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net: dsa: microchip: Fix LAN937X set_ageing_time function

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[ 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: 2c119d9982 ("net: dsa: microchip: add the support for set_ageing_time")
Signed-off-by: Tristram Ha <tristram.ha@microchip.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20241218020224.70590-3-Tristram.Ha@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Tristram Ha 2024-12-17 18:02:24 -08:00 committed by Greg Kroah-Hartman
parent 9d00ab0e0d
commit ba4014276b
2 changed files with 65 additions and 6 deletions
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62
drivers/net/dsa/microchip/lan937x_main.c
View File

@ -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>
@ -249,10 +249,66 @@ 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);

9
drivers/net/dsa/microchip/lan937x_reg.h
View File

@ -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)