[U-Boot] [PATCH 2/6] nand: Add SPL_NAND support to mxc_nand_spl

Tom Rini
2013-04-19T16:20:26Z

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On 04/19/2013 11:41 AM, Philip Paeps wrote:
> On 2013-04-19 17:21:49 (+0200), Beno?t Th?baudeau
> <benoit.thebaudeau@advansee.com> wrote:
>> On Friday, April 19, 2013 5:09:59 PM,Philip Paeps wrote:
>>> On 2013-04-19 16:48:42 (+0200), Philip Paeps <philip@paeps.cx>
>>> wrote:
>>>> A first build with CONFIG_SPL_FRAMEWORK came out to nearly
>>>> 4K. Large contributors being (unsurprisingly) libcommon and
>>>> libgeneric. I had to get rid of a puts() in libspl to make
>>>> it build without those libraries. Unfortunately, that still
>>>> came out to 2.2K. Close. :-)
>>>>
>>>> I couldn't identify any obvious 100 bytes to scrap from
>>>> glancing at u-boot-spl.map or objdump -D u-boot-spl, but I'll
>>>> take a look.
>>>
>>> Just as I hit 'send', it occurred to me that this configuration
>>> is with a fairly lengthy lowlevel_init.S to support external
>>> boot. Paring that to the bare minimum gives a u-boot-spl.bin
>>> of 1821 bytes.
>>
>> But this requires a board-specific lowlevel_init() and a hack for
>> puts() (which is perhaps already solved by Andreas' series), just
>> to bloat the SPL with stuff useless for those boards, vs. a
>> simple nand_boot() that can be made common to all SPLs with size
>> restrictions.
>
> Comparing the contents of "framework" SPL with "old" SPL, it looks
> like the only thing we gain is support for booting uImage files.
> At the cost of significantly reduced room for flexibility in
> lowlevel_init().
>
> I agree that a simple nand_boot() is probably the way forward.

Note that PowerPC has had to deal with this as well, see
drivers/mtd/nand/fsl_elbc_spl.c and I suspect some amount of that
should be made more easily borrowable for the case where SPL doesn't
(or can't/won't) deal with image headers.

- --
Tom
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