Re: [1/2] RTC: Add core rtc support for Gemini Soc devices

[Roman Yeryomin <roman@advem.lv>]

[-- Attachment #1: Type: text/plain, Size: 1332 bytes --]

On 2015-05-08 19:08, Arnd Bergmann wrote:
> On Thursday 07 May 2015 12:03:25 Roman Yeryomin wrote:
>> On 2015-05-06 22:22, Arnd Bergmann wrote:
>> > On Wednesday 06 May 2015 19:21:21 Roman Yeryomin wrote:
>> >>
>> >> > Thanks to point that, I'll merge that one which seems clean enough:
>> >> > http://git.openwrt.org/?p=openwrt.git;a=blob;f=target/linux/gemini/files/drivers/rtc/rtc-gemini.c;h=587d8122b2fbb1230437eadcce4789a53aa60ee5;hb=4c637410a2a1ab45988e8ca6202554a502102039
>> >>
>> >> For 3.18 (and up) to work on gemini 160-gemini-timers.patch is vital.
>> >> Without that timers are broken and cpu is super slow.
>> >
>> > Do you know what part of the patch is the actual bug fix? We should
>> > probably
>> > merge that separately and mark it for stable backports, while the bulk
>> > of that
>> > patch seems to just rearrange code.
>> >
>> >       Arnd
>> 
>> Sorry, didn't try to extract the exact lines it but I guess it's that
>> part which touches the scheduler clock code.
>> Because without that patch sched clock runs at 100Hz instead of 25MHz.
>> I can dive into this deeper if you want, I just didn't see the need.
> 
> I think that would be helpful, yes.
> 

OK, here are the minimal changes required (see attachment). Tested on 
4.1.1
Let me know if you want me to submit it in some other way.

Regards,
Roman

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 160-gemini-timers.patch --]
[-- Type: text/x-diff; name=160-gemini-timers.patch, Size: 1986 bytes --]

--- a/arch/arm/mach-gemini/time.c
+++ b/arch/arm/mach-gemini/time.c
@@ -15,6 +15,7 @@
 #include <asm/mach/time.h>
 #include <linux/clockchips.h>
 #include <linux/clocksource.h>
+#include <linux/sched_clock.h>
 
 /*
  * Register definitions for the timers
@@ -34,9 +35,17 @@
 #define TIMER_3_CR_ENABLE		(1 << 6)
 #define TIMER_3_CR_CLOCK		(1 << 7)
 #define TIMER_3_CR_INT			(1 << 8)
+#define TIMER_1_CR_UPDOWN		(1 << 9)
+#define TIMER_2_CR_UPDOWN		(1 << 10)
+#define TIMER_3_CR_UPDOWN		(1 << 11)
 
 static unsigned int tick_rate;
 
+static u64 notrace gemini_read_sched_clock(void)
+{
+	return readl(TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER3_BASE)));
+}
+
 static int gemini_timer_set_next_event(unsigned long cycles,
 				       struct clock_event_device *evt)
 {
@@ -155,14 +164,18 @@ void __init gemini_timer_init(void)
 	 */
 	setup_irq(IRQ_TIMER2, &gemini_timer_irq);
 
-	/* Enable and use TIMER1 as clock source */
-	writel(0xffffffff, TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER1_BASE)));
-	writel(0xffffffff, TIMER_LOAD(IO_ADDRESS(GEMINI_TIMER1_BASE)));
-	writel(TIMER_1_CR_ENABLE, TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
-	if (clocksource_mmio_init(TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER1_BASE)),
-				  "TIMER1", tick_rate, 300, 32,
+	/* Enable and use TIMER3 as clock source */
+	writel(0, TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER3_BASE)));
+	writel(0, TIMER_LOAD(IO_ADDRESS(GEMINI_TIMER3_BASE)));
+	writel(0, TIMER_MATCH1(IO_ADDRESS(GEMINI_TIMER3_BASE)));
+	writel(0, TIMER_MATCH2(IO_ADDRESS(GEMINI_TIMER3_BASE)));
+	writel(TIMER_3_CR_ENABLE | TIMER_3_CR_UPDOWN,
+		TIMER_CR(IO_ADDRESS(GEMINI_TIMER_BASE)));
+	if (clocksource_mmio_init(TIMER_COUNT(IO_ADDRESS(GEMINI_TIMER3_BASE)),
+				  "TIMER3", tick_rate, 300, 32,
 				  clocksource_mmio_readl_up))
 		pr_err("timer: failed to initialize gemini clock source\n");
+	sched_clock_register(gemini_read_sched_clock, 32, tick_rate);
 
 	/* Configure and register the clockevent */
 	clockevents_config_and_register(&gemini_clockevent, tick_rate,