[PATCH 4.4 14/27] r8152: fix rx issue for runtime suspend

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.4-stable review patch.  If anyone has any objections, please let me know.

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

From: hayeswang <hayeswang@realtek.com>


[ Upstream commit 75dc692eda114cb234a46cb11893a9c3ea520934 ]

Pause the rx and make sure the rx fifo is empty when the autosuspend
occurs.

If the rx data comes when the driver is canceling the rx urb, the host
controller would stop getting the data from the device and continue
it after next rx urb is submitted. That is, one continuing data is
split into two different urb buffers. That let the driver take the
data as a rx descriptor, and unexpected behavior happens.

Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/usb/r8152.c |   31 ++++++++++++++++++++++++++++---
 1 file changed, 28 insertions(+), 3 deletions(-)

--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -3452,17 +3452,42 @@ static int rtl8152_rumtime_suspend(struc
 	int ret = 0;
 
 	if (netif_running(netdev) && test_bit(WORK_ENABLE, &tp->flags)) {
+		u32 rcr = 0;
+
 		if (delay_autosuspend(tp)) {
 			ret = -EBUSY;
 			goto out1;
 		}
 
+		if (netif_carrier_ok(netdev)) {
+			u32 ocp_data;
+
+			rcr = ocp_read_dword(tp, MCU_TYPE_PLA, PLA_RCR);
+			ocp_data = rcr & ~RCR_ACPT_ALL;
+			ocp_write_dword(tp, MCU_TYPE_PLA, PLA_RCR, ocp_data);
+			rxdy_gated_en(tp, true);
+			ocp_data = ocp_read_byte(tp, MCU_TYPE_PLA,
+						 PLA_OOB_CTRL);
+			if (!(ocp_data & RXFIFO_EMPTY)) {
+				rxdy_gated_en(tp, false);
+				ocp_write_dword(tp, MCU_TYPE_PLA, PLA_RCR, rcr);
+				ret = -EBUSY;
+				goto out1;
+			}
+		}
+
 		clear_bit(WORK_ENABLE, &tp->flags);
 		usb_kill_urb(tp->intr_urb);
-		napi_disable(&tp->napi);
-		rtl_stop_rx(tp);
+
 		rtl_runtime_suspend_enable(tp, true);
-		napi_enable(&tp->napi);
+
+		if (netif_carrier_ok(netdev)) {
+			napi_disable(&tp->napi);
+			rtl_stop_rx(tp);
+			rxdy_gated_en(tp, false);
+			ocp_write_dword(tp, MCU_TYPE_PLA, PLA_RCR, rcr);
+			napi_enable(&tp->napi);
+		}
 	}
 
 	set_bit(SELECTIVE_SUSPEND, &tp->flags);