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linux-next/drivers/clocksource/time-armada-370-xp.c
Stephen Boyd 38ff87f77a sched_clock: Make ARM's sched_clock generic for all architectures 
Nothing about the sched_clock implementation in the ARM port is
specific to the architecture. Generalize the code so that other
architectures can use it by selecting GENERIC_SCHED_CLOCK.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
[jstultz: Merge minor collisions with other patches in my tree]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-06-12 14:02:13 -07:00

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/*
* Marvell Armada 370/XP SoC timer handling.
*
* Copyright (C) 2012 Marvell
*
* Lior Amsalem <alior@marvell.com>
* Gregory CLEMENT <gregory.clement@free-electrons.com>
* Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*
* Timer 0 is used as free-running clocksource, while timer 1 is
* used as clock_event_device.
*/
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/kernel.h>
#include <linux/clk.h>
#include <linux/timer.h>
#include <linux/clockchips.h>
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/sched_clock.h>
#include <asm/localtimer.h>
#include <linux/percpu.h>
/*
* Timer block registers.
*/
#define TIMER_CTRL_OFF 0x0000
#define TIMER0_EN 0x0001
#define TIMER0_RELOAD_EN 0x0002
#define TIMER0_25MHZ 0x0800
#define TIMER0_DIV(div) ((div) << 19)
#define TIMER1_EN 0x0004
#define TIMER1_RELOAD_EN 0x0008
#define TIMER1_25MHZ 0x1000
#define TIMER1_DIV(div) ((div) << 22)
#define TIMER_EVENTS_STATUS 0x0004
#define TIMER0_CLR_MASK (~0x1)
#define TIMER1_CLR_MASK (~0x100)
#define TIMER0_RELOAD_OFF 0x0010
#define TIMER0_VAL_OFF 0x0014
#define TIMER1_RELOAD_OFF 0x0018
#define TIMER1_VAL_OFF 0x001c
#define LCL_TIMER_EVENTS_STATUS 0x0028
/* Global timers are connected to the coherency fabric clock, and the
below divider reduces their incrementing frequency. */
#define TIMER_DIVIDER_SHIFT 5
#define TIMER_DIVIDER (1 << TIMER_DIVIDER_SHIFT)
/*
* SoC-specific data.
*/
static void __iomem *timer_base, *local_base;
static unsigned int timer_clk;
static bool timer25Mhz = true;
/*
* Number of timer ticks per jiffy.
*/
static u32 ticks_per_jiffy;
static struct clock_event_device __percpu **percpu_armada_370_xp_evt;
static u32 notrace armada_370_xp_read_sched_clock(void)
{
return ~readl(timer_base + TIMER0_VAL_OFF);
}
/*
* Clockevent handling.
*/
static int
armada_370_xp_clkevt_next_event(unsigned long delta,
struct clock_event_device *dev)
{
u32 u;
/*
* Clear clockevent timer interrupt.
*/
writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
/*
* Setup new clockevent timer value.
*/
writel(delta, local_base + TIMER0_VAL_OFF);
/*
* Enable the timer.
*/
u = readl(local_base + TIMER_CTRL_OFF);
u = ((u & ~TIMER0_RELOAD_EN) | TIMER0_EN |
TIMER0_DIV(TIMER_DIVIDER_SHIFT));
writel(u, local_base + TIMER_CTRL_OFF);
return 0;
}
static void
armada_370_xp_clkevt_mode(enum clock_event_mode mode,
struct clock_event_device *dev)
{
u32 u;
if (mode == CLOCK_EVT_MODE_PERIODIC) {
/*
* Setup timer to fire at 1/HZ intervals.
*/
writel(ticks_per_jiffy - 1, local_base + TIMER0_RELOAD_OFF);
writel(ticks_per_jiffy - 1, local_base + TIMER0_VAL_OFF);
/*
* Enable timer.
*/
u = readl(local_base + TIMER_CTRL_OFF);
writel((u | TIMER0_EN | TIMER0_RELOAD_EN |
TIMER0_DIV(TIMER_DIVIDER_SHIFT)),
local_base + TIMER_CTRL_OFF);
} else {
/*
* Disable timer.
*/
u = readl(local_base + TIMER_CTRL_OFF);
writel(u & ~TIMER0_EN, local_base + TIMER_CTRL_OFF);
/*
* ACK pending timer interrupt.
*/
writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
}
}
static struct clock_event_device armada_370_xp_clkevt = {
.name = "armada_370_xp_per_cpu_tick",
.features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
.shift = 32,
.rating = 300,
.set_next_event = armada_370_xp_clkevt_next_event,
.set_mode = armada_370_xp_clkevt_mode,
};
static irqreturn_t armada_370_xp_timer_interrupt(int irq, void *dev_id)
{
/*
* ACK timer interrupt and call event handler.
*/
struct clock_event_device *evt = *(struct clock_event_device **)dev_id;
writel(TIMER0_CLR_MASK, local_base + LCL_TIMER_EVENTS_STATUS);
evt->event_handler(evt);
return IRQ_HANDLED;
}
/*
* Setup the local clock events for a CPU.
*/
static int __cpuinit armada_370_xp_timer_setup(struct clock_event_device *evt)
{
u32 u;
int cpu = smp_processor_id();
/* Use existing clock_event for cpu 0 */
if (!smp_processor_id())
return 0;
u = readl(local_base + TIMER_CTRL_OFF);
if (timer25Mhz)
writel(u | TIMER0_25MHZ, local_base + TIMER_CTRL_OFF);
else
writel(u & ~TIMER0_25MHZ, local_base + TIMER_CTRL_OFF);
evt->name = armada_370_xp_clkevt.name;
evt->irq = armada_370_xp_clkevt.irq;
evt->features = armada_370_xp_clkevt.features;
evt->shift = armada_370_xp_clkevt.shift;
evt->rating = armada_370_xp_clkevt.rating,
evt->set_next_event = armada_370_xp_clkevt_next_event,
evt->set_mode = armada_370_xp_clkevt_mode,
evt->cpumask = cpumask_of(cpu);
*__this_cpu_ptr(percpu_armada_370_xp_evt) = evt;
clockevents_config_and_register(evt, timer_clk, 1, 0xfffffffe);
enable_percpu_irq(evt->irq, 0);
return 0;
}
static void armada_370_xp_timer_stop(struct clock_event_device *evt)
{
evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
disable_percpu_irq(evt->irq);
}
static struct local_timer_ops armada_370_xp_local_timer_ops __cpuinitdata = {
.setup = armada_370_xp_timer_setup,
.stop = armada_370_xp_timer_stop,
};
void __init armada_370_xp_timer_init(void)
{
u32 u;
struct device_node *np;
int res;
np = of_find_compatible_node(NULL, NULL, "marvell,armada-370-xp-timer");
timer_base = of_iomap(np, 0);
WARN_ON(!timer_base);
local_base = of_iomap(np, 1);
if (of_find_property(np, "marvell,timer-25Mhz", NULL)) {
/* The fixed 25MHz timer is available so let's use it */
u = readl(local_base + TIMER_CTRL_OFF);
writel(u | TIMER0_25MHZ,
local_base + TIMER_CTRL_OFF);
u = readl(timer_base + TIMER_CTRL_OFF);
writel(u | TIMER0_25MHZ,
timer_base + TIMER_CTRL_OFF);
timer_clk = 25000000;
} else {
unsigned long rate = 0;
struct clk *clk = of_clk_get(np, 0);
WARN_ON(IS_ERR(clk));
rate = clk_get_rate(clk);
u = readl(local_base + TIMER_CTRL_OFF);
writel(u & ~(TIMER0_25MHZ),
local_base + TIMER_CTRL_OFF);
u = readl(timer_base + TIMER_CTRL_OFF);
writel(u & ~(TIMER0_25MHZ),
timer_base + TIMER_CTRL_OFF);
timer_clk = rate / TIMER_DIVIDER;
timer25Mhz = false;
}
/*
* We use timer 0 as clocksource, and private(local) timer 0
* for clockevents
*/
armada_370_xp_clkevt.irq = irq_of_parse_and_map(np, 4);
ticks_per_jiffy = (timer_clk + HZ / 2) / HZ;
/*
* Set scale and timer for sched_clock.
*/
setup_sched_clock(armada_370_xp_read_sched_clock, 32, timer_clk);
/*
* Setup free-running clocksource timer (interrupts
* disabled).
*/
writel(0xffffffff, timer_base + TIMER0_VAL_OFF);
writel(0xffffffff, timer_base + TIMER0_RELOAD_OFF);
u = readl(timer_base + TIMER_CTRL_OFF);
writel((u | TIMER0_EN | TIMER0_RELOAD_EN |
TIMER0_DIV(TIMER_DIVIDER_SHIFT)), timer_base + TIMER_CTRL_OFF);
clocksource_mmio_init(timer_base + TIMER0_VAL_OFF,
"armada_370_xp_clocksource",
timer_clk, 300, 32, clocksource_mmio_readl_down);
/* Register the clockevent on the private timer of CPU 0 */
armada_370_xp_clkevt.cpumask = cpumask_of(0);
clockevents_config_and_register(&armada_370_xp_clkevt,
timer_clk, 1, 0xfffffffe);
percpu_armada_370_xp_evt = alloc_percpu(struct clock_event_device *);
/*
* Setup clockevent timer (interrupt-driven).
*/
*__this_cpu_ptr(percpu_armada_370_xp_evt) = &armada_370_xp_clkevt;
res = request_percpu_irq(armada_370_xp_clkevt.irq,
armada_370_xp_timer_interrupt,
armada_370_xp_clkevt.name,
percpu_armada_370_xp_evt);
if (!res) {
enable_percpu_irq(armada_370_xp_clkevt.irq, 0);
#ifdef CONFIG_LOCAL_TIMERS
local_timer_register(&armada_370_xp_local_timer_ops);
#endif
}
}
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