[PATCH net 1/3] r8152: fix flow control issue of RTL8156A

[Hayes Wang <hayeswang@xxxxxxxxxxx>]

The feature of flow control becomes abnormal, if the device sends a
pause frame and the tx/rx is disabled before sending a release frame. It
causes the lost of packets.

Set PLA_RX_FIFO_FULL and PLA_RX_FIFO_EMPTY to zeros before disabling the
tx/rx. And, toggle FC_PATCH_TASK before enabling tx/rx to reset the flow
control patch and timer. Then, the hardware could clear the state and
the flow control becomes normal after enabling tx/rx.

Fixes: 195aae321c82 ("r8152: support new chips")
Signed-off-by: Hayes Wang <hayeswang@xxxxxxxxxxx>
---
 drivers/net/usb/r8152.c | 56 ++++++++++++++++++++++++++---------------
 1 file changed, 36 insertions(+), 20 deletions(-)

diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index 0fc4b959edc1..08d1786135f2 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -5986,6 +5986,25 @@ static void rtl8153_disable(struct r8152 *tp)
 	r8153_aldps_en(tp, true);
 }
 
+static inline u32 fc_pause_on_auto(struct r8152 *tp)
+{
+	return (ALIGN(mtu_to_size(tp->netdev->mtu), 1024) + 6 * 1024);
+}
+
+static inline u32 fc_pause_off_auto(struct r8152 *tp)
+{
+	return (ALIGN(mtu_to_size(tp->netdev->mtu), 1024) + 14 * 1024);
+}
+
+static void r8156_fc_parameter(struct r8152 *tp)
+{
+	u32 pause_on = tp->fc_pause_on ? tp->fc_pause_on : fc_pause_on_auto(tp);
+	u32 pause_off = tp->fc_pause_off ? tp->fc_pause_off : fc_pause_off_auto(tp);
+
+	ocp_write_word(tp, MCU_TYPE_PLA, PLA_RX_FIFO_FULL, pause_on / 16);
+	ocp_write_word(tp, MCU_TYPE_PLA, PLA_RX_FIFO_EMPTY, pause_off / 16);
+}
+
 static int rtl8156_enable(struct r8152 *tp)
 {
 	u32 ocp_data;
@@ -5994,6 +6013,7 @@ static int rtl8156_enable(struct r8152 *tp)
 	if (test_bit(RTL8152_UNPLUG, &tp->flags))
 		return -ENODEV;
 
+	r8156_fc_parameter(tp);
 	set_tx_qlen(tp);
 	rtl_set_eee_plus(tp);
 	r8153_set_rx_early_timeout(tp);
@@ -6025,9 +6045,24 @@ static int rtl8156_enable(struct r8152 *tp)
 		ocp_write_word(tp, MCU_TYPE_USB, USB_L1_CTRL, ocp_data);
 	}
 
+	ocp_data = ocp_read_word(tp, MCU_TYPE_USB, USB_FW_TASK);
+	ocp_data &= ~FC_PATCH_TASK;
+	ocp_write_word(tp, MCU_TYPE_USB, USB_FW_TASK, ocp_data);
+	usleep_range(1000, 2000);
+	ocp_data |= FC_PATCH_TASK;
+	ocp_write_word(tp, MCU_TYPE_USB, USB_FW_TASK, ocp_data);
+
 	return rtl_enable(tp);
 }
 
+static void rtl8156_disable(struct r8152 *tp)
+{
+	ocp_write_word(tp, MCU_TYPE_PLA, PLA_RX_FIFO_FULL, 0);
+	ocp_write_word(tp, MCU_TYPE_PLA, PLA_RX_FIFO_EMPTY, 0);
+
+	rtl8153_disable(tp);
+}
+
 static int rtl8156b_enable(struct r8152 *tp)
 {
 	u32 ocp_data;
@@ -6429,25 +6464,6 @@ static void rtl8153c_up(struct r8152 *tp)
 	r8153b_u1u2en(tp, true);
 }
 
-static inline u32 fc_pause_on_auto(struct r8152 *tp)
-{
-	return (ALIGN(mtu_to_size(tp->netdev->mtu), 1024) + 6 * 1024);
-}
-
-static inline u32 fc_pause_off_auto(struct r8152 *tp)
-{
-	return (ALIGN(mtu_to_size(tp->netdev->mtu), 1024) + 14 * 1024);
-}
-
-static void r8156_fc_parameter(struct r8152 *tp)
-{
-	u32 pause_on = tp->fc_pause_on ? tp->fc_pause_on : fc_pause_on_auto(tp);
-	u32 pause_off = tp->fc_pause_off ? tp->fc_pause_off : fc_pause_off_auto(tp);
-
-	ocp_write_word(tp, MCU_TYPE_PLA, PLA_RX_FIFO_FULL, pause_on / 16);
-	ocp_write_word(tp, MCU_TYPE_PLA, PLA_RX_FIFO_EMPTY, pause_off / 16);
-}
-
 static void rtl8156_change_mtu(struct r8152 *tp)
 {
 	u32 rx_max_size = mtu_to_size(tp->netdev->mtu);
@@ -9340,7 +9356,7 @@ static int rtl_ops_init(struct r8152 *tp)
 	case RTL_VER_10:
 		ops->init		= r8156_init;
 		ops->enable		= rtl8156_enable;
-		ops->disable		= rtl8153_disable;
+		ops->disable		= rtl8156_disable;
 		ops->up			= rtl8156_up;
 		ops->down		= rtl8156_down;
 		ops->unload		= rtl8153_unload;
-- 
2.40.0