[PATCH 5/9] ARM: dts: Add GPMC node for OMAP2, OMAP4 and OMAP5

Jon Hunter jon-hunter at ti.com
Thu Mar 14 11:50:27 EDT 2013


On 03/14/2013 10:45 AM, Benoit Cousson wrote:
> On 03/11/2013 06:56 PM, Jon Hunter wrote:
>>
>> On 03/09/2013 06:42 AM, Ezequiel Garcia wrote:
>>> On Fri, Mar 8, 2013 at 10:25 PM, Javier Martinez Canillas
>>> <javier at dowhile0.org> wrote:
>>>> On Fri, Mar 8, 2013 at 10:41 PM, Jon Hunter <jon-hunter at ti.com> wrote:
>>>>>
>>>>> Yes you are correct. In general, I have been trying to stay some-what
>>>>> consistent with what hwmod was doing as this was being auto-generated by
>>>>> some hardware design specs and I believe they wanted to eventually get
>>>>> to the point where DT files would be auto-generated too for OMAP.
>>>>> Furthermore my understanding is that the smallest page that can be
>>>>> mapped by the kernel for ARM is 4kB. So if you declare it as 0x2d0 or
>>>>> 0x1000 it will map a 4kB page (I could be wrong here).
>>>>>
>>>>> I don't have any strong feelings here but will do what the consensus
>>>>> prefers.
>>>>>
>>>>
>>>> Yes, you are right here.
>>>>
>>>> I forget that ioremap() does a page-aligned mapping and since the
>>>> minimum page size for ARM is 4KB as you said, there is no difference
>>>> between using 0x2d0 and 0x1000. Sorry for the noise.
>>>>
>>>
>>> Certainly, I don't have strong feelings about this.
>>> FWIW, mvebu maintainers imposes a "minimal" address space request
>>> policy.
>>>
>>> On the other side, it seems to me we shouldn't look at internal kernel
>>> implementation (i.e. ioremap page-alignment) to make this decision.
>>
>> I agree with that. I am not sure if Tony/Benoit have any comments on
>> what they would like to do here to be consistent for the omap bindings.
> 
> Yes, I full agree with that as well. The size should be purely HW
> related. So we should not take any assumption about the page size /
> alignment.

Ok, what is best to use? The size from hwmod structures or the size from
the documentation?

Cheers
Jon



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