linux-stable/arch/arm/common/timer-sp.c
Viresh Kumar 887708f0ac ARM: timer-sp: Set dynamic irq affinity
When a cpu goes to a deep idle state where its local timer is shutdown, it
notifies the time frame work to use the broadcast timer instead.

Unfortunately, the broadcast device could wake up any CPU, including an idle one
which is not concerned by the wake up at all.

This implies, in the worst case, an idle CPU will wake up to send an IPI to
another idle cpu.

This patch fixes this for ARM platforms using timer-sp, by setting
CLOCK_EVT_FEAT_DYNIRQ feature.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
2013-08-22 00:18:53 +02:00

300 lines
6.9 KiB
C

/*
* linux/arch/arm/common/timer-sp.c
*
* Copyright (C) 1999 - 2003 ARM Limited
* Copyright (C) 2000 Deep Blue Solutions Ltd
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/clk.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/sched_clock.h>
#include <asm/hardware/arm_timer.h>
#include <asm/hardware/timer-sp.h>
static long __init sp804_get_clock_rate(struct clk *clk)
{
long rate;
int err;
err = clk_prepare(clk);
if (err) {
pr_err("sp804: clock failed to prepare: %d\n", err);
clk_put(clk);
return err;
}
err = clk_enable(clk);
if (err) {
pr_err("sp804: clock failed to enable: %d\n", err);
clk_unprepare(clk);
clk_put(clk);
return err;
}
rate = clk_get_rate(clk);
if (rate < 0) {
pr_err("sp804: clock failed to get rate: %ld\n", rate);
clk_disable(clk);
clk_unprepare(clk);
clk_put(clk);
}
return rate;
}
static void __iomem *sched_clock_base;
static u32 sp804_read(void)
{
return ~readl_relaxed(sched_clock_base + TIMER_VALUE);
}
void __init __sp804_clocksource_and_sched_clock_init(void __iomem *base,
const char *name,
struct clk *clk,
int use_sched_clock)
{
long rate;
if (!clk) {
clk = clk_get_sys("sp804", name);
if (IS_ERR(clk)) {
pr_err("sp804: clock not found: %d\n",
(int)PTR_ERR(clk));
return;
}
}
rate = sp804_get_clock_rate(clk);
if (rate < 0)
return;
/* setup timer 0 as free-running clocksource */
writel(0, base + TIMER_CTRL);
writel(0xffffffff, base + TIMER_LOAD);
writel(0xffffffff, base + TIMER_VALUE);
writel(TIMER_CTRL_32BIT | TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC,
base + TIMER_CTRL);
clocksource_mmio_init(base + TIMER_VALUE, name,
rate, 200, 32, clocksource_mmio_readl_down);
if (use_sched_clock) {
sched_clock_base = base;
setup_sched_clock(sp804_read, 32, rate);
}
}
static void __iomem *clkevt_base;
static unsigned long clkevt_reload;
/*
* IRQ handler for the timer
*/
static irqreturn_t sp804_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
/* clear the interrupt */
writel(1, clkevt_base + TIMER_INTCLR);
evt->event_handler(evt);
return IRQ_HANDLED;
}
static void sp804_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
unsigned long ctrl = TIMER_CTRL_32BIT | TIMER_CTRL_IE;
writel(ctrl, clkevt_base + TIMER_CTRL);
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
writel(clkevt_reload, clkevt_base + TIMER_LOAD);
ctrl |= TIMER_CTRL_PERIODIC | TIMER_CTRL_ENABLE;
break;
case CLOCK_EVT_MODE_ONESHOT:
/* period set, and timer enabled in 'next_event' hook */
ctrl |= TIMER_CTRL_ONESHOT;
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
default:
break;
}
writel(ctrl, clkevt_base + TIMER_CTRL);
}
static int sp804_set_next_event(unsigned long next,
struct clock_event_device *evt)
{
unsigned long ctrl = readl(clkevt_base + TIMER_CTRL);
writel(next, clkevt_base + TIMER_LOAD);
writel(ctrl | TIMER_CTRL_ENABLE, clkevt_base + TIMER_CTRL);
return 0;
}
static struct clock_event_device sp804_clockevent = {
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
CLOCK_EVT_FEAT_DYNIRQ,
.set_mode = sp804_set_mode,
.set_next_event = sp804_set_next_event,
.rating = 300,
};
static struct irqaction sp804_timer_irq = {
.name = "timer",
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
.handler = sp804_timer_interrupt,
.dev_id = &sp804_clockevent,
};
void __init __sp804_clockevents_init(void __iomem *base, unsigned int irq, struct clk *clk, const char *name)
{
struct clock_event_device *evt = &sp804_clockevent;
long rate;
if (!clk)
clk = clk_get_sys("sp804", name);
if (IS_ERR(clk)) {
pr_err("sp804: %s clock not found: %d\n", name,
(int)PTR_ERR(clk));
return;
}
rate = sp804_get_clock_rate(clk);
if (rate < 0)
return;
clkevt_base = base;
clkevt_reload = DIV_ROUND_CLOSEST(rate, HZ);
evt->name = name;
evt->irq = irq;
evt->cpumask = cpu_possible_mask;
writel(0, base + TIMER_CTRL);
setup_irq(irq, &sp804_timer_irq);
clockevents_config_and_register(evt, rate, 0xf, 0xffffffff);
}
static void __init sp804_of_init(struct device_node *np)
{
static bool initialized = false;
void __iomem *base;
int irq;
u32 irq_num = 0;
struct clk *clk1, *clk2;
const char *name = of_get_property(np, "compatible", NULL);
base = of_iomap(np, 0);
if (WARN_ON(!base))
return;
/* Ensure timers are disabled */
writel(0, base + TIMER_CTRL);
writel(0, base + TIMER_2_BASE + TIMER_CTRL);
if (initialized || !of_device_is_available(np))
goto err;
clk1 = of_clk_get(np, 0);
if (IS_ERR(clk1))
clk1 = NULL;
/* Get the 2nd clock if the timer has 2 timer clocks */
if (of_count_phandle_with_args(np, "clocks", "#clock-cells") == 3) {
clk2 = of_clk_get(np, 1);
if (IS_ERR(clk2)) {
pr_err("sp804: %s clock not found: %d\n", np->name,
(int)PTR_ERR(clk2));
goto err;
}
} else
clk2 = clk1;
irq = irq_of_parse_and_map(np, 0);
if (irq <= 0)
goto err;
of_property_read_u32(np, "arm,sp804-has-irq", &irq_num);
if (irq_num == 2) {
__sp804_clockevents_init(base + TIMER_2_BASE, irq, clk2, name);
__sp804_clocksource_and_sched_clock_init(base, name, clk1, 1);
} else {
__sp804_clockevents_init(base, irq, clk1 , name);
__sp804_clocksource_and_sched_clock_init(base + TIMER_2_BASE,
name, clk2, 1);
}
initialized = true;
return;
err:
iounmap(base);
}
CLOCKSOURCE_OF_DECLARE(sp804, "arm,sp804", sp804_of_init);
static void __init integrator_cp_of_init(struct device_node *np)
{
static int init_count = 0;
void __iomem *base;
int irq;
const char *name = of_get_property(np, "compatible", NULL);
base = of_iomap(np, 0);
if (WARN_ON(!base))
return;
/* Ensure timer is disabled */
writel(0, base + TIMER_CTRL);
if (init_count == 2 || !of_device_is_available(np))
goto err;
if (!init_count)
sp804_clocksource_init(base, name);
else {
irq = irq_of_parse_and_map(np, 0);
if (irq <= 0)
goto err;
sp804_clockevents_init(base, irq, name);
}
init_count++;
return;
err:
iounmap(base);
}
CLOCKSOURCE_OF_DECLARE(intcp, "arm,integrator-cp-timer", integrator_cp_of_init);