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clocksource: tegra: Use us counter as delay timer

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All Tegra SoCs have a freerunning microsecond counter which can be used as a
delay timer.

Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
This commit is contained in:
Peter De Schrijver 2014-06-12 18:58:29 +03:00 committed by Stephen Warren
parent 5930c1a1f7
commit 0ff36b4f47
1 changed files with 13 additions and 0 deletions
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13
drivers/clocksource/tegra20_timer.c
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@ -27,6 +27,7 @@
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/sched_clock.h>
#include <linux/delay.h>
#include <asm/mach/time.h>
#include <asm/smp_twd.h>
@ -53,6 +54,8 @@ static void __iomem *rtc_base;
static struct timespec persistent_ts;
static u64 persistent_ms, last_persistent_ms;
static struct delay_timer tegra_delay_timer;
#define timer_writel(value, reg) \
__raw_writel(value, timer_reg_base + (reg))
#define timer_readl(reg) \
@ -139,6 +142,11 @@ static void tegra_read_persistent_clock(struct timespec *ts)
*ts = *tsp;
}
static unsigned long tegra_delay_timer_read_counter_long(void)
{
return readl(timer_reg_base + TIMERUS_CNTR_1US);
}
static irqreturn_t tegra_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = (struct clock_event_device *)dev_id;
@ -206,6 +214,11 @@ static void __init tegra20_init_timer(struct device_node *np)
BUG();
}
tegra_delay_timer.read_current_timer =
tegra_delay_timer_read_counter_long;
tegra_delay_timer.freq = 1000000;
register_current_timer_delay(&tegra_delay_timer);
ret = setup_irq(tegra_timer_irq.irq, &tegra_timer_irq);
if (ret) {
pr_err("Failed to register timer IRQ: %d\n", ret);