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ARM: 7538/1: delay: add registration mechanism for delay timer sources

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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>
This commit is contained in:
Jonathan Austin
2012-09-21 18:51:44 +01:00
committed by Russell King
parent a1b2dde704
commit 56942fec06
5 changed files with 43 additions and 24 deletions
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9
arch/arm/include/asm/delay.h
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@@ -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_delay(unsigned long loops);
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) */