diff mbox

ARM: rcar-gen2: Do not attempt to re-setup timer if running correctly

Message ID 1386753916-25648-1-git-send-email-ben.dooks@codethink.co.uk (mailing list archive)
State Superseded
Headers show

Commit Message

Ben Dooks Dec. 11, 2013, 9:25 a.m. UTC
If the system has been started in non-secure mode, then the ARM generic
timer is not configurable during the kernel initialisation. Currently
the only thing we can check for is if the timer has been correctly
configured during the boot process.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Reviewed-by: Ian Molton <ian.molton@codethink.co.uk>
---
 arch/arm/mach-shmobile/setup-rcar-gen2.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

Comments

Magnus Damm Dec. 11, 2013, 9:36 a.m. UTC | #1
On Wed, Dec 11, 2013 at 6:25 PM, Ben Dooks <ben.dooks@codethink.co.uk> wrote:
> If the system has been started in non-secure mode, then the ARM generic
> timer is not configurable during the kernel initialisation. Currently
> the only thing we can check for is if the timer has been correctly
> configured during the boot process.
>
> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
> Reviewed-by: Ian Molton <ian.molton@codethink.co.uk>

Looks fine, thanks!

Acked-by: Magnus Damm <damm@opensource.se>
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Ben Dooks Dec. 11, 2013, 10:06 a.m. UTC | #2
On 11/12/13 09:25, Ben Dooks wrote:
> If the system has been started in non-secure mode, then the ARM generic
> timer is not configurable during the kernel initialisation. Currently
> the only thing we can check for is if the timer has been correctly
> configured during the boot process.
>
> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
> Reviewed-by: Ian Molton <ian.molton@codethink.co.uk>

Sorry, I've gone and re-posted the same patch as yesterday.
Sergei Shtylyov Dec. 11, 2013, 5:14 p.m. UTC | #3
Hello.

On 11-12-2013 13:25, Ben Dooks wrote:

> If the system has been started in non-secure mode, then the ARM generic
> timer is not configurable during the kernel initialisation. Currently
> the only thing we can check for is if the timer has been correctly
> configured during the boot process.

> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
> Reviewed-by: Ian Molton <ian.molton@codethink.co.uk>
> ---
>   arch/arm/mach-shmobile/setup-rcar-gen2.c | 18 +++++++++++++-----
>   1 file changed, 13 insertions(+), 5 deletions(-)

> diff --git a/arch/arm/mach-shmobile/setup-rcar-gen2.c b/arch/arm/mach-shmobile/setup-rcar-gen2.c
> index 5734c24..6b7b7f1 100644
> --- a/arch/arm/mach-shmobile/setup-rcar-gen2.c
> +++ b/arch/arm/mach-shmobile/setup-rcar-gen2.c
> @@ -78,12 +78,20 @@ void __init rcar_gen2_timer_init(void)
>   	/* Remap "armgcnt address map" space */
>   	base = ioremap(0xe6080000, PAGE_SIZE);
>
> -	/* Update registers with correct frequency */
> -	iowrite32(freq, base + CNTFID0);
> -	asm volatile("mcr p15, 0, %0, c14, c0, 0" : : "r" (freq));
> +	/* Update the timer if it is either not running, or is not at the
> +	 * right frequency. The timer is only configurable in secure mode
> +	 * so this avoids an abort if the loader started the timer and
> +	 * started the kernel in non-secure mode. */

    You said you've fixed the comment style but you haven't as I see.

WBR, Sergei

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Ben Dooks Dec. 11, 2013, 5:15 p.m. UTC | #4
On 11/12/13 17:14, Sergei Shtylyov wrote:
> Hello.
>
> On 11-12-2013 13:25, Ben Dooks wrote:
>
>> If the system has been started in non-secure mode, then the ARM generic
>> timer is not configurable during the kernel initialisation. Currently
>> the only thing we can check for is if the timer has been correctly
>> configured during the boot process.
>
>> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
>> Reviewed-by: Ian Molton <ian.molton@codethink.co.uk>
>> ---
>>   arch/arm/mach-shmobile/setup-rcar-gen2.c | 18 +++++++++++++-----
>>   1 file changed, 13 insertions(+), 5 deletions(-)
>
>> diff --git a/arch/arm/mach-shmobile/setup-rcar-gen2.c
>> b/arch/arm/mach-shmobile/setup-rcar-gen2.c
>> index 5734c24..6b7b7f1 100644
>> --- a/arch/arm/mach-shmobile/setup-rcar-gen2.c
>> +++ b/arch/arm/mach-shmobile/setup-rcar-gen2.c
>> @@ -78,12 +78,20 @@ void __init rcar_gen2_timer_init(void)
>>       /* Remap "armgcnt address map" space */
>>       base = ioremap(0xe6080000, PAGE_SIZE);
>>
>> -    /* Update registers with correct frequency */
>> -    iowrite32(freq, base + CNTFID0);
>> -    asm volatile("mcr p15, 0, %0, c14, c0, 0" : : "r" (freq));
>> +    /* Update the timer if it is either not running, or is not at the
>> +     * right frequency. The timer is only configurable in secure mode
>> +     * so this avoids an abort if the loader started the timer and
>> +     * started the kernel in non-secure mode. */
>
>     You said you've fixed the comment style but you haven't as I see.

I also said I reposted the previous patch by accident this morning
and posted the corrected one after it.
Sergei Shtylyov Dec. 11, 2013, 5:20 p.m. UTC | #5
Hello.

On 11-12-2013 21:15, Ben Dooks wrote:

>>> If the system has been started in non-secure mode, then the ARM generic
>>> timer is not configurable during the kernel initialisation. Currently
>>> the only thing we can check for is if the timer has been correctly
>>> configured during the boot process.

>>> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
>>> Reviewed-by: Ian Molton <ian.molton@codethink.co.uk>
>>> ---
>>>   arch/arm/mach-shmobile/setup-rcar-gen2.c | 18 +++++++++++++-----
>>>   1 file changed, 13 insertions(+), 5 deletions(-)

>>> diff --git a/arch/arm/mach-shmobile/setup-rcar-gen2.c
>>> b/arch/arm/mach-shmobile/setup-rcar-gen2.c
>>> index 5734c24..6b7b7f1 100644
>>> --- a/arch/arm/mach-shmobile/setup-rcar-gen2.c
>>> +++ b/arch/arm/mach-shmobile/setup-rcar-gen2.c
>>> @@ -78,12 +78,20 @@ void __init rcar_gen2_timer_init(void)
>>>       /* Remap "armgcnt address map" space */
>>>       base = ioremap(0xe6080000, PAGE_SIZE);
>>>
>>> -    /* Update registers with correct frequency */
>>> -    iowrite32(freq, base + CNTFID0);
>>> -    asm volatile("mcr p15, 0, %0, c14, c0, 0" : : "r" (freq));
>>> +    /* Update the timer if it is either not running, or is not at the
>>> +     * right frequency. The timer is only configurable in secure mode
>>> +     * so this avoids an abort if the loader started the timer and
>>> +     * started the kernel in non-secure mode. */

>>     You said you've fixed the comment style but you haven't as I see.

> I also said I reposted the previous patch by accident this morning
> and posted the corrected one after it.

    Sorry, I've only read that after sending my comment. I thought that was an 
intended repost with a slightly corrected subject.

WBR, Sergei

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diff mbox

Patch

diff --git a/arch/arm/mach-shmobile/setup-rcar-gen2.c b/arch/arm/mach-shmobile/setup-rcar-gen2.c
index 5734c24..6b7b7f1 100644
--- a/arch/arm/mach-shmobile/setup-rcar-gen2.c
+++ b/arch/arm/mach-shmobile/setup-rcar-gen2.c
@@ -78,12 +78,20 @@  void __init rcar_gen2_timer_init(void)
 	/* Remap "armgcnt address map" space */
 	base = ioremap(0xe6080000, PAGE_SIZE);
 
-	/* Update registers with correct frequency */
-	iowrite32(freq, base + CNTFID0);
-	asm volatile("mcr p15, 0, %0, c14, c0, 0" : : "r" (freq));
+	/* Update the timer if it is either not running, or is not at the
+	 * right frequency. The timer is only configurable in secure mode
+	 * so this avoids an abort if the loader started the timer and
+	 * started the kernel in non-secure mode. */
+	if ((ioread32(base + CNTCR) & 1) == 0 ||
+	    ioread32(base + CNTFID0) != freq) {
+		/* Update registers with correct frequency */
+		iowrite32(freq, base + CNTFID0);
+		asm volatile("mcr p15, 0, %0, c14, c0, 0" : : "r" (freq));
+
+		/* make sure arch timer is started by setting bit 0 of CNTCR */
+		iowrite32(1, base + CNTCR);
+	}
 
-	/* make sure arch timer is started by setting bit 0 of CNTCR */
-	iowrite32(1, base + CNTCR);
 	iounmap(base);
 #endif /* CONFIG_ARM_ARCH_TIMER */