On Tue, Dec 03, 2024 at 10:40:29PM +0200, Roger Quadros wrote:
Hello Roger,
> CONFIG_USB_XHCI_DWC3 is not required for AM62x as the XHCI
> driver is registered through the dwc3-generic driver.
>
> CONFIG_USB_XHCI_DWC3 causes problems by hijacking the
> USB controller even if it is not set for Host mode in
> device tree.
>
> 'dm tree' output after 'usb start' is fixed from
>
> simple_bus 5 [ + ] dwc3-am62 | |-- dwc3-usb@f900000
> usb_gadget 0 [ ] dwc3-generic-periphe | | |-- usb@31000000
> usb 0 [ + ] xhci-dwc3 | | `-- usb@31000000
> usb_hub 0 [ + ] usb_hub | | `-- usb_hub
> simple_bus 6 [ + ] dwc3-am62 | |-- dwc3-usb@f910000
> usb 1 [ + ] dwc3-generic-host | | |-- usb@31100000
> usb_hub 1 [ + ] usb_hub | | | `-- usb_hub
> usb 1 [ + ] xhci-dwc3 | | `-- usb@31100000
> usb_hub 2 [ + ] usb_hub | | `-- usb_hub
>
> [notice that 'xhci-dwc3' and 'usb_hub' drivers are probed
> for both USB instances although the first instance
> is supposed to be 'peripheral' only]
>
> to
>
> simple_bus 5 [ ] dwc3-am62 | |-- dwc3-usb@f900000
> usb_gadget 0 [ ] dwc3-generic-periphe | | `-- usb@31000000
> simple_bus 6 [ + ] dwc3-am62 | |-- dwc3-usb@f910000
> usb 1 [ + ] dwc3-generic-host | | `-- usb@31100000
> usb_hub 0 [ + ] usb_hub | | `-- usb_hub
While this fixes the issue, I am wondering if the issue lies elsewhere.
In U-Boot, the compatible "snps,dwc3" is associated with:
drivers/usb/host/xhci-dwc3.c
while in Linux, the compatible "snps,dwc3" is associated with:
drivers/usb/dwc3/core.c
So there seem to be two alternatives that I could think of:
1. Modify U-Boot to match Linux in the sense that we associate
"snps,dwc3" with drivers/usb/dwc3/core.c in U-Boot.
2. With the understanding that "dr_mode" doesn't have to be host/otg for
the compatible "snps,dwc3" which is tied to drivers/usb/host/xhci-dwc3.c,
do the following to exit probe when "dr_mode" is "peripheral":
-------------------------------------------------------------------------
diff --git a/drivers/usb/host/xhci-dwc3.c b/drivers/usb/host/xhci-dwc3.c
index e3e0ceff43e..edfd7b97a73 100644
--- a/drivers/usb/host/xhci-dwc3.c
+++ b/drivers/usb/host/xhci-dwc3.c
@@ -208,6 +208,8 @@ static int xhci_dwc3_probe(struct udevice *dev)
writel(reg, &dwc3_reg->g_usb2phycfg[0]);
dr_mode = usb_get_dr_mode(dev_ofnode(dev));
+ if (dr_mode == USB_DR_MODE_PERIPHERAL)
+ return -ENODEV;
if (dr_mode == USB_DR_MODE_OTG &&
dev_read_bool(dev, "usb-role-switch")) {
dr_mode = usb_get_role_switch_default_mode(dev_ofnode(dev));
-------------------------------------------------------------------------
which will still show "xhci-dwc3" in the output of "dm tree" after "usb
start", but the driver won't be probed (absence of "+" in the "Probed"
column of "dm tree" output).
I just wanted to point this out as a possible fix for other scenarios.
Disabling "CONFIG_USB_XHCI_DWC3" seems to be the best choice in the
current scenario (i.e. it shouldn't have been set in "USB DFU" fragment
to begin with).
>
> Fixes: dfc2dff5a844 ("configs: am62x_evm_*: Enable USB and DFU support")
> Signed-off-by: Roger Quadros <rog...@kernel.org>
Reviewed-by: Siddharth Vadapalli <s-vadapa...@ti.com>
> ---
> configs/am62x_a53_usbdfu.config | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/configs/am62x_a53_usbdfu.config b/configs/am62x_a53_usbdfu.config
> index 3a19cf23287..0d3c6df1e73 100644
> --- a/configs/am62x_a53_usbdfu.config
> +++ b/configs/am62x_a53_usbdfu.config
> @@ -16,7 +16,6 @@ CONFIG_USB=y
> CONFIG_DM_USB_GADGET=y
> CONFIG_SPL_DM_USB_GADGET=y
> CONFIG_USB_XHCI_HCD=y
> -CONFIG_USB_XHCI_DWC3=y
> CONFIG_USB_DWC3=y
> CONFIG_USB_DWC3_GENERIC=y
> CONFIG_SPL_USB_DWC3_GENERIC=y
>
> ---
> base-commit: 3073246d1be682071d8b3d07d06c2484907aed60
> change-id: 20241203-am62-usb-xhci-be62bc9584c9
>
> Best regards,
> --
> Roger Quadros <rog...@kernel.org>
>
