[U-Boot] Bottleneck of NAND copy speed

[Simon Schwarz]

Hi List,

ATM I'm working on a DMA transfer from NAND to RAM of the Linux-image in
my SPL.

I’m searching for the speed bottleneck of the MT29F1G16ABBHC-ET 
NAND-Flash on the devkit8000 (OMAP3).

 From the timings I set on the GPMC I calced a max. speed of around 26 
MiB/s. In my measurements I have a speed of around 10 MiB/s.

Here is the image of my the calculation:
https://docs.google.com/leaf?id=0B_wpO5K0MQSlYTcxMWVlOGEtY2FmYy00ODMyLWE1MTUtN2ZiZGViOWVhMzYw&hl=en_US

tcmd: The time for the initial read command
twr: time to write the address
tDn: Time for a 16bit read of Data

Does anyone has an idea where the bottleneck could be? Is my calculation 
wrong?
(ecc is done parallel to the DMA transfer).

Regards
Simon