[U-Boot-Users] SoC -- a new port and coding style

[U-Boot-Users] SoC -- a new port and coding style

[Curt Brune]

I have a "porting to a new chip" question.  I see the u-boot directory
structure allows for CPU specific stuff to go in cpu/ and board
specific stuff to go in board/ .  My question regards a SoC based on
an ARM7TDMI core from Samsung called the s3c4510.

The "s3c4510" has a whole bunch of registers for the ethernet, uart,
timers, i2c -- none of which has anything to do with the ARM7TDMI
core or the board.

There does not seem to be an appropriate place in the u-boot directory
structure to put the "s3c4510" specific stuff -- it has nothing to do
the CPU and it is not board specific either (I've seen at least 3
other boards based on the Samsung chip which configure the s3c4510
differently).

Where would be the "right" place to put such changes?  Seems I could:

a. jam them in cpu/arm720t with #ifdef
b. create cpu/arm7tdmi and include the s3c4510 in board/
c. create cpu/s3c4510 

Cheers,
Curt

[U-Boot-Users] SoC -- a new port and coding style

[Wolfgang Denk]

Dear Curt,

in message <20040229145211.B7611@curtisb.com> you wrote:
> I have a "porting to a new chip" question.  I see the u-boot directory
> structure allows for CPU specific stuff to go in cpu/ and board
> specific stuff to go in board/ .  My question regards a SoC based on

And drivers/ for device drivers - just to mention it.

> an ARM7TDMI core from Samsung called the s3c4510.

OK, arm720t.

> The "s3c4510" has a whole bunch of registers for the ethernet, uart,
> timers, i2c -- none of which has anything to do with the ARM7TDMI
> core or the board.

Registers? What has on-chip peripherals to do with the  core  or  the
board?

> There does not seem to be an appropriate place in the u-boot directory
> structure to put the "s3c4510" specific stuff -- it has nothing to do

I must be mnissing something. If  you  are  talking  about  structure
definitions for these "registers", please follow the example of other
processors.  I  would  expect  that include/s3c4510.h might be a good
place for such definitions.

Or are you talking about drivers for these devices?  Then  you  might
create files like cpu/arm720t/eth_s3c4510.[ch] etc.

> the CPU and it is not board specific either (I've seen at least 3
> other boards based on the Samsung chip which configure the s3c4510
> differently).

Then please consider this in your port.

> Where would be the "right" place to put such changes?  Seems I could:
> 
> a. jam them in cpu/arm720t with #ifdef

I don;t see any need to "jam" anything with #ifdef's.

> b. create cpu/arm7tdmi and include the s3c4510 in board/

No, this is definitely wrong.

> c. create cpu/s3c4510 

Wrong, too.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
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