[PATCH net-next v9 10/10] net: ethernet: ti: am65-cpsw: add sw tx/rx irq coalescing based on hrtimers

Roger Quadros
2023-12-15T13:21:35Z

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

Add SW IRQ coalescing based on hrtimers for TX and RX data path which
can be enabled by ethtool commands:

- RX coalescing
ethtool -C eth1 rx-usecs 50

- TX coalescing can be enabled per TX queue

- by default enables coalesing for TX0
ethtool -C eth1 tx-usecs 50
- configure TX0
ethtool -Q eth0 queue_mask 1 --coalesce tx-usecs 100
- configure TX1
ethtool -Q eth0 queue_mask 2 --coalesce tx-usecs 100
- configure TX0 and TX1
ethtool -Q eth0 queue_mask 3 --coalesce tx-usecs 100 --coalesce tx-usecs 100

show configuration for TX0 and TX1:
ethtool -Q eth0 queue_mask 3 --show-coalesce

Comparing to gro_flush_timeout and napi_defer_hard_irqs, this patch
allows to enable IRQ coalesing for RX path separately.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
drivers/net/ethernet/ti/am65-cpsw-ethtool.c | 79 +++++++++++++++++++++
drivers/net/ethernet/ti/am65-cpsw-nuss.c | 59 ++++++++++++---
drivers/net/ethernet/ti/am65-cpsw-nuss.h | 4 ++
3 files changed, 134 insertions(+), 8 deletions(-)

Changelog:

v9: no change
v8: no change
v7: no change
v6: no change
v5: initial commit

diff --git a/drivers/net/ethernet/ti/am65-cpsw-ethtool.c b/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
index 0a6134cdf39f..35fceba01ea4 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
@@ -904,6 +904,80 @@ static void am65_cpsw_get_mm_stats(struct net_device *ndev,
s->MACMergeHoldCount = readl(base + AM65_CPSW_STATN_IET_TX_HOLD);
}

+static int am65_cpsw_get_coalesce(struct net_device *ndev, struct ethtool_coalesce *coal,
+ struct kernel_ethtool_coalesce *kernel_coal,
+ struct netlink_ext_ack *extack)
+{
+ struct am65_cpsw_common *common = am65_ndev_to_common(ndev);
+ struct am65_cpsw_tx_chn *tx_chn;
+
+ tx_chn = &common->tx_chns[0];
+
+ coal->rx_coalesce_usecs = common->rx_pace_timeout / 1000;
+ coal->tx_coalesce_usecs = tx_chn->tx_pace_timeout / 1000;
+
+ return 0;
+}
+
+static int am65_cpsw_get_per_queue_coalesce(struct net_device *ndev, u32 queue,
+ struct ethtool_coalesce *coal)
+{
+ struct am65_cpsw_common *common = am65_ndev_to_common(ndev);
+ struct am65_cpsw_tx_chn *tx_chn;
+
+ if (queue >= AM65_CPSW_MAX_TX_QUEUES)
+ return -EINVAL;
+
+ tx_chn = &common->tx_chns[queue];
+
+ coal->tx_coalesce_usecs = tx_chn->tx_pace_timeout / 1000;
+
+ return 0;
+}
+
+static int am65_cpsw_set_coalesce(struct net_device *ndev, struct ethtool_coalesce *coal,
+ struct kernel_ethtool_coalesce *kernel_coal,
+ struct netlink_ext_ack *extack)
+{
+ struct am65_cpsw_common *common = am65_ndev_to_common(ndev);
+ struct am65_cpsw_tx_chn *tx_chn;
+
+ tx_chn = &common->tx_chns[0];
+
+ if (coal->rx_coalesce_usecs && coal->rx_coalesce_usecs < 20)
+ return -EINVAL;
+
+ if (coal->tx_coalesce_usecs && coal->tx_coalesce_usecs < 20)
+ return -EINVAL;
+
+ common->rx_pace_timeout = coal->rx_coalesce_usecs * 1000;
+ tx_chn->tx_pace_timeout = coal->tx_coalesce_usecs * 1000;
+
+ return 0;
+}
+
+static int am65_cpsw_set_per_queue_coalesce(struct net_device *ndev, u32 queue,
+ struct ethtool_coalesce *coal)
+{
+ struct am65_cpsw_common *common = am65_ndev_to_common(ndev);
+ struct am65_cpsw_tx_chn *tx_chn;
+
+ if (queue >= AM65_CPSW_MAX_TX_QUEUES)
+ return -EINVAL;
+
+ tx_chn = &common->tx_chns[queue];
+
+ if (coal->tx_coalesce_usecs && coal->tx_coalesce_usecs < 20) {
+ dev_info(common->dev, "defaulting to min value of 20us for tx-usecs for tx-%u\n",
+ queue);
+ coal->tx_coalesce_usecs = 20;
+ }
+
+ tx_chn->tx_pace_timeout = coal->tx_coalesce_usecs * 1000;
+
+ return 0;
+}
+
const struct ethtool_ops am65_cpsw_ethtool_ops_slave = {
.begin = am65_cpsw_ethtool_op_begin,
.complete = am65_cpsw_ethtool_op_complete,
@@ -922,6 +996,11 @@ const struct ethtool_ops am65_cpsw_ethtool_ops_slave = {
.get_ts_info = am65_cpsw_get_ethtool_ts_info,
.get_priv_flags = am65_cpsw_get_ethtool_priv_flags,
.set_priv_flags = am65_cpsw_set_ethtool_priv_flags,
+ .supported_coalesce_params = ETHTOOL_COALESCE_USECS,
+ .get_coalesce = am65_cpsw_get_coalesce,
+ .set_coalesce = am65_cpsw_set_coalesce,
+ .get_per_queue_coalesce = am65_cpsw_get_per_queue_coalesce,
+ .set_per_queue_coalesce = am65_cpsw_set_per_queue_coalesce,

.get_link = ethtool_op_get_link,
.get_link_ksettings = am65_cpsw_get_link_ksettings,
diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index 41e0046a52d5..faa0561e988e 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -596,8 +596,10 @@ static int am65_cpsw_nuss_common_stop(struct am65_cpsw_common *common)
msecs_to_jiffies(1000));
if (!i)
dev_err(common->dev, "tx timeout\n");
- for (i = 0; i < common->tx_ch_num; i++)
+ for (i = 0; i < common->tx_ch_num; i++) {
napi_disable(&common->tx_chns[i].napi_tx);
+ hrtimer_cancel(&common->tx_chns[i].tx_hrtimer);
+ }

for (i = 0; i < common->tx_ch_num; i++) {
k3_udma_glue_reset_tx_chn(common->tx_chns[i].tx_chn,
@@ -616,6 +618,7 @@ static int am65_cpsw_nuss_common_stop(struct am65_cpsw_common *common)
}

napi_disable(&common->napi_rx);
+ hrtimer_cancel(&common->rx_hrtimer);

for (i = 0; i < AM65_CPSW_MAX_RX_FLOWS; i++)
k3_udma_glue_reset_rx_chn(common->rx_chns.rx_chn, i,
@@ -885,6 +888,15 @@ static int am65_cpsw_nuss_rx_packets(struct am65_cpsw_common *common,
return ret;
}

+static enum hrtimer_restart am65_cpsw_nuss_rx_timer_callback(struct hrtimer *timer)
+{
+ struct am65_cpsw_common *common =
+ container_of(timer, struct am65_cpsw_common, rx_hrtimer);
+
+ enable_irq(common->rx_chns.irq);
+ return HRTIMER_NORESTART;
+}
+
static int am65_cpsw_nuss_rx_poll(struct napi_struct *napi_rx, int budget)
{
struct am65_cpsw_common *common = am65_cpsw_napi_to_common(napi_rx);
@@ -912,7 +924,13 @@ static int am65_cpsw_nuss_rx_poll(struct napi_struct *napi_rx, int budget)
if (num_rx < budget && napi_complete_done(napi_rx, num_rx)) {
if (common->rx_irq_disabled) {
common->rx_irq_disabled = false;
- enable_irq(common->rx_chns.irq);
+ if (unlikely(common->rx_pace_timeout)) {
+ hrtimer_start(&common->rx_hrtimer,
+ ns_to_ktime(common->rx_pace_timeout),
+ HRTIMER_MODE_REL_PINNED);
+ } else {
+ enable_irq(common->rx_chns.irq);
+ }
}
}

@@ -968,7 +986,7 @@ static void am65_cpsw_nuss_tx_wake(struct am65_cpsw_tx_chn *tx_chn, struct net_d
}

static int am65_cpsw_nuss_tx_compl_packets(struct am65_cpsw_common *common,
- int chn, unsigned int budget)
+ int chn, unsigned int budget, bool *tdown)
{
struct device *dev = common->dev;
struct am65_cpsw_tx_chn *tx_chn;
@@ -991,6 +1009,7 @@ static int am65_cpsw_nuss_tx_compl_packets(struct am65_cpsw_common *common,
if (cppi5_desc_is_tdcm(desc_dma)) {
if (atomic_dec_and_test(&common->tdown_cnt))
complete(&common->tdown_complete);
+ *tdown = true;
break;
}

@@ -1013,7 +1032,7 @@ static int am65_cpsw_nuss_tx_compl_packets(struct am65_cpsw_common *common,
}

static int am65_cpsw_nuss_tx_compl_packets_2g(struct am65_cpsw_common *common,
- int chn, unsigned int budget)
+ int chn, unsigned int budget, bool *tdown)
{
struct device *dev = common->dev;
struct am65_cpsw_tx_chn *tx_chn;
@@ -1034,6 +1053,7 @@ static int am65_cpsw_nuss_tx_compl_packets_2g(struct am65_cpsw_common *common,
if (cppi5_desc_is_tdcm(desc_dma)) {
if (atomic_dec_and_test(&common->tdown_cnt))
complete(&common->tdown_complete);
+ *tdown = true;
break;
}

@@ -1059,21 +1079,40 @@ static int am65_cpsw_nuss_tx_compl_packets_2g(struct am65_cpsw_common *common,
return num_tx;
}

+static enum hrtimer_restart am65_cpsw_nuss_tx_timer_callback(struct hrtimer *timer)
+{
+ struct am65_cpsw_tx_chn *tx_chns =
+ container_of(timer, struct am65_cpsw_tx_chn, tx_hrtimer);
+
+ enable_irq(tx_chns->irq);
+ return HRTIMER_NORESTART;
+}
+
static int am65_cpsw_nuss_tx_poll(struct napi_struct *napi_tx, int budget)
{
struct am65_cpsw_tx_chn *tx_chn = am65_cpsw_napi_to_tx_chn(napi_tx);
+ bool tdown = false;
int num_tx;

if (AM65_CPSW_IS_CPSW2G(tx_chn->common))
- num_tx = am65_cpsw_nuss_tx_compl_packets_2g(tx_chn->common, tx_chn->id, budget);
+ num_tx = am65_cpsw_nuss_tx_compl_packets_2g(tx_chn->common, tx_chn->id,
+ budget, &tdown);
else
- num_tx = am65_cpsw_nuss_tx_compl_packets(tx_chn->common, tx_chn->id, budget);
+ num_tx = am65_cpsw_nuss_tx_compl_packets(tx_chn->common,
+ tx_chn->id, budget, &tdown);

if (num_tx >= budget)
return budget;

- if (napi_complete_done(napi_tx, num_tx))
- enable_irq(tx_chn->irq);
+ if (napi_complete_done(napi_tx, num_tx)) {
+ if (unlikely(tx_chn->tx_pace_timeout && !tdown)) {
+ hrtimer_start(&tx_chn->tx_hrtimer,
+ ns_to_ktime(tx_chn->tx_pace_timeout),
+ HRTIMER_MODE_REL_PINNED);
+ } else {
+ enable_irq(tx_chn->irq);
+ }
+ }

return 0;
}
@@ -1705,6 +1744,8 @@ static int am65_cpsw_nuss_ndev_add_tx_napi(struct am65_cpsw_common *common)

netif_napi_add_tx(common->dma_ndev, &tx_chn->napi_tx,
am65_cpsw_nuss_tx_poll);
+ hrtimer_init(&tx_chn->tx_hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED);
+ tx_chn->tx_hrtimer.function = &am65_cpsw_nuss_tx_timer_callback;

ret = devm_request_irq(dev, tx_chn->irq,
am65_cpsw_nuss_tx_irq,
@@ -1930,6 +1971,8 @@ static int am65_cpsw_nuss_init_rx_chns(struct am65_cpsw_common *common)

netif_napi_add(common->dma_ndev, &common->napi_rx,
am65_cpsw_nuss_rx_poll);
+ hrtimer_init(&common->rx_hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_PINNED);
+ common->rx_hrtimer.function = &am65_cpsw_nuss_rx_timer_callback;

ret = devm_request_irq(dev, rx_chn->irq,
am65_cpsw_nuss_rx_irq,
diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.h b/drivers/net/ethernet/ti/am65-cpsw-nuss.h
index 1e4a045057fc..7da0492dc091 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.h
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.h
@@ -75,6 +75,8 @@ struct am65_cpsw_tx_chn {
struct k3_cppi_desc_pool *desc_pool;
struct k3_udma_glue_tx_channel *tx_chn;
spinlock_t lock; /* protect TX rings in multi-port mode */
+ struct hrtimer tx_hrtimer;
+ unsigned long tx_pace_timeout;
int irq;
u32 id;
u32 descs_num;
@@ -138,6 +140,8 @@ struct am65_cpsw_common {
struct napi_struct napi_rx;

bool rx_irq_disabled;
+ struct hrtimer rx_hrtimer;
+ unsigned long rx_pace_timeout;

u32 nuss_ver;
u32 cpsw_ver;
--
2.34.1