This patch adds a clocksource driver for the ARM versatile board,
allowing it to use the generic time-of-day code.
Signed-off-by: Deepak Saxena <[email protected]>
Index: linux-2.6-rt/arch/arm/mach-versatile/core.c
===================================================================
--- linux-2.6-rt.orig/arch/arm/mach-versatile/core.c
+++ linux-2.6-rt/arch/arm/mach-versatile/core.c
@@ -27,6 +27,7 @@
#include <linux/interrupt.h>
#include <linux/amba/bus.h>
#include <linux/amba/clcd.h>
+#include <linux/clockchips.h>
#include <asm/system.h>
#include <asm/hardware.h>
@@ -815,46 +816,6 @@ void __init versatile_init(void)
#endif
/*
- * Returns number of ms since last clock interrupt. Note that interrupts
- * will have been disabled by do_gettimeoffset()
- */
-static unsigned long versatile_gettimeoffset(void)
-{
- unsigned long ticks1, ticks2, status;
-
- /*
- * Get the current number of ticks. Note that there is a race
- * condition between us reading the timer and checking for
- * an interrupt. We get around this by ensuring that the
- * counter has not reloaded between our two reads.
- */
- ticks2 = readl(TIMER0_VA_BASE + TIMER_VALUE) & 0xffff;
- do {
- ticks1 = ticks2;
- status = __raw_readl(VA_IC_BASE + VIC_RAW_STATUS);
- ticks2 = readl(TIMER0_VA_BASE + TIMER_VALUE) & 0xffff;
- } while (ticks2 > ticks1);
-
- /*
- * Number of ticks since last interrupt.
- */
- ticks1 = TIMER_RELOAD - ticks2;
-
- /*
- * Interrupt pending? If so, we've reloaded once already.
- *
- * FIXME: Need to check this is effectively timer 0 that expires
- */
- if (status & IRQMASK_TIMERINT0_1)
- ticks1 += TIMER_RELOAD;
-
- /*
- * Convert the ticks to usecs
- */
- return TICKS2USECS(ticks1);
-}
-
-/*
* IRQ handler for the timer
*/
static irqreturn_t versatile_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
@@ -917,5 +878,36 @@ static void __init versatile_timer_init(
struct sys_timer versatile_timer = {
.init = versatile_timer_init,
- .offset = versatile_gettimeoffset,
};
+
+cycle_t versatile_get_cycles(void)
+{
+ return ~readl(TIMER3_VA_BASE + TIMER_VALUE);
+}
+
+static struct clocksource clocksource_versatile = {
+ .name = "timer3",
+ .rating = 200,
+ .read = versatile_get_cycles,
+ .mask = 0xFFFFFFFF,
+ .shift = 10,
+ .is_continuous = 1,
+};
+
+static int __init versatile_clocksource_init(void)
+{
+ writel(0, TIMER3_VA_BASE + TIMER_CTRL);
+ writel(0xffffffff, TIMER3_VA_BASE + TIMER_LOAD);
+ writel(0xffffffff, TIMER3_VA_BASE + TIMER_VALUE);
+ writel(TIMER_CTRL_32BIT | TIMER_CTRL_ENABLE | TIMER_CTRL_PERIODIC,
+ TIMER3_VA_BASE + TIMER_CTRL);
+
+ clocksource_versatile.mult =
+ clocksource_khz2mult(1000, clocksource_versatile.shift);
+ register_clocksource(&clocksource_versatile);
+
+ return 0;
+}
+
+device_initcall(versatile_clocksource_init);
+
--
Deepak Saxena - [email protected] - http://www.plexity.net
In the end, they will not say, "those were dark times," they will ask
"why were their poets silent?" - Bertold Brecht
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