[U-Boot] [PATCH 2/3] arm: mx31: use common timer functions

[andrew.ruder at elecsyscorp.com]

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

This patch moves mx31 to the common timer functions added in commit

  8dfafdd - Introduce common timer functions <Rob Herring>

The (removed) mx31 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 mx31 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: Linus Walleij <linus.walleij at linaro.org>
Cc: Wolfgang Denk <wd at denx.de>
Cc: Fabio Estevam <fabio.estevam at freescale.com>
Cc: Helmut Raiger <helmut.raiger at hale.at>
---

This patch has been COMPILE tested only.  The situation isn't quite as
bad on mx31 as 32-bit rollover occurs in about a day and a half.

Before patch:
Configuring for qong board...
456 -rw-r--r-- 1 andy andy 463236 Aug 12 08:36 u-boot.bin

After patch:
Configuring for qong board...
456 -rw-r--r-- 1 andy andy 463248 Aug 12 08:38 u-boot.bin

 arch/arm/cpu/arm1136/mx31/timer.c         | 104 +-----------------------------
 arch/arm/include/asm/arch-mx31/imx-regs.h |  10 +++
 2 files changed, 12 insertions(+), 102 deletions(-)

diff --git a/arch/arm/cpu/arm1136/mx31/timer.c b/arch/arm/cpu/arm1136/mx31/timer.c
index f111242..3a81ce4 100644
--- a/arch/arm/cpu/arm1136/mx31/timer.c
+++ b/arch/arm/cpu/arm1136/mx31/timer.c
@@ -7,9 +7,6 @@
 
 #include <common.h>
 #include <asm/arch/imx-regs.h>
-#include <asm/arch/clock.h>
-#include <div64.h>
-#include <watchdog.h>
 #include <asm/io.h>
 
 #define TIMER_BASE 0x53f90000 /* General purpose timer 1 */
@@ -28,57 +25,6 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-/*
- * "time" is measured in 1 / CONFIG_SYS_HZ seconds,
- * "tick" is internal timer period
- */
-
-#ifdef CONFIG_MX31_TIMER_HIGH_PRECISION
-/* ~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 time_to_tick(unsigned long long time)
-{
-	time *= MXC_CLK32;
-	do_div(time, CONFIG_SYS_HZ);
-	return time;
-}
-
-static inline unsigned long long us_to_tick(unsigned long long us)
-{
-	us = us * MXC_CLK32 + 999999;
-	do_div(us, 1000000);
-	return us;
-}
-#else
-/* ~2% error */
-#define TICK_PER_TIME	((MXC_CLK32 + CONFIG_SYS_HZ / 2) / CONFIG_SYS_HZ)
-#define US_PER_TICK	(1000000 / MXC_CLK32)
-
-static inline unsigned long long tick_to_time(unsigned long long tick)
-{
-	do_div(tick, TICK_PER_TIME);
-	return tick;
-}
-
-static inline unsigned long long time_to_tick(unsigned long long time)
-{
-	return time * TICK_PER_TIME;
-}
-
-static inline unsigned long long us_to_tick(unsigned long long us)
-{
-	us += US_PER_TICK - 1;
-	do_div(us, US_PER_TICK);
-	return us;
-}
-#endif
-
 /* The 32768Hz 32-bit timer overruns in 131072 seconds */
 int timer_init(void)
 {
@@ -95,53 +41,7 @@ int timer_init(void)
 	return 0;
 }
 
-unsigned long long get_ticks(void)
-{
-	ulong now = GPTCNT; /* current tick value */
-
-	if (now >= gd->arch.lastinc)	/* normal mode (non roll) */
-		/* move stamp forward with absolut diff ticks */
-		gd->arch.tbl += (now - gd->arch.lastinc);
-	else			/* we have rollover of incrementer */
-		gd->arch.tbl += (0xFFFFFFFF - gd->arch.lastinc) + now;
-	gd->arch.lastinc = now;
-	return gd->arch.tbl;
-}
-
-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 timestamp 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)
+unsigned long timer_read_counter(void)
 {
-	return MXC_CLK32;
+	return GPTCNT;
 }
diff --git a/arch/arm/include/asm/arch-mx31/imx-regs.h b/arch/arm/include/asm/arch-mx31/imx-regs.h
index f23350e..71ebd24 100644
--- a/arch/arm/include/asm/arch-mx31/imx-regs.h
+++ b/arch/arm/include/asm/arch-mx31/imx-regs.h
@@ -909,9 +909,19 @@ struct esdc_regs {
 #define MXC_CSPIPERIOD_32KHZ	(1 << 15)
 #define MAX_SPI_BYTES	4
 
+
 #define MXC_SPI_BASE_ADDRESSES \
 	0x43fa4000, \
 	0x50010000, \
 	0x53f84000,
 
+/*
+ * Generic timer support
+ */
+#ifdef CONFIG_MX31_CLK32
+#define	CONFIG_SYS_TIMER_RATE	CONFIG_MX31_CLK32
+#else
+#define	CONFIG_SYS_TIMER_RATE	32768
+#endif
+
 #endif /* __ASM_ARCH_MX31_IMX_REGS_H */
-- 
2.0.1