arm: pxa: use common timer functions

PATCH Superseded Andrew Ruder 2 participants 2 messages Oct 9, 2014 Arm (32-bit)

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Andrew Ruder

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2014-10-09 23:00 UTC #0 lore raw

PATCH v2 1/1 arm: pxa: use common timer functions

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

8dfafdd - Introduce common timer functions <Rob Herring>

The (removed) pxa 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 locked the processor. Rather than patch the specific pxa issues, simply move everything over to the common code.

Signed-off-by Andrew Ruder <[email protected]>

Cc Marek Vasut <[email protected]>

Cc Tom Rini <[email protected]>

---

FIRST VERSION AVAILABLE AT:
http://article.gmane.org/gmane.comp.boot-loaders.u-boot/192978

I missed some compile-testing last time and didn't notice that not every board includes configs/pxa-common.h. Rather than try to fix-up every board config (and possibly break out of tree ones, etc.), add a PXA-specific config.h. In any case, it must be something included via common.h as the generic time framework requires the CONFIG_SYS_TIMER_COUNTER definition.

One potential gotcha here is that now pxa-regs gets included via common.h which adds lots of short register names to the global namespace. Compile-tested every PXA board from the generated boards.cfg and didn't see any issues. Board-tested the PXA270.

checkpatch output:
total: 0 errors, 0 warnings, 0 checks, 75 lines checked

NOTE: Ignored message types: COMPLEX_MACRO CONSIDER_KSTRTO MINMAX MULTISTATEMENT_MACRO_USE_DO_WHILE NETWORKING_BLOCK_COMMENT_STYLE USLEEP_RANGE

0001-arm-pxa-use-common-timer-functions.patch has no obvious style problems and is ready for submission.

 arch/arm/cpu/pxa/timer.c               | 69 +---------------------------------
 arch/arm/include/asm/arch-pxa/config.h | 25 ++++++++++++
 arch/arm/include/asm/config.h          |  5 ++-
 3 files changed, 30 insertions(+), 69 deletions(-)
 create mode 100644 arch/arm/include/asm/arch-pxa/config.h

arch/arm/cpu/pxa/timer.c +1 ~~-68~~

index c4717de..11fefd5 100644
@@ -6,80 +6,13 @@
  * SPDX-License-Identifier:	GPL-2.0+
  */
 
-#include <asm/arch/pxa-regs.h>
 #include <asm/io.h>
 #include <common.h>
-#include <div64.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
-#define	TIMER_LOAD_VAL	0xffffffff
-
-#define	timestamp	(gd->arch.tbl)
-#define	lastinc		(gd->arch.lastinc)
-
-#if defined(CONFIG_CPU_PXA27X) || defined(CONFIG_CPU_MONAHANS)
-#define	TIMER_FREQ_HZ	3250000
-#elif defined(CONFIG_CPU_PXA25X)
-#define	TIMER_FREQ_HZ	3686400
-#else
-#error "Timer frequency unknown - please config PXA CPU type"
-#endif
-
-static unsigned long long tick_to_time(unsigned long long tick)
-{
-	return lldiv(tick * CONFIG_SYS_HZ, TIMER_FREQ_HZ);
-}
-
-static unsigned long long us_to_tick(unsigned long long us)
-{
-	return lldiv(us * TIMER_FREQ_HZ, 1000000);
-}
-
 int timer_init(void)
 {
-	writel(0, OSCR);
+	writel(0, CONFIG_SYS_TIMER_COUNTER);
 	return 0;
 }
-
-unsigned long long get_ticks(void)
-{
-	/* Current tick value */
-	uint32_t now = readl(OSCR);
-
-	if (now >= lastinc) {
-		/*
-		 * Normal mode (non roll)
-		 * Move stamp forward with absolute diff ticks
-		 */
-		timestamp += (now - lastinc);
-	} else {
-		/* We have rollover of incrementer */
-		timestamp += (TIMER_LOAD_VAL - lastinc) + now;
-	}
-
-	lastinc = now;
-	return timestamp;
-}
-
-ulong get_timer(ulong base)
-{
-	return tick_to_time(get_ticks()) - base;
-}
-
-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*/;
-}
-
-ulong get_tbclk(void)
-{
-	return TIMER_FREQ_HZ;
-}

arch/arm/include/asm/arch-pxa/config.h new file +25 -0

new file mode 100644
index 0000000..5836945
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2014 Andrew Ruder <[email protected]>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _ASM_ARM_PXA_CONFIG_
+#define _ASM_ARM_PXA_CONFIG_
+
+#include <asm/arch/pxa-regs.h>
+
+/*
+ * Generic timer support
+ */
+#if defined(CONFIG_CPU_PXA27X) || defined(CONFIG_CPU_MONAHANS)
+#define	CONFIG_SYS_TIMER_RATE	3250000
+#elif defined(CONFIG_CPU_PXA25X)
+#define	CONFIG_SYS_TIMER_RATE	3686400
+#else
+#error "Timer frequency unknown - please config PXA CPU type"
+#endif
+
+#define CONFIG_SYS_TIMER_COUNTER	OSCR
+
+#endif /* _ASM_ARM_PXA_CONFIG_ */

arch/arm/include/asm/config.h +4 -1

index be80434..1cfc83b 100644
@@ -23,7 +23,10 @@
 #include <asm/arch-fsl-lsch3/config.h>
 #endif
 
-#ifdef CONFIG_LS102XA
+#if defined(CONFIG_LS102XA) || \
+	defined(CONFIG_CPU_PXA27X) || \
+	defined(CONFIG_CPU_MONAHANS) || \
+	defined(CONFIG_CPU_PXA25X)
 #include <asm/arch/config.h>
 #endif

Signature · 1 line

2.1.1

Marek Vasut

2014-10-09 23:25 UTC #1 lore raw

PATCH v2 1/1 arm: pxa: use common timer functions

Quoted 11 lines · Andrew Ruder

This patch moves pxa to the common timer functions added in commit
8dfafdd - Introduce common timer functions <Rob Herring>
The (removed) pxa 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 locked the processor. Rather than patch the specific pxa issues, simply move everything over to the common code.

Quoted 3 lines

Signed-off-by Andrew Ruder <[email protected]>
Cc Marek Vasut <[email protected]>
Cc Tom Rini <[email protected]>

Reviewed-by Marek Vasut <[email protected]>

Best regards,
Marek Vasut