Hi Wolfgang,
On Monday 16 May 2011 01:18 AM, Wolfgang Denk wrote:
Dear Aneesh V,
In message1305472900-4004-7-git-send-email-aneesh@ti.com you wrote:
Define a new type of SPL that is not tied to any particular media.
- Create a top level directory 'spl' that has a structure similar to the existing 'nand_spl'
- Make necessary changes to top-level Makefile to build such an spl
Rationale for this approach:
- There may be SPLs(like the OMAP x-loader) that support booting from multiple media.
- Also, there is no harm in keeping SPLs specific to a particular media also under this directory. In fact it makes sense to merge all the different spl directories into this one.
Thanks a lot for addressing this. This is an area that has long been on my mind, and I'm really happy to see someone starting to work on this.
In addition to booting from different types of media, I see at least two more topics that scould and should addressed by this work:
- Get rid of xloader. I cannot see any good reasons why we need it, i. e. which functions if performs that cannot be as well (and eventually even more efficiently) be performed in the U-Boot SPL code.
Indeed, SPL is seen as a replacement for x-loader.
- Become more flexible regarding the kind of second stage payload. It is definitely very powerful and convenient during development to be able to load U-Boot with all it's capabilities as payload of the SPL, but then, except for image size and parameter passing, there is little or no difference to loading a Linux kernel directly instead (and actually this is what most of the super-fast booting approaches do). If done right, we may even have the flexibility to do both, just by providing different images as payload.
How do we handle the differences you just mentioned, namely the size, parameter passing etc. Maybe, we should have special handling for each and define config flags like CONFIG_SPL_PAYLOAD_UBOOT, CONFIG_SPL_PAYLOAD_LINUX_KERNEL etc?
Signed-off-by: Aneesh Vaneesh@ti.com
This patch generates 1 checkpatch warning due to declaration of DECLARE_GLOBAL_DATA_PTR. This is un-avoidable
Makefile | 24 ++++++++++++++++++++++++ arch/arm/include/asm/global_data.h | 5 +++++ 2 files changed, 29 insertions(+), 0 deletions(-)
Here the commit message and the implementation do not agree. You wrote "Create a top level directory 'spl'" - but I don't see any of that here?
In this patch, I just created the makefile infrastructure that expects this directory structure. The files are created later in an OMAP specific patch.
I think I should have used something like "define a directory structure" instead of "create".
I think this should be split into a separate patch series, and care should be taken that commit messages and implementaiton match.
Ok.
Best regards,
Wolfgang Denk