diff options
| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-12-16 00:56:47 +0300 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-12-23 01:44:50 +0300 |
| commit | 1da0c89c66753860ccfe81eb327c25db46c2a24a (patch) | |
| tree | 565710dc2a57dca18a17d3e34465485f32191b81 /arch/arm/plat-versatile | |
| parent | f06a1624621527ef597ae4b3b795553fc1b2eff2 (diff) | |
| download | linux-1da0c89c66753860ccfe81eb327c25db46c2a24a.tar.xz | |
ARM: versatile: convert sched_clock() to use new infrastructure
Convert versatile platforms to use the new sched_clock() infrastructure
for extending 32bit counters to full 64-bit nanoseconds.
Tested-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/plat-versatile')
| -rw-r--r-- | arch/arm/plat-versatile/include/plat/sched_clock.h | 6 | ||||
| -rw-r--r-- | arch/arm/plat-versatile/sched-clock.c | 48 |
2 files changed, 32 insertions, 22 deletions
diff --git a/arch/arm/plat-versatile/include/plat/sched_clock.h b/arch/arm/plat-versatile/include/plat/sched_clock.h new file mode 100644 index 000000000000..5c3e4fc9fa0c --- /dev/null +++ b/arch/arm/plat-versatile/include/plat/sched_clock.h @@ -0,0 +1,6 @@ +#ifndef ARM_PLAT_SCHED_CLOCK_H +#define ARM_PLAT_SCHED_CLOCK_H + +void versatile_sched_clock_init(void __iomem *, unsigned long); + +#endif diff --git a/arch/arm/plat-versatile/sched-clock.c b/arch/arm/plat-versatile/sched-clock.c index 42efd14ed4b3..3d6a4c292cab 100644 --- a/arch/arm/plat-versatile/sched-clock.c +++ b/arch/arm/plat-versatile/sched-clock.c @@ -18,37 +18,41 @@ * 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> +#include <asm/sched_clock.h> +#include <plat/sched_clock.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 +static DEFINE_CLOCK_DATA(cd); +static void __iomem *ctr; /* - * 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. + * Constants generated by clocks_calc_mult_shift(m, s, 24MHz, NSEC_PER_SEC, 60). + * This gives a resolution of about 41ns and a wrap period of about 178s. */ +#define SC_MULT 2796202667u +#define SC_SHIFT 26 + unsigned long long notrace sched_clock(void) { - unsigned long long v = cnt32_to_63(readl(REFCOUNTER)); + if (ctr) { + u32 cyc = readl(ctr); + return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0, + SC_MULT, SC_SHIFT); + } else + return 0; +} - /* 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); +static void notrace versatile_update_sched_clock(void) +{ + u32 cyc = readl(ctr); + update_sched_clock(&cd, cyc, (u32)~0); +} - return v; +void __init versatile_sched_clock_init(void __iomem *reg, unsigned long rate) +{ + ctr = reg; + init_fixed_sched_clock(&cd, versatile_update_sched_clock, + 32, rate, SC_MULT, SC_SHIFT); } |