From f5fc00826d1e60af0e22cb9f65b933d823a8ed84 Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 14 Jan 2010 20:07:35 +0000 Subject: ARM: Realview/Versatile: separate out common sched_clock() Provide a common sched_clock() implementation for Versatile and Realview. Signed-off-by: Russell King --- arch/arm/plat-versatile/sched-clock.c | 53 +++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 arch/arm/plat-versatile/sched-clock.c (limited to 'arch/arm/plat-versatile/sched-clock.c') diff --git a/arch/arm/plat-versatile/sched-clock.c b/arch/arm/plat-versatile/sched-clock.c new file mode 100644 index 000000000000..9768cf7e83d7 --- /dev/null +++ b/arch/arm/plat-versatile/sched-clock.c @@ -0,0 +1,53 @@ +/* + * 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 +#include +#include + +#include +#include + +#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 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; +} -- cgit v1.2.3