arm: pxa: use common timer functions

PATCH New Andrew Ruder 2 participants 3 messages Aug 12, 2015 Arm (32-bit)

lore

Share & tools

lore

Andrew Ruder

author

2015-08-12 18:18 UTC #0 lore raw

PATCH 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]>

---

Tom,

You had asked me to fix up this patch back on August 30, 2014. It broke compilation on some PXA ports. I have compile-tested on every PXA board in the tree, I believe. I have tested it on a yet-to-be-upstreamed board port based on the PXA270.

 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 7a34a01..22fff02 100644
@@ -19,7 +19,10 @@
 #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

2.1.4

Andrew Ruder

author

2015-08-12 18:21 UTC #1 lore raw

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

Tom,

Just replying so you see this since apparently I should have used copy-paste on your e-mail address for the Cc: and not attempted to read after 45 cups of tea.

- Andy

Marek Vasut

2015-08-12 19:27 UTC #2 lore raw

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

In reply to Andrew Ruder

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]>

Applied to u-boot-pxa/master, thanks.

Best regards,
Marek Vasut