[PATCH 0/2] AM62A DWC3: Add support for USB DFU boot in OTG mode

[Tom Rini]

On Tue, 26 Nov 2024 17:33:17 +0530, Siddharth Vadapalli wrote:

> This series adds support for USB DFU boot on TI's AM62A SoC which has
> two instances of DWC3 USB Controllers namely USB0 and USB1. The USB0
> instance of the USB Controller supports USB DFU boot:
> ROM => tiboot3.bin => tispl.bin => u-boot.img
> 
> USB DFU Boot requires the USB Controller to be configured for Gadget
> mode of operation. Since the USB0 instance of the DWC3 USB Controller
> supports both Host and Gadget modes of operation via the Type-C interface
> on the AM62A7-SK board, the device-tree specifies the "dr_mode" as "OTG".
> However, there is currently no support for dynamically switching the "mode"
> from Host to Gadget and vice-versa with the help of a state-machine.
> The OTG mode is treated as a separate mode in itself rather than being
> treated as an intermediate stage before assuming the Host/Gadget mode.
> Due to this, USB DFU boot via the Type-C interface doesn't work as the
> USB Controller hasn't been appropriately configured for Device/Gadget
> mode of operation. One option is to change the device-tree to specify
> "dr_mode" as "peripheral" and force the controller to assume the Device
> role. This will imply that the U-Boot device-tree for AM62A diverges
> from its Linux counterpart. Therefore, with the intent of keeping the
> device-tree uniform across Linux and U-Boot, and at the same time, in
> order to enable USB DFU boot in "OTG" mode with the DWC3 Controller,
> the first patch in this series sets the "mode" on the basis of the
> caller function, rather than using the "dr_mode" property in the
> device-tree. There are only two callers of "dwc3_generic_probe()",
> each of which clearly specify the expected mode of configuration.
> This will enable both Host and Device mode of operation based on the
> command executed by the user, thereby truly supporting "OTG"
> functionality when the USB Controller supports it.
> 
> [...]

Applied to u-boot/next, thanks!

-- 
Tom