From: cw00.choi@samsung•com (Chanwoo Choi)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCHv2 8/8] ARM: dts: Add device tree sources for Exynos3250
Date: Wed, 16 Apr 2014 17:22:24 +0900 [thread overview]
Message-ID: <534E3DC0.40502@samsung.com> (raw)
In-Reply-To: <534CFAD7.4030508@arm.com>
Hi Marc,
On 04/15/2014 06:24 PM, Marc Zyngier wrote:
> On 15/04/14 10:19, Chanwoo Choi wrote:
>> On 04/15/2014 06:13 PM, Marc Zyngier wrote:
>>> On 15/04/14 09:27, Chanwoo Choi wrote:
>>>> Hi,
>>>>
>>>> On 04/15/2014 05:15 PM, Marc Zyngier wrote:
>>>>> On 15/04/14 02:59, Chanwoo Choi wrote:
>>>>>> From: Tomasz Figa <t.figa@samsung•com>
>>>>>>
>>>>>> This patch add new exynos3250.dtsi to support Exynos3250 SoC based on Cortex-A7
>>>>>> dual core and includes following dt nodes:
>>>>>>
>>>>>> - GIC interrupt controller
>>>>>> - Pinctrl to control GPIOs
>>>>>> - Clock controller
>>>>>> - CPU information (Cortex-A7 dual core)
>>>>>> - UART to support serial port
>>>>>> - MCT (Multi Core Timer)
>>>>>> - ADC (Analog Digital Converter)
>>>>>> - I2C/SPI bus
>>>>>> - Power domain
>>>>>> - PMU (Performance Monitoring Unit)
>>>>>> - MSHC (Mobile Storage Host Controller)
>>>>>> - PWM (Pluse Width Modulation)
>>>>>> - AMBA bus
>>>>>
>>>>> [...]
>>>>>
>>>>> Where is the arch timer node?
>>>>
>>>> Exynos3250 uses MCT (Multi Core Timer) instead of ARM_ARCH_TIMER.
>>>> - in drivers/clocksource/exynos_mct.c
>>>
>>> Don't you have a Cortex-A7? If so, you have the arch timer.
>>
>> Do you means that 'arch timer" is ARM_ARCH_TIMER?
>
> Yes.
>
>> As I knew, ARM_ARCH_TIMER is clocksource driver for system timer.
>> But, Exynos SoC used MCT clocksource for system timer.
>>
>> Exynos dts file didn't include arch timer node but only include mct node.
>
> Well, it is a bug, and a recurrent one. A Cortex-A7 has the arch timers
> implemented. Always.
>
> http://infocenter.arm.com/help/topic/com.arm.doc.ddi0464f/BABFEBJJ.html
>
> All Cortex-A7 have it, and so do A12, A15, A17, A53, A57.
I tested 'arch_timer'(drivers/clocksource/arm_arch_timer.c) on Exynos3250 based on Cortex-A7.
To test arch timer, I used the clocksource of arch_timer for timekeeping instead of clocksource
of Exynos MCT. But, I faced with issue. The following function return only same value(zero)
as following kernel log:
- arch_counter_get_cntvct() in arch/arm/include/asm/arch_timer.h
Uncompressing Linux... done, booting the kernel.
[ 0.000000] Booting Linux on physical CPU 0x0
[ 0.000000] Initializing cgroup subsys cpuset
[ 0.000000] Initializing cgroup subsys cpu
[ 0.000000] Initializing cgroup subsys cpuacct
[ 0.000000] Linux version 3.15.0-rc1-00020-gf452826-dirty ...
[ 0.000000] CPU: ARMv7 Processor ...
...
[ 0.000000] Architected cp15 timer(s) running at 24.00MHz (virt).
[ 0.000000] sched_clock: 56 bits at 24MHz, resolution 41ns, wraps every 2863311519744ns
...
Could you give me a solution to resolve this issue or a expected cause?
Best Regards,
Chanwoo Choi
next prev parent reply other threads:[~2014-04-16 8:22 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-15 1:59 [PATCHv2 0/8] Support new Exynos3250 SoC based on Cortex-A7 dual core Chanwoo Choi
2014-04-15 1:59 ` [PATCHv2 1/8] ARM: EXYNOS: Add Exynos3250 SoC ID Chanwoo Choi
2014-04-15 1:59 ` [PATCHv2 2/8] ARM: EXYNOS: Add IO mapping for non-secure SYSRAM of Exynos3250 Chanwoo Choi
2014-04-15 1:59 ` [PATCHv2 3/8] ARM: EXYNOS: Add IO mapping for PMU " Chanwoo Choi
2014-04-15 8:11 ` Arnd Bergmann
2014-04-15 8:32 ` Chanwoo Choi
2014-04-15 8:39 ` Vikas Sajjan
2014-04-15 8:41 ` Chanwoo Choi
2014-04-15 8:46 ` Arnd Bergmann
2014-04-15 8:51 ` Chanwoo Choi
2014-04-15 1:59 ` [PATCHv2 4/8] ARM: EXYNOS: Support secondary CPU boot of Exynos4212 Chanwoo Choi
2014-04-15 1:59 ` [PATCHv2 5/8] ARM: EXYNOS: Support secondary CPU boot of Exynos3250 Chanwoo Choi
2014-04-15 5:09 ` Tushar Behera
2014-04-17 10:15 ` Chanwoo Choi
2014-04-16 14:28 ` Tomasz Figa
2014-04-17 8:04 ` Chanwoo Choi
2014-04-15 1:59 ` [PATCHv2 6/8] ARM: EXYNOS: Enter a15 lowpower mode for Exynos3250 based on Cortex-a7 Chanwoo Choi
2014-04-16 14:35 ` Tomasz Figa
2014-04-16 14:39 ` Chanwoo Choi
2014-04-15 1:59 ` [PATCHv2 7/8] clk: samsung: exynos3250: Add clocks using common clock framework Chanwoo Choi
2014-04-15 1:59 ` [PATCHv2 8/8] ARM: dts: Add device tree sources for Exynos3250 Chanwoo Choi
2014-04-15 8:15 ` Marc Zyngier
2014-04-15 8:27 ` Chanwoo Choi
2014-04-15 9:13 ` Marc Zyngier
2014-04-15 9:19 ` Chanwoo Choi
2014-04-15 9:24 ` Marc Zyngier
2014-04-16 8:22 ` Chanwoo Choi [this message]
2014-04-16 8:34 ` Marc Zyngier
2014-04-16 8:45 ` Chanwoo Choi
2014-04-16 10:23 ` Chanwoo Choi
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