[GitHub/mt8127/android_kernel_alcatel_ttab.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;
		__raw_writel(twd_timer_rate / HZ, twd_base + TWD_TIMER_LOAD);
		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 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);
	}
}

/*
 * 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;
03399c1c	39	__raw_writel(twd_timer_rate / HZ, twd_base + TWD_TIMER_LOAD);
f32f4ce2 RK	40	break;
	41	case CLOCK_EVT_MODE_ONESHOT:
	42	/* period set, and timer enabled in 'next_event' hook */
	43	ctrl = TWD_TIMER_CONTROL_IT_ENABLE \| TWD_TIMER_CONTROL_ONESHOT;
	44	break;
	45	case CLOCK_EVT_MODE_UNUSED:
	46	case CLOCK_EVT_MODE_SHUTDOWN:
	47	default:
	48	ctrl = 0;
	49	}
	50
	51	__raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL);
	52	}
	53
	54	static int twd_set_next_event(unsigned long evt,
	55	struct clock_event_device *unused)
	56	{
	57	unsigned long ctrl = __raw_readl(twd_base + TWD_TIMER_CONTROL);
	58
4c5158d4 RK	59	ctrl \|= TWD_TIMER_CONTROL_ENABLE;
4c5158d4 RK	60
f32f4ce2	61	__raw_writel(evt, twd_base + TWD_TIMER_COUNTER);
4c5158d4	62	__raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL);
f32f4ce2 RK	63
	64	return 0;
	65	}
	66
	67	/*
	68	* local_timer_ack: checks for a local timer interrupt.
	69	*
	70	* If a local timer interrupt has occurred, acknowledge and return 1.
	71	* Otherwise, return 0.
	72	*/
	73	int twd_timer_ack(void)
	74	{
	75	if (__raw_readl(twd_base + TWD_TIMER_INTSTAT)) {
	76	__raw_writel(1, twd_base + TWD_TIMER_INTSTAT);
	77	return 1;
	78	}
	79
	80	return 0;
	81	}
	82
	83	static void __cpuinit twd_calibrate_rate(void)
	84	{
03399c1c	85	unsigned long count;
f32f4ce2 RK	86	u64 waitjiffies;
	87
	88	/*
	89	* If this is the first time round, we need to work out how fast
	90	* the timer ticks
	91	*/
	92	if (twd_timer_rate == 0) {
4c5158d4	93	printk(KERN_INFO "Calibrating local timer... ");
f32f4ce2 RK	94
	95	/* Wait for a tick to start */
	96	waitjiffies = get_jiffies_64() + 1;
	97
	98	while (get_jiffies_64() < waitjiffies)
	99	udelay(10);
	100
	101	/* OK, now the tick has started, let's get the timer going */
	102	waitjiffies += 5;
	103
	104	/* enable, no interrupt or reload */
	105	__raw_writel(0x1, twd_base + TWD_TIMER_CONTROL);
	106
	107	/* maximum value */
	108	__raw_writel(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER);
	109
	110	while (get_jiffies_64() < waitjiffies)
	111	udelay(10);
	112
	113	count = __raw_readl(twd_base + TWD_TIMER_COUNTER);
	114
	115	twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5);
	116
	117	printk("%lu.%02luMHz.\n", twd_timer_rate / 1000000,
6426d2c2	118	(twd_timer_rate / 1000000) % 100);
f32f4ce2	119	}
f32f4ce2 RK	120	}
	121
	122	/*
	123	* Setup the local clock events for a CPU.
	124	*/
	125	void __cpuinit twd_timer_setup(struct clock_event_device *clk)
	126	{
f32f4ce2 RK	127	twd_calibrate_rate();
f32f4ce2 RK	128
4c5158d4	129	clk->name = "local_timer";
5388a6b2 RK	130	clk->features = CLOCK_EVT_FEAT_PERIODIC \| CLOCK_EVT_FEAT_ONESHOT \|
5388a6b2 RK	131	CLOCK_EVT_FEAT_C3STOP;
4c5158d4 RK	132	clk->rating = 350;
	133	clk->set_mode = twd_set_mode;
	134	clk->set_next_event = twd_set_next_event;
	135	clk->shift = 20;
	136	clk->mult = div_sc(twd_timer_rate, NSEC_PER_SEC, clk->shift);
	137	clk->max_delta_ns = clockevent_delta2ns(0xffffffff, clk);
	138	clk->min_delta_ns = clockevent_delta2ns(0xf, clk);
f32f4ce2 RK	139
f32f4ce2 RK	140	/* Make sure our local interrupt controller has this enabled */
ac61d143	141	gic_enable_ppi(clk->irq);
f32f4ce2 RK	142
	143	clockevents_register_device(clk);
	144	}