Is it possible to update the QSPI LUT entry using the PBL

[raymondhaas]

I was hoping to change the default LUT entry used to access the QSPI.  I would like to be able to read the device faster. Is it possible to add PBI commands to unlock the LUT, modify the first (default) entry, and lock the LUT?

My code copies itself from QSPI to ISRAM.  This works well, but I have rather tight boot up time requirements. I was hoping to shorten the copy time by configuring the default LUT entry for fast quad read cycles.

If altering the default LUT using the PBL is not possible, is it possible to change the LUT while I am executing from the part?  It seems to me that would not be recommended.

FYI, I am using an LS1021a.

Thank you for your help

[GyM]

The application Note AN12279, released after this post gives details about how to do this...

[alexander_yakov]

Sorry for delayed response to this.

LUT registers are usual memory-mapped registers, so updating LUT register via PBL is theoretically possible, but we have not tried this in lab, so - we do not have ready to use solution for this.

I assume you are using any other memory for RCW and PBL, not QSPI memory. Updating QSPI controller LUT registers via PBL while executing PBL commands from this QSPI memory device - is not possible.

As an alternative (and more "Safe") solution I recommend implementing LUT update procedure in boot loader. Assuming U-boot and Linux - in U-boot just before loading Linux kernel. U-boot copies itself to DDR memory, so updating QSPI settings while executing from DDR is more safe, than doing this while executing from QSPI itself.

Have a great day,
Alexander
TIC

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------