From 6fe2677bcf24d624bfc95a42960494082a977b1e Mon Sep 17 00:00:00 2001 From: Wayne Chang Date: Fri, 18 Apr 2025 16:12:28 +0800 Subject: [PATCH] usb: gadget: tegra-xudc: ACK ST_RC after clearing CTRL_RUN commit 59820fde001500c167342257650541280c622b73 upstream. We identified a bug where the ST_RC bit in the status register was not being acknowledged after clearing the CTRL_RUN bit in the control register. This could lead to unexpected behavior in the USB gadget drivers. This patch resolves the issue by adding the necessary code to explicitly acknowledge ST_RC after clearing CTRL_RUN based on the programming sequence, ensuring proper state transition. Fixes: 49db427232fe ("usb: gadget: Add UDC driver for tegra XUSB device mode controller") Cc: stable Signed-off-by: Wayne Chang Link: https://lore.kernel.org/r/20250418081228.1194779-1-waynec@nvidia.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/udc/tegra-xudc.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/usb/gadget/udc/tegra-xudc.c b/drivers/usb/gadget/udc/tegra-xudc.c index fd7a9535973e..771466cdf385 100644 --- a/drivers/usb/gadget/udc/tegra-xudc.c +++ b/drivers/usb/gadget/udc/tegra-xudc.c @@ -1743,6 +1743,10 @@ static int __tegra_xudc_ep_disable(struct tegra_xudc_ep *ep) val = xudc_readl(xudc, CTRL); val &= ~CTRL_RUN; xudc_writel(xudc, val, CTRL); + + val = xudc_readl(xudc, ST); + if (val & ST_RC) + xudc_writel(xudc, ST_RC, ST); } dev_info(xudc->dev, "ep %u disabled\n", ep->index);