ARM: nomadik: convert sched_clock() to use new infrastructure

Convert nomadik platforms to use the new sched_clock() infrastructure
for extending 32bit counters to full 64-bit nanoseconds.

Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 10 insertions, 67 deletions

diff --git a/arch/arm/plat-nomadik/Kconfig b/arch/arm/plat-nomadik/Kconfig
index 5da3f97c537b..187f4e84bb22 100644
--- a/arch/arm/plat-nomadik/Kconfig
+++ b/arch/arm/plat-nomadik/Kconfig
@@ -14,6 +14,7 @@ if PLAT_NOMADIK
 
 config HAS_MTU
         bool
+        select HAVE_SCHED_CLOCK
         help
           Support for Multi Timer Unit. MTU provides access
           to multiple interrupt generating programmable
diff --git a/arch/arm/plat-nomadik/timer.c b/arch/arm/plat-nomadik/timer.c
index c3b8a2246b99..41723402006b 100644
--- a/arch/arm/plat-nomadik/timer.c
+++ b/arch/arm/plat-nomadik/timer.c
@@ -17,10 +17,9 @@
 #include <linux/clk.h>
 #include <linux/jiffies.h>
 #include <linux/err.h>
-#include <linux/cnt32_to_63.h>
-#include <linux/timer.h>
 #include <linux/sched.h>
 #include <asm/mach/time.h>
+#include <asm/sched_clock.h>
 
 #include <plat/mtu.h>
 
@@ -53,81 +52,24 @@ static struct clocksource nmdk_clksrc = {
  * Override the global weak sched_clock symbol with this
  * local implementation which uses the clocksource to get some
  * better resolution when scheduling the kernel.
- *
- * Because the hardware timer period may be quite short
- * (32.3 secs on the 133 MHz MTU timer selection on ux500)
- * and because cnt32_to_63() needs to be called at least once per
- * half period to work properly, a kernel keepwarm() timer is set up
- * to ensure this requirement is always met.
- *
- * Also the sched_clock timer will wrap around at some point,
- * here we set it to run continously for a year.
  */
-#define SCHED_CLOCK_MIN_WRAP 3600*24*365
-static struct timer_list cnt32_to_63_keepwarm_timer;
-static u32 sched_mult;
-static u32 sched_shift;
+static DEFINE_CLOCK_DATA(cd);
 
 unsigned long long notrace sched_clock(void)
 {
-        u64 cycles;
+        u32 cyc;
 
         if (unlikely(!mtu_base))
                 return 0;
 
-        cycles = cnt32_to_63(-readl(mtu_base + MTU_VAL(0)));
-        /*
-         * sched_mult is guaranteed to be even so will
-         * shift out bit 63
-         */
-        return (cycles * sched_mult) >> sched_shift;
+        cyc = -readl(mtu_base + MTU_VAL(0));
+        return cyc_to_sched_clock(&cd, cyc, (u32)~0);
 }
 
-/* Just kick sched_clock every so often */
-static void cnt32_to_63_keepwarm(unsigned long data)
+static void notrace nomadik_update_sched_clock(void)
 {
-        mod_timer(&cnt32_to_63_keepwarm_timer, round_jiffies(jiffies + data));
-        (void) sched_clock();
-}
-
-/*
- * Set up a timer to keep sched_clock():s 32_to_63 algorithm warm
- * once in half a 32bit timer wrap interval.
- */
-static void __init nmdk_sched_clock_init(unsigned long rate)
-{
-        u32 v;
-        unsigned long delta;
-        u64 days;
-
-        /* Find the apropriate mult and shift factors */
-        clocks_calc_mult_shift(&sched_mult, &sched_shift,
-                               rate, NSEC_PER_SEC, SCHED_CLOCK_MIN_WRAP);
-        /* We need to multiply by an even number to get rid of bit 63 */
-        if (sched_mult & 1)
-                sched_mult++;
-
-        /* Let's see what we get, take max counter and scale it */
-        days = (0xFFFFFFFFFFFFFFFFLLU * sched_mult) >> sched_shift;
-        do_div(days, NSEC_PER_SEC);
-        do_div(days, (3600*24));
-
-        pr_info("sched_clock: using %d bits @ %lu Hz wrap in %lu days\n",
-                (64 - sched_shift), rate, (unsigned long) days);
-
-        /*
-         * Program a timer to kick us at half 32bit wraparound
-         * Formula: seconds per wrap = (2^32) / f
-         */
-        v = 0xFFFFFFFFUL / rate;
-        /* We want half of the wrap time to keep cnt32_to_63 warm */
-        v /= 2;
-        pr_debug("sched_clock: prescaled timer rate: %lu Hz, "
-                 "initialize keepwarm timer every %d seconds\n", rate, v);
-        /* Convert seconds to jiffies */
-        delta = msecs_to_jiffies(v*1000);
-        setup_timer(&cnt32_to_63_keepwarm_timer, cnt32_to_63_keepwarm, delta);
-        mod_timer(&cnt32_to_63_keepwarm_timer, round_jiffies(jiffies + delta));
+        u32 cyc = -readl(mtu_base + MTU_VAL(0));
+        update_sched_clock(&cd, cyc, (u32)~0);
 }
 
 /* Clockevent device: use one-shot mode */
@@ -237,7 +179,7 @@ void __init nmdk_timer_init(void)
                 pr_err("timer: failed to initialize clock source %s\n",
                        nmdk_clksrc.name);
 
-        nmdk_sched_clock_init(rate);
+        init_sched_clock(&cd, nomadik_update_sched_clock, 32, rate);
 
         /* Timer 1 is used for events */