From: santosh.shilimkar@ti•com (Santosh Shilimkar)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH V4] ARM: OMAP5/DRA7: realtime_counter: Configure CNTFRQ register
Date: Wed, 9 Oct 2013 09:23:44 -0400 [thread overview]
Message-ID: <525558E0.3040901@ti.com> (raw)
In-Reply-To: <52555817.7070703@ti.com>
On Wednesday 09 October 2013 09:20 AM, Sricharan R wrote:
> On Wednesday 09 October 2013 06:47 PM, Santosh Shilimkar wrote:
>> On Wednesday 09 October 2013 09:15 AM, Sricharan R wrote:
>>> Santosh,
>>>
>>> On Wednesday 09 October 2013 03:35 AM, Santosh Shilimkar wrote:
>>>> On Tuesday 08 October 2013 05:45 PM, Tony Lindgren wrote:
>>>>> * Sricharan R <r.sricharan@ti•com> [131003 03:27]:
>>>>>> On Wednesday 18 September 2013 09:32 PM, Sricharan R wrote:
>>>>>>> --- a/arch/arm/boot/dts/omap5.dtsi
>>>>>>> +++ b/arch/arm/boot/dts/omap5.dtsi
>>>>>>> @@ -52,7 +52,6 @@
>>>>>>> <GIC_PPI 14 (GIC_CPU_MASK_RAW(3) | IRQ_TYPE_LEVEL_LOW)>,
>>>>>>> <GIC_PPI 11 (GIC_CPU_MASK_RAW(3) | IRQ_TYPE_LEVEL_LOW)>,
>>>>>>> <GIC_PPI 10 (GIC_CPU_MASK_RAW(3) | IRQ_TYPE_LEVEL_LOW)>;
>>>>>>> - clock-frequency = <6144000>;
>>>>>>> };
>>>>>>>
>>>>>>> gic: interrupt-controller at 48211000 {
>>>>> Can the above be done later on in a separate clean-up patch?
>>>>> If so I can drop that part as that removes a dependency to the
>>>>> .dts patches queued by Benoit.
>>>>>
>>>> This can be applied separately.
>>>>
>>>>
>>>>>>> --- a/arch/arm/mach-omap2/omap-smp.c
>>>>>>> +++ b/arch/arm/mach-omap2/omap-smp.c
>>>>>>> @@ -41,6 +41,8 @@
>>>>>>>
>>>>>>> u16 pm44xx_errata;
>>>>>>>
>>>>>>> +extern unsigned long arch_timer_freq;
>>>>>>> +
>>>>>>> /* SCU base address */
>>>>>>> static void __iomem *scu_base;
>>>>>>>
>>>>> No externs in *.c files please, checkpatch.pl and sparse should warn
>>>>> about this.
>>>>>
>>>>>> Are you planning to pull this patch and the below $subject patch as well? They are
>>>>>> acked and tested.
>>>>>>
>>>>>> ARM: DRA7: realtime_counter: Add ratio registers for 20MHZ sys-clk frequency
>>>>>>
>>>>>> http://www.spinics.net/lists/linux-omap/msg97281.html
>>>>> The 20MHz patch I've applied, just noticed the above things
>>>>> when was about to apply this.
>>>>>
>>>> Now re-looking at the patch, I think this extern stuff can be and
>>>> should be avoided. It needs order change though like below. Not
>>>> tested but should work.
>>>>
>>>> diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
>>>> index fa74a06..c8d8308 100644
>>>> --- a/arch/arm/mach-omap2/timer.c
>>>> +++ b/arch/arm/mach-omap2/timer.c
>>>> @@ -631,10 +631,9 @@ void __init omap4_local_timer_init(void)
>>>> #ifdef CONFIG_SOC_OMAP5
>>>> void __init omap5_realtime_timer_init(void)
>>>> {
>>>> - omap4_sync32k_timer_init();
>>>> realtime_counter_init();
>>>> -
>>>> clocksource_of_init();
>>>> + omap4_sync32k_timer_init();
>>>> }
>>>> #endif /* CONFIG_SOC_OMAP5 */
>>>>
>>>> Then, the CNTFREQ programming needs to be moved to
>>>> realtime_counter_init(). It should be actually part of that
>>>> first place instead of timer_init().
>>>>
>>>> On secondary CPU then a simple asm accessor can
>>>> read the CNTFREQ and pass that to SMC.
>>> Sorry, I did not quite get you here. You mean an asm accessor to
>>> the read the variable that is set in timer.c ?
>>>
>> Reading CNTFREQ CP15 directly....
>>
> Sorry, Still not clear. CNTFREQ is per-cpu register. So when
> the secondary cpu init happens on CPU1, then you mean we will have
> to read it from CPU0 register and pass it for secondary ?
>
Create a function within timer.c which sets the freq for a given CPU.
On Boot CPU you figure out frequency and then just use that static
variable.
Regards,
Santosh
prev parent reply other threads:[~2013-10-09 13:23 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-18 16:02 [PATCH V4] ARM: OMAP5/DRA7: realtime_counter: Configure CNTFRQ register Sricharan R
2013-10-03 10:19 ` Sricharan R
2013-10-08 21:45 ` Tony Lindgren
2013-10-08 22:05 ` Santosh Shilimkar
2013-10-09 13:15 ` Sricharan R
2013-10-09 13:16 ` Sricharan R
2013-10-09 13:18 ` Santosh Shilimkar
2013-10-09 13:17 ` Santosh Shilimkar
2013-10-09 13:20 ` Sricharan R
2013-10-09 13:23 ` Santosh Shilimkar [this message]
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