On 09/17/2012 11:51:52 AM, Tom Rini wrote:
On 09/17/12 09:27, Scott Wood wrote:
On 09/17/2012 04:24:34 AM, José Miguel Gonçalves wrote:
[snip]
If no one else has anything against, I will change the name of the
new
target to u-boot-pad.bin
What exactly is u-boot-pad.bin supposed to be? I hope that's not
being
proposed as the final output file the user sees.
With old nand_spl we had u-boot-nand.bin for the final concatenated binary, but that's not appropriate for a generic spl. I think it
would
be better for the user to see "u-boot.bin" as the actual image to
put on
the boot device, regardless of implementation details like spl, if there's no requirement of a specific file format. The second stage could become "u-boot-main.bin" or similar on builds where spl is
used.
We need some name that means "U-Boot SPL with U-Boot tacked on at the end". This can optionally be padded to a defined size to make writing to hardware easier. We also have the problem that "u-boot.bin" already means something so it needs to be clear.
u-boot.bin has traditionally (except for nand_spl and derivatives) meant the final image ready to put into flash, after any platform-specific layout issues are taken care of (e.g. on mpc83xx it will have a reset control word embedded, on mpc85xx it will be padded to 512K with a reset vector at the end, etc.). That we did the tweaking in the linker script rather than after linking seems like an inconsequential implementation detail.
I further fear that even if we made an "out" directory if we put u-boot.bin in there and it's not the same as the objcopy -O binary u-boot u-boot.bin as before we've violated the rule of least surprise and the end user problems from people that read "the" document (that happened to be out of date) will be our problem.
In this case I think you can't meet one user's expectations without violating another's. I think it's more important to make it clear to the user what file they're supposed to put into flash. Users of platforms that are currently supported by nand_spl would probably like to continue seeing u-boot-nand.bin -- it's a tradeoff of historical stability versus current consistency.
In short, at least a few people have said something along the lines of "We need generic output nameo $mediums and targets" but there's two hard problems, one of which is that every SoC _needs_ things tweaked just so (no header? no boot!), sometimes wants things tweaked further (pad the final image out to be easier to write to $medium) and sometimes needs multiple files (the whole of 'SPL' will be read so it must fit into $SMALL_MEMORY). The other is naming.
A simple concatenation of a padded SPL plus the main U-Boot was good enough for all the nand_spl boards AFAIK, so it's not quite every SoC that needs something special here. For those that do require a special format (or multiple files) with a file extension that is familiar to people working with that platform, using that extension makes sense. "pad" does not, and a proliferation of SoC-specific suffixes isn't much better.
-Scott