[deliverable/linux.git] / arch / arm / kernel / smp_twd.c

/*
 *  linux/arch/arm/kernel/smp_twd.c
 *
 *  Copyright (C) 2002 ARM Ltd.
 *  All Rights Reserved
 *
 * 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/init.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/smp.h>
#include <linux/jiffies.h>
#include <linux/clockchips.h>
#include <linux/irq.h>
#include <linux/io.h>

#include <asm/smp_twd.h>
#include <asm/hardware/gic.h>

/* set up by the platform code */
void __iomem *twd_base;

static unsigned long twd_timer_rate;

static void twd_set_mode(enum clock_event_mode mode,
			struct clock_event_device *clk)
{
	unsigned long ctrl;

	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
		/* timer load already set up */
		ctrl = TWD_TIMER_CONTROL_ENABLE | TWD_TIMER_CONTROL_IT_ENABLE
			| TWD_TIMER_CONTROL_PERIODIC;
		break;
	case CLOCK_EVT_MODE_ONESHOT:
		/* period set, and timer enabled in 'next_event' hook */
		ctrl = TWD_TIMER_CONTROL_IT_ENABLE | TWD_TIMER_CONTROL_ONESHOT;
		break;
	case CLOCK_EVT_MODE_UNUSED:
	case CLOCK_EVT_MODE_SHUTDOWN:
	default:
		ctrl = 0;
	}

	__raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL);
}

static int twd_set_next_event(unsigned long evt,
			struct clock_event_device *unused)
{
	unsigned long ctrl = __raw_readl(twd_base + TWD_TIMER_CONTROL);

	ctrl |= TWD_TIMER_CONTROL_ENABLE;

	__raw_writel(evt, twd_base + TWD_TIMER_COUNTER);
	__raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL);

	return 0;
}

/*
 * local_timer_ack: checks for a local timer interrupt.
 *
 * If a local timer interrupt has occurred, acknowledge and return 1.
 * Otherwise, return 0.
 */
int twd_timer_ack(void)
{
	if (__raw_readl(twd_base + TWD_TIMER_INTSTAT)) {
		__raw_writel(1, twd_base + TWD_TIMER_INTSTAT);
		return 1;
	}

	return 0;
}

static void __cpuinit twd_calibrate_rate(void)
{
	unsigned long load, count;
	u64 waitjiffies;

	/*
	 * If this is the first time round, we need to work out how fast
	 * the timer ticks
	 */
	if (twd_timer_rate == 0) {
		printk(KERN_INFO "Calibrating local timer... ");

		/* Wait for a tick to start */
		waitjiffies = get_jiffies_64() + 1;

		while (get_jiffies_64() < waitjiffies)
			udelay(10);

		/* OK, now the tick has started, let's get the timer going */
		waitjiffies += 5;

				 /* enable, no interrupt or reload */
		__raw_writel(0x1, twd_base + TWD_TIMER_CONTROL);

				 /* maximum value */
		__raw_writel(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER);

		while (get_jiffies_64() < waitjiffies)
			udelay(10);

		count = __raw_readl(twd_base + TWD_TIMER_COUNTER);

		twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5);

		printk("%lu.%02luMHz.\n", twd_timer_rate / 1000000,
			(twd_timer_rate / 1000000) % 100);
	}

	load = twd_timer_rate / HZ;

	__raw_writel(load, twd_base + TWD_TIMER_LOAD);
}

/*
 * Setup the local clock events for a CPU.
 */
void __cpuinit twd_timer_setup(struct clock_event_device *clk)
{
	twd_calibrate_rate();

	clk->name = "local_timer";
	clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
			CLOCK_EVT_FEAT_C3STOP;
	clk->rating = 350;
	clk->set_mode = twd_set_mode;
	clk->set_next_event = twd_set_next_event;
	clk->shift = 20;
	clk->mult = div_sc(twd_timer_rate, NSEC_PER_SEC, clk->shift);
	clk->max_delta_ns = clockevent_delta2ns(0xffffffff, clk);
	clk->min_delta_ns = clockevent_delta2ns(0xf, clk);

	/* Make sure our local interrupt controller has this enabled */
	gic_enable_ppi(clk->irq);

	clockevents_register_device(clk);
}
Commit	Line	Data
f32f4ce2 RK	1	/*
	2	* linux/arch/arm/kernel/smp_twd.c
	3	*
	4	* Copyright (C) 2002 ARM Ltd.
	5	* All Rights Reserved
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*/
	11	#include <linux/init.h>
	12	#include <linux/kernel.h>
	13	#include <linux/delay.h>
	14	#include <linux/device.h>
	15	#include <linux/smp.h>
	16	#include <linux/jiffies.h>
	17	#include <linux/clockchips.h>
	18	#include <linux/irq.h>
	19	#include <linux/io.h>
	20
	21	#include <asm/smp_twd.h>
	22	#include <asm/hardware/gic.h>
	23
f32f4ce2 RK	24	/* set up by the platform code */
	25	void __iomem *twd_base;
	26
	27	static unsigned long twd_timer_rate;
	28
	29	static void twd_set_mode(enum clock_event_mode mode,
	30	struct clock_event_device *clk)
	31	{
	32	unsigned long ctrl;
	33
4c5158d4	34	switch (mode) {
f32f4ce2 RK	35	case CLOCK_EVT_MODE_PERIODIC:
	36	/* timer load already set up */
	37	ctrl = TWD_TIMER_CONTROL_ENABLE \| TWD_TIMER_CONTROL_IT_ENABLE
	38	\| TWD_TIMER_CONTROL_PERIODIC;
	39	break;
	40	case CLOCK_EVT_MODE_ONESHOT:
	41	/* period set, and timer enabled in 'next_event' hook */
	42	ctrl = TWD_TIMER_CONTROL_IT_ENABLE \| TWD_TIMER_CONTROL_ONESHOT;
	43	break;
	44	case CLOCK_EVT_MODE_UNUSED:
	45	case CLOCK_EVT_MODE_SHUTDOWN:
	46	default:
	47	ctrl = 0;
	48	}
	49
	50	__raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL);
	51	}
	52
	53	static int twd_set_next_event(unsigned long evt,
	54	struct clock_event_device *unused)
	55	{
	56	unsigned long ctrl = __raw_readl(twd_base + TWD_TIMER_CONTROL);
	57
4c5158d4 RK	58	ctrl \|= TWD_TIMER_CONTROL_ENABLE;
4c5158d4 RK	59
f32f4ce2	60	__raw_writel(evt, twd_base + TWD_TIMER_COUNTER);
4c5158d4	61	__raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL);
f32f4ce2 RK	62
	63	return 0;
	64	}
	65
	66	/*
	67	* local_timer_ack: checks for a local timer interrupt.
	68	*
	69	* If a local timer interrupt has occurred, acknowledge and return 1.
	70	* Otherwise, return 0.
	71	*/
	72	int twd_timer_ack(void)
	73	{
	74	if (__raw_readl(twd_base + TWD_TIMER_INTSTAT)) {
	75	__raw_writel(1, twd_base + TWD_TIMER_INTSTAT);
	76	return 1;
	77	}
	78
	79	return 0;
	80	}
	81
	82	static void __cpuinit twd_calibrate_rate(void)
	83	{
	84	unsigned long load, count;
	85	u64 waitjiffies;
	86
	87	/*
	88	* If this is the first time round, we need to work out how fast
	89	* the timer ticks
	90	*/
	91	if (twd_timer_rate == 0) {
4c5158d4	92	printk(KERN_INFO "Calibrating local timer... ");
f32f4ce2 RK	93
	94	/* Wait for a tick to start */
	95	waitjiffies = get_jiffies_64() + 1;
	96
	97	while (get_jiffies_64() < waitjiffies)
	98	udelay(10);
	99
	100	/* OK, now the tick has started, let's get the timer going */
	101	waitjiffies += 5;
	102
	103	/* enable, no interrupt or reload */
	104	__raw_writel(0x1, twd_base + TWD_TIMER_CONTROL);
	105
	106	/* maximum value */
	107	__raw_writel(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER);
	108
	109	while (get_jiffies_64() < waitjiffies)
	110	udelay(10);
	111
	112	count = __raw_readl(twd_base + TWD_TIMER_COUNTER);
	113
	114	twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5);
	115
	116	printk("%lu.%02luMHz.\n", twd_timer_rate / 1000000,
6426d2c2	117	(twd_timer_rate / 1000000) % 100);
f32f4ce2 RK	118	}
	119
	120	load = twd_timer_rate / HZ;
	121
	122	__raw_writel(load, twd_base + TWD_TIMER_LOAD);
	123	}
	124
	125	/*
	126	* Setup the local clock events for a CPU.
	127	*/
	128	void __cpuinit twd_timer_setup(struct clock_event_device *clk)
	129	{
f32f4ce2 RK	130	twd_calibrate_rate();
f32f4ce2 RK	131
4c5158d4	132	clk->name = "local_timer";
5388a6b2 RK	133	clk->features = CLOCK_EVT_FEAT_PERIODIC \| CLOCK_EVT_FEAT_ONESHOT \|
5388a6b2 RK	134	CLOCK_EVT_FEAT_C3STOP;
4c5158d4 RK	135	clk->rating = 350;
	136	clk->set_mode = twd_set_mode;
	137	clk->set_next_event = twd_set_next_event;
	138	clk->shift = 20;
	139	clk->mult = div_sc(twd_timer_rate, NSEC_PER_SEC, clk->shift);
	140	clk->max_delta_ns = clockevent_delta2ns(0xffffffff, clk);
	141	clk->min_delta_ns = clockevent_delta2ns(0xf, clk);
f32f4ce2 RK	142
f32f4ce2 RK	143	/* Make sure our local interrupt controller has this enabled */
ac61d143	144	gic_enable_ppi(clk->irq);
f32f4ce2 RK	145
	146	clockevents_register_device(clk);
	147	}