clocksource/clockevents fixes for 3.13

Hi Thomas, Ingo,

here are the fixes for 3.13 based on timers/urgent

* Axel Lin added a missing dependency on CLKSRC_MMIO in the Kconfig
for the time-efm32

* Dinh Nguyen fixed read_sched_clock to return the right value and
added the clksrc-of missing definition for the dw_apb_timer

* Ezequiel Garcia registered the sched clock after the counter, thus
preventing time jump in the traces for the armada-370-xp

* Marc Zyngier stopped the timer before enabling the irq in order to
prevent it to be fired before the clockevent is registered for the sunxi

* Thierry Reding removed a of_node_put in clksrc-of because the
reference is not held

Thanks
-- Daniel

----------------------------------------------------------------

The following changes since commit 0e576acbc1d9600cf2d9b4a141a2554639959d50:

nohz: Fix another inconsistency between CONFIG_NO_HZ=n and nohz=off
(2013-11-29 12:23:03 +0100)

are available in the git repository at:

git://git.linaro.org/people/daniel.lezcano/linux.git clockevents/fixes

for you to fetch changes up to 9ab4727c1d41e50b67aecde4bf11879560a3ca78:

clocksource: dw_apb_timer_of: Fix support for dts binding
"snps,dw-apb-timer" (2013-12-10 19:49:18 +0100)

----------------------------------------------------------------
Axel Lin (1):
clocksource: time-efm32: Select CLKSRC_MMIO

Dinh Nguyen (2):
clocksource: dw_apb_timer_of: Fix read_sched_clock
clocksource: dw_apb_timer_of: Fix support for dts binding
"snps,dw-apb-timer"

Ezequiel Garcia (1):
clocksource: armada-370-xp: Register sched_clock after the
counter reset

Marc Zyngier (1):
clocksource: sunxi: Stop timer from ticking before enabling
interrupts

Thierry Reding (1):
clocksource: clksrc-of: Do not drop unheld reference on device node

  drivers/clocksource/Kconfig              |    1 +
  drivers/clocksource/clksrc-of.c          |    1 -
  drivers/clocksource/dw_apb_timer_of.c    |    7 ++++---
  drivers/clocksource/sun4i_timer.c        |    3 +++
  drivers/clocksource/time-armada-370-xp.c |   10 +++++-----
  5 files changed, 13 insertions(+), 9 deletions(-)

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From: Axel Lin <[email protected]>

The time-efm32 driver uses the clocksource MMIO functions. Thus it needs to select CLKSRC_MMIO in Kconfig.

---
 drivers/clocksource/Kconfig |    1 +
 1 file changed, 1 insertion(+)

index 5c07a56..634c4d6 100644
@@ -75,6 +75,7 @@ config CLKSRC_DBX500_PRCMU_SCHED_CLOCK
 config CLKSRC_EFM32
 	bool "Clocksource for Energy Micro's EFM32 SoCs" if !ARCH_EFM32
 	depends on OF && ARM && (ARCH_EFM32 || COMPILE_TEST)
+	select CLKSRC_MMIO
 	default ARCH_EFM32
 	help
 	  Support to use the timers of EFM32 SoCs as clock source and clock

1.7.9.5

From: Ezequiel Garcia <[email protected]>

This commit registers the sched_clock _after_ the counter reset (instead of before). This removes the timestamp 'jump' in kernel log messages.

Before this change:

[    0.000000] sched_clock: 32 bits at 25MHz, resolution 40ns, wraps every 171798691800ns
[    0.000000] Initializing Coherency fabric
[    0.000000] Aurora cache controller enabled
[    0.000000] l2x0: 16 ways, CACHE_ID 0x00000100, AUX_CTRL 0x1a696b12, Cache size: 1024 kB
[  163.507447] Calibrating delay loop... 1325.05 BogoMIPS (lpj=662528)
[  163.521419] pid_max: default: 32768 minimum: 301
[  163.526185] Mount-cache hash table entries: 512
[  163.531095] CPU: Testing write buffer coherency: ok

After this change:

[    0.000000] sched_clock: 32 bits at 25MHz, resolution 40ns, wraps every 171798691800ns
[    0.000000] Initializing Coherency fabric
[    0.000000] Aurora cache controller enabled
[    0.000000] l2x0: 16 ways, CACHE_ID 0x00000100, AUX_CTRL 0x1a696b12, Cache size: 1024 kB
[    0.016849] Calibrating delay loop... 1325.05 BogoMIPS (lpj=662528)
[    0.030820] pid_max: default: 32768 minimum: 301
[    0.035588] Mount-cache hash table entries: 512
[    0.040500] CPU: Testing write buffer coherency: ok

---
 drivers/clocksource/time-armada-370-xp.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

index d8e47e5..4e7f680 100644
@@ -256,11 +256,6 @@ static void __init armada_370_xp_timer_common_init(struct device_node *np)
 	ticks_per_jiffy = (timer_clk + HZ / 2) / HZ;
 
 	/*
-	 * Set scale and timer for sched_clock.
-	 */
-	sched_clock_register(armada_370_xp_read_sched_clock, 32, timer_clk);
-
-	/*
 	 * Setup free-running clocksource timer (interrupts
 	 * disabled).
 	 */

@@ -270,6 +265,11 @@ static void __init armada_370_xp_timer_common_init(struct device_node *np)
 	timer_ctrl_clrset(0, TIMER0_EN | TIMER0_RELOAD_EN |
 			     TIMER0_DIV(TIMER_DIVIDER_SHIFT));
 
+	/*
+	 * Set scale and timer for sched_clock.
+	 */
+	sched_clock_register(armada_370_xp_read_sched_clock, 32, timer_clk);
+
 	clocksource_mmio_init(timer_base + TIMER0_VAL_OFF,
 			      "armada_370_xp_clocksource",
 			      timer_clk, 300, 32, clocksource_mmio_readl_down);

1.7.9.5

From: Thierry Reding <[email protected]>

When booting a recent kernel on ARM with OF_DYNAMIC enabled, the kernel warns about the following:

	[    0.000000] ERROR: Bad of_node_put() on /timer at 50004600
	[    0.000000] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.12.0-rc5-next-20131017-00077-gedfd827-dirty #406
	[    0.000000] [<c0015b68>] (unwind_backtrace+0x0/0xf4) from [<c00117e4>] (show_stack+0x10/0x14)
	[    0.000000] [<c00117e4>] (show_stack+0x10/0x14) from [<c055f734>] (dump_stack+0x9c/0xc8)
	[    0.000000] [<c055f734>] (dump_stack+0x9c/0xc8) from [<c03b47d4>] (of_node_release+0x90/0x9c)
	[    0.000000] [<c03b47d4>] (of_node_release+0x90/0x9c) from [<c03b5084>] (of_find_matching_node_and_match+0x78/0xb4)
	[    0.000000] [<c03b5084>] (of_find_matching_node_and_match+0x78/0xb4) from [<c07887c8>] (clocksource_of_init+0x60/0x70)
	[    0.000000] [<c07887c8>] (clocksource_of_init+0x60/0x70) from [<c076e99c>] (start_kernel+0x1f4/0x33c)
	[    0.000000] [<c076e99c>] (start_kernel+0x1f4/0x33c) from [<80008074>] (0x80008074)

This is caused by clocksource_of_init() dropping a reference on the device node that it never took. The reference taken by the loop is implicitly dropped on subsequent iterations. See the implementation of and the comment on top of the of_find_matching_node_and_match() function for reference (no pun intended).

---
 drivers/clocksource/clksrc-of.c |    1 -
 1 file changed, 1 deletion(-)

index 35639cf4..b9ddd9e 100644
@@ -35,6 +35,5 @@ void __init clocksource_of_init(void)
 
 		init_func = match->data;
 		init_func(np);
-		of_node_put(np);
 	}
 }

1.7.9.5

From: Marc Zyngier <[email protected]>

The sun4i timer can still be ticking when we enable the interrupt. If another timer is actually used (A7 architected timer, for example), odds are that the interrupt will eventually fire with the event_handler pointer being NULL.

The obvious fix it to stop the timer before registering the interrupt.

Observed and tested on sun7i (cubietruck).

---
 drivers/clocksource/sun4i_timer.c |    3 +++
 1 file changed, 3 insertions(+)

index 2fb4695..a4f6119 100644
@@ -179,6 +179,9 @@ static void __init sun4i_timer_init(struct device_node *node)
 	writel(TIMER_CTL_CLK_SRC(TIMER_CTL_CLK_SRC_OSC24M),
 	       timer_base + TIMER_CTL_REG(0));
 
+	/* Make sure timer is stopped before playing with interrupts */
+	sun4i_clkevt_time_stop(0);
+
 	ret = setup_irq(irq, &sun4i_timer_irq);
 	if (ret)
 		pr_warn("failed to setup irq %d\n", irq);

1.7.9.5

From: Dinh Nguyen <[email protected]>

The read_sched_clock should return the ~value because the clock is a countdown implementation. read_sched_clock() should be the same as
__apbt_read_clocksource().

---
 drivers/clocksource/dw_apb_timer_of.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 45ba8ae..b29d7cd 100644
@@ -108,7 +108,7 @@ static void __init add_clocksource(struct device_node *source_timer)
 
 static u64 read_sched_clock(void)
 {
-	return __raw_readl(sched_io_base);
+	return ~__raw_readl(sched_io_base);
 }
 
 static const struct of_device_id sptimer_ids[] __initconst = {

1.7.9.5

From: Dinh Nguyen <[email protected]>

In commit 620f5e1cbf (dts: Rename DW APB timer compatible strings), both "snps,dw-apb-timer-sp" and "snps,dw-apb-timer-osc" were deprecated in place of "snps,dw-apb-timer". But the driver also needs to be udpated in order to support this new binding "snps,dw-apb-timer".

---
 drivers/clocksource/dw_apb_timer_of.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

index b29d7cd..2a2ea27 100644
@@ -113,7 +113,6 @@ static u64 read_sched_clock(void)
 
 static const struct of_device_id sptimer_ids[] __initconst = {
 	{ .compatible = "picochip,pc3x2-rtc" },
-	{ .compatible = "snps,dw-apb-timer-sp" },
 	{ /* Sentinel */ },
 };
 

@@ -151,4 +150,6 @@ static void __init dw_apb_timer_init(struct device_node *timer)
 	num_called++;
 }
 CLOCKSOURCE_OF_DECLARE(pc3x2_timer, "picochip,pc3x2-timer", dw_apb_timer_init);
-CLOCKSOURCE_OF_DECLARE(apb_timer, "snps,dw-apb-timer-osc", dw_apb_timer_init);
+CLOCKSOURCE_OF_DECLARE(apb_timer_osc, "snps,dw-apb-timer-osc", dw_apb_timer_init);
+CLOCKSOURCE_OF_DECLARE(apb_timer_sp, "snps,dw-apb-timer-sp", dw_apb_timer_init);
+CLOCKSOURCE_OF_DECLARE(apb_timer, "snps,dw-apb-timer", dw_apb_timer_init);

1.7.9.5

Hi Daniel, Dinh,

I guess this (and the previous one) should also be pushed to v3.12-stable, isn't it?

baruch

     http://baruch.siach.name/blog/                  ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch at tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -

Mmh, yes.

Thomas,

will you send those patches to Greg-KH ? Otherwise I am willing to create a -stable branch for each release to put those in and send them to stable@ directly.

Thanks
-- Daniel

  <http://www.linaro.org/> Linaro.org ? Open source software for ARM SoCs

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Pulled into tip:timers/urgent, thanks a lot Daniel!

Ingo

On 12/10/2013 08:48 PM, Ingo Molnar wrote:

[ ... ]

Thanks to you for helping me to be a better maintainer. All you comments and advices were very valuable.

-- Daniel

  <http://www.linaro.org/> Linaro.org ? Open source software for ARM SoCs

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You are welcome!

Thanks,

Ingo