From:   Neal Liu <neal_liu@aspeedtech.com>
To:     Felipe Balbi <balbi@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Joel Stanley <joel@jms.id.au>,
        Andrew Jeffery <andrew@aj.id.au>,
        Cai Huoqing <caihuoqing@baidu.com>,
        Tao Ren <rentao.bupt@gmail.com>,
        Julia Lawall <julia.lawall@inria.fr>,
        "kernel test robot" <lkp@intel.com>,
        Sasha Levin <sashal@kernel.org>, <linux-usb@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-aspeed@lists.ozlabs.org>
CC:     Neal Liu <neal_liu@aspeedtech.com>, <BMC-SW@aspeedtech.com>
Subject: [PATCH 3/3] usb: aspeed-vhub: fix ep0 OUT ack received wrong length issue
Date:   Fri, 26 Nov 2021 19:09:54 +0800
Message-ID: <20211126110954.2677627-4-neal_liu@aspeedtech.com>
In-Reply-To: <20211126110954.2677627-1-neal_liu@aspeedtech.com>
References: <20211126110954.2677627-1-neal_liu@aspeedtech.com>
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Precedence: bulk

If multiple devices in vhub are enumerated simultaneously, ep0 OUT
ack might received wrong data length. Using expected data length
instead.

Signed-off-by: Neal Liu <neal_liu@aspeedtech.com>
---
 drivers/usb/gadget/udc/aspeed-vhub/ep0.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/usb/gadget/udc/aspeed-vhub/ep0.c b/drivers/usb/gadget/udc/aspeed-vhub/ep0.c
index 74ea36c19b1e..bea9cbb191a2 100644
--- a/drivers/usb/gadget/udc/aspeed-vhub/ep0.c
+++ b/drivers/usb/gadget/udc/aspeed-vhub/ep0.c
@@ -251,6 +251,13 @@ static void ast_vhub_ep0_do_receive(struct ast_vhub_ep *ep, struct ast_vhub_req
 		len = remain;
 		rc = -EOVERFLOW;
 	}
+
+	/* HW return wrong data len */
+	if (len < ep->ep.maxpacket && len != remain) {
+		EPDBG(ep, "using expected data len instead\n");
+		len = remain;
+	}
+
 	if (len && req->req.buf)
 		memcpy(req->req.buf + req->req.actual, ep->buf, len);
 	req->req.actual += len;
-- 
2.25.1