usb: gadget: aspeed: fix stop dma register setting.

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: 7ecca2a ("usb/gadget: Add driver for Aspeed SoC virtual hub")
Cc: stable <[email protected]>
Acked-by: Felipe Balbi <[email protected]>
Acked-by: Joel Stanley <[email protected]>
Signed-off-by: Ryan Chen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: aspeedtech

drivers/usb/gadget/udc/aspeed-vhub/epn.c

@@ -420,7 +420,10 @@ static void ast_vhub_stop_active_req(struct ast_vhub_ep *ep,
 	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++) {