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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
net: dsa: microchip: add ETS scheduler support for KSZ88x3 switches
Implement Enhanced Transmission Selection scheduler (ETS) support for
KSZ88x3 devices, which support two fixed egress scheduling modes:
Strict Priority and Weighted Fair Queuing (WFQ).
Since the switch does not allow remapping priorities to queues or
adjusting weights, this implementation only supports enabling
strict priority mode. If strict mode is not explicitly requested,
the switch falls back to its default WFQ mode.
This patch introduces KSZ88x3-specific handlers for ETS add and
delete operations and uses TXQ Split Control registers to toggle
the WFQ enable bit per queue. Corresponding macros are also added
for register access.
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://patch.msgid.link/20250410124249.2728568-1-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
authored by
Oleksij Rempel
and committed by
Jakub Kicinski
4129a75a
b8ebc893
+113
-3
+94
-3
drivers/net/dsa/microchip/ksz_common.c
+94
-3
drivers/net/dsa/microchip/ksz_common.c
···
3999
3999
return p->bands - 1 - band;
4000
4000
}
4001
4001
4002
+
/**
4003
+
* ksz88x3_tc_ets_add - Configure ETS (Enhanced Transmission Selection)
4004
+
* for a port on KSZ88x3 switch
4005
+
* @dev: Pointer to the KSZ switch device structure
4006
+
* @port: Port number to configure
4007
+
* @p: Pointer to offload replace parameters describing ETS bands and mapping
4008
+
*
4009
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* The KSZ88x3 supports two scheduling modes: Strict Priority and
4010
+
* Weighted Fair Queuing (WFQ). Both modes have fixed behavior:
4011
+
* - No configurable queue-to-priority mapping
4012
+
* - No weight adjustment in WFQ mode
4013
+
*
4014
+
* This function configures the switch to use strict priority mode by
4015
+
* clearing the WFQ enable bit for all queues associated with ETS bands.
4016
+
* If strict priority is not explicitly requested, the switch will default
4017
+
* to WFQ mode.
4018
+
*
4019
+
* Return: 0 on success, or a negative error code on failure
4020
+
*/
4021
+
static int ksz88x3_tc_ets_add(struct ksz_device *dev, int port,
4022
+
struct tc_ets_qopt_offload_replace_params *p)
4023
+
{
4024
+
int ret, band;
4025
+
4026
+
/* Only strict priority mode is supported for now.
4027
+
* WFQ is implicitly enabled when strict mode is disabled.
4028
+
*/
4029
+
for (band = 0; band < p->bands; band++) {
4030
+
int queue = ksz_ets_band_to_queue(p, band);
4031
+
u8 reg;
4032
+
4033
+
/* Calculate TXQ Split Control register address for this
4034
+
* port/queue
4035
+
*/
4036
+
reg = KSZ8873_TXQ_SPLIT_CTRL_REG(port, queue);
4037
+
4038
+
/* Clear WFQ enable bit to select strict priority scheduling */
4039
+
ret = ksz_rmw8(dev, reg, KSZ8873_TXQ_WFQ_ENABLE, 0);
4040
+
if (ret)
4041
+
return ret;
4042
+
}
4043
+
4044
+
return 0;
4045
+
}
4046
+
4047
+
/**
4048
+
* ksz88x3_tc_ets_del - Reset ETS (Enhanced Transmission Selection) config
4049
+
* for a port on KSZ88x3 switch
4050
+
* @dev: Pointer to the KSZ switch device structure
4051
+
* @port: Port number to reset
4052
+
*
4053
+
* The KSZ88x3 supports only fixed scheduling modes: Strict Priority or
4054
+
* Weighted Fair Queuing (WFQ), with no reconfiguration of weights or
4055
+
* queue mapping. This function resets the port’s scheduling mode to
4056
+
* the default, which is WFQ, by enabling the WFQ bit for all queues.
4057
+
*
4058
+
* Return: 0 on success, or a negative error code on failure
4059
+
*/
4060
+
static int ksz88x3_tc_ets_del(struct ksz_device *dev, int port)
4061
+
{
4062
+
int ret, queue;
4063
+
4064
+
/* Iterate over all transmit queues for this port */
4065
+
for (queue = 0; queue < dev->info->num_tx_queues; queue++) {
4066
+
u8 reg;
4067
+
4068
+
/* Calculate TXQ Split Control register address for this
4069
+
* port/queue
4070
+
*/
4071
+
reg = KSZ8873_TXQ_SPLIT_CTRL_REG(port, queue);
4072
+
4073
+
/* Set WFQ enable bit to revert back to default scheduling
4074
+
* mode
4075
+
*/
4076
+
ret = ksz_rmw8(dev, reg, KSZ8873_TXQ_WFQ_ENABLE,
4077
+
KSZ8873_TXQ_WFQ_ENABLE);
4078
+
if (ret)
4079
+
return ret;
4080
+
}
4081
+
4082
+
return 0;
4083
+
}
4084
+
4002
4085
static int ksz_queue_set_strict(struct ksz_device *dev, int port, int queue)
4003
4086
{
4004
4087
int ret;
···
4163
4080
for (queue = 0; queue < dev->info->num_tx_queues; queue++) {
4164
4081
ret = ksz_queue_set_wrr(dev, port, queue,
4165
4082
KSZ9477_DEFAULT_WRR_WEIGHT);
4083
+
4166
4084
if (ret)
4167
4085
return ret;
4168
4086
}
···
4216
4132
struct ksz_device *dev = ds->priv;
4217
4133
int ret;
4218
4134
4219
-
if (is_ksz8(dev))
4135
+
if (is_ksz8(dev) && !ksz_is_ksz88x3(dev))
4220
4136
return -EOPNOTSUPP;
4221
4137
4222
4138
if (qopt->parent != TC_H_ROOT) {
···
4230
4146
if (ret)
4231
4147
return ret;
4232
4148
4233
-
return ksz_tc_ets_add(dev, port, &qopt->replace_params);
4149
+
if (ksz_is_ksz88x3(dev))
4150
+
return ksz88x3_tc_ets_add(dev, port,
4151
+
&qopt->replace_params);
4152
+
else
4153
+
return ksz_tc_ets_add(dev, port, &qopt->replace_params);
4234
4154
case TC_ETS_DESTROY:
4235
-
return ksz_tc_ets_del(dev, port);
4155
+
if (ksz_is_ksz88x3(dev))
4156
+
return ksz88x3_tc_ets_del(dev, port);
4157
+
else
4158
+
return ksz_tc_ets_del(dev, port);
4236
4159
case TC_ETS_STATS:
4237
4160
case TC_ETS_GRAFT:
4238
4161
return -EOPNOTSUPP;
+19
drivers/net/dsa/microchip/ksz_common.h
+19
drivers/net/dsa/microchip/ksz_common.h
···
836
836
#define SW_HI_SPEED_DRIVE_STRENGTH_S 4
837
837
#define SW_LO_SPEED_DRIVE_STRENGTH_S 0
838
838
839
+
/* TXQ Split Control Register for per-port, per-queue configuration.
840
+
* Register 0xAF is TXQ Split for Q3 on Port 1.
841
+
* Register offset formula: 0xAF + (port * 4) + (3 - queue)
842
+
* where: port = 0..2, queue = 0..3
843
+
*/
844
+
#define KSZ8873_TXQ_SPLIT_CTRL_REG(port, queue) \
845
+
(0xAF + ((port) * 4) + (3 - (queue)))
846
+
847
+
/* Bit 7 selects between:
848
+
* 0 = Strict priority mode (highest-priority queue first)
849
+
* 1 = Weighted Fair Queuing (WFQ) mode:
850
+
* Queue weights: Q3:Q2:Q1:Q0 = 8:4:2:1
851
+
* If any queues are empty, weight is redistributed.
852
+
*
853
+
* Note: This is referred to as "Weighted Fair Queuing" (WFQ) in KSZ8863/8873
854
+
* documentation, and as "Weighted Round Robin" (WRR) in KSZ9477 family docs.
855
+
*/
856
+
#define KSZ8873_TXQ_WFQ_ENABLE BIT(7)
857
+
839
858
#define KSZ9477_REG_PORT_OUT_RATE_0 0x0420
840
859
#define KSZ9477_OUT_RATE_NO_LIMIT 0
841
860