Merge tag 'tegra-for-3.17-delay-timer' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux into next/soc

Merge "ARM: tegra: use us counter as delay timer" from Stephen Warren:

Tegra has a micro-second counter whose rate doesn't vary with cpufreq
changes. Register it so it can be used as the delay timer, so delays
aren't influenced by cpufreq.

* tag 'tegra-for-3.17-delay-timer' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux:
  clocksource: tegra: Use us counter as delay timer
  ARM: choose highest resolution delay timer
  kernel: add calibration_delay_done()

Signed-off-by: Olof Johansson <olof@lixom.net>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/clocksource/tegra20_timer.c b/drivers/clocksource/tegra20_timer.c
index d1869f02051c..d2616ef16770 100644
--- a/drivers/clocksource/tegra20_timer.c
+++ b/drivers/clocksource/tegra20_timer.c
@@ -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);