This is a note to let you know that I've just added the patch titled
net: dsa: microchip: fix initial port flush problem
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-dsa-microchip-fix-initial-port-flush-problem.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 89af5b76e55d2ea52b3b505b3d4680d415a51943
Author: Tristram Ha <tristram.ha@xxxxxxxxxxxxx>
Date: Tue Jun 18 17:16:42 2024 -0700
net: dsa: microchip: fix initial port flush problem
[ Upstream commit ad53f5f54f351e967128edbc431f0f26427172cf ]
The very first flush in any port will flush all learned addresses in all
ports. This can be observed by unplugging the cable from one port while
additional ports are connected and dumping the fdb entries.
This problem is caused by the initially wrong value programmed to the
REG_SW_LUE_CTRL_1 register. Setting SW_FLUSH_STP_TABLE and
SW_FLUSH_MSTP_TABLE bits does not have an immediate effect. It is when
ksz9477_flush_dyn_mac_table() is called then the SW_FLUSH_STP_TABLE bit
takes effect and flushes all learned entries. After that call both bits
are reset and so the next port flush will not cause such problem again.
Fixes: b987e98e50ab ("dsa: add DSA switch driver for Microchip KSZ9477")
Signed-off-by: Tristram Ha <tristram.ha@xxxxxxxxxxxxx>
Link: https://patch.msgid.link/1718756202-2731-1-git-send-email-Tristram.Ha@xxxxxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/dsa/microchip/ksz9477.c b/drivers/net/dsa/microchip/ksz9477.c
index ba2dc01e0f6bf..5b398608f2975 100644
--- a/drivers/net/dsa/microchip/ksz9477.c
+++ b/drivers/net/dsa/microchip/ksz9477.c
@@ -206,10 +206,8 @@ static int ksz9477_reset_switch(struct ksz_device *dev)
SPI_AUTO_EDGE_DETECTION, 0);
/* default configuration */
- ksz_read8(dev, REG_SW_LUE_CTRL_1, &data8);
- data8 = SW_AGING_ENABLE | SW_LINK_AUTO_AGING |
- SW_SRC_ADDR_FILTER | SW_FLUSH_STP_TABLE | SW_FLUSH_MSTP_TABLE;
- ksz_write8(dev, REG_SW_LUE_CTRL_1, data8);
+ ksz_write8(dev, REG_SW_LUE_CTRL_1,
+ SW_AGING_ENABLE | SW_LINK_AUTO_AGING | SW_SRC_ADDR_FILTER);
/* disable interrupts */
ksz_write32(dev, REG_SW_INT_MASK__4, SWITCH_INT_MASK);
