On Sun, Jul 03, 2022 at 06:26:22PM -0500, Samuel Holland wrote: > Hi Michal, > > On 7/3/22 2:20 PM, Michal Suchanek wrote: > > > > Hello, > > > > many ARM SoCs have a mask rom feature that provides interface for > > downloading firmware over USB. > > > > Downstream rockchip u-boot has 'brom' or 'rbrom' command for this > > purpose, and downstream sunxi u-boot provides 'efex' command. p-boot has > > code for entering FEL on A64 SoC. > > > > With this patch I am able to activate the USB downloader on a rk3399 but > > the rkflashtool fails to communicate with the device. On a H2+ I can get > > into the FEL mode and get flash parameters. YMMV > > > > I don't have any great idea how to structure this so that the command > > does not need platform-specific code. Is there an example of a command > > that has platform-specific implementations? > > Generally you would do this by having the driver interact with some DM uclass. > Platforms may or may not provide a driver implementing that uclass; the > details > are hidden behind the uclass's interface. All the command has to do is search > for a DM device by uclass, and if one is found, call some operation on it. > > In this case, UCLASS_REBOOT_MODE already exists. It sounds like what we need > is > the inverse of dm_reboot_mode_update() -- a function that takes a string and > programs the device with the corresponding mode value. > > To be generic, you could call this function from do_reset() if some positional > argument is provided, allowing usage like "reset bootloader" or "reset fel". > > Rockchip platforms already have syscon-reboot-mode hooked up in their > devicetrees. The driver for this should be trivial. > > Allwinner platforms would need to add a nvmem-reboot-mode node, and a bit more > driver infrastructure. U-Boot does not have NVMEM uclass, so you would need to > add one or reuse UCLASS_MISC.
Not sure I understand the DM enough but as firt step I can at least hook it to the do_reset function. Thanks Michal
