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>
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);
}