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net: dsa: microchip: add ETS Qdisc support for KSZ9477 series
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Add ETS Qdisc support for KSZ9477 of switches. Current implementation is
limited to strict priority mode.

Tested on KSZ8563R with following configuration:
tc qdisc replace dev lan2 root handle 1: ets strict 4 \
  priomap 3 3 2 2 1 1 0 0
ip link add link lan2 name v1 type vlan id 1 \
  egress-qos-map 0:0 1:1 2:2 3:3 4:4 5:5 6:6 7:7

and patched iperf3 version:
esnet/iperf#1476
iperf3 -c 172.17.0.1 -b100M  -l1472 -t100 -u -R --sock-prio 2

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Acked-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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@olerem
olerem authored and Tariq Toukan committed Mar 15, 2023
1 parent bd37c66 commit c2df86e
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Showing 2 changed files with 230 additions and 0 deletions.
218 changes: 218 additions & 0 deletions drivers/net/dsa/microchip/ksz_common.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1085,6 +1085,7 @@ const struct ksz_chip_data ksz_switch_chips[] = {
.port_nirqs = 3,
.num_tx_queues = 4,
.tc_cbs_supported = true,
.tc_ets_supported = true,
.ops = &ksz9477_dev_ops,
.mib_names = ksz9477_mib_names,
.mib_cnt = ARRAY_SIZE(ksz9477_mib_names),
Expand Down Expand Up @@ -1224,6 +1225,7 @@ const struct ksz_chip_data ksz_switch_chips[] = {
.port_nirqs = 4,
.num_tx_queues = 4,
.tc_cbs_supported = true,
.tc_ets_supported = true,
.ops = &ksz9477_dev_ops,
.phy_errata_9477 = true,
.mib_names = ksz9477_mib_names,
Expand Down Expand Up @@ -1348,6 +1350,7 @@ const struct ksz_chip_data ksz_switch_chips[] = {
.port_nirqs = 3,
.num_tx_queues = 4,
.tc_cbs_supported = true,
.tc_ets_supported = true,
.ops = &ksz9477_dev_ops,
.mib_names = ksz9477_mib_names,
.mib_cnt = ARRAY_SIZE(ksz9477_mib_names),
Expand Down Expand Up @@ -1375,6 +1378,7 @@ const struct ksz_chip_data ksz_switch_chips[] = {
.port_nirqs = 3,
.num_tx_queues = 4,
.tc_cbs_supported = true,
.tc_ets_supported = true,
.ops = &ksz9477_dev_ops,
.phy_errata_9477 = true,
.mib_names = ksz9477_mib_names,
Expand Down Expand Up @@ -1407,6 +1411,7 @@ const struct ksz_chip_data ksz_switch_chips[] = {
.port_nirqs = 6,
.num_tx_queues = 8,
.tc_cbs_supported = true,
.tc_ets_supported = true,
.ops = &lan937x_dev_ops,
.mib_names = ksz9477_mib_names,
.mib_cnt = ARRAY_SIZE(ksz9477_mib_names),
Expand All @@ -1433,6 +1438,7 @@ const struct ksz_chip_data ksz_switch_chips[] = {
.port_nirqs = 6,
.num_tx_queues = 8,
.tc_cbs_supported = true,
.tc_ets_supported = true,
.ops = &lan937x_dev_ops,
.mib_names = ksz9477_mib_names,
.mib_cnt = ARRAY_SIZE(ksz9477_mib_names),
Expand All @@ -1459,6 +1465,7 @@ const struct ksz_chip_data ksz_switch_chips[] = {
.port_nirqs = 6,
.num_tx_queues = 8,
.tc_cbs_supported = true,
.tc_ets_supported = true,
.ops = &lan937x_dev_ops,
.mib_names = ksz9477_mib_names,
.mib_cnt = ARRAY_SIZE(ksz9477_mib_names),
Expand Down Expand Up @@ -1489,6 +1496,7 @@ const struct ksz_chip_data ksz_switch_chips[] = {
.port_nirqs = 6,
.num_tx_queues = 8,
.tc_cbs_supported = true,
.tc_ets_supported = true,
.ops = &lan937x_dev_ops,
.mib_names = ksz9477_mib_names,
.mib_cnt = ARRAY_SIZE(ksz9477_mib_names),
Expand Down Expand Up @@ -1519,6 +1527,7 @@ const struct ksz_chip_data ksz_switch_chips[] = {
.port_nirqs = 6,
.num_tx_queues = 8,
.tc_cbs_supported = true,
.tc_ets_supported = true,
.ops = &lan937x_dev_ops,
.mib_names = ksz9477_mib_names,
.mib_cnt = ARRAY_SIZE(ksz9477_mib_names),
Expand Down Expand Up @@ -3144,12 +3153,221 @@ static int ksz_setup_tc_cbs(struct dsa_switch *ds, int port,
MTI_SHAPING_SRP);
}

static int ksz_disable_egress_rate_limit(struct ksz_device *dev, int port)
{
int queue, ret;

/* Configuration will not take effect until the last Port Queue X
* Egress Limit Control Register is written.
*/
for (queue = 0; queue < dev->info->num_tx_queues; queue++) {
ret = ksz_pwrite8(dev, port, KSZ9477_REG_PORT_OUT_RATE_0 + queue,
KSZ9477_OUT_RATE_NO_LIMIT);
if (ret)
return ret;
}

return 0;
}

static int ksz_ets_band_to_queue(struct tc_ets_qopt_offload_replace_params *p,
int band)
{
/* Compared to queues, bands prioritize packets differently. In strict
* priority mode, the lowest priority is assigned to Queue 0 while the
* highest priority is given to Band 0.
*/
return p->bands - 1 - band;
}

static int ksz_queue_set_strict(struct ksz_device *dev, int port, int queue)
{
int ret;

ret = ksz_pwrite32(dev, port, REG_PORT_MTI_QUEUE_INDEX__4, queue);
if (ret)
return ret;

return ksz_setup_tc_mode(dev, port, MTI_SCHEDULE_STRICT_PRIO,
MTI_SHAPING_OFF);
}

static int ksz_queue_set_wrr(struct ksz_device *dev, int port, int queue,
int weight)
{
int ret;

ret = ksz_pwrite32(dev, port, REG_PORT_MTI_QUEUE_INDEX__4, queue);
if (ret)
return ret;

ret = ksz_setup_tc_mode(dev, port, MTI_SCHEDULE_WRR,
MTI_SHAPING_OFF);
if (ret)
return ret;

return ksz_pwrite8(dev, port, KSZ9477_PORT_MTI_QUEUE_CTRL_1, weight);
}

static int ksz_tc_ets_add(struct ksz_device *dev, int port,
struct tc_ets_qopt_offload_replace_params *p)
{
int ret, band, tc_prio;
u32 queue_map = 0;

/* In order to ensure proper prioritization, it is necessary to set the
* rate limit for the related queue to zero. Otherwise strict priority
* or WRR mode will not work. This is a hardware limitation.
*/
ret = ksz_disable_egress_rate_limit(dev, port);
if (ret)
return ret;

/* Configure queue scheduling mode for all bands. Currently only strict
* prio mode is supported.
*/
for (band = 0; band < p->bands; band++) {
int queue = ksz_ets_band_to_queue(p, band);

ret = ksz_queue_set_strict(dev, port, queue);
if (ret)
return ret;
}

/* Configure the mapping between traffic classes and queues. Note:
* priomap variable support 16 traffic classes, but the chip can handle
* only 8 classes.
*/
for (tc_prio = 0; tc_prio < ARRAY_SIZE(p->priomap); tc_prio++) {
int queue;

if (tc_prio > KSZ9477_MAX_TC_PRIO)
break;

queue = ksz_ets_band_to_queue(p, p->priomap[tc_prio]);
queue_map |= queue << (tc_prio * KSZ9477_PORT_TC_MAP_S);
}

return ksz_pwrite32(dev, port, KSZ9477_PORT_MRI_TC_MAP__4, queue_map);
}

static int ksz_tc_ets_del(struct ksz_device *dev, int port)
{
int ret, queue, tc_prio, s;
u32 queue_map = 0;

/* To restore the default chip configuration, set all queues to use the
* WRR scheduler with a weight of 1.
*/
for (queue = 0; queue < dev->info->num_tx_queues; queue++) {
ret = ksz_queue_set_wrr(dev, port, queue,
KSZ9477_DEFAULT_WRR_WEIGHT);
if (ret)
return ret;
}

switch (dev->info->num_tx_queues) {
case 2:
s = 2;
break;
case 4:
s = 1;
break;
case 8:
s = 0;
break;
default:
return -EINVAL;
}

/* Revert the queue mapping for TC-priority to its default setting on
* the chip.
*/
for (tc_prio = 0; tc_prio <= KSZ9477_MAX_TC_PRIO; tc_prio++) {
int queue;

queue = tc_prio >> s;
queue_map |= queue << (tc_prio * KSZ9477_PORT_TC_MAP_S);
}

return ksz_pwrite32(dev, port, KSZ9477_PORT_MRI_TC_MAP__4, queue_map);
}

static int ksz_tc_ets_validate(struct ksz_device *dev, int port,
struct tc_ets_qopt_offload_replace_params *p)
{
int band;

/* Since it is not feasible to share one port among multiple qdisc,
* the user must configure all available queues appropriately.
*/
if (p->bands != dev->info->num_tx_queues) {
dev_err(dev->dev, "Not supported amount of bands. It should be %d\n",
dev->info->num_tx_queues);
return -EOPNOTSUPP;
}

for (band = 0; band < p->bands; ++band) {
/* The KSZ switches utilize a weighted round robin configuration
* where a certain number of packets can be transmitted from a
* queue before the next queue is serviced. For more information
* on this, refer to section 5.2.8.4 of the KSZ8565R
* documentation on the Port Transmit Queue Control 1 Register.
* However, the current ETS Qdisc implementation (as of February
* 2023) assigns a weight to each queue based on the number of
* bytes or extrapolated bandwidth in percentages. Since this
* differs from the KSZ switches' method and we don't want to
* fake support by converting bytes to packets, it is better to
* return an error instead.
*/
if (p->quanta[band]) {
dev_err(dev->dev, "Quanta/weights configuration is not supported.\n");
return -EOPNOTSUPP;
}
}

return 0;
}

static int ksz_tc_setup_qdisc_ets(struct dsa_switch *ds, int port,
struct tc_ets_qopt_offload *qopt)
{
struct ksz_device *dev = ds->priv;
int ret;

if (!dev->info->tc_ets_supported)
return -EOPNOTSUPP;

if (qopt->parent != TC_H_ROOT) {
dev_err(dev->dev, "Parent should be \"root\"\n");
return -EOPNOTSUPP;
}

switch (qopt->command) {
case TC_ETS_REPLACE:
ret = ksz_tc_ets_validate(dev, port, &qopt->replace_params);
if (ret)
return ret;

return ksz_tc_ets_add(dev, port, &qopt->replace_params);
case TC_ETS_DESTROY:
return ksz_tc_ets_del(dev, port);
case TC_ETS_STATS:
case TC_ETS_GRAFT:
return -EOPNOTSUPP;
}

return -EOPNOTSUPP;
}

static int ksz_setup_tc(struct dsa_switch *ds, int port,
enum tc_setup_type type, void *type_data)
{
switch (type) {
case TC_SETUP_QDISC_CBS:
return ksz_setup_tc_cbs(ds, port, type_data);
case TC_SETUP_QDISC_ETS:
return ksz_tc_setup_qdisc_ets(ds, port, type_data);
default:
return -EOPNOTSUPP;
}
Expand Down
12 changes: 12 additions & 0 deletions drivers/net/dsa/microchip/ksz_common.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,7 @@ struct ksz_chip_data {
u8 port_nirqs;
u8 num_tx_queues;
bool tc_cbs_supported;
bool tc_ets_supported;
const struct ksz_dev_ops *ops;
bool phy_errata_9477;
bool ksz87xx_eee_link_erratum;
Expand Down Expand Up @@ -649,6 +650,14 @@ static inline int is_lan937x(struct ksz_device *dev)
#define KSZ8_LEGAL_PACKET_SIZE 1518
#define KSZ9477_MAX_FRAME_SIZE 9000

#define KSZ9477_REG_PORT_OUT_RATE_0 0x0420
#define KSZ9477_OUT_RATE_NO_LIMIT 0

#define KSZ9477_PORT_MRI_TC_MAP__4 0x0808

#define KSZ9477_PORT_TC_MAP_S 4
#define KSZ9477_MAX_TC_PRIO 7

/* CBS related registers */
#define REG_PORT_MTI_QUEUE_INDEX__4 0x0900

Expand All @@ -662,6 +671,9 @@ static inline int is_lan937x(struct ksz_device *dev)
#define MTI_SHAPING_SRP 1
#define MTI_SHAPING_TIME_AWARE 2

#define KSZ9477_PORT_MTI_QUEUE_CTRL_1 0x0915
#define KSZ9477_DEFAULT_WRR_WEIGHT 1

#define REG_PORT_MTI_HI_WATER_MARK 0x0916
#define REG_PORT_MTI_LO_WATER_MARK 0x0918

Expand Down

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