[U-Boot] [RFC 0/2] Add support for bootstrap stage and compressed U-Boot image

[Shinya Kuribayashi <skuribay@pobox.com>]

Hi,

On 11/30/2010 11:35 PM, Luigi 'Comio' Mantellini wrote:
> Look the following benchmark (qemu-mips board):
> 
> U-Boot Vanilla
> 179600 bytes u-boot.bin
> 
> Bootstrap code w/o compresion (memcpy)
> 189224 bytes u-boot-bootstrap.bin
> --> size 105%
> 
> Bootstrap code using BZIP2 compression
> 114388 bytes u-boot-bootstrap.bin
> -->size 64%
> 
> Bootstrap code using GZIP compression
> 114204 bytes u-boot-bootstrap.bin
> -->size 64%
> 
> Bootstrap code using LZMA compression
> 89456 bytes u-boot-bootstrap.bin
> -->size 50% <-- BEST
> 
> Bootstrap code using LZO compression
> 104388 bytes u-boot-bootstrap.bin
> -->size 58%

Personally, I don't much care about the size of U-Boot bin itself
(179kB or 104kB), but it depends.  And I'd like to see how much boot
time of U-Boot improved on your environment.

> >> The following patches introduce the bootstrap support that enable to have a
>> compressed U-Boot image. The bootstrap code supports the uncompressed as
>> well as compressed payloads, using LZMA, GZIP, BZIP2 and LZO.
>>
>> Actually I developed just the mips version (using qemu-mips board)...
>>
>> Please see the Patch #1 for the required defines to enable the required
>> features.

Not having a closer look at the patch yet, some general comments:

* Two patches posted, but contains multiple logical changes:
  - CONFIG_BOOTSTRAP* build infrastructure (main body)
  - common: Introduce console_bootstrap
  - MIPS: Separate _machine_restart() and do_reset() into reset.c
  - MIPS: config.mk: Append -g debug option to PLATFORM_CPPFLAGS,
    which is already provided by $(TOPDIR)/config.mk.
  - MIPS: qemu_mips: bootstrap support enablement (experimental)

  Please break into logical changes, please.

* '_bootstrap' suffixed files are almost identical to the original
  ones:
  - arch/mips/cpu/reset{,_bootstrap}.c
  - arch/mips/cpu/start{,_bootstrap}.S
  - board/qemu-mips/u-boot{,_bootstrap}.lds

  Is there any way not to duplicate them?  Do we really need to have
  _bootstrap files separated?

Once this bootstrap feature approved as general U-Boot feature, I'd
like to take MIPS-related changes.

Thanks,

  Ralf