402 lines
8.8 KiB
C
402 lines
8.8 KiB
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/clk.h>
|
|
#include <linux/delay.h>
|
|
#include <linux/device.h>
|
|
#include <linux/err.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/jiffies.h>
|
|
#include <linux/clockchips.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/io.h>
|
|
#include <linux/of_irq.h>
|
|
#include <linux/of_address.h>
|
|
|
|
#include <asm/smp_plat.h>
|
|
#include <asm/smp_twd.h>
|
|
#include <asm/localtimer.h>
|
|
|
|
/* set up by the platform code */
|
|
static void __iomem *twd_base;
|
|
|
|
static struct clk *twd_clk;
|
|
static unsigned long twd_timer_rate;
|
|
static DEFINE_PER_CPU(bool, percpu_setup_called);
|
|
|
|
static struct clock_event_device __percpu **twd_evt;
|
|
static int twd_ppi;
|
|
|
|
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:
|
|
ctrl = TWD_TIMER_CONTROL_ENABLE | TWD_TIMER_CONTROL_IT_ENABLE
|
|
| TWD_TIMER_CONTROL_PERIODIC;
|
|
__raw_writel(DIV_ROUND_CLOSEST(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.
|
|
*/
|
|
static 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 twd_timer_stop(struct clock_event_device *clk)
|
|
{
|
|
twd_set_mode(CLOCK_EVT_MODE_UNUSED, clk);
|
|
disable_percpu_irq(clk->irq);
|
|
}
|
|
|
|
#ifdef CONFIG_COMMON_CLK
|
|
|
|
/*
|
|
* Updates clockevent frequency when the cpu frequency changes.
|
|
* Called on the cpu that is changing frequency with interrupts disabled.
|
|
*/
|
|
static void twd_update_frequency(void *new_rate)
|
|
{
|
|
twd_timer_rate = *((unsigned long *) new_rate);
|
|
|
|
clockevents_update_freq(*__this_cpu_ptr(twd_evt), twd_timer_rate);
|
|
}
|
|
|
|
static int twd_rate_change(struct notifier_block *nb,
|
|
unsigned long flags, void *data)
|
|
{
|
|
struct clk_notifier_data *cnd = data;
|
|
|
|
/*
|
|
* The twd clock events must be reprogrammed to account for the new
|
|
* frequency. The timer is local to a cpu, so cross-call to the
|
|
* changing cpu.
|
|
*/
|
|
if (flags == POST_RATE_CHANGE)
|
|
smp_call_function(twd_update_frequency,
|
|
(void *)&cnd->new_rate, 1);
|
|
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static struct notifier_block twd_clk_nb = {
|
|
.notifier_call = twd_rate_change,
|
|
};
|
|
|
|
static int twd_clk_init(void)
|
|
{
|
|
if (twd_evt && *__this_cpu_ptr(twd_evt) && !IS_ERR(twd_clk))
|
|
return clk_notifier_register(twd_clk, &twd_clk_nb);
|
|
|
|
return 0;
|
|
}
|
|
core_initcall(twd_clk_init);
|
|
|
|
#elif defined (CONFIG_CPU_FREQ)
|
|
|
|
#include <linux/cpufreq.h>
|
|
|
|
/*
|
|
* Updates clockevent frequency when the cpu frequency changes.
|
|
* Called on the cpu that is changing frequency with interrupts disabled.
|
|
*/
|
|
static void twd_update_frequency(void *data)
|
|
{
|
|
twd_timer_rate = clk_get_rate(twd_clk);
|
|
|
|
clockevents_update_freq(*__this_cpu_ptr(twd_evt), twd_timer_rate);
|
|
}
|
|
|
|
static int twd_cpufreq_transition(struct notifier_block *nb,
|
|
unsigned long state, void *data)
|
|
{
|
|
struct cpufreq_freqs *freqs = data;
|
|
|
|
/*
|
|
* The twd clock events must be reprogrammed to account for the new
|
|
* frequency. The timer is local to a cpu, so cross-call to the
|
|
* changing cpu.
|
|
*/
|
|
if (state == CPUFREQ_POSTCHANGE || state == CPUFREQ_RESUMECHANGE)
|
|
smp_call_function_single(freqs->cpu, twd_update_frequency,
|
|
NULL, 1);
|
|
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static struct notifier_block twd_cpufreq_nb = {
|
|
.notifier_call = twd_cpufreq_transition,
|
|
};
|
|
|
|
static int twd_cpufreq_init(void)
|
|
{
|
|
if (twd_evt && *__this_cpu_ptr(twd_evt) && !IS_ERR(twd_clk))
|
|
return cpufreq_register_notifier(&twd_cpufreq_nb,
|
|
CPUFREQ_TRANSITION_NOTIFIER);
|
|
|
|
return 0;
|
|
}
|
|
core_initcall(twd_cpufreq_init);
|
|
|
|
#endif
|
|
|
|
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 / 10000) % 100);
|
|
}
|
|
}
|
|
|
|
static irqreturn_t twd_handler(int irq, void *dev_id)
|
|
{
|
|
struct clock_event_device *evt = *(struct clock_event_device **)dev_id;
|
|
|
|
if (twd_timer_ack()) {
|
|
evt->event_handler(evt);
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
return IRQ_NONE;
|
|
}
|
|
|
|
static void twd_get_clock(struct device_node *np)
|
|
{
|
|
int err;
|
|
|
|
if (np)
|
|
twd_clk = of_clk_get(np, 0);
|
|
else
|
|
twd_clk = clk_get_sys("smp_twd", NULL);
|
|
|
|
if (IS_ERR(twd_clk)) {
|
|
pr_err("smp_twd: clock not found %d\n", (int) PTR_ERR(twd_clk));
|
|
return;
|
|
}
|
|
|
|
err = clk_prepare_enable(twd_clk);
|
|
if (err) {
|
|
pr_err("smp_twd: clock failed to prepare+enable: %d\n", err);
|
|
clk_put(twd_clk);
|
|
return;
|
|
}
|
|
|
|
twd_timer_rate = clk_get_rate(twd_clk);
|
|
}
|
|
|
|
/*
|
|
* Setup the local clock events for a CPU.
|
|
*/
|
|
static int __cpuinit twd_timer_setup(struct clock_event_device *clk)
|
|
{
|
|
struct clock_event_device **this_cpu_clk;
|
|
int cpu = smp_processor_id();
|
|
|
|
/*
|
|
* If the basic setup for this CPU has been done before don't
|
|
* bother with the below.
|
|
*/
|
|
if (per_cpu(percpu_setup_called, cpu)) {
|
|
__raw_writel(0, twd_base + TWD_TIMER_CONTROL);
|
|
clockevents_register_device(*__this_cpu_ptr(twd_evt));
|
|
enable_percpu_irq(clk->irq, 0);
|
|
return 0;
|
|
}
|
|
per_cpu(percpu_setup_called, cpu) = true;
|
|
|
|
twd_calibrate_rate();
|
|
|
|
/*
|
|
* The following is done once per CPU the first time .setup() is
|
|
* called.
|
|
*/
|
|
__raw_writel(0, twd_base + TWD_TIMER_CONTROL);
|
|
|
|
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->irq = twd_ppi;
|
|
|
|
this_cpu_clk = __this_cpu_ptr(twd_evt);
|
|
*this_cpu_clk = clk;
|
|
|
|
clockevents_config_and_register(clk, twd_timer_rate,
|
|
0xf, 0xffffffff);
|
|
enable_percpu_irq(clk->irq, 0);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct local_timer_ops twd_lt_ops __cpuinitdata = {
|
|
.setup = twd_timer_setup,
|
|
.stop = twd_timer_stop,
|
|
};
|
|
|
|
static int __init twd_local_timer_common_register(struct device_node *np)
|
|
{
|
|
int err;
|
|
|
|
twd_evt = alloc_percpu(struct clock_event_device *);
|
|
if (!twd_evt) {
|
|
err = -ENOMEM;
|
|
goto out_free;
|
|
}
|
|
|
|
err = request_percpu_irq(twd_ppi, twd_handler, "twd", twd_evt);
|
|
if (err) {
|
|
pr_err("twd: can't register interrupt %d (%d)\n", twd_ppi, err);
|
|
goto out_free;
|
|
}
|
|
|
|
err = local_timer_register(&twd_lt_ops);
|
|
if (err)
|
|
goto out_irq;
|
|
|
|
twd_get_clock(np);
|
|
|
|
return 0;
|
|
|
|
out_irq:
|
|
free_percpu_irq(twd_ppi, twd_evt);
|
|
out_free:
|
|
iounmap(twd_base);
|
|
twd_base = NULL;
|
|
free_percpu(twd_evt);
|
|
|
|
return err;
|
|
}
|
|
|
|
int __init twd_local_timer_register(struct twd_local_timer *tlt)
|
|
{
|
|
if (twd_base || twd_evt)
|
|
return -EBUSY;
|
|
|
|
twd_ppi = tlt->res[1].start;
|
|
|
|
twd_base = ioremap(tlt->res[0].start, resource_size(&tlt->res[0]));
|
|
if (!twd_base)
|
|
return -ENOMEM;
|
|
|
|
return twd_local_timer_common_register(NULL);
|
|
}
|
|
|
|
#ifdef CONFIG_OF
|
|
const static struct of_device_id twd_of_match[] __initconst = {
|
|
{ .compatible = "arm,cortex-a9-twd-timer", },
|
|
{ .compatible = "arm,cortex-a5-twd-timer", },
|
|
{ .compatible = "arm,arm11mp-twd-timer", },
|
|
{ },
|
|
};
|
|
|
|
void __init twd_local_timer_of_register(void)
|
|
{
|
|
struct device_node *np;
|
|
int err;
|
|
|
|
if (!is_smp() || !setup_max_cpus)
|
|
return;
|
|
|
|
np = of_find_matching_node(NULL, twd_of_match);
|
|
if (!np)
|
|
return;
|
|
|
|
twd_ppi = irq_of_parse_and_map(np, 0);
|
|
if (!twd_ppi) {
|
|
err = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
twd_base = of_iomap(np, 0);
|
|
if (!twd_base) {
|
|
err = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
err = twd_local_timer_common_register(np);
|
|
|
|
out:
|
|
WARN(err, "twd_local_timer_of_register failed (%d)\n", err);
|
|
}
|
|
#endif
|