target/linux/bcm27xx/patches-5.4/950-1031-net-lan78xx-Ack-pending-PHY-ints-when-resetting.patch

   1 From 598d6389f41c1e01b70df7d8b1056c3839e0c1c2 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.com>
   3 Date: Tue, 15 Dec 2020 16:38:37 +0000
   4 Subject: [PATCH] net: lan78xx: Ack pending PHY ints when resetting
   5
   6 lan78xx_link_reset explicitly clears the MAC's view of the PHY's IRQ
   7 status. In doing so it potentially leaves the PHY with a pending
   8 interrupt that will never be acknowledged, at which point no further
   9 interrupts will be generated.
  10
  11 Avoid the problem by acknowledging any pending PHY interrupt after
  12 clearing the MAC's status bit.
  13
  14 See: https://github.com/raspberrypi/linux/issues/2937
  15
  16 Signed-off-by: Phil Elwell <phil@raspberrypi.com>
  17 ---
  18  drivers/net/usb/lan78xx.c | 3 +++
  19  1 file changed, 3 insertions(+)
  20
  21 --- a/drivers/net/usb/lan78xx.c
  22 +++ b/drivers/net/usb/lan78xx.c
  23 @@ -1183,6 +1183,9 @@ static int lan78xx_link_reset(struct lan
  24         if (unlikely(ret < 0))
  25                 return -EIO;
  26
  27 +       /* Acknowledge any pending PHY interrupt, lest it be the last */
  28 +       phy_read(phydev, LAN88XX_INT_STS);
  29 +
  30         mutex_lock(&phydev->lock);
  31         phy_read_status(phydev);
  32         link = phydev->link;