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r: 18642
b: refs/heads/master
c: aa01666
h: refs/heads/master
v: v3
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Paul Mundt authored and Linus Torvalds committed Jan 17, 2006
1 parent 7e8e659 commit 8f34941
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2 changes: 1 addition & 1 deletion [refs]
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---
refs/heads/master: 36ddf31b689a8c11d424e43565d2aa440b77bbf4
refs/heads/master: aa01666df35cd769c0957d4b3ae6ee99d680ab88
8 changes: 8 additions & 0 deletions trunk/arch/sh/kernel/timers/Makefile
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#
# Makefile for the various Linux/SuperH timers
#

obj-y := timer.o

obj-$(CONFIG_SH_TMU) += timer-tmu.o

229 changes: 229 additions & 0 deletions trunk/arch/sh/kernel/timers/timer-tmu.c
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/*
* arch/sh/kernel/timers/timer-tmu.c - TMU Timer Support
*
* Copyright (C) 2005 Paul Mundt
*
* TMU handling code hacked out of arch/sh/kernel/time.c
*
* Copyright (C) 1999 Tetsuya Okada & Niibe Yutaka
* Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
* Copyright (C) 2002, 2003, 2004 Paul Mundt
* Copyright (C) 2002 M. R. Brown <mrbrown@linux-sh.org>
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/seqlock.h>
#include <asm/timer.h>
#include <asm/rtc.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/clock.h>

#define TMU_TOCR_INIT 0x00
#define TMU0_TCR_INIT 0x0020
#define TMU_TSTR_INIT 1

#define TMU0_TCR_CALIB 0x0000

static DEFINE_SPINLOCK(tmu0_lock);

static unsigned long tmu_timer_get_offset(void)
{
int count;
unsigned long flags;

static int count_p = 0x7fffffff; /* for the first call after boot */
static unsigned long jiffies_p = 0;

/*
* cache volatile jiffies temporarily; we have IRQs turned off.
*/
unsigned long jiffies_t;

spin_lock_irqsave(&tmu0_lock, flags);
/* timer count may underflow right here */
count = ctrl_inl(TMU0_TCNT); /* read the latched count */

jiffies_t = jiffies;

/*
* avoiding timer inconsistencies (they are rare, but they happen)...
* there is one kind of problem that must be avoided here:
* 1. the timer counter underflows
*/

if (jiffies_t == jiffies_p) {
if (count > count_p) {
/* the nutcase */
if (ctrl_inw(TMU0_TCR) & 0x100) { /* Check UNF bit */
count -= LATCH;
} else {
printk("%s (): hardware timer problem?\n",
__FUNCTION__);
}
}
} else
jiffies_p = jiffies_t;

count_p = count;
spin_unlock_irqrestore(&tmu0_lock, flags);

count = ((LATCH-1) - count) * TICK_SIZE;
count = (count + LATCH/2) / LATCH;

return count;
}

static irqreturn_t tmu_timer_interrupt(int irq, void *dev_id,
struct pt_regs *regs)
{
unsigned long timer_status;

/* Clear UNF bit */
timer_status = ctrl_inw(TMU0_TCR);
timer_status &= ~0x100;
ctrl_outw(timer_status, TMU0_TCR);

/*
* Here we are in the timer irq handler. We just have irqs locally
* disabled but we don't know if the timer_bh is running on the other
* CPU. We need to avoid to SMP race with it. NOTE: we don' t need
* the irq version of write_lock because as just said we have irq
* locally disabled. -arca
*/
write_seqlock(&xtime_lock);
handle_timer_tick(regs);
write_sequnlock(&xtime_lock);

return IRQ_HANDLED;
}

static struct irqaction tmu_irq = {
.name = "timer",
.handler = tmu_timer_interrupt,
.flags = SA_INTERRUPT,
.mask = CPU_MASK_NONE,
};

/*
* Hah! We'll see if this works (switching from usecs to nsecs).
*/
static unsigned long tmu_timer_get_frequency(void)
{
u32 freq;
struct timespec ts1, ts2;
unsigned long diff_nsec;
unsigned long factor;

/* Setup the timer: We don't want to generate interrupts, just
* have it count down at its natural rate.
*/
ctrl_outb(0, TMU_TSTR);
#if !defined(CONFIG_CPU_SUBTYPE_SH7300) && !defined(CONFIG_CPU_SUBTYPE_SH7760)
ctrl_outb(TMU_TOCR_INIT, TMU_TOCR);
#endif
ctrl_outw(TMU0_TCR_CALIB, TMU0_TCR);
ctrl_outl(0xffffffff, TMU0_TCOR);
ctrl_outl(0xffffffff, TMU0_TCNT);

rtc_get_time(&ts2);

do {
rtc_get_time(&ts1);
} while (ts1.tv_nsec == ts2.tv_nsec && ts1.tv_sec == ts2.tv_sec);

/* actually start the timer */
ctrl_outb(TMU_TSTR_INIT, TMU_TSTR);

do {
rtc_get_time(&ts2);
} while (ts1.tv_nsec == ts2.tv_nsec && ts1.tv_sec == ts2.tv_sec);

freq = 0xffffffff - ctrl_inl(TMU0_TCNT);
if (ts2.tv_nsec < ts1.tv_nsec) {
ts2.tv_nsec += 1000000000;
ts2.tv_sec--;
}

diff_nsec = (ts2.tv_sec - ts1.tv_sec) * 1000000000 + (ts2.tv_nsec - ts1.tv_nsec);

/* this should work well if the RTC has a precision of n Hz, where
* n is an integer. I don't think we have to worry about the other
* cases. */
factor = (1000000000 + diff_nsec/2) / diff_nsec;

if (factor * diff_nsec > 1100000000 ||
factor * diff_nsec < 900000000)
panic("weird RTC (diff_nsec %ld)", diff_nsec);

return freq * factor;
}

static void tmu_clk_init(struct clk *clk)
{
u8 divisor = TMU0_TCR_INIT & 0x7;
ctrl_outw(TMU0_TCR_INIT, TMU0_TCR);
clk->rate = clk->parent->rate / (4 << (divisor << 1));
}

static void tmu_clk_recalc(struct clk *clk)
{
u8 divisor = ctrl_inw(TMU0_TCR) & 0x7;
clk->rate = clk->parent->rate / (4 << (divisor << 1));
}

static struct clk_ops tmu_clk_ops = {
.init = tmu_clk_init,
.recalc = tmu_clk_recalc,
};

static struct clk tmu0_clk = {
.name = "tmu0_clk",
.ops = &tmu_clk_ops,
};

static int tmu_timer_init(void)
{
unsigned long interval;

setup_irq(TIMER_IRQ, &tmu_irq);

tmu0_clk.parent = clk_get("module_clk");

/* Start TMU0 */
ctrl_outb(0, TMU_TSTR);
#if !defined(CONFIG_CPU_SUBTYPE_SH7300) && !defined(CONFIG_CPU_SUBTYPE_SH7760)
ctrl_outb(TMU_TOCR_INIT, TMU_TOCR);
#endif

clk_register(&tmu0_clk);
clk_enable(&tmu0_clk);

interval = (clk_get_rate(&tmu0_clk) + HZ / 2) / HZ;
printk(KERN_INFO "Interval = %ld\n", interval);

ctrl_outl(interval, TMU0_TCOR);
ctrl_outl(interval, TMU0_TCNT);

ctrl_outb(TMU_TSTR_INIT, TMU_TSTR);

return 0;
}

struct sys_timer_ops tmu_timer_ops = {
.init = tmu_timer_init,
.get_frequency = tmu_timer_get_frequency,
.get_offset = tmu_timer_get_offset,
};

struct sys_timer tmu_timer = {
.name = "tmu",
.ops = &tmu_timer_ops,
};

50 changes: 50 additions & 0 deletions trunk/arch/sh/kernel/timers/timer.c
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/*
* arch/sh/kernel/timers/timer.c - Common timer code
*
* Copyright (C) 2005 Paul Mundt
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <asm/timer.h>

static struct sys_timer *sys_timers[] __initdata = {
#ifdef CONFIG_SH_TMU
&tmu_timer,
#endif
NULL,
};

static char timer_override[10] __initdata;
static int __init timer_setup(char *str)
{
if (str)
strlcpy(timer_override, str, sizeof(timer_override));
return 1;
}
__setup("timer=", timer_setup);

struct sys_timer *get_sys_timer(void)
{
int i;

for (i = 0; i < ARRAY_SIZE(sys_timers); i++) {
struct sys_timer *t = sys_timers[i];

if (unlikely(!t))
break;
if (unlikely(timer_override[0]))
if ((strcmp(timer_override, t->name) != 0))
continue;
if (likely(t->ops->init() == 0))
return t;
}

return NULL;
}

42 changes: 42 additions & 0 deletions trunk/include/asm-sh/timer.h
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#ifndef __ASM_SH_TIMER_H
#define __ASM_SH_TIMER_H

#include <linux/sysdev.h>
#include <asm/cpu/timer.h>

struct sys_timer_ops {
int (*init)(void);
unsigned long (*get_offset)(void);
unsigned long (*get_frequency)(void);
};

struct sys_timer {
const char *name;

struct sys_device dev;
struct sys_timer_ops *ops;
};

#define TICK_SIZE (tick_nsec / 1000)

extern struct sys_timer tmu_timer;
extern struct sys_timer *sys_timer;

static inline unsigned long get_timer_offset(void)
{
return sys_timer->ops->get_offset();
}

static inline unsigned long get_timer_frequency(void)
{
return sys_timer->ops->get_frequency();
}

/* arch/sh/kernel/timers/timer.c */
struct sys_timer *get_sys_timer(void);

/* arch/sh/kernel/time.c */
void handle_timer_tick(struct pt_regs *);

#endif /* __ASM_SH_TIMER_H */

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