This is a note to let you know that I've just added the patch titled
net: dsa: microchip: Fix LAN937X set_ageing_time function
to the 6.6-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-lan937x-set_ageing_time-functi.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit efe8b8781f0ea811cba585159f9db5c12bc64882
Author: Tristram Ha <tristram.ha@xxxxxxxxxxxxx>
Date: Tue Dec 17 18:02:24 2024 -0800
net: dsa: microchip: Fix LAN937X set_ageing_time function
[ Upstream commit bb9869043438af5b94230f94fb4c39206525d758 ]
The aging count is not a simple 20-bit value but comprises a 3-bit
multiplier and a 20-bit second time. The code tries to use the
original multiplier which is 4 as the second count is still 300 seconds
by default.
As the 20-bit number is now too large for practical use there is an option
to interpret it as microseconds instead of seconds.
Fixes: 2c119d9982b1 ("net: dsa: microchip: add the support for set_ageing_time")
Signed-off-by: Tristram Ha <tristram.ha@xxxxxxxxxxxxx>
Reviewed-by: Andrew Lunn <andrew@xxxxxxx>
Link: https://patch.msgid.link/20241218020224.70590-3-Tristram.Ha@xxxxxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/dsa/microchip/lan937x_main.c b/drivers/net/dsa/microchip/lan937x_main.c
index b479a628b1ae..dde37e61faa3 100644
--- a/drivers/net/dsa/microchip/lan937x_main.c
+++ b/drivers/net/dsa/microchip/lan937x_main.c
@@ -1,6 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
/* Microchip LAN937X switch driver main logic
- * Copyright (C) 2019-2022 Microchip Technology Inc.
+ * Copyright (C) 2019-2024 Microchip Technology Inc.
*/
#include <linux/kernel.h>
#include <linux/module.h>
@@ -257,10 +257,66 @@ int lan937x_change_mtu(struct ksz_device *dev, int port, int new_mtu)
int lan937x_set_ageing_time(struct ksz_device *dev, unsigned int msecs)
{
- u32 secs = msecs / 1000;
- u32 value;
+ u8 data, mult, value8;
+ bool in_msec = false;
+ u32 max_val, value;
+ u32 secs = msecs;
int ret;
+#define MAX_TIMER_VAL ((1 << 20) - 1)
+
+ /* The aging timer comprises a 3-bit multiplier and a 20-bit second
+ * value. Either of them cannot be zero. The maximum timer is then
+ * 7 * 1048575 = 7340025 seconds. As this value is too large for
+ * practical use it can be interpreted as microseconds, making the
+ * maximum timer 7340 seconds with finer control. This allows for
+ * maximum 122 minutes compared to 29 minutes in KSZ9477 switch.
+ */
+ if (msecs % 1000)
+ in_msec = true;
+ else
+ secs /= 1000;
+ if (!secs)
+ secs = 1;
+
+ /* Return error if too large. */
+ else if (secs > 7 * MAX_TIMER_VAL)
+ return -EINVAL;
+
+ /* Configure how to interpret the number value. */
+ ret = ksz_rmw8(dev, REG_SW_LUE_CTRL_2, SW_AGE_CNT_IN_MICROSEC,
+ in_msec ? SW_AGE_CNT_IN_MICROSEC : 0);
+ if (ret < 0)
+ return ret;
+
+ ret = ksz_read8(dev, REG_SW_LUE_CTRL_0, &value8);
+ if (ret < 0)
+ return ret;
+
+ /* Check whether there is need to update the multiplier. */
+ mult = FIELD_GET(SW_AGE_CNT_M, value8);
+ max_val = MAX_TIMER_VAL;
+ if (mult > 0) {
+ /* Try to use the same multiplier already in the register as
+ * the hardware default uses multiplier 4 and 75 seconds for
+ * 300 seconds.
+ */
+ max_val = DIV_ROUND_UP(secs, mult);
+ if (max_val > MAX_TIMER_VAL || max_val * mult != secs)
+ max_val = MAX_TIMER_VAL;
+ }
+
+ data = DIV_ROUND_UP(secs, max_val);
+ if (mult != data) {
+ value8 &= ~SW_AGE_CNT_M;
+ value8 |= FIELD_PREP(SW_AGE_CNT_M, data);
+ ret = ksz_write8(dev, REG_SW_LUE_CTRL_0, value8);
+ if (ret < 0)
+ return ret;
+ }
+
+ secs = DIV_ROUND_UP(secs, data);
+
value = FIELD_GET(SW_AGE_PERIOD_7_0_M, secs);
ret = ksz_write8(dev, REG_SW_AGE_PERIOD__1, value);
diff --git a/drivers/net/dsa/microchip/lan937x_reg.h b/drivers/net/dsa/microchip/lan937x_reg.h
index 45b606b6429f..b3e536e7c686 100644
--- a/drivers/net/dsa/microchip/lan937x_reg.h
+++ b/drivers/net/dsa/microchip/lan937x_reg.h
@@ -1,6 +1,6 @@
/* SPDX-License-Identifier: GPL-2.0 */
/* Microchip LAN937X switch register definitions
- * Copyright (C) 2019-2021 Microchip Technology Inc.
+ * Copyright (C) 2019-2024 Microchip Technology Inc.
*/
#ifndef __LAN937X_REG_H
#define __LAN937X_REG_H
@@ -48,8 +48,7 @@
#define SW_VLAN_ENABLE BIT(7)
#define SW_DROP_INVALID_VID BIT(6)
-#define SW_AGE_CNT_M 0x7
-#define SW_AGE_CNT_S 3
+#define SW_AGE_CNT_M GENMASK(5, 3)
#define SW_RESV_MCAST_ENABLE BIT(2)
#define REG_SW_LUE_CTRL_1 0x0311
@@ -62,6 +61,10 @@
#define SW_FAST_AGING BIT(1)
#define SW_LINK_AUTO_AGING BIT(0)
+#define REG_SW_LUE_CTRL_2 0x0312
+
+#define SW_AGE_CNT_IN_MICROSEC BIT(7)
+
#define REG_SW_AGE_PERIOD__1 0x0313
#define SW_AGE_PERIOD_7_0_M GENMASK(7, 0)
