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/* SDE_1 for CS1 */ > > > > /* Step 8: Write Mode Registers to Init DDR3 devices */ > > > > + mdelay(1); /* Wait before issuing the first MRS command > > > > + (tXPR / 500us CKE delay after reset deassertion) */ > > > > > > Should we infer this delay from tXPR instead ? > > > > I could just delay(tXPR + 500us) and do the exact worst case delay. > > > > However I wonder if it is worth doing it, the 1ms delay works in > > practice, it is big enough to be correct in any case, but small enough > > not to be a concern on the boot time. > > > > Please note that I do not know which timing is violated here > > (tXPR, the 500us after reset de-assertion or both of them). > > Can the tXPR ever be larger than 500us ? No, it can't. Max value for 8GB density is 360ns, min value 120ns for 1GB density (see JEDEC standard, but also mx6/ddr.c). Would be fine for you to improve the commit message and code comment to make this discussion we just had transparent, while keeping the 1ms delay? Francesco