linux/arch/arm/plat-versatile/sched-clock.c
Russell King 5e06b6492e ARM: ensure all sched_clock() implementations are notrace marked
ftrace requires sched_clock() to be notrace.  Ensure that all
implementations are so marked.  Also make sure that they include
linux/sched.h

Also ensure OMAP clocksource read functions are marked notrace as
they're used for sched_clock() too.

Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Will Deacon <will.deacon@arm.com>
Tested-by: Mikael Pettersson <mikpe@it.uu.se>
Tested-by: Eric Miao <eric.y.miao@gmail.com>
Tested-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-12-22 22:44:42 +00:00

55 lines
1.7 KiB
C

/*
* linux/arch/arm/plat-versatile/sched-clock.c
*
* Copyright (C) 1999 - 2003 ARM Limited
* Copyright (C) 2000 Deep Blue Solutions Ltd
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/cnt32_to_63.h>
#include <linux/io.h>
#include <linux/sched.h>
#include <asm/div64.h>
#include <mach/hardware.h>
#include <mach/platform.h>
#ifdef VERSATILE_SYS_BASE
#define REFCOUNTER (__io_address(VERSATILE_SYS_BASE) + VERSATILE_SYS_24MHz_OFFSET)
#endif
#ifdef REALVIEW_SYS_BASE
#define REFCOUNTER (__io_address(REALVIEW_SYS_BASE) + REALVIEW_SYS_24MHz_OFFSET)
#endif
/*
* This is the Realview and Versatile sched_clock implementation. This
* has a resolution of 41.7ns, and a maximum value of about 35583 days.
*
* The return value is guaranteed to be monotonic in that range as
* long as there is always less than 89 seconds between successive
* calls to this function.
*/
unsigned long long notrace sched_clock(void)
{
unsigned long long v = cnt32_to_63(readl(REFCOUNTER));
/* the <<1 gets rid of the cnt_32_to_63 top bit saving on a bic insn */
v *= 125<<1;
do_div(v, 3<<1);
return v;
}