diff options
| author | Will Deacon <will.deacon@arm.com> | 2012-07-06 18:46:45 +0400 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2012-07-09 20:42:23 +0400 |
| commit | 923df96b9f31b7d08d8438ff9677326d9537accf (patch) | |
| tree | 3df937a0431a2ae0500ae011f5742a28611490fa /arch/arm | |
| parent | f8f5701bdaf9134b1f90e5044a82c66324d2073f (diff) | |
| download | linux-923df96b9f31b7d08d8438ff9677326d9537accf.tar.xz | |
ARM: 7451/1: arch timer: implement read_current_timer and get_cycles
This patch implements read_current_timer using the architected timers
when they are selected via CONFIG_ARM_ARCH_TIMER. If they are detected
not to be usable at runtime, we return -ENXIO to the caller.
Furthermore, if read_current_timer is exported then we can implement
get_cycles in terms of it for use as both an entropy source and for
implementing __udelay and friends.
Tested-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/include/asm/arch_timer.h | 3 | ||||
| -rw-r--r-- | arch/arm/include/asm/timex.h | 10 | ||||
| -rw-r--r-- | arch/arm/kernel/arch_timer.c | 8 |
3 files changed, 17 insertions, 4 deletions
diff --git a/arch/arm/include/asm/arch_timer.h b/arch/arm/include/asm/arch_timer.h index ed2e95d46e29..62e75475e57e 100644 --- a/arch/arm/include/asm/arch_timer.h +++ b/arch/arm/include/asm/arch_timer.h @@ -1,7 +1,10 @@ #ifndef __ASMARM_ARCH_TIMER_H #define __ASMARM_ARCH_TIMER_H +#include <asm/errno.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); #else diff --git a/arch/arm/include/asm/timex.h b/arch/arm/include/asm/timex.h index 3be8de3adaba..ce119442277c 100644 --- a/arch/arm/include/asm/timex.h +++ b/arch/arm/include/asm/timex.h @@ -12,13 +12,15 @@ #ifndef _ASMARM_TIMEX_H #define _ASMARM_TIMEX_H +#include <asm/arch_timer.h> #include <mach/timex.h> typedef unsigned long cycles_t; -static inline cycles_t get_cycles (void) -{ - return 0; -} +#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 diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c index dd58035621f7..dbbeec4f06e2 100644 --- a/arch/arm/kernel/arch_timer.c +++ b/arch/arm/kernel/arch_timer.c @@ -223,6 +223,14 @@ static cycle_t arch_counter_read(struct clocksource *cs) return arch_counter_get_cntpct(); } +int read_current_timer(unsigned long *timer_val) +{ + if (!arch_timer_rate) + return -ENXIO; + *timer_val = arch_counter_get_cntpct(); + return 0; +} + static struct clocksource clocksource_counter = { .name = "arch_sys_counter", .rating = 400, |