[U-Boot-Users] decrease boot time

Grant Likely glikely at gmail.com
Mon Feb 14 09:36:39 CET 2005


On Sun, 13 Feb 2005 14:02:16 +0100, Konstantin Kletschke
<lists at ku-gbr.de> wrote:
> Am 2005-02-12 14:02 -0700 schrieb Grant Likely:
>
> > arch/arm/boot/compressed/head.S.  You will see a branch to cache_on at
> > line 287 before decompress_kernel at line 310.  (2.6.10)  According to
> > the comment on line 422 the page tables are setup for wherever the
> > compressed image is; including if it is in FLASH.
> 
> Yes I see. But I don't understand the assembler code really yet. Do you
> mean "add     r0, r3, r2, lsl #2" by line 422, where addresses above
> 0x10040000 (there my kernel lives) are added to cacheable area?

Sorry; I meant line 412.  That block of code adds a cache mapping to
where the PC is currently running.  This means that the compressed
image is cached.  Note: this cache enable is for uncompressing the
kernel; the caches are reconfigured inside the kernel itself.

> 
> > Linux can spew a lot of log messages; I suspect your time difference
> > would be more bounded by the baud rate of the port rather than the
> > serial device driver itself.  U-boot on the other had is quite a bit
> 
> T thought also and measured and my result is the same.

???

Cheers,
g.




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