Re: [PATCH v1 08/10] arm64: dts: exynos: Add initial support for exynos8895 SoC

[Krzysztof Kozlowski <krzk@xxxxxxxxxx>]

On 07/08/2024 19:29, David Virag wrote:
> On Wed, 2024-08-07 at 14:20 +0300, Ivaylo Ivanov wrote:
>>
>> On 8/7/24 12:20, Krzysztof Kozlowski wrote:
>>> On 07/08/2024 10:28, ivo.ivanov.ivanov1@xxxxxxxxx wrote:
>>>> From: Ivaylo Ivanov <ivo.ivanov.ivanov1@xxxxxxxxx>
> [snip]
>>>>
>>>> +
>>>> +	timer {
>>>> +		compatible = "arm,armv8-timer";
>>>> +		/* Hypervisor Virtual Timer interrupt is not
>>>> wired to GIC */
>>>> +		interrupts = <GIC_PPI 13 (GIC_CPU_MASK_SIMPLE(8)
>>>> | IRQ_TYPE_LEVEL_LOW)>,
>>>> +			     <GIC_PPI 14 (GIC_CPU_MASK_SIMPLE(8)
>>>> | IRQ_TYPE_LEVEL_LOW)>,
>>>> +			     <GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(8)
>>>> | IRQ_TYPE_LEVEL_LOW)>,
>>>> +			     <GIC_PPI 10 (GIC_CPU_MASK_SIMPLE(8)
>>>> | IRQ_TYPE_LEVEL_LOW)>;
>>>> +		clock-frequency = <26000000>;
>>> Hm? I think this was explicitly disallowed.
>>
>> It's weird. Without the clock-frequency property it fails early
>> during the
>>
>> boot process and I can't get any logs from pstore or simple-
>> framebuffer.
>>
>> Yet it's not set on similar platforms (exynos7885, autov9). Perhaps I
>>
>> could alias the node and set it in the board device tree..? That
>> doesn't
>>
>> sound right.
> 
> This sounds like CNTFRQ_EL0 is not set properly by the firmware.
> Now, if I read the documentation properly, this can be only set from
> EL3, which in your case is... not easy.
> 
> On my Galaxy A8 2018 (Exynos7885) I remember the old Android 8
> bootloader not being able to boot mainline, but Android 9 bootloaders
> did. I did not take the time to check if it was related to this, but it
> is my guess.
> 
> Your best bet is that maybe Samsung decided to fix this on the latest
> bootloader, and upgrading will fix it. (Though if it's already on an
> Android 9 based bootloader and it's still broken, my guess is a newer
> version won't fix it, but who knows)

If you can update your device to newer Android and it fixes the issue,
then please drop the property. If this does not work, then please add a
comment like: /* Non-updatable, broken stock Samsung bootloader does not
configure CNTFRQ_EL0 */

Best regards,
Krzysztof