On Fri, Feb 25, 2022 at 03:47:47PM +0100, Joacim Zetterling wrote: > There is some issues with the imx8 ddrc sdram size calculation. > > If we compare the imx8mn DDR4 evk against the LPDDR4 variant in > code and in the datasheets, we see the following: > > DDR4 LPDDR4 > ======================== > Bus width 16 16 > Rank 1 1 > Ranks 1 1 > Banks 4 8 > Banks grps 2 1 > Rows 17 15 > Col 10 10 > > This gives us the following problems: > > 1. Bus width problem. > Does not support 16 bit SDRAM bus mode, only 32 bit supported > > 2. Row size problem. > Only up to 16 bit row size support. > > 3. Bank groups support. > Only support of 1 bank group. > > 4. Bit count problem. > The imx_ddrc_count_bits function does not do a correct count. > Found out during test of the 1-3 part fixes. > > The fact that the code only handled a 32 bit bus width, compensated > the problems with rows, banks and rank. So this means this series causes a regression in between which is fixed at the end of the series, right? I think this is ok in this case and is better than putting everything in a single patch. I just want to make sure everyone who bisects barebox and ends up in one of these patches and likely reads this thread knows that this is expected. Sascha -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
