Hi Andre,
On 12/5/22 17:45, Andre Przywara wrote:
Please let me know if you have any opinions!
I believe I promised you last month I'd let you know once I had a build I'm happy with, and I'm pleased to say that I think I've reached that point. I'm running quite rapidly out of sharp edges to sand down, too.
I have a build of U-Boot for my target, complete with: - UART3 initialized correctly - DRAM coming up correctly - SPL sets configured boot clock correctly - SPI-NAND support (SPL and U-Boot proper) - MMC support (SPL and U-Boot proper) - SPL boot from FEL - USB gadget support - Ethernet MAC+PHY support - I²C support * - GPIO support (LEDs, buttons, misc. board management) - `reset` working (requries CONFIG_SYSRESET unset, WDT key) - PSCI, nonsec - Able to boot Linux ;)
* Requires nonzero `MVTWSI_CONTROL_CLEAR_IFLG` for NCAT2, and a patch to the pinctrl driver to configure the proper mux function for my necessary pins.
I figured I'd share this list as a sort of checklist for your own work, too. The remainder of my efforts now will probably be focused on mainlining this stuff (let me know how else I can be of help), and then I'm afraid I'll have to disappear back downstream to the Turing Pi 2 development effort, but maybe our paths will cross again in the kernel lists. :)
Thank you greatly, Sam
P.S. I figure the reason there aren't I²C function defs in the d1 pinctrl table already is because Allwinner tends to kick around the I²C mux values a lot and we would need a per-pin lookup table that would eat up too much valuable image space?
In an entirely JUST FOR FUN exercise to give myself a break from staring at datasheets/patches and do a "pure CS" coding challenge for a change, I came up with a terse encoding scheme for this table. Here is the size (in bits) for a selection of D1's functions (pin assignments harvested from Linux):
'emac': 50, 'i2c0': 101, 'i2c1': 64, 'i2c2': 109, 'i2c3': 91, 'mmc0': 23, 'mmc1': 23, 'mmc2': 20, 'spi0': 41, 'spi1': 48, 'uart0': 78, 'uart1': 87, 'uart2': 88, 'uart3': 102, 'uart4': 68, 'uart5': 66,
...and yes, it also identifies invalid pin assignments! I'd be willing to contribute something like this if there's big interest, but I figure needing to compress this at build-time might be a bit too complicated for the U-Boot project's liking.