[U-Boot] [PATCH 3/3] arm: mx35: use common timer functions

[andrew.ruder at elecsyscorp.com]

From: Andrew Ruder <andrew.ruder at elecsyscorp.com>

This patch moves mx35 to the common timer functions added in commit

  8dfafdd - Introduce common timer functions <Rob Herring>

The (removed) mx35 timer code (specifically __udelay()) could deadlock at
the 32-bit boundary of get_ticks().  get_ticks() returned a 32-bit value
cast up to a 64-bit value.  If get_ticks() + tmo in __udelay() crossed
the 32-bit boundary, the while condition became unconditionally true and
locks the processor.  Rather than patch the specific mx35 issues, simply
move everything over to the common code.

Signed-off-by: Andrew Ruder <andrew.ruder at elecsyscorp.com>
Cc: Marek Vasut <marex at denx.de>
Cc: Stefano Babic <sbabic at denx.de>
---

This patch has been COMPILE tested only.  The situation isn't quite as
bad on mx35 as 32-bit rollover occurs in about a day and a half.

Before patch:
Configuring for woodburn board...
308 -rw-r--r-- 1 andy andy 314232 Aug 12 08:36 u-boot.bin

After patch:
Configuring for woodburn board...
308 -rw-r--r-- 1 andy andy 314208 Aug 12 08:37 u-boot.bin

 arch/arm/cpu/arm1136/mx35/timer.c         | 83 -------------------------------
 arch/arm/include/asm/arch-mx35/imx-regs.h | 12 +++++
 2 files changed, 12 insertions(+), 83 deletions(-)

diff --git a/arch/arm/cpu/arm1136/mx35/timer.c b/arch/arm/cpu/arm1136/mx35/timer.c
index cc6166f..4edf533 100644
--- a/arch/arm/cpu/arm1136/mx35/timer.c
+++ b/arch/arm/cpu/arm1136/mx35/timer.c
@@ -9,16 +9,11 @@
 
 #include <common.h>
 #include <asm/io.h>
-#include <div64.h>
 #include <asm/arch/imx-regs.h>
 #include <asm/arch/crm_regs.h>
-#include <asm/arch/clock.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
-#define timestamp	(gd->arch.tbl)
-#define lastinc		(gd->arch.lastinc)
-
 /* General purpose timers bitfields */
 #define GPTCR_SWR       (1<<15)	/* Software reset */
 #define GPTCR_FRR       (1<<9)	/* Freerun / restart */
@@ -26,27 +21,6 @@ DECLARE_GLOBAL_DATA_PTR;
 #define GPTCR_TEN       (1)	/* Timer enable */
 
 /*
- * "time" is measured in 1 / CONFIG_SYS_HZ seconds,
- * "tick" is internal timer period
- */
-/* ~0.4% error - measured with stop-watch on 100s boot-delay */
-static inline unsigned long long tick_to_time(unsigned long long tick)
-{
-	tick *= CONFIG_SYS_HZ;
-	do_div(tick, MXC_CLK32);
-
-	return tick;
-}
-
-static inline unsigned long long us_to_tick(unsigned long long us)
-{
-	us = us * MXC_CLK32 + 999999;
-	do_div(us, 1000000);
-
-	return us;
-}
-
-/*
  * nothing really to do with interrupts, just starts up a counter.
  * The 32KHz 32-bit timer overruns in 134217 seconds
  */
@@ -71,60 +45,3 @@ int timer_init(void)
 
 	return 0;
 }
-
-unsigned long long get_ticks(void)
-{
-	struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR;
-	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;
-}
-
-ulong get_timer_masked(void)
-{
-	/*
-	 * get_ticks() returns a long long (64 bit), it wraps in
-	 * 2^64 / MXC_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)
-{
-	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*/;
-}
-
-/*
- * This function is derived from PowerPC code (timebase clock frequency).
- * On ARM it returns the number of timer ticks per second.
- */
-ulong get_tbclk(void)
-{
-	return MXC_CLK32;
-}
diff --git a/arch/arm/include/asm/arch-mx35/imx-regs.h b/arch/arm/include/asm/arch-mx35/imx-regs.h
index b530029..28a47ed 100644
--- a/arch/arm/include/asm/arch-mx35/imx-regs.h
+++ b/arch/arm/include/asm/arch-mx35/imx-regs.h
@@ -372,4 +372,16 @@ struct aips_regs {
 #define CCM_RCSR_NF_16BIT_SEL	(1 << 14)
 
 #endif
+
+/*
+ * Generic timer support
+ */
+#ifdef CONFIG_MX35_CLK32
+#define	CONFIG_SYS_TIMER_RATE	CONFIG_MX35_CLK32
+#else
+#define	CONFIG_SYS_TIMER_RATE	32768
+#endif
+
+#define CONFIG_SYS_TIMER_COUNTER	(GPT1_BASE_ADDR+36)
+
 #endif /* __ASM_ARCH_MX35_H */
-- 
2.0.1