[PATCH] ARM64: dts: meson-gxbb: set reset for ethernet

[narmstrong@baylibre.com (Neil Armstrong)]

On 02/07/2017 09:43 PM, Heiner Kallweit wrote:
> Am 06.02.2017 um 10:29 schrieb Neil Armstrong:
>> On 01/29/2017 03:07 PM, Heiner Kallweit wrote:
>>> Add reset control for ethernet.
>>>
>>> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
>>> ---
>>>  arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi | 2 ++
>>>  1 file changed, 2 insertions(+)
>>>
>>> diff --git a/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi b/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi
>>> index 39a774ad..753fddf6 100644
>>> --- a/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi
>>> +++ b/arch/arm64/boot/dts/amlogic/meson-gxbb.dtsi
>>> @@ -113,6 +113,8 @@
>>>  		 <&clkc CLKID_FCLK_DIV2>,
>>>  		 <&clkc CLKID_MPLL2>;
>>>  	clock-names = "stmmaceth", "clkin0", "clkin1";
>>> +	resets = <&reset RESET_ETHERNET>;
>>> +	reset-names = "stmmaceth";
>>>  };
>>>  
>>>  &aobus {
>>>
>>
>> Hi,
>>
>> Actually this is a no-op since the Amlogic reset controller only supports "pulse" resets and the
>> STMMAC driver only supports "level" resets. If you want to use this reset, you must add the
>> corresponding support code in the meson8b glue code to call device_reset().
>>
> Thanks for the hint! I did some further tests to check the "nature" of the reset register bits.
> Setting a reset bit and immediately reading it back always returns 0.
> And the chip spec doesn't mention whether writing a reset bit triggers a reset pulse or
> whether it asserts the reset line.
> Therefore I'm a little clueless whether it's possible to have "level" resets.

It seems that there is some "level" register in the next addresses used by the VPU reset in u-boot,
but I did not get the same behaviour as the pulse reset registers.
It seems the resets are not mapped the same way.

Neil

> 
>> Neil
>>
>