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

[Jon Hunter <jon-hunter@ti.com>]

On 03/14/2013 10:58 AM, Benoit Cousson wrote:
> On 03/14/2013 04:50 PM, Jon Hunter wrote:
>>
>> 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@dowhile0.org> wrote:
>>>>>> On Fri, Mar 8, 2013 at 10:41 PM, Jon Hunter <jon-hunter@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?
> 
> Well, in theory both are supposed to be identical :-)
> I'm just applying a rounding to the closet power of two, that's why it
> cannot be 0x2d0.

Ok I understand. However, still not clear what you want me to use :-(

Jon