[PATCH net-next v2 3/4] r8152: Add irq mitigation for RTL8157/9

[Birger Koblitz <mail@birger-koblitz.de>]

Add interrupt mitigation code for both RTL8157 and RTL8159 that prevents
USB interrupt callbacks with urb->status ESHUTDOWN being triggered. While the
issue is rarely seen on the RTL8157, without the mitigation, it is
common on the RTL8159:
[273.561863] r8152 7-1:1.0 enx88c9b3b5xxxx: Stop submitting intr, status -108

Signed-off-by: Birger Koblitz <mail@birger-koblitz.de>
---
 drivers/net/usb/r8152.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index 2a07dde289e2240b221664ae5c5bceec35b5a1ef..9fcad3dac76f8aa76ef074cabd3b08348dc234bc 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -8452,6 +8452,12 @@ static void r8156_init(struct r8152 *tp)
 	else
 		r8153_u2p3en(tp, false);
 
+	if (tp->version >= RTL_VER_16) {
+		/* Disable Interrupt Mitigation */
+		ocp_byte_clr_bits(tp, MCU_TYPE_USB, 0xcf04,
+				  BIT(0) | BIT(1) | BIT(2) | BIT(7));
+	}
+
 	/* MSC timer = 0xfff * 8ms = 32760 ms */
 	ocp_write_word(tp, MCU_TYPE_USB, USB_MSC_TIMER, 0x0fff);
 

-- 
2.47.3