From: Ryan Chen <ryan_chen@xxxxxxxxxxxxxx> commit 4e0dcf62ab4cf917d0cbe751b8bf229a065248d4 upstream. The vhub engine has two dma mode, one is descriptor list, another is single stage DMA. Each mode has different stop register setting. Descriptor list operation (bit2) : 0 disable reset, 1: enable reset Single mode operation (bit0) : 0 : disable, 1: enable Fixes: 7ecca2a4080c ("usb/gadget: Add driver for Aspeed SoC virtual hub") Cc: stable <stable@xxxxxxxxxxxxxxx> Acked-by: Felipe Balbi <balbi@xxxxxxxxxx> Acked-by: Joel Stanley <joel@xxxxxxxxx> Signed-off-by: Ryan Chen <ryan_chen@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210108081238.10199-2-ryan_chen@xxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/gadget/udc/aspeed-vhub/epn.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/drivers/usb/gadget/udc/aspeed-vhub/epn.c +++ b/drivers/usb/gadget/udc/aspeed-vhub/epn.c @@ -420,7 +420,10 @@ static void ast_vhub_stop_active_req(str u32 state, reg, loops; /* Stop DMA activity */ - writel(0, ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT); + if (ep->epn.desc_mode) + writel(VHUB_EP_DMA_CTRL_RESET, ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT); + else + writel(0, ep->epn.regs + AST_VHUB_EP_DMA_CTLSTAT); /* Wait for it to complete */ for (loops = 0; loops < 1000; loops++) {