interrupt */	*timer_en &= ~2;	*timer_en |= 2;	/*	 * AHEM..HACK	 *	 * Since the timer interrupt is cascaded through the CPLD and	 * the 80312 and the demux code calls do_IRQ, the irq count is	 * going to be atleast 2 when we get here and this will cause the	 * kernel to increment the system tick counter even if we're	 * idle. This causes it to look like there's always 100% system	 * time, which is not the case.  To get around it, we just decrement	 * the IRQ count before calling do_timer. We increment it again	 * b/c otherwise it will go negative and than bad things happen.	 *	 * -DS	 */	do_timer(regs);}extern unsigned long (*gettimeoffset)(void);static struct irqaction timer_irq = {	name:		"timer",	handler:	iq80310_timer_interrupt,};void __init time_init(void){	volatile u_char *timer_en = (volatile u_char *)IQ80310_TIMER_EN;	gettimeoffset = iq80310_gettimeoffset;	setup_irq(IRQ_IQ80310_TIMER, &timer_irq);	*timer_en = 0;	iq80310_write_timer(LATCH);	*timer_en |= 2;	*timer_en |= 1;}