[U-Boot] [PATCH 04/10] video: exynos_fimd: Add framework to disable FIMD sysmmu

[Ajay kumar]

Simon,

On Mon, Jun 23, 2014 at 5:45 PM, Simon Glass <sjg at google.com> wrote:
> Hi Ajay,
>
> On 20 June 2014 00:42, Ajay kumar <ajaynumb at gmail.com> wrote:
>> Hi Simon,
>>
>>
>> On Fri, Jun 20, 2014 at 8:59 AM, Simon Glass <sjg at google.com> wrote:
>>> On 17 June 2014 03:06, Ajay Kumar <ajaykumar.rs at samsung.com> wrote:
>>>> On Exynos5420 and newer versions, the FIMD sysmmus are in
>>>> "on state" by default.
>>>> We have to disable them in order to make FIMD DMA work.
>>>> This patch adds the required framework to exynos_fimd driver,
>>>> and disables FIMD sysmmu on Exynos5420.
>>>>
>>>> Signed-off-by: Ajay Kumar <ajaykumar.rs at samsung.com>
>>>
>>> Acked-by: Simon Glass <sjg at chromium.org>
>>> Tested-by: Simon Glass <sjg at chromium.org>
>>>
>>> (I assume this is the same device tree binding as Linux?)
>> Actually, No!
>> Kernel has a generic binding named "samsung,sysmmu-v3.3", and it is common
>> for all sysmmu nodes. There is a seperate IOMMU driver to handle the same.
>> We can port the device probing part from kernel to u-boot, but we would need
>> to add seperate driver(since the name is generic) to handle the same.
>> That driver, even though being generic, will be used only by FIMD
>> sysmmus(that too, just to turn them off).
>
> OK. I suppose you could add a very short new C file with a function
> which finds the device tree node by its compatible string or whatever,
> and then updates the hardware.
Ok. I will add this.

Ajay
> Regards,
> Simon