[PATCH 12/13] ARM: versatile: convert sched_clock() to use new infrastructure
Russell King - ARM Linux
linux at arm.linux.org.uk
Thu Dec 16 04:31:43 EST 2010
Convert versatile platforms to use the new sched_clock() infrastructure
for extending 32bit counters to full 64-bit nanoseconds.
Signed-off-by: Russell King <rmk+kernel at arm.linux.org.uk>
---
arch/arm/Kconfig | 2 +
arch/arm/mach-realview/core.c | 10 ++++
arch/arm/mach-versatile/core.c | 10 ++++
arch/arm/plat-versatile/include/plat/sched_clock.h | 6 +++
arch/arm/plat-versatile/sched-clock.c | 48 +++++++++++---------
5 files changed, 54 insertions(+), 22 deletions(-)
create mode 100644 arch/arm/plat-versatile/include/plat/sched_clock.h
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 92e8c01..34311f4 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -236,6 +236,7 @@ config ARCH_REALVIEW
bool "ARM Ltd. RealView family"
select ARM_AMBA
select COMMON_CLKDEV
+ select HAVE_SCHED_CLOCK
select ICST
select GENERIC_CLOCKEVENTS
select ARCH_WANT_OPTIONAL_GPIOLIB
@@ -250,6 +251,7 @@ config ARCH_VERSATILE
select ARM_AMBA
select ARM_VIC
select COMMON_CLKDEV
+ select HAVE_SCHED_CLOCK
select ICST
select GENERIC_CLOCKEVENTS
select ARCH_WANT_OPTIONAL_GPIOLIB
diff --git a/arch/arm/mach-realview/core.c b/arch/arm/mach-realview/core.c
index 07c0815..3d653e0 100644
--- a/arch/arm/mach-realview/core.c
+++ b/arch/arm/mach-realview/core.c
@@ -52,6 +52,8 @@
#include <mach/irqs.h>
#include <plat/timer-sp.h>
+#include <plat/sched_clock.h>
+
#include "core.h"
/* used by entry-macro.S and platsmp.c */
@@ -658,6 +660,12 @@ void realview_leds_event(led_event_t ledevt)
#endif /* CONFIG_LEDS */
/*
+ * The sched_clock counter
+ */
+#define REFCOUNTER (__io_address(REALVIEW_SYS_BASE) + \
+ REALVIEW_SYS_24MHz_OFFSET)
+
+/*
* Where is the timer (VA)?
*/
void __iomem *timer0_va_base;
@@ -672,6 +680,8 @@ void __init realview_timer_init(unsigned int timer_irq)
{
u32 val;
+ versatile_sched_clock_init(REFCOUNTER, 24000000);
+
/*
* set clock frequency:
* REALVIEW_REFCLK is 32KHz
diff --git a/arch/arm/mach-versatile/core.c b/arch/arm/mach-versatile/core.c
index e38acb0..56cdc22 100644
--- a/arch/arm/mach-versatile/core.c
+++ b/arch/arm/mach-versatile/core.c
@@ -51,6 +51,8 @@
#include <mach/platform.h>
#include <plat/timer-sp.h>
+#include <plat/sched_clock.h>
+
#include "core.h"
/*
@@ -886,6 +888,12 @@ void __init versatile_init(void)
}
/*
+ * The sched_clock counter
+ */
+#define REFCOUNTER (__io_address(VERSATILE_SYS_BASE) + \
+ VERSATILE_SYS_24MHz_OFFSET)
+
+/*
* Where is the timer (VA)?
*/
#define TIMER0_VA_BASE __io_address(VERSATILE_TIMER0_1_BASE)
@@ -900,6 +908,8 @@ static void __init versatile_timer_init(void)
{
u32 val;
+ versatile_sched_clock_init(REFCOUNTER, 24000000);
+
/*
* set clock frequency:
* VERSATILE_REFCLK is 32KHz
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 0000000..5c3e4fc
--- /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 42efd14..3d6a4c2 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);
}
--
1.6.2.5
More information about the linux-arm-kernel
mailing list