[ARM] rtc-sa1100: don't assume CLOCK_TICK_RATE to be a constant

As Nicolas and Russell pointed out, CLOCK_TICK_RATE is no more
a constant on PXA when multiple processors and platforms are
selected, change TIMER_FREQ in rtc-sa1100.c into a variable.

Since the code to decide the clock tick rate is re-used from
timer.c, introduce a common get_clock_tick_rate() for this.

Signed-off-by: Eric Miao <eric.miao@marvell.com>
Acked-by: Nicolas Pitre <nico@marvell.com>

arch/arm/mach-pxa/generic.c

@@ -24,6 +24,7 @@
 #include <asm/system.h>
 #include <asm/pgtable.h>
 #include <asm/mach/map.h>
+#include <asm/mach-types.h>
 
 #include <mach/pxa-regs.h>
 #include <mach/reset.h>
@@ -39,6 +40,21 @@ void clear_reset_status(unsigned int mask)
 		pxa3xx_clear_reset_status(mask);
 }
 
+unsigned long get_clock_tick_rate(void)
+{
+	unsigned long clock_tick_rate;
+
+	if (cpu_is_pxa25x())
+		clock_tick_rate = 3686400;
+	else if (machine_is_mainstone())
+		clock_tick_rate = 3249600;
+	else
+		clock_tick_rate = 3250000;
+
+	return clock_tick_rate;
+}
+EXPORT_SYMBOL(get_clock_tick_rate);
+
 /*
  * Get the clock frequency as reflected by CCCR and the turbo flag.
  * We assume these values have been applied via a fcs.

arch/arm/mach-pxa/include/mach/hardware.h

@@ -291,6 +291,8 @@
  */
 extern unsigned int get_memclk_frequency_10khz(void);
 
+/* return the clock tick rate of the OS timer */
+extern unsigned long get_clock_tick_rate(void);
 #endif
 
 #if defined(CONFIG_MACH_ARMCORE) && defined(CONFIG_PCI)

arch/arm/mach-pxa/include/mach/timex.h

@@ -10,6 +10,14 @@
  * published by the Free Software Foundation.
  */
 
+/* Various drivers are still using the constant of CLOCK_TICK_RATE, for
+ * those drivers to at least work, the definition is provided here.
+ *
+ * NOTE: this is no longer accurate when multiple processors and boards
+ * are selected, newer drivers should not depend on this any more.  Use
+ * either the clocksource/clockevent or get this at run-time by calling
+ * get_clock_tick_rate() (as defined in generic.c).
+ */
 
 #if defined(CONFIG_PXA25x)
 /* PXA250/210 timer base */

arch/arm/mach-pxa/time.c

@@ -23,7 +23,6 @@
 #include <asm/mach/irq.h>
 #include <asm/mach/time.h>
 #include <mach/pxa-regs.h>
-#include <asm/mach-types.h>
 
 /*
  * This is PXA's sched_clock implementation. This has a resolution
@@ -150,18 +149,11 @@ static struct irqaction pxa_ost0_irq = {
 
 static void __init pxa_timer_init(void)
 {
-	unsigned long clock_tick_rate;
+	unsigned long clock_tick_rate = get_clock_tick_rate();
 
 	OIER = 0;
 	OSSR = OSSR_M0 | OSSR_M1 | OSSR_M2 | OSSR_M3;
 
-	if (cpu_is_pxa25x())
-		clock_tick_rate = 3686400;
-	else if (machine_is_mainstone())
-		clock_tick_rate = 3249600;
-	else
-		clock_tick_rate = 3250000;
-
 	set_oscr2ns_scale(clock_tick_rate);
 
 	ckevt_pxa_osmr0.mult =

arch/arm/mach-sa1100/include/mach/hardware.h

@@ -59,6 +59,10 @@
 # define __REG(x)	(*((volatile unsigned long *)io_p2v(x)))
 # define __PREG(x)	(io_v2p((unsigned long)&(x)))
 
+static inline unsigned long get_clock_tick_rate(void)
+{
+	return 3686400;
+}
 #else
 
 # define __REG(x)	io_p2v(x)

drivers/rtc/rtc-sa1100.c

@@ -38,11 +38,11 @@
 #include <mach/pxa-regs.h>
 #endif
 
-#define TIMER_FREQ		CLOCK_TICK_RATE
 #define RTC_DEF_DIVIDER		32768 - 1
 #define RTC_DEF_TRIM		0
 
 static unsigned long rtc_freq = 1024;
+static unsigned long timer_freq;
 static struct rtc_time rtc_alarm;
 static DEFINE_SPINLOCK(sa1100_rtc_lock);
 
@@ -157,7 +157,7 @@ static irqreturn_t timer1_interrupt(int irq, void *dev_id)
 	rtc_update_irq(rtc, rtc_timer1_count, RTC_PF | RTC_IRQF);
 
 	if (rtc_timer1_count == 1)
-		rtc_timer1_count = (rtc_freq * ((1<<30)/(TIMER_FREQ>>2)));
+		rtc_timer1_count = (rtc_freq * ((1 << 30) / (timer_freq >> 2)));
 
 	return IRQ_HANDLED;
 }
@@ -166,7 +166,7 @@ static int sa1100_rtc_read_callback(struct device *dev, int data)
 {
 	if (data & RTC_PF) {
 		/* interpolate missed periods and set match for the next */
-		unsigned long period = TIMER_FREQ/rtc_freq;
+		unsigned long period = timer_freq / rtc_freq;
 		unsigned long oscr = OSCR;
 		unsigned long osmr1 = OSMR1;
 		unsigned long missed = (oscr - osmr1)/period;
@@ -263,7 +263,7 @@ static int sa1100_rtc_ioctl(struct device *dev, unsigned int cmd,
 		return 0;
 	case RTC_PIE_ON:
 		spin_lock_irq(&sa1100_rtc_lock);
-		OSMR1 = TIMER_FREQ/rtc_freq + OSCR;
+		OSMR1 = timer_freq / rtc_freq + OSCR;
 		OIER |= OIER_E1;
 		rtc_timer1_count = 1;
 		spin_unlock_irq(&sa1100_rtc_lock);
@@ -271,7 +271,7 @@ static int sa1100_rtc_ioctl(struct device *dev, unsigned int cmd,
 	case RTC_IRQP_READ:
 		return put_user(rtc_freq, (unsigned long *)arg);
 	case RTC_IRQP_SET:
-		if (arg < 1 || arg > TIMER_FREQ)
+		if (arg < 1 || arg > timer_freq)
 			return -EINVAL;
 		rtc_freq = arg;
 		return 0;
@@ -352,6 +352,8 @@ static int sa1100_rtc_probe(struct platform_device *pdev)
 {
 	struct rtc_device *rtc;
 
+	timer_freq = get_clock_tick_rate();
+
 	/*
 	 * According to the manual we should be able to let RTTR be zero
 	 * and then a default diviser for a 32.768KHz clock is used.