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

stable inclusion
from stable-5.10.11
commit ea0dd2da3ac756b8c6d32b4b17c642e64d5d908d
bugzilla: 47621

--------------------------------

commit 4e0dcf62 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: 7ecca2a4 ("usb/gadget: Add driver for Aspeed SoC virtual hub")
Cc: stable <stable@vger.kernel.org>
Acked-by: NFelipe Balbi <balbi@kernel.org>
Acked-by: NJoel Stanley <joel@jms.id.au>
Signed-off-by: NRyan Chen <ryan_chen@aspeedtech.com>
Link: https://lore.kernel.org/r/20210108081238.10199-2-ryan_chen@aspeedtech.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

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++) {