bcm27xx: add support for linux v5.15

Build system: x86_64
Build-tested: bcm2708, bcm2709, bcm2710, bcm2711
Run-tested: bcm2708/RPiB+, bcm2709/RPi3B, bcm2710/RPi3B, bcm2711/RPi4B

Signed-off-by: Marty Jones <mj8263788@gmail.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/target/linux/bcm27xx/patches-5.15/950-0323-net-lan78xx-Ack-pending-PHY-ints-when-resetting.patch b/target/linux/bcm27xx/patches-5.15/950-0323-net-lan78xx-Ack-pending-PHY-ints-when-resetting.patch
new file mode 100644
index 0000000000..1fea6bd153
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.15/950-0323-net-lan78xx-Ack-pending-PHY-ints-when-resetting.patch
@@ -0,0 +1,32 @@
+From 107e14fb85b57eca17266a62c7cba81b22448953 Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.com>
+Date: Tue, 15 Dec 2020 16:38:37 +0000
+Subject: [PATCH] net: lan78xx: Ack pending PHY ints when resetting
+
+lan78xx_link_reset explicitly clears the MAC's view of the PHY's IRQ
+status. In doing so it potentially leaves the PHY with a pending
+interrupt that will never be acknowledged, at which point no further
+interrupts will be generated.
+
+Avoid the problem by acknowledging any pending PHY interrupt after
+clearing the MAC's status bit.
+
+See: https://github.com/raspberrypi/linux/issues/2937
+
+Signed-off-by: Phil Elwell <phil@raspberrypi.com>
+---
+ drivers/net/usb/lan78xx.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+--- a/drivers/net/usb/lan78xx.c
++++ b/drivers/net/usb/lan78xx.c
+@@ -1274,6 +1274,9 @@ static int lan78xx_link_reset(struct lan
+ 	if (unlikely(ret < 0))
+ 		return ret;
+ 
++	/* Acknowledge any pending PHY interrupt, lest it be the last */
++	phy_read(phydev, LAN88XX_INT_STS);
++
+ 	mutex_lock(&phydev->lock);
+ 	phy_read_status(phydev);
+ 	link = phydev->link;