Support for ARM940T core Samsung S3C2510A MCU under Linux

Support for ARM940T core Samsung S3C2510A MCU under Linux

[Madhavi Manchala]

Dear All,

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.

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?

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?

Please suggest me. It would be appreciated your help / suggestions.

Thanks and Regards,
Madhavi M.

Re: Support for ARM940T core Samsung S3C2510A MCU under Linux

[Geert Uytterhoeven]

On Sat, Mar 19, 2011 at 10:53, Madhavi Manchala <madhavi.linux@gmail.com> 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.
>
> 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?
>
> 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?
>
> Please suggest me. It would be appreciated your help / suggestions.

I think the uClinux mailing list (CCed) is a more appropriate mailing list for
your questions.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: Support for ARM940T core Samsung S3C2510A MCU under Linux

[Arnd Bergmann]

On Saturday 19 March 2011, Geert Uytterhoeven wrote:
> On Sat, Mar 19, 2011 at 10:53, Madhavi Manchala <madhavi.linux@gmail.com> 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.
> >
> > 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?
> >
> > 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?
> >
> > Please suggest me. It would be appreciated your help / suggestions.
> 
> I think the uClinux mailing list (CCed) is a more appropriate mailing list for
> your questions.

It depends. Any questions regarding the ARM kernel should be on the
arm-linux-kernel (also CCed now), since the nommu support is merged
with the mainline kernel.

uClinux seems to be rather focused on m68knommu (coldfire) these days,
and contains both a kernel and user space. The last uClinux release
containst some changes for Samsung platforms (s3c24a0, s3c3410,
s3c44b0x and s5c7375). It's probably a good idea to look at that
code for reference, but I would suggest integrating the code for
your platform in the upstream  tree directly.

I could not find a git tree for uClinux that contains any recent
kernel. Does that exist?

	Arnd

Re: Support for ARM940T core Samsung S3C2510A MCU under Linux

[Greg Ungerer]

Hi Arnd,

On 20/03/11 06:14, Arnd Bergmann wrote:
> On Saturday 19 March 2011, Geert Uytterhoeven wrote:
>> On Sat, Mar 19, 2011 at 10:53, Madhavi Manchala<madhavi.linux@gmail.com>  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.
>>>
>>> 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?
>>>
>>> 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?
>>>
>>> Please suggest me. It would be appreciated your help / suggestions.
>>
>> I think the uClinux mailing list (CCed) is a more appropriate mailing list for
>> your questions.
>
> It depends. Any questions regarding the ARM kernel should be on the
> arm-linux-kernel (also CCed now), since the nommu support is merged
> with the mainline kernel.
>
> uClinux seems to be rather focused on m68knommu (coldfire) these days,

That is more a factor of who shows interest and is active on
the uclinux-dev mailing list more than anything else though.
Quite of few different groups of people interested in non-MMU
ARM platforms have shown up over the years, but none seem to stay
active for long.


> and contains both a kernel and user space. The last uClinux release
> containst some changes for Samsung platforms (s3c24a0, s3c3410,
> s3c44b0x and s5c7375). It's probably a good idea to look at that
> code for reference, but I would suggest integrating the code for
> your platform in the upstream  tree directly.

Yes, highly encourage this.


> I could not find a git tree for uClinux that contains any recent
> kernel. Does that exist?

I used to keep one on git.kernel.org for promoting non-architectural
but non-MMU specific changes to mainline.

http://git.kernel.org/?p=linux/kernel/git/gerg/uclinux.git;a=summary

But I have had so few changes that fit in that category that I
haven't used it in quite a while.

Regards
Greg


------------------------------------------------------------------------
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

Re: Support for ARM940T core Samsung S3C2510A MCU under Linux

[Arnd Bergmann]

On Monday 21 March 2011, Greg Ungerer wrote:
> > I could not find a git tree for uClinux that contains any recent
> > kernel. Does that exist?
> 
> I used to keep one on git.kernel.org for promoting non-architectural
> but non-MMU specific changes to mainline.
> 
> http://git.kernel.org/?p=linux/kernel/git/gerg/uclinux.git;a=summary
> 
> But I have had so few changes that fit in that category that I
> haven't used it in quite a while.

Yes, I found that tree when I looked last week. I was wondering
if there is any git or other repo for the files that are in
http://sourceforge.net/projects/uclinux/files/uClinux%20Stable/

The kernel sources there are newer than the ones from uclinux.git,
but I could not find a pointer to who maintains them or how.

	Arnd

Re: Support for ARM940T core Samsung S3C2510A MCU under Linux

[Greg Ungerer]

Hi Arnd,

On 21/03/11 22:20, Arnd Bergmann wrote:
> On Monday 21 March 2011, Greg Ungerer wrote:
>>> I could not find a git tree for uClinux that contains any recent
>>> kernel. Does that exist?
>>
>> I used to keep one on git.kernel.org for promoting non-architectural
>> but non-MMU specific changes to mainline.
>>
>> http://git.kernel.org/?p=linux/kernel/git/gerg/uclinux.git;a=summary
>>
>> But I have had so few changes that fit in that category that I
>> haven't used it in quite a while.
>
> Yes, I found that tree when I looked last week. I was wondering
> if there is any git or other repo for the files that are in
> http://sourceforge.net/projects/uclinux/files/uClinux%20Stable/
>
> The kernel sources there are newer than the ones from uclinux.git,
> but I could not find a pointer to who maintains them or how.

There is no git tree or otherwise for the code in the uclinux-dist
source package. It is just a random collection of patches collected
over the years, with new kernels "imported" every new release.

Regards
Greg


------------------------------------------------------------------------
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

Support for ARM940T core Samsung S3C2510A MCU under Linux

[Madhavi Manchala]

Dear All,

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.

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?

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.

Thanks and Regards,
Madhavi M.

Re: Support for ARM940T core Samsung S3C2510A MCU under Linux

[Greg Ungerer]

Hi Madhavi,

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.


> 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.


> 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).

Regards
Greg


------------------------------------------------------------------------
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

Re: Support for ARM940T core Samsung S3C2510A MCU under Linux

[Madhavi Manchala]

Hi Greg,

Thank you very much for your valuable information and suggestions.

On Mon, Mar 21, 2011 at 4:57 PM, Greg Ungerer <gerg@snapgear.com> wrote:
>
> Hi Madhavi,
>
> 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?

I found only at91_aic_init() function only called from at91x40.c file.
What about other initialization like serial etc.?  Is this included
from common files for Atmel boards?

>
>> 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.

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.

Thanks and Regards,
Madhavi. M

> Regards
> Greg
>
>
> ------------------------------------------------------------------------
> 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
>

Re: Support for ARM940T core Samsung S3C2510A MCU under Linux

[Arnd Bergmann]

On Tuesday 22 March 2011, Madhavi Manchala wrote:

> 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.
> 
> 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?

The CPU support is really separate from the platform, and
ARM9TDMI/ARM940T is supported by the platform-independent code.

In the s3c2510-specific portion, you should need very little
code that has dependencies on the specific ARM code besides
for the Kconfig 'select CPU_ARM940T' statement.

> I am extreamly sorry, If I asked silly questions here.

No problem at all, these things are not well documented, so it's
good if at least people can refer to this conversation in the
email archives.

	Arnd

Re: Support for ARM940T core Samsung S3C2510A MCU under Linux

[Greg Ungerer]

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>  wrote:
>> 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.?  Is 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.


> 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  --  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

Re: Support for ARM940T core Samsung S3C2510A MCU under Linux

[Madhavi Manchala]

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>  wrote:
>>>
>>> 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.?  Is 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?

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  --  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
>

Re: Support for ARM940T core Samsung S3C2510A MCU under Linux

[Greg Ungerer]

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
>> 8 Gardner Close á á á á á á á á á á á á á á FAX: á á á á +61 7 3217 5323
>> Milton, QLD, 4064, Australia á á á á á á á áWEB: http://www.SnapGear.com
>>
>
>
>


-- 
------------------------------------------------------------------------
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