Hi all,
We are trying to accelerate significantly the timing between uboot launch and Linux kernel boot. We now have a few seconds for a full Linux with libraries. But we still get nearly 2s in uboot due to Linux kernel copy to DDR2. While digging further, we were stunned to see that the Nand to DDR2 copy was so slow. We made tests with uboot nand utils. we also get a maximum 1.1MB/s with a Micron Flash (raw copy from Flash to DDR2, no filesystem).
While reading the sprs496a (about LSP 1.2 Linux Drivers and performances), we discovered official Nand MLC read speed around 0.56 Mbytes/s in low latency mode (with filesystem however). The DM355 has a nand controller. So, how can it be so slow ? The same Nand chips in USB keys may reach 20MB/s under Linux !
We modified uboot to disable ECC during read. But the speed didn't increase really. Maybe there is an issue in the EMIF default configuration ? (or management of the R/B# bit of the Flash) ?
Any idea to reach a descent performance ? Best regards. Yves LE HENAFF. _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
