[U-Boot] L2 cache and LCD on sunxi

[Hans de Goede]

Hi,

On 29-12-14 17:23, Simon Glass wrote:
> Hi Hans,
>
> On 24 December 2014 at 09:47, Hans de Goede <hdegoede at redhat.com> wrote:
>> Hi,
>>
>> On 23-12-14 05:36, Simon Glass wrote:
>>>
>>> Hi Hans,
>>>
>>> On 22 December 2014 at 09:45, Hans de Goede <hdegoede at redhat.com> wrote:
>>>>
>>>> Hi,
>>>>
>>>> On 21-12-14 19:52, Simon Glass wrote:
>>>>>
>>>>>
>>>>> Hi,
>>>>>
>>>>> I ran up a banana PI and noticed that HDMI works in U-Boot. Great!
>>>>>
>>>>> Scrolling seems very slow though - is the L2 cache disabled perhaps?
>>>>
>>>>
>>>>
>>>> I don't think so, but it could be, I think the scrolling code is just
>>>> very inefficient. Feel free to poke things a bit around this, ARM
>>>> cache management is not my forte.
>>>
>>>
>>> I think it need ssomething like the code in exynos/soc.c - see
>>> v7_outer_cache_enable().
>>>
>>> Even with the 7 inch it's very slow.
>>
>>
>> I've run some tests, and it is not slower then on say the A10 (cortex A8),
>> also I've been unable to find any docs or allwinner code pointing to
>> allwinner specific l2 cache init. As such ATM I do not believe that we've
>> the l2 cache disabled.
>
> Yes the code is not super-efficient (and could use the arch-specific
> memcpy()) but I'm mostly interested in whether the platform is running
> at full speed.
>
> I'm comparing it to say an Exynos 5250 which is 1.7GHz Cortex-A15.
> Without the L2 cache it scrolls quite slowly but with it it is fast.

Well this is a 1 GHz Cortex A7, and one with likely a much less
efficient DRAM controller / less DRAM bandwidth.

> There is probably some cache setup required.

That could be, but if that is the case then I don't know where to start
looking for it. I certainly cannot find any such thing in allwinner;s
boot0 / boot1 bootloader.

Regards,

Hans