MX35: add missing get_ticks() and get_tbclk()

commit f31a911fe (arm, post: add missing post_time_ms for arm)
enables get_ticks and get_tbclk for all arm based boards,
MX5/MX6 have not yet implemented.

Signed-off-by: Stefano Babic <sbabic@denx.de>

arch/arm/cpu/arm1136/mx35/timer.c

@@ -25,7 +25,14 @@
 
 #include <common.h>
 #include <asm/io.h>
+#include <div64.h>
 #include <asm/arch/imx-regs.h>
+#include <asm/arch/clock.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define timestamp	(gd->tbl)
+#define lastinc		(gd->lastinc)
 
 /* General purpose timers bitfields */
 #define GPTCR_SWR       (1<<15)	/* Software reset */
@@ -33,7 +40,24 @@
 #define GPTCR_CLKSOURCE_32   (0x100<<6)	/* Clock source */
 #define GPTCR_CLKSOURCE_IPG (0x001<<6)	/* Clock source */
 #define GPTCR_TEN       (1)	/* Timer enable */
-#define GPTPR_VAL	(66)
+
+#define	TIMER_FREQ_HZ	mxc_get_clock(MXC_IPG_CLK)
+
+static inline unsigned long long tick_to_time(unsigned long long tick)
+{
+	tick *= CONFIG_SYS_HZ;
+	do_div(tick, TIMER_FREQ_HZ);
+
+	return tick;
+}
+
+static inline unsigned long long us_to_tick(unsigned long long usec)
+{
+	usec *= TIMER_FREQ_HZ;
+	do_div(usec, 1000000);
+
+	return usec;
+}
 
 int timer_init(void)
 {
@@ -45,7 +69,7 @@ int timer_init(void)
 	for (i = 0; i < 100; i++)
 		writel(0, &gpt->ctrl);	/* We have no udelay by now */
 
-	writel(GPTPR_VAL, &gpt->pre);
+	writel(0, &gpt->pre);
 	/* Freerun Mode, PERCLK1 input */
 	writel(readl(&gpt->ctrl) |
 		GPTCR_CLKSOURCE_IPG | GPTCR_TEN,
@@ -54,58 +78,59 @@ int timer_init(void)
 	return 0;
 }
 
-void reset_timer_masked(void)
+unsigned long long get_ticks(void)
 {
 	struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR;
-
-	writel(0, &gpt->ctrl);
-	/* Freerun Mode, PERCLK1 input */
-	writel(GPTCR_CLKSOURCE_IPG | GPTCR_TEN,
-		&gpt->ctrl);
+	ulong now = readl(&gpt->counter); /* current tick value */
+
+	if (now >= lastinc) {
+		/*
+		 * normal mode (non roll)
+		 * move stamp forward with absolut diff ticks
+		 */
+		timestamp += (now - lastinc);
+	} else {
+		/* we have rollover of incrementer */
+		timestamp += (0xFFFFFFFF - lastinc) + now;
+	}
+	lastinc = now;
+	return timestamp;
 }
 
-inline ulong get_timer_masked(void)
+ulong get_timer_masked(void)
 {
-
-	struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR;
-	ulong val = readl(&gpt->counter);
-
-	return val;
+	/*
+	 * get_ticks() returns a long long (64 bit), it wraps in
+	 * 2^64 / CONFIG_MX25_CLK32 = 2^64 / 2^15 = 2^49 ~ 5 * 10^14 (s) ~
+	 * 5 * 10^9 days... and get_ticks() * CONFIG_SYS_HZ wraps in
+	 * 5 * 10^6 days - long enough.
+	 */
+	return tick_to_time(get_ticks());
 }
 
 ulong get_timer(ulong base)
 {
-	ulong tmp;
+	return get_timer_masked() - base;
+}
 
-	tmp = get_timer_masked();
+/* delay x useconds AND preserve advance timstamp value */
+void __udelay(unsigned long usec)
+{
+	unsigned long long tmp;
+	ulong tmo;
 
-	if (tmp <= (base * 1000)) {
-		/* Overflow */
-		tmp += (0xffffffff -  base);
-	}
+	tmo = us_to_tick(usec);
+	tmp = get_ticks() + tmo;	/* get current timestamp */
 
-	return (tmp / 1000) - base;
+	while (get_ticks() < tmp)	/* loop till event */
+		 /*NOP*/;
 }
 
 /*
- * delay x useconds AND preserve advance timstamp value
- * GPTCNT is now supposed to tick 1 by 1 us.
+ * This function is derived from PowerPC code (timebase clock frequency).
+ * On ARM it returns the number of timer ticks per second.
  */
-void __udelay(unsigned long usec)
+ulong get_tbclk(void)
 {
-	ulong tmp;
-
-	tmp = get_timer_masked();	/* get current timestamp */
-
-	/* if setting this forward will roll time stamp */
-	if ((usec + tmp + 1) < tmp) {
-		/* reset "advancing" timestamp to 0, set lastinc value */
-		reset_timer_masked();
-	} else {
-		/* else, set advancing stamp wake up time */
-		tmp += usec;
-	}
-
-	while (get_timer_masked() < tmp)	/* loop till event */
-		 /*NOP*/;
+	return TIMER_FREQ_HZ;
 }