clocksource/drivers/orion: Add delay_timer implementation

Add an implementation for the ARM delay timer, which is used for
udelay().  This provides less CPU dependent and more accurate delays -
the CPU loop on Marvell Dove appears to calibrate to around 6% too
short.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

diff --git a/drivers/clocksource/time-orion.c b/drivers/clocksource/time-orion.c
index c4818a5dc8e5080b4bf251db34d1d8fc6835257a..7eb2ab0bd1146b50c635963c45e88fde74ab1834 100644 (file)
--- a/drivers/clocksource/time-orion.c
+++ b/drivers/clocksource/time-orion.c
@@ -15,6 +15,7 @@
 #include <linux/bitops.h>
 #include <linux/clk.h>
 #include <linux/clockchips.h>
+#include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
@@ -36,6 +37,21 @@
 
 static void __iomem *timer_base;
 
+static unsigned long notrace orion_read_timer(void)
+{
+       return ~readl(timer_base + TIMER0_VAL);
+}
+
+static struct delay_timer orion_delay_timer = {
+       .read_current_timer = orion_read_timer,
+};
+
+static void orion_delay_timer_init(unsigned long rate)
+{
+       orion_delay_timer.freq = rate;
+       register_current_timer_delay(&orion_delay_timer);
+}
+
 /*
  * Free-running clocksource handling.
  */
@@ -168,6 +184,9 @@ static int __init orion_timer_init(struct device_node *np)
        clockevents_config_and_register(&orion_clkevt, rate,
                                        ORION_ONESHOT_MIN, ORION_ONESHOT_MAX);
 
+
+       orion_delay_timer_init(rate);
+
        return 0;
 }
 CLOCKSOURCE_OF_DECLARE(orion_timer, "marvell,orion-timer", orion_timer_init);