Re: uboot performances

[Gianluca <gianlucarenzi@eptar.com>]

On Friday 23 June 2006 12:55, Davide CASCONE wrote:
> I'm working with the OMAP5912 OSK platform. I have the boot-loader code and
> the Linux OS compressed image in a Sibley flash. When I run the system, the
> boot loader (uBoot) have to copy the Kernel Image (about 700KB) in RAM. It
> takes about 300ms in order to perform that copy. But I have read some
> benchmark results in which the copy of the kernel in RAM lasts only
> 80-100ms. In order to reduce the time of the copy on my platform, the only
> solution that I found (after checking the memory controller settings) is to
> modify the copy function memmove (uboot/ lib_generic/string.c). This
> function performs the copy byte by byte. If I modify this function to
> perform the copy 4byte by 4byte, the bootloader only takes about 80 ms. Do
> you think this is a good workaround for this problem? Can you suggest me
> anything better?
Sometime (I don't know about uboot) first-stage bootloaders are executing 
themselves at very low clock timing due to flash-timing constraints (i.e.: 
4Mhz/16Mhz/25Mhz). Are you sure your board is running at the maximum speed 
allowed by Sibley flash device?
Your consideration about memmove (4byte by 4byte (a single word) in a 32bit 
micro) is correct. But what about other functions that are using memmove and 
complain about byte ordering?
It is better to write a memmove32() and use this instead.

Regards,  
-- 
Gianluca Renzi
Eptar s.r.l.
Via Celletta 8/B
40026 Imola (BO) ITALY
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