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author | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-01-14 20:07:35 +0000 |
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committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-05-02 09:35:36 +0100 |
commit | f5fc00826d1e60af0e22cb9f65b933d823a8ed84 (patch) | |
tree | bcff2df77e951dbfc0833cda47620ee3c65694ac /arch/arm/plat-versatile/sched-clock.c | |
parent | 6be4826e37122b25cb10b215fc84c3a0b1fe1402 (diff) | |
download | linux-stable-f5fc00826d1e60af0e22cb9f65b933d823a8ed84.tar.gz linux-stable-f5fc00826d1e60af0e22cb9f65b933d823a8ed84.tar.bz2 linux-stable-f5fc00826d1e60af0e22cb9f65b933d823a8ed84.zip |
ARM: Realview/Versatile: separate out common sched_clock()
Provide a common sched_clock() implementation for Versatile and
Realview.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/plat-versatile/sched-clock.c')
-rw-r--r-- | arch/arm/plat-versatile/sched-clock.c | 53 |
1 files changed, 53 insertions, 0 deletions
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 <linux/cnt32_to_63.h> +#include <linux/io.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 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; +} |