On 12/16/2011 11:20 AM, jonsmirl@gmail.com wrote:
The CPU I'm working with, the LPC3130, is kind of an in-between CPU for SPL. Instead of a tightly constrained RAM of 16KB or so I have
16K? Luxury! :-)
Many boards have only 4K, and IIRC some have only 2K.
96KB to work with. 96KB is enough room to support all of the various boot modes (uart, nand, spi, USB, etc) but not enough room for the full uboot command set. So I'm still stuck with the SPL model, but my constraints are much less.
All the SPL model is really supposed to be is makefile infrastructure for building the two stages. What code you pull in is configurable.
One example of a conflict with SPL is NAND support. With SPL you hard code in the NAND type.
This is only required with nand_spl_simple.c.
You could provide an alternate SPL driver, or even pull in the standard SPL stack if you want. No need to hack up nand_spl_simple.c.
I'm wondering if SPL could be designed in a more generic manner. Another model would be to use SPL as the base layer for all u-boot builds. You would then start turning on features until full uboot capability was reached.
A while back I suggested tracking a fully separate config for SPL, but Wolfgang didn't like it. Maybe a larger set of concrete use cases (and what it looks like to deal with each one manually as would currently be needed) would be convincing -- at the time it was just about having a separate CONFIG_SYS_TEXT_BASE_SPL.
-Scott