linux_dsm_epyc7002/arch/arm/include/asm/timex.h
Will Deacon 923df96b9f 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>
2012-07-09 17:42:23 +01:00

27 lines
610 B
C

/*
* arch/arm/include/asm/timex.h
*
* Copyright (C) 1997,1998 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Architecture Specific TIME specifications
*/
#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