Dear Wolfgang Denk,
a comment from your side would be nice - in what approach do you see the best chance for getting it into mainline?
Regards Simon
2011/7/1 Simon Schwarz simonschwarzcor@googlemail.com:
Thanks for your feedback Igor!
2011/7/1 Igor Grinberg grinberg@compulab.co.il:
On 07/01/11 12:17, Simon Schwarz wrote:
Ok, topic ATAGS: I see three ways doing ATAGS init for SPL:
- use bootm.c which means init bd correctly and add a bunch of #ifdef
CONFIG_PRELOADER to it - maybe also to some others i don't have on the radar yet.
While this is not clean, it might work good.
- Have ATAGS config in board config file and init it at compile time
This is a problematic approach, because memory size, board revision, serial number and may be some others are only known in runtime.
- Doing it like Heiko and copy the ATAGS config done by u-boot
This one is probably the most clean way.
The problem with approach 3 is that you need to copy the ATAGS image. Is there a way to do this without a debugger? If yes it really could be an alternative. If ATAGS and Kernel can be reflashed you can update the kernel without a bootloader update (That's the main reason why i switched to 1).
Regarding the device tree on ARM, it is still not fully functional. Nevertheless, currently there is an attempt ([1] and [2]) to make kernel work with both, device tree and ATAGS and if I understood correctly, the ATAGS will have precedence over the DT, so closed source boot loaders will still work.
[1] - http://www.spinics.net/lists/arm-kernel/msg128172.html [2] - http://www.spinics.net/lists/arm-kernel/msg129270.html
So, IMHO an ATAGS implementation for now is the better choice - a DT patch then is, depending on the approach, not a big problem.
Regards Simon