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/***************************************************************************/
/*
* timers.c -- generic ColdFire hardware timer support.
*
* Copyright (C) 1999-2008, Greg Ungerer <gerg@snapgear.com>
*/
/***************************************************************************/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/profile.h>
#include <linux/clocksource.h>
#include <asm/io.h>
#include <asm/traps.h>
#include <asm/machdep.h>
#include <asm/coldfire.h>
#include <asm/mcftimer.h>
#include <asm/mcfsim.h>
/***************************************************************************/
/*
* By default use timer1 as the system clock timer.
*/
#define FREQ (MCF_BUSCLK / 16)
#define TA(a) (MCFTIMER_BASE1 + (a))
/*
* These provide the underlying interrupt vector support.
* Unfortunately it is a little different on each ColdFire.
*/
void coldfire_profile_init(void);
#if defined(CONFIG_M532x)
#define __raw_readtrr __raw_readl
#define __raw_writetrr __raw_writel
#else
#define __raw_readtrr __raw_readw
#define __raw_writetrr __raw_writew
#endif
static u32 mcftmr_cycles_per_jiffy;
static u32 mcftmr_cnt;
/***************************************************************************/
static irqreturn_t mcftmr_tick(int irq, void *dummy)
{
/* Reset the ColdFire timer */
__raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, TA(MCFTIMER_TER));
mcftmr_cnt += mcftmr_cycles_per_jiffy;
return arch_timer_interrupt(irq, dummy);
}
/***************************************************************************/
static struct irqaction mcftmr_timer_irq = {
.name = "timer",
.flags = IRQF_DISABLED | IRQF_TIMER,
.handler = mcftmr_tick,
};
/***************************************************************************/
static cycle_t mcftmr_read_clk(struct clocksource *cs)
{
unsigned long flags;
u32 cycles;
u16 tcn;
local_irq_save(flags);
tcn = __raw_readw(TA(MCFTIMER_TCN));
cycles = mcftmr_cnt;
local_irq_restore(flags);
return cycles + tcn;
}
/***************************************************************************/
static struct clocksource mcftmr_clk = {
.name = "tmr",
.rating = 250,
.read = mcftmr_read_clk,
.shift = 20,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
/***************************************************************************/
void hw_timer_init(void)
{
__raw_writew(MCFTIMER_TMR_DISABLE, TA(MCFTIMER_TMR));
mcftmr_cycles_per_jiffy = FREQ / HZ;
/*
* The coldfire timer runs from 0 to TRR included, then 0
* again and so on. It counts thus actually TRR + 1 steps
* for 1 tick, not TRR. So if you want n cycles,
* initialize TRR with n - 1.
*/
__raw_writetrr(mcftmr_cycles_per_jiffy - 1, TA(MCFTIMER_TRR));
__raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, TA(MCFTIMER_TMR));
mcftmr_clk.mult = clocksource_hz2mult(FREQ, mcftmr_clk.shift);
clocksource_register(&mcftmr_clk);
setup_irq(MCF_IRQ_TIMER, &mcftmr_timer_irq);
#ifdef CONFIG_HIGHPROFILE
coldfire_profile_init();
#endif
}
/***************************************************************************/
#ifdef CONFIG_HIGHPROFILE
/***************************************************************************/
/*
* By default use timer2 as the profiler clock timer.
*/
#define PA(a) (MCFTIMER_BASE2 + (a))
/*
* Choose a reasonably fast profile timer. Make it an odd value to
* try and get good coverage of kernel operations.
*/
#define PROFILEHZ 1013
/*
* Use the other timer to provide high accuracy profiling info.
*/
irqreturn_t coldfire_profile_tick(int irq, void *dummy)
{
/* Reset ColdFire timer2 */
__raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, PA(MCFTIMER_TER));
if (current->pid)
profile_tick(CPU_PROFILING);
return IRQ_HANDLED;
}
/***************************************************************************/
static struct irqaction coldfire_profile_irq = {
.name = "profile timer",
.flags = IRQF_DISABLED | IRQF_TIMER,
.handler = coldfire_profile_tick,
};
void coldfire_profile_init(void)
{
printk(KERN_INFO "PROFILE: lodging TIMER2 @ %dHz as profile timer\n",
PROFILEHZ);
/* Set up TIMER 2 as high speed profile clock */
__raw_writew(MCFTIMER_TMR_DISABLE, PA(MCFTIMER_TMR));
__raw_writetrr(((MCF_BUSCLK / 16) / PROFILEHZ), PA(MCFTIMER_TRR));
__raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 |
MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, PA(MCFTIMER_TMR));
setup_irq(MCF_IRQ_PROFILER, &coldfire_profile_irq);
}
/***************************************************************************/
#endif /* CONFIG_HIGHPROFILE */
/***************************************************************************/
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