This is a note to let you know that I've just added the patch titled
net: dsa: microchip: Fix KSZ9477 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-ksz9477-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 2f41924c9360698d52faddb92bc78724a2d69d98
Author: Tristram Ha <tristram.ha@xxxxxxxxxxxxx>
Date: Tue Dec 17 18:02:23 2024 -0800
net: dsa: microchip: Fix KSZ9477 set_ageing_time function
[ Upstream commit 262bfba8ab820641c8cfbbf03b86d6c00242c078 ]
The aging count is not a simple 11-bit value but comprises a 3-bit
multiplier and an 8-bit second count. The code tries to use the
original multiplier which is 4 as the second count is still 300 seconds
by default.
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/20241218020224.70590-2-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 a7e8fcdf2576..59134d117846 100644
--- a/drivers/net/dsa/microchip/ksz9477.c
+++ b/drivers/net/dsa/microchip/ksz9477.c
@@ -2,7 +2,7 @@
/*
* Microchip KSZ9477 switch driver main logic
*
- * Copyright (C) 2017-2019 Microchip Technology Inc.
+ * Copyright (C) 2017-2024 Microchip Technology Inc.
*/
#include <linux/kernel.h>
@@ -916,26 +916,51 @@ void ksz9477_get_caps(struct ksz_device *dev, int port,
int ksz9477_set_ageing_time(struct ksz_device *dev, unsigned int msecs)
{
u32 secs = msecs / 1000;
- u8 value;
- u8 data;
+ u8 data, mult, value;
+ u32 max_val;
int ret;
- value = FIELD_GET(SW_AGE_PERIOD_7_0_M, secs);
+#define MAX_TIMER_VAL ((1 << 8) - 1)
- ret = ksz_write8(dev, REG_SW_LUE_CTRL_3, value);
- if (ret < 0)
- return ret;
+ /* The aging timer comprises a 3-bit multiplier and an 8-bit second
+ * value. Either of them cannot be zero. The maximum timer is then
+ * 7 * 255 = 1785 seconds.
+ */
+ if (!secs)
+ secs = 1;
- data = FIELD_GET(SW_AGE_PERIOD_10_8_M, secs);
+ /* Return error if too large. */
+ else if (secs > 7 * MAX_TIMER_VAL)
+ return -EINVAL;
ret = ksz_read8(dev, REG_SW_LUE_CTRL_0, &value);
if (ret < 0)
return ret;
- value &= ~SW_AGE_CNT_M;
- value |= FIELD_PREP(SW_AGE_CNT_M, data);
+ /* Check whether there is need to update the multiplier. */
+ mult = FIELD_GET(SW_AGE_CNT_M, value);
+ 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) {
+ value &= ~SW_AGE_CNT_M;
+ value |= FIELD_PREP(SW_AGE_CNT_M, data);
+ ret = ksz_write8(dev, REG_SW_LUE_CTRL_0, value);
+ if (ret < 0)
+ return ret;
+ }
- return ksz_write8(dev, REG_SW_LUE_CTRL_0, value);
+ value = DIV_ROUND_UP(secs, data);
+ return ksz_write8(dev, REG_SW_LUE_CTRL_3, value);
}
void ksz9477_port_queue_split(struct ksz_device *dev, int port)
diff --git a/drivers/net/dsa/microchip/ksz9477_reg.h b/drivers/net/dsa/microchip/ksz9477_reg.h
index a2ef4b18349c..d0886ed984c5 100644
--- a/drivers/net/dsa/microchip/ksz9477_reg.h
+++ b/drivers/net/dsa/microchip/ksz9477_reg.h
@@ -2,7 +2,7 @@
/*
* Microchip KSZ9477 register definitions
*
- * Copyright (C) 2017-2018 Microchip Technology Inc.
+ * Copyright (C) 2017-2024 Microchip Technology Inc.
*/
#ifndef __KSZ9477_REGS_H
@@ -190,8 +190,6 @@
#define SW_VLAN_ENABLE BIT(7)
#define SW_DROP_INVALID_VID BIT(6)
#define SW_AGE_CNT_M GENMASK(5, 3)
-#define SW_AGE_CNT_S 3
-#define SW_AGE_PERIOD_10_8_M GENMASK(10, 8)
#define SW_RESV_MCAST_ENABLE BIT(2)
#define SW_HASH_OPTION_M 0x03
#define SW_HASH_OPTION_CRC 1
