[PATCH net-next v9 08/10] net: ethernet: ti: am65-cpsw: add mqprio qdisc offload in channel mode

Roger Quadros
2023-12-15T13:21:27Z

From: Grygorii Strashko <grygorii.strashko@ti.com>

This patch adds MQPRIO Qdisc offload in full 'channel' mode which allows
not only setting up pri:tc mapping, but also configuring TX shapers
(rate-limiting) on external port FIFOs.

The MQPRIO Qdisc offload is expected to work with or without VLAN/priority
tagged packets.

The CPSW external Port FIFO has 8 Priority queues. The rate-limit can be
set for each of these priority queues. Which Priority queue a packet is
assigned to depends on PN_REG_TX_PRI_MAP register which maps header
priority to switch priority.

The header priority of a packet is assigned via the RX_PRI_MAP_REG which
maps packet priority to header priority.

The packet priority is either the VLAN priority (for VLAN tagged packets)
or the thread/channel offset.

For simplicity, we assign the same priority queue to all queues of a
Traffic Class so it can be rate-limited correctly.

Configuration example:
ethtool -L eth1 tx 5
ethtool --set-priv-flags eth1 p0-rx-ptype-rrobin off

tc qdisc add dev eth1 parent root handle 100: mqprio num_tc 3 \
map 0 0 1 2 0 0 0 0 0 0 0 0 0 0 0 0 \
queues 1@0 1@1 1@2 hw 1 mode channel \
shaper bw_rlimit min_rate 0 100mbit 200mbit max_rate 0 101mbit 202mbit

tc qdisc replace dev eth2 handle 100: parent root mqprio num_tc 1 \
map 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 queues 1@0 hw 1

ip link add link eth1 name eth1.100 type vlan id 100
ip link set eth1.100 type vlan egress 0:0 1:1 2:2 3:3 4:4 5:5 6:6 7:7

In the above example two ports share the same TX CPPI queue 0 for low
priority traffic. 3 traffic classes are defined for eth1 and mapped to:
TC0 - low priority, TX CPPI queue 0 -> ext Port 1 fifo0, no rate limit
TC1 - prio 2, TX CPPI queue 1 -> ext Port 1 fifo1, CIR=100Mbit/s, EIR=1Mbit/s
TC2 - prio 3, TX CPPI queue 2 -> ext Port 1 fifo2, CIR=200Mbit/s, EIR=2Mbit/s

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
drivers/net/ethernet/ti/Kconfig | 3 +-
drivers/net/ethernet/ti/am65-cpsw-nuss.c | 3 +
drivers/net/ethernet/ti/am65-cpsw-qos.c | 255 ++++++++++++++++++++++-
drivers/net/ethernet/ti/am65-cpsw-qos.h | 20 ++
4 files changed, 277 insertions(+), 4 deletions(-)

Changelog

v9:
- drop "\n" from message string passed to NL_SET_ERR_MSG_FMT_MOD()

v8:
- optimize TO_MBPS()
- mention MQPRIO support in TI_AM65_CPSW_QOS Kconfig help text

v7:
- don't return -EINVAL if num_tc is 0 in setup

v6:
- fixed typo in comment "packet_priorit"->"packet_priority"
- don't call netif_set_real_num_tx_queues() from am65_cpsw_reset_tc_mqprio()
- reset TX queue priorities to zero at init. AM65_CPSW_PN_REG_TX_PRI_MAP = 0
- don't ignore return value in am65_cpsw_setup_mqprio()

v5:
- fix warning at NL_SET_ERR_MSG_FMT_MOD()

v4:
- use macro TO_MBPS()
- use bool for 'shaper_en'
- split code movement into separate patch
- drop rate vs link speed check as mqprio can be set at link down
- call am65_cpsw_reset_tc_mqprio() after pm_runtime_get_sync()

v2:
- clean up commit message
- avoid forward declarations
- use tc_mqprio_qopt_offload :: extack for error message reporting
- avoid unnecessary mqprio->qopt.hw == 0 checks
- set struct tc_mqprio_caps :: validate_queue_counts = true and get rid of
am65_cpsw_mqprio_verify()
- do not modify AM65_CPSW_P0_REG_RX_PRI_MAP register.

diff --git a/drivers/net/ethernet/ti/Kconfig b/drivers/net/ethernet/ti/Kconfig
index 49cd96c4f532..f76532443298 100644
--- a/drivers/net/ethernet/ti/Kconfig
+++ b/drivers/net/ethernet/ti/Kconfig
@@ -139,7 +139,8 @@ config TI_AM65_CPSW_QOS
depends on TI_K3_AM65_CPSW_NUSS && NET_SCH_TAPRIO && TI_K3_AM65_CPTS
help
This option enables QoS offload features in AM65 CPSW like
- Time Aware Shaper (TAS) / Enhanced Scheduled Traffic (EST).
+ Time Aware Shaper (TAS) / Enhanced Scheduled Traffic (EST)
+ and MQPRIO qdisc offload.
The EST scheduler runs on CPTS and the TAS/EST schedule is
updated in the Fetch RAM memory of the CPSW.

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index 7651f90f51f2..2e374745f239 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -2127,6 +2127,9 @@ static int am65_cpsw_nuss_init_slave_ports(struct am65_cpsw_common *common)
dev_err(dev, "Use random MAC address\n");
}
}
+
+ /* Reset all Queue priorities to 0 */
+ writel(0, port->port_base + AM65_CPSW_PN_REG_TX_PRI_MAP);
}
of_node_put(node);

diff --git a/drivers/net/ethernet/ti/am65-cpsw-qos.c b/drivers/net/ethernet/ti/am65-cpsw-qos.c
index 9f0a05e763d1..7ad7af3b3c60 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-qos.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-qos.c
@@ -7,6 +7,7 @@
*/

#include <linux/pm_runtime.h>
+#include <linux/math.h>
#include <linux/time.h>
#include <net/pkt_cls.h>

@@ -15,6 +16,8 @@
#include "am65-cpts.h"
#include "cpsw_ale.h"

+#define TO_MBPS(x) DIV_ROUND_UP((x), BYTES_PER_MBIT)
+
enum timer_act {
TACT_PROG, /* need program timer */
TACT_NEED_STOP, /* need stop first */
@@ -31,6 +34,232 @@ am65_cpsw_qos_tx_rate_calc(u32 rate_mbps, unsigned long bus_freq)
return ir;
}

+static void am65_cpsw_tx_pn_shaper_reset(struct am65_cpsw_port *port)
+{
+ int prio;
+
+ for (prio = 0; prio < AM65_CPSW_PN_FIFO_PRIO_NUM; prio++) {
+ writel(0, port->port_base + AM65_CPSW_PN_REG_PRI_CIR(prio));
+ writel(0, port->port_base + AM65_CPSW_PN_REG_PRI_EIR(prio));
+ }
+}
+
+static void am65_cpsw_tx_pn_shaper_apply(struct am65_cpsw_port *port)
+{
+ struct am65_cpsw_mqprio *p_mqprio = &port->qos.mqprio;
+ struct am65_cpsw_common *common = port->common;
+ struct tc_mqprio_qopt_offload *mqprio;
+ bool enable, shaper_susp = false;
+ u32 rate_mbps;
+ int tc, prio;
+
+ mqprio = &p_mqprio->mqprio_hw;
+ /* takes care of no link case as well */
+ if (p_mqprio->max_rate_total > port->qos.link_speed)
+ shaper_susp = true;
+
+ am65_cpsw_tx_pn_shaper_reset(port);
+
+ enable = p_mqprio->shaper_en && !shaper_susp;
+ if (!enable)
+ return;
+
+ /* Rate limit is specified per Traffic Class but
+ * for CPSW, rate limit can be applied per priority
+ * at port FIFO.
+ *
+ * We have assigned the same priority (TCn) to all queues
+ * of a Traffic Class so they share the same shaper
+ * bandwidth.
+ */
+ for (tc = 0; tc < mqprio->qopt.num_tc; tc++) {
+ prio = tc;
+
+ rate_mbps = TO_MBPS(mqprio->min_rate[tc]);
+ rate_mbps = am65_cpsw_qos_tx_rate_calc(rate_mbps,
+ common->bus_freq);
+ writel(rate_mbps,
+ port->port_base + AM65_CPSW_PN_REG_PRI_CIR(prio));
+
+ rate_mbps = 0;
+
+ if (mqprio->max_rate[tc]) {
+ rate_mbps = mqprio->max_rate[tc] - mqprio->min_rate[tc];
+ rate_mbps = TO_MBPS(rate_mbps);
+ rate_mbps = am65_cpsw_qos_tx_rate_calc(rate_mbps,
+ common->bus_freq);
+ }
+
+ writel(rate_mbps,
+ port->port_base + AM65_CPSW_PN_REG_PRI_EIR(prio));
+ }
+}
+
+static int am65_cpsw_mqprio_verify_shaper(struct am65_cpsw_port *port,
+ struct tc_mqprio_qopt_offload *mqprio)
+{
+ struct am65_cpsw_mqprio *p_mqprio = &port->qos.mqprio;
+ struct netlink_ext_ack *extack = mqprio->extack;
+ u64 min_rate_total = 0, max_rate_total = 0;
+ u32 min_rate_msk = 0, max_rate_msk = 0;
+ bool has_min_rate, has_max_rate;
+ int num_tc, i;
+
+ if (!(mqprio->flags & TC_MQPRIO_F_SHAPER))
+ return 0;
+
+ if (mqprio->shaper != TC_MQPRIO_SHAPER_BW_RATE)
+ return 0;
+
+ has_min_rate = !!(mqprio->flags & TC_MQPRIO_F_MIN_RATE);
+ has_max_rate = !!(mqprio->flags & TC_MQPRIO_F_MAX_RATE);
+
+ if (!has_min_rate && has_max_rate) {
+ NL_SET_ERR_MSG_MOD(extack, "min_rate is required with max_rate");
+ return -EOPNOTSUPP;
+ }
+
+ if (!has_min_rate)
+ return 0;
+
+ num_tc = mqprio->qopt.num_tc;
+
+ for (i = num_tc - 1; i >= 0; i--) {
+ u32 ch_msk;
+
+ if (mqprio->min_rate[i])
+ min_rate_msk |= BIT(i);
+ min_rate_total += mqprio->min_rate[i];
+
+ if (has_max_rate) {
+ if (mqprio->max_rate[i])
+ max_rate_msk |= BIT(i);
+ max_rate_total += mqprio->max_rate[i];
+
+ if (!mqprio->min_rate[i] && mqprio->max_rate[i]) {
+ NL_SET_ERR_MSG_FMT_MOD(extack,
+ "TX tc%d rate max>0 but min=0",
+ i);
+ return -EINVAL;
+ }
+
+ if (mqprio->max_rate[i] &&
+ mqprio->max_rate[i] < mqprio->min_rate[i]) {
+ NL_SET_ERR_MSG_FMT_MOD(extack,
+ "TX tc%d rate min(%llu)>max(%llu)",
+ i, mqprio->min_rate[i],
+ mqprio->max_rate[i]);
+ return -EINVAL;
+ }
+ }
+
+ ch_msk = GENMASK(num_tc - 1, i);
+ if ((min_rate_msk & BIT(i)) && (min_rate_msk ^ ch_msk)) {
+ NL_SET_ERR_MSG_FMT_MOD(extack,
+ "Min rate must be set sequentially hi->lo tx_rate_msk%x",
+ min_rate_msk);
+ return -EINVAL;
+ }
+
+ if ((max_rate_msk & BIT(i)) && (max_rate_msk ^ ch_msk)) {
+ NL_SET_ERR_MSG_FMT_MOD(extack,
+ "Max rate must be set sequentially hi->lo tx_rate_msk%x",
+ max_rate_msk);
+ return -EINVAL;
+ }
+ }
+
+ min_rate_total = TO_MBPS(min_rate_total);
+ max_rate_total = TO_MBPS(max_rate_total);
+
+ p_mqprio->shaper_en = true;
+ p_mqprio->max_rate_total = max_t(u64, min_rate_total, max_rate_total);
+
+ return 0;
+}
+
+static void am65_cpsw_reset_tc_mqprio(struct net_device *ndev)
+{
+ struct am65_cpsw_port *port = am65_ndev_to_port(ndev);
+ struct am65_cpsw_mqprio *p_mqprio = &port->qos.mqprio;
+
+ p_mqprio->shaper_en = false;
+ p_mqprio->max_rate_total = 0;
+
+ am65_cpsw_tx_pn_shaper_reset(port);
+ netdev_reset_tc(ndev);
+
+ /* Reset all Queue priorities to 0 */
+ writel(0, port->port_base + AM65_CPSW_PN_REG_TX_PRI_MAP);
+}
+
+static int am65_cpsw_setup_mqprio(struct net_device *ndev, void *type_data)
+{
+ struct am65_cpsw_port *port = am65_ndev_to_port(ndev);
+ struct am65_cpsw_mqprio *p_mqprio = &port->qos.mqprio;
+ struct tc_mqprio_qopt_offload *mqprio = type_data;
+ struct am65_cpsw_common *common = port->common;
+ struct tc_mqprio_qopt *qopt = &mqprio->qopt;
+ int i, tc, offset, count, prio, ret;
+ u8 num_tc = qopt->num_tc;
+ u32 tx_prio_map = 0;
+
+ memcpy(&p_mqprio->mqprio_hw, mqprio, sizeof(*mqprio));
+
+ ret = pm_runtime_get_sync(common->dev);
+ if (ret < 0) {
+ pm_runtime_put_noidle(common->dev);
+ return ret;
+ }
+
+ if (!num_tc) {
+ am65_cpsw_reset_tc_mqprio(ndev);
+ ret = 0;
+ goto exit_put;
+ }
+
+ ret = am65_cpsw_mqprio_verify_shaper(port, mqprio);
+ if (ret)
+ goto exit_put;
+
+ netdev_set_num_tc(ndev, num_tc);
+
+ /* Multiple Linux priorities can map to a Traffic Class
+ * A Traffic Class can have multiple contiguous Queues,
+ * Queues get mapped to Channels (thread_id),
+ * if not VLAN tagged, thread_id is used as packet_priority
+ * if VLAN tagged. VLAN priority is used as packet_priority
+ * packet_priority gets mapped to header_priority in p0_rx_pri_map,
+ * header_priority gets mapped to switch_priority in pn_tx_pri_map.
+ * As p0_rx_pri_map is left at defaults (0x76543210), we can
+ * assume that Queue_n gets mapped to header_priority_n. We can then
+ * set the switch priority in pn_tx_pri_map.
+ */
+
+ for (tc = 0; tc < num_tc; tc++) {
+ prio = tc;
+
+ /* For simplicity we assign the same priority (TCn) to
+ * all queues of a Traffic Class.
+ */
+ for (i = qopt->offset[tc]; i < qopt->offset[tc] + qopt->count[tc]; i++)
+ tx_prio_map |= prio << (4 * i);
+
+ count = qopt->count[tc];
+ offset = qopt->offset[tc];
+ netdev_set_tc_queue(ndev, tc, count, offset);
+ }
+
+ writel(tx_prio_map, port->port_base + AM65_CPSW_PN_REG_TX_PRI_MAP);
+
+ am65_cpsw_tx_pn_shaper_apply(port);
+
+exit_put:
+ pm_runtime_put(common->dev);
+
+ return ret;
+}
+
static int am65_cpsw_port_est_enabled(struct am65_cpsw_port *port)
{
return port->qos.est_oper || port->qos.est_admin;
@@ -414,6 +643,8 @@ static void am65_cpsw_taprio_destroy(struct net_device *ndev)

port->qos.est_oper = NULL;
port->qos.est_admin = NULL;
+
+ am65_cpsw_reset_tc_mqprio(ndev);
}

static void am65_cpsw_cp_taprio(struct tc_taprio_qopt_offload *from,
@@ -462,6 +693,10 @@ static int am65_cpsw_taprio_replace(struct net_device *ndev,
if (!est_new)
return -ENOMEM;

+ ret = am65_cpsw_setup_mqprio(ndev, &taprio->mqprio);
+ if (ret)
+ return ret;
+
am65_cpsw_cp_taprio(taprio, &est_new->taprio);

am65_cpsw_est_update_state(ndev);
@@ -505,6 +740,7 @@ static int am65_cpsw_taprio_replace(struct net_device *ndev,
return 0;

fail:
+ am65_cpsw_reset_tc_mqprio(ndev);
devm_kfree(&ndev->dev, est_new);
return ret;
}
@@ -515,7 +751,6 @@ static void am65_cpsw_est_link_up(struct net_device *ndev, int link_speed)
ktime_t cur_time;
s64 delta;

- port->qos.link_speed = link_speed;
if (!am65_cpsw_port_est_enabled(port))
return;

@@ -559,6 +794,14 @@ static int am65_cpsw_tc_query_caps(struct net_device *ndev, void *type_data)
struct tc_query_caps_base *base = type_data;

switch (base->type) {
+ case TC_SETUP_QDISC_MQPRIO: {
+ struct tc_mqprio_caps *caps = base->caps;
+
+ caps->validate_queue_counts = true;
+
+ return 0;
+ }
+
case TC_SETUP_QDISC_TAPRIO: {
struct tc_taprio_caps *caps = base->caps;

@@ -857,6 +1100,8 @@ int am65_cpsw_qos_ndo_setup_tc(struct net_device *ndev, enum tc_setup_type type,
return am65_cpsw_tc_query_caps(ndev, type_data);
case TC_SETUP_QDISC_TAPRIO:
return am65_cpsw_setup_taprio(ndev, type_data);
+ case TC_SETUP_QDISC_MQPRIO:
+ return am65_cpsw_setup_mqprio(ndev, type_data);
case TC_SETUP_BLOCK:
return am65_cpsw_qos_setup_tc_block(ndev, type_data);
default:
@@ -868,6 +1113,9 @@ void am65_cpsw_qos_link_up(struct net_device *ndev, int link_speed)
{
struct am65_cpsw_port *port = am65_ndev_to_port(ndev);

+ port->qos.link_speed = link_speed;
+ am65_cpsw_tx_pn_shaper_apply(port);
+
am65_cpsw_est_link_up(ndev, link_speed);
port->qos.link_down_time = 0;
}
@@ -876,8 +1124,9 @@ void am65_cpsw_qos_link_down(struct net_device *ndev)
{
struct am65_cpsw_port *port = am65_ndev_to_port(ndev);

+ port->qos.link_speed = SPEED_UNKNOWN;
+ am65_cpsw_tx_pn_shaper_apply(port);
+
if (!port->qos.link_down_time)
port->qos.link_down_time = ktime_get();
-
- port->qos.link_speed = SPEED_UNKNOWN;
}
diff --git a/drivers/net/ethernet/ti/am65-cpsw-qos.h b/drivers/net/ethernet/ti/am65-cpsw-qos.h
index e3259f27baad..b54c34c0aa7f 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-qos.h
+++ b/drivers/net/ethernet/ti/am65-cpsw-qos.h
@@ -9,6 +9,7 @@
#include <net/pkt_sched.h>

struct am65_cpsw_common;
+struct am65_cpsw_port;

struct am65_cpsw_est {
int buf;
@@ -16,6 +17,12 @@ struct am65_cpsw_est {
struct tc_taprio_qopt_offload taprio;
};

+struct am65_cpsw_mqprio {
+ struct tc_mqprio_qopt_offload mqprio_hw;
+ u64 max_rate_total;
+ bool shaper_en;
+};
+
struct am65_cpsw_ale_ratelimit {
unsigned long cookie;
u64 rate_packet_ps;
@@ -26,6 +33,7 @@ struct am65_cpsw_qos {
struct am65_cpsw_est *est_oper;
ktime_t link_down_time;
int link_speed;
+ struct am65_cpsw_mqprio mqprio;

struct am65_cpsw_ale_ratelimit ale_bc_ratelimit;
struct am65_cpsw_ale_ratelimit ale_mc_ratelimit;
@@ -36,6 +44,15 @@ struct am65_cpsw_qos {
#define AM65_CPSW_PN_REG_FIFO_STATUS 0x050
#define AM65_CPSW_PN_REG_EST_CTL 0x060
#define AM65_CPSW_PN_REG_PRI_CIR(pri) (0x140 + 4 * (pri))
+#define AM65_CPSW_P0_REG_PRI_EIR(pri) (0x160 + 4 * (pri))
+
+#define AM65_CPSW_PN_REG_CTL 0x004
+#define AM65_CPSW_PN_REG_TX_PRI_MAP 0x018
+#define AM65_CPSW_PN_REG_RX_PRI_MAP 0x020
+#define AM65_CPSW_PN_REG_FIFO_STATUS 0x050
+#define AM65_CPSW_PN_REG_EST_CTL 0x060
+#define AM65_CPSW_PN_REG_PRI_CIR(pri) (0x140 + 4 * (pri))
+#define AM65_CPSW_PN_REG_PRI_EIR(pri) (0x160 + 4 * (pri))

/* AM65_CPSW_REG_CTL register fields */
#define AM65_CPSW_CTL_EST_EN BIT(18)
@@ -66,6 +83,9 @@ struct am65_cpsw_qos {
#define AM65_CPSW_FETCH_ALLOW_MSK GENMASK(7, 0)
#define AM65_CPSW_FETCH_ALLOW_MAX AM65_CPSW_FETCH_ALLOW_MSK

+/* number of priority queues per port FIFO */
+#define AM65_CPSW_PN_FIFO_PRIO_NUM 8
+
#if IS_ENABLED(CONFIG_TI_AM65_CPSW_QOS)
int am65_cpsw_qos_ndo_setup_tc(struct net_device *ndev, enum tc_setup_type type,
void *type_data);
--
2.34.1