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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>
27 lines
610 B
C
27 lines
610 B
C
/*
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* arch/arm/include/asm/timex.h
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*
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* Copyright (C) 1997,1998 Russell King
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Architecture Specific TIME specifications
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*/
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#ifndef _ASMARM_TIMEX_H
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#define _ASMARM_TIMEX_H
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#include <asm/arch_timer.h>
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#include <mach/timex.h>
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typedef unsigned long cycles_t;
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#ifdef ARCH_HAS_READ_CURRENT_TIMER
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#define get_cycles() ({ cycles_t c; read_current_timer(&c) ? 0 : c; })
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#else
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#define get_cycles() (0)
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#endif
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#endif
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