[PATCH v2 2/2] ARM: delay: allow timer-based delay implementation to be selected
From: Shinya Kuribayashi <hidden>
Date: 2012-07-05 13:06:13
On 6/30/2012 2:33 AM, Will Deacon wrote:
quoted hunk ↗ jump to hunk
diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c index dbbeec4..675cee0 100644 --- a/arch/arm/kernel/arch_timer.c +++ b/arch/arm/kernel/arch_timer.c@@ -32,6 +32,8 @@ static int arch_timer_ppi2; static struct clock_event_device __percpu **arch_timer_evt; +extern void init_current_timer_delay(unsigned long freq); +
This is needed for all users of the new timer-baed delay routine. How about moving this extern declaration to more generic place, in <asm/timex.h>?
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/* * Architected system timer support. */@@ -304,6 +306,7 @@ static int __init arch_timer_register(void) if (err) goto out_free_irq; + init_current_timer_delay(arch_timer_rate); return 0; out_free_irq:
This is arch_timer-land change. I'd prefer to see general part changes first, followed by arch_timer ones making use of them.
quoted hunk ↗ jump to hunk
diff --git a/arch/arm/lib/delay.c b/arch/arm/lib/delay.c new file mode 100644 index 0000000..e1030e1 --- /dev/null +++ b/arch/arm/lib/delay.c@@ -0,0 +1,66 @@
[...]
+void __init init_current_timer_delay(unsigned long freq)
+{
+ pr_info("Switching to timer-based delay loop\n");
+ lpj_fine = freq / HZ;
I've been preparing for lpj_fine with rounding it up by HZ like this:
lpj_fine = (freq + (HZ/2)) / HZ;
It's not necessarily required, but just in case.
+ arm_delay_ops.delay = __timer_delay; + arm_delay_ops.const_udelay = __timer_const_udelay; + arm_delay_ops.udelay = __timer_udelay; +} +#endif
I modified pr_info() at the end of function to print (lpj=%lu),
+ pr_info("Switching to timer-based delay loop (lpj=%lu)\n", lpj_fine);
but turned out to be printed twice, no-so-great:
sched_clock: 32 bits at 13MHz, resolution 76ns, wraps every 330382ms
cmt: CMCLKE e6131000 mapped to e6131000
sh_cmt.11 at 0xe6130100 probed with CMCLKE
sh_cmt.12 at 0xe6130200 probed with CMCLKE
sh_cmt.11 used for periodic clock events
sh_cmt.11 used for clock events
Switching to timer-based delay loop (lpj=101562) <<<
Console: colour dummy device 80x30
Calibrating delay loop (skipped), value calculated using timer frequency.. 26.04 BogoMIPS (lpj=101562) <<<
Anyway,
Tested-off-by: Shinya Kuribayashi [off-list ref]
Thank for the work, hope this to be merged soon!
Shinya