Hi Rogan, On Sun, Sep 24, 2023 at 5:16 PM Rogan Dawes <ro...@dawes.za.net> wrote: > > Hi folks, > > I eventually decided that I did need to figure out the DRAM timings for the > Micron chip on my board, but I found an easier way than actually > "understanding what I'm doing"! :-) > > I pulled the vendor U-Boot image off the flash, skipped the appropriate > number of bytes until I was actually dealing with a u-boot.sb formatted image > (looking for the STMP signature I found in the compiled mainline u-boot), > then used the Rockbox project's sbtoelf tool to convert the SB back to two > ELF files, the SPL.elf and the u-boot.elf. From there I loaded the SPL.elf > into ghidra, then went looking for byte sequences found in > arch/arm/cpu/arm926ejs/mxs/spl_mem_init.c to see if I could locate them in > the vendor blob. I did, right at the end of the binary, then converted bytes > into uint32 sequences so that I could compare with the mxs_dram_vals for > CONFIG_MX28. > > Did the compare and found a single bit that is different between the two > sequences of initialisation values. Literally a 1 to a 0, and that is all. So > I built mainline with that change, and an updated iomux_setup because the > Wink Hub v1 uses MX28_PAD_I2C0_SCL__DUART_RX and MX28_PAD_I2C0_SDA__DUART_TX > for its console pins. i was hoping to see it boot via mxsldr, but > unfortunately, I got nothing.
Ideally, you should create a new imx28-wink_defconfig. For a quick test, besides changing iomux_setup, please make sure that arch/arm/dts/imx28-evk.dts also has the duart pins changed. > How can I get the SPL to emit something on the console to confirm it is > running? i.e. before the DRAM initialisation? SPL runs from the internal RAM, and should print something to the console prior to the DRAM init.
