Re: Support for ARM940T core Samsung S3C2510A MCU under Linux

[Greg Ungerer <gerg@snapgear.com>]

Hi Madhavi,

On 23/03/11 22:36, Madhavi Manchala wrote:
> Hi Greg,
>
> Thanks for your information.
>
> On Wed, Mar 23, 2011 at 5:37 PM, Greg Ungerer<gerg@snapgear.com>  wrote:
>> Hi Madhavi,
>>
>> On 22/03/11 22:43, Madhavi Manchala wrote:
>>>
>>> Thank you very much for your valuable information and suggestions.
>>>
>>> On Mon, Mar 21, 2011 at 4:57 PM, Greg Ungerer<gerg@snapgear.com>  áwrote:
>>>>
>>>> On 19/03/11 01:54, Madhavi Manchala wrote:
>>>>>
>>>>> I have one basic question about the architecture files in Linux
>>>>> kernels. We have a board with Samsung S3C2510A MCU (ARM940T core)
>>>>> which is a no-mmu based CPU. I heard that "there was not a lot of ARM
>>>>> no-mmu support at the moment" from Ben Dooks.
>>>>
>>>> The core is there, but there is very little specific machine support.
>>>> The one I use for testing is non-MMU ARM is the Atmel/AT91X40 (that is
>>>> CONFIG_ARCH_AT91X40). I don't run it on real hardware, but on the
>>>> SkyEye emulator.
>>>
>>> I saw the mach-at91/at91x40.c and mach-at91/at91x40_time.c file
>>> sources. There is a few lines of code is available in these two files.
>>> I guess, some of the common files are there for all Atmel boards and
>>> that is also included as a part of at91x40 board. Am I correct?
>>
>> Yes, exactly. Much of the code is shared by all type of at91 parts,
>> irrespective of whether they have the MMU or not. (Most of the
>> internal peripherals at either the same or very similar - so
>> things like interrupts, etc).
>>
>>
>>> I found only at91_aic_init() function only called from at91x40.c file.
>>> What about other initialization like serial etc.? áIs this included
>>> from common files for Atmel boards?
>>
>> Serial is a problem for this target, it is a little different
>> on the old at91x40 series to most of the newer at91 parts. Currently
>> it requires a different driver than the standard at91 serial driver.
>> (And that driver is not in mainline, and is not a platform type
>> driver either).
>>
>>
>>>>> So, I started developing the architecture files for my Samsung
>>>>> S3C2510A MCU (ARM940T core) by looking at the existing S3C2410A
>>>>> (ARM920 core) architecture files. Is this my porting (developing the
>>>>> architecture files) correct?
>>>>
>>>> Would make sense to start on something similar, yes.
>>>
>>> I downloaded the latest uClinux sources from
>>> http://sourceforge.net/projects/uclinux/files/uClinux%20Stable/ and
>>> the name of the file is uClinux-dist-20101026.tar.bz2. In this
>>> distribution, I found mach-s3c24a0, mach-s3c3410, s3c44b0x and
>>> mach-s5c7375 sources in linux-2.6.x/arch/arm/ directory. (Arnd asked
>>> me to see these sources as a reference, only). So, I am looking at
>>> these sources and especially s3c3410 sources as remaining are
>>> different like s3c24a0 is a MMU based etc.
>>>
>>>>
>>>>> How can I port the Linux on to my board which has a Samsung S3C2510A
>>>>> MCU (ARM940T core) which is a NO-MMU based CPU?
>>>>>
>>>>> Thanks for your suggestions / hints / comments.
>>>>
>>>> You can look at what I did with the AT91X40 for an example.
>>>> Or look at the patches that Ithamar Adema sent to the ARM linux
>>>> mailing list in the last few days for supporting the NXP LPC2K
>>>> family as another example (they are also non-MMU parts).
>>>
>>> As I said above, there are only two files which are related to at91x40
>>> board. However, I found some sources for the Ithamar Adema patches at
>>> the following link.
>>> http://www.spinics.net/lists/arm-kernel/msg118932.html
>>>
>>> These sources (patches) are similar to samsung sources which are
>>> available in uClinux-dist. So, I will look into the Ithamar Adema
>>> patches and uClinux-dist samsung machine directory sources. Please
>>> suggest me.
>>
>> Looking at all of these will be useful. The AT91 changes where quite
>> simple due to the high degree of similarity.
>
> Do you mean similarity between AT91 and S3C2510A processors? Am I
> understand your statement correct?

No, I meant the similarity between the non-MMU AT91x40 and the
other MMU AT91 parts.

Regards
Greg



> Thanks and Regards,
> Madhavi M.
>
>>
>>> My final question, All these samsung machines (s3c24a0, s3c3410,
>>> s3c44b0x and s5c7375) are ARM7TDMI core based MCUs. My MCU (Samsung
>>> s3c2510A) is a ARM9TDMI core based. So, is this porting will help?
>>>
>>> I am extreamly sorry, If I asked silly questions here.
>>>
>>> Once again, thanks for your suggestions and valuable inforamtion.
>>
>> No problem, glad to help.
>>
>> Regards
>> Greg
>>
>>
>> ------------------------------------------------------------------------
>> Greg Ungerer á-- áPrincipal Engineer á á á áEMAIL: á á gerg@snapgear.com
>> SnapGear Group, McAfee á á á á á á á á á á áPHONE: á á á +61 7 3435 2888
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>
>
>


-- 
------------------------------------------------------------------------
Greg Ungerer  --  Principal Engineer        EMAIL:     gerg@snapgear.com
SnapGear Group, McAfee                      PHONE:       +61 7 3435 2888
8 Gardner Close                             FAX:         +61 7 3217 5323
Milton, QLD, 4064, Australia                WEB: http://www.SnapGear.com