imx-common: timer: clean up code

We can reuse common functions in lib/time.c, but not reimplement
functions in imx-common/time.c.
Only keep timer_init ,get_tbclk and implement timer_read_counter in
imx-common/time.c.

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>

arch/arm/imx-common/timer.c

@@ -66,25 +66,6 @@ static inline ulong gpt_get_clk(void)
 	return MXC_CLK32;
 #endif
 }
-static inline unsigned long long tick_to_time(unsigned long long tick)
-{
-	ulong gpt_clk = gpt_get_clk();
-
-	tick *= CONFIG_SYS_HZ;
-	do_div(tick, gpt_clk);
-
-	return tick;
-}
-
-static inline unsigned long long us_to_tick(unsigned long long usec)
-{
-	ulong gpt_clk = gpt_get_clk();
-
-	usec = usec * gpt_clk + 999999;
-	do_div(usec, 1000000);
-
-	return usec;
-}
 
 int timer_init(void)
 {
@@ -130,44 +111,9 @@ int timer_init(void)
 	return 0;
 }
 
-unsigned long long get_ticks(void)
+unsigned long timer_read_counter(void)
 {
-	ulong now = __raw_readl(&cur_gpt->counter); /* current tick value */
-
-	/* increment tbu if tbl has rolled over */
-	if (now < gd->arch.tbl)
-		gd->arch.tbu++;
-	gd->arch.tbl = now;
-	return (((unsigned long long)gd->arch.tbu) << 32) | gd->arch.tbl;
-}
-
-ulong get_timer_masked(void)
-{
-	/*
-	 * get_ticks() returns a long long (64 bit), it wraps in
-	 * 2^64 / GPT_CLK = 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)
-{
-	return get_timer_masked() - base;
-}
-
-/* delay x useconds AND preserve advance timstamp value */
-void __udelay(unsigned long usec)
-{
-	unsigned long long tmp;
-	ulong tmo;
-
-	tmo = us_to_tick(usec);
-	tmp = get_ticks() + tmo;	/* get current timestamp */
-
-	while (get_ticks() < tmp)	/* loop till event */
-		 /*NOP*/;
+	return __raw_readl(&cur_gpt->counter); /* current tick value */
 }
 
 /*
@@ -178,20 +124,3 @@ ulong get_tbclk(void)
 {
 	return gpt_get_clk();
 }
-
-/*
- * This function is intended for SHORT delays only.
- * It will overflow at around 10 seconds @ 400MHz,
- * or 20 seconds @ 200MHz.
- */
-unsigned long usec2ticks(unsigned long usec)
-{
-	ulong ticks;
-
-	if (usec < 1000)
-		ticks = ((usec * (get_tbclk()/1000)) + 500) / 1000;
-	else
-		ticks = ((usec / 10) * (get_tbclk() / 100000));
-
-	return ticks;
-}