U-Boot NOR Flash Copy Time Reduction

[yyurtcan]

We have P4080DS board and u-boot for bootloader. We want to reduce to time to copy kernel image from NOR Flash to RAM.  Can we optimize p4080ds u-boot NOR Flash copy time? If so, How?

Best Regards.

[yaseryurtcan]

Thank you for shared information. We could not find NOR Flash controller settings in u-boot. How can we find it? Which component do we need to check/ change in u-boot?

Best Regards.

[alexander_yakov]

Copy procedure consists of two steps - read from NOR and write to RAM. I'm quite sure U-boot writes to RAM very effectively, and RAM settings are correct, so there is nothing to further optimize in write to RAM part. The only thing you can try to optimize is read from NOR flash - please verify NOR flash read cycle length is optimal for actually used NOR flash memory. But strictly speaking I do not expect significant issues with NOR flash settings.

Besides optimizing NOR read cycle time and write to RAM time, I do not see any other way to reduce copy time.

Have a great day,
Alexander

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[yaseryurtcan]

How can we learn that NOR flash read cycle length is optimal? We have checked, but we couldn’t find any document about it. How can we optimize it?

Best regards.

[alexander_yakov]

To check if NOR flash cycle is optimal, you can check the exact partnumber of NOR flash you are using, this partnumber usually contains speed grade mark. For this particular speed grade please check NOR flash datasheet for minimum timing requirements. Comparing these timing requirements from NOR flash datasheet with NOR flash controller settings, you can verify if your NOR flash controller settings are optimal for your flash.