ARM: 7538/1: delay: add registration mechanism for delay timer sources
The current timer-based delay loop relies on the architected timer to
initiate the switch away from the polling-based implementation. This is
unfortunate for platforms without the architected timers but with a
suitable delay source (that is, constant frequency, always powered-up
and ticking as long as the CPUs are online).
This patch introduces a registration mechanism for the delay timer
(which provides an unconditional read_current_timer implementation) and
updates the architected timer code to use the new interface.
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/include/asm/arch_timer.h b/arch/arm/include/asm/arch_timer.h
index ad9b155..d40229d 100644
--- a/arch/arm/include/asm/arch_timer.h
+++ b/arch/arm/include/asm/arch_timer.h
@@ -5,7 +5,6 @@
#include <linux/clocksource.h>
#ifdef CONFIG_ARM_ARCH_TIMER
-#define ARCH_HAS_READ_CURRENT_TIMER
int arch_timer_of_register(void);
int arch_timer_sched_clock_init(void);
struct timecounter *arch_timer_get_timecounter(void);
diff --git a/arch/arm/include/asm/delay.h b/arch/arm/include/asm/delay.h
index dc61451..ab98fdd 100644
--- a/arch/arm/include/asm/delay.h
+++ b/arch/arm/include/asm/delay.h
@@ -15,6 +15,11 @@
#ifndef __ASSEMBLY__
+struct delay_timer {
+ unsigned long (*read_current_timer)(void);
+ unsigned long freq;
+};
+
extern struct arm_delay_ops {
void (*delay)(unsigned long);
void (*const_udelay)(unsigned long);
@@ -56,6 +61,10 @@
extern void __loop_udelay(unsigned long usecs);
extern void __loop_const_udelay(unsigned long);
+/* Delay-loop timer registration. */
+#define ARCH_HAS_READ_CURRENT_TIMER
+extern void register_current_timer_delay(const struct delay_timer *timer);
+
#endif /* __ASSEMBLY__ */
#endif /* defined(_ARM_DELAY_H) */
diff --git a/arch/arm/include/asm/timex.h b/arch/arm/include/asm/timex.h
index ce11944..9acc135 100644
--- a/arch/arm/include/asm/timex.h
+++ b/arch/arm/include/asm/timex.h
@@ -12,15 +12,9 @@
#ifndef _ASMARM_TIMEX_H
#define _ASMARM_TIMEX_H
-#include <asm/arch_timer.h>
#include <mach/timex.h>
typedef unsigned long cycles_t;
-
-#ifdef ARCH_HAS_READ_CURRENT_TIMER
#define get_cycles() ({ cycles_t c; read_current_timer(&c) ? 0 : c; })
-#else
-#define get_cycles() (0)
-#endif
#endif