[PATCH net-next v4 3/7] net: dsa: motorcomm: Split MIB buffers

[David Yang <mmyangfl@gmail.com>]

With MIB improvement introduced later, struct yt921x_priv will be over
20k which is not very good for a single kmalloc(). Dynamically allocate
the MIB structures to reduce the size of struct yt921x_priv, and do not
waste memory on dummy ports.

Signed-off-by: David Yang <mmyangfl@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
---
 drivers/net/dsa/motorcomm/chip.c | 115 ++++++++++++++++++++++++-------
 drivers/net/dsa/motorcomm/chip.h |  16 +++--
 2 files changed, 100 insertions(+), 31 deletions(-)

diff --git a/drivers/net/dsa/motorcomm/chip.c b/drivers/net/dsa/motorcomm/chip.c
index d0b25ded2447..ad06d894b001 100644
--- a/drivers/net/dsa/motorcomm/chip.c
+++ b/drivers/net/dsa/motorcomm/chip.c
@@ -549,10 +549,13 @@ static int yt921x_mib_read(struct yt921x_priv *priv, int port)
 {
 	struct yt921x_port *pp = &priv->ports[port];
 	struct device *dev = to_device(priv);
-	struct yt921x_mib_stats *mib = &pp->mib;
+	struct yt921x_mib *pm = pp->mib;
+	struct yt921x_mib_stats *mib;
 	int res = 0;
 
-	/* Reading of yt921x_port::mib is not protected by a lock and it's vain
+	mib = &pm->stats;
+
+	/* Reading of yt921x_mib_stats is not protected by a lock and it's vain
 	 * to keep its consistency, since we have to read registers one by one
 	 * and there is no way to make a snapshot of MIB stats.
 	 *
@@ -589,11 +592,11 @@ static int yt921x_mib_read(struct yt921x_priv *priv, int port)
 		WRITE_ONCE(*valp, val);
 	}
 
-	pp->rx_frames = mib->rx_64byte + mib->rx_65_127byte +
+	pm->rx_frames = mib->rx_64byte + mib->rx_65_127byte +
 			mib->rx_128_255byte + mib->rx_256_511byte +
 			mib->rx_512_1023byte + mib->rx_1024_1518byte +
 			mib->rx_jumbo;
-	pp->tx_frames = mib->tx_64byte + mib->tx_65_127byte +
+	pm->tx_frames = mib->tx_64byte + mib->tx_65_127byte +
 			mib->tx_128_255byte + mib->tx_256_511byte +
 			mib->tx_512_1023byte + mib->tx_1024_1518byte +
 			mib->tx_jumbo;
@@ -606,8 +609,9 @@ static int yt921x_mib_read(struct yt921x_priv *priv, int port)
 
 static void yt921x_mib_poll(struct work_struct *work)
 {
-	struct yt921x_port *pp = container_of_const(work, struct yt921x_port,
-						    mib_read.work);
+	struct yt921x_mib *pm = container_of_const(work, struct yt921x_mib,
+						   work.work);
+	struct yt921x_port *pp = pm->port;
 	unsigned long delay = YT921X_STATS_INTERVAL_JIFFIES;
 	struct yt921x_priv *priv = yt921x_port_to_priv(pp);
 	int port = pp->index;
@@ -619,7 +623,7 @@ static void yt921x_mib_poll(struct work_struct *work)
 	if (res)
 		delay *= 4;
 
-	schedule_delayed_work(&pp->mib_read, delay);
+	schedule_delayed_work(&pm->work, delay);
 }
 
 static void
@@ -642,9 +646,14 @@ yt921x_dsa_get_ethtool_stats(struct dsa_switch *ds, int port, uint64_t *data)
 {
 	struct yt921x_priv *priv = to_yt921x_priv(ds);
 	struct yt921x_port *pp = &priv->ports[port];
-	struct yt921x_mib_stats *mib = &pp->mib;
+	struct yt921x_mib *pm = pp->mib;
+	struct yt921x_mib_stats *mib;
 	size_t j;
 
+	if (!pm)
+		return;
+	mib = &pm->stats;
+
 	mutex_lock(&priv->reg_lock);
 	yt921x_mib_read(priv, port);
 	mutex_unlock(&priv->reg_lock);
@@ -684,16 +693,21 @@ yt921x_dsa_get_eth_mac_stats(struct dsa_switch *ds, int port,
 {
 	struct yt921x_priv *priv = to_yt921x_priv(ds);
 	struct yt921x_port *pp = &priv->ports[port];
-	struct yt921x_mib_stats *mib = &pp->mib;
+	struct yt921x_mib *pm = pp->mib;
+	struct yt921x_mib_stats *mib;
+
+	if (!pm)
+		return;
+	mib = &pm->stats;
 
 	mutex_lock(&priv->reg_lock);
 	yt921x_mib_read(priv, port);
 	mutex_unlock(&priv->reg_lock);
 
-	mac_stats->FramesTransmittedOK = pp->tx_frames;
+	mac_stats->FramesTransmittedOK = pm->tx_frames;
 	mac_stats->SingleCollisionFrames = mib->tx_single_collisions;
 	mac_stats->MultipleCollisionFrames = mib->tx_multiple_collisions;
-	mac_stats->FramesReceivedOK = pp->rx_frames;
+	mac_stats->FramesReceivedOK = pm->rx_frames;
 	mac_stats->FrameCheckSequenceErrors = mib->rx_crc_errors;
 	mac_stats->AlignmentErrors = mib->rx_alignment_errors;
 	mac_stats->OctetsTransmittedOK = mib->tx_good_bytes;
@@ -720,7 +734,12 @@ yt921x_dsa_get_eth_ctrl_stats(struct dsa_switch *ds, int port,
 {
 	struct yt921x_priv *priv = to_yt921x_priv(ds);
 	struct yt921x_port *pp = &priv->ports[port];
-	struct yt921x_mib_stats *mib = &pp->mib;
+	struct yt921x_mib *pm = pp->mib;
+	struct yt921x_mib_stats *mib;
+
+	if (!pm)
+		return;
+	mib = &pm->stats;
 
 	mutex_lock(&priv->reg_lock);
 	yt921x_mib_read(priv, port);
@@ -749,7 +768,12 @@ yt921x_dsa_get_rmon_stats(struct dsa_switch *ds, int port,
 {
 	struct yt921x_priv *priv = to_yt921x_priv(ds);
 	struct yt921x_port *pp = &priv->ports[port];
-	struct yt921x_mib_stats *mib = &pp->mib;
+	struct yt921x_mib *pm = pp->mib;
+	struct yt921x_mib_stats *mib;
+
+	if (!pm)
+		return;
+	mib = &pm->stats;
 
 	mutex_lock(&priv->reg_lock);
 	yt921x_mib_read(priv, port);
@@ -785,7 +809,12 @@ yt921x_dsa_get_stats64(struct dsa_switch *ds, int port,
 {
 	struct yt921x_priv *priv = to_yt921x_priv(ds);
 	struct yt921x_port *pp = &priv->ports[port];
-	struct yt921x_mib_stats *mib = &pp->mib;
+	struct yt921x_mib *pm = pp->mib;
+	struct yt921x_mib_stats *mib;
+
+	if (!pm)
+		return;
+	mib = &pm->stats;
 
 	stats->rx_length_errors = mib->rx_undersize_errors +
 				  mib->rx_fragment_errors;
@@ -801,8 +830,8 @@ yt921x_dsa_get_stats64(struct dsa_switch *ds, int port,
 	/* stats->tx_heartbeat_errors */
 	stats->tx_window_errors = mib->tx_late_collisions;
 
-	stats->rx_packets = pp->rx_frames;
-	stats->tx_packets = pp->tx_frames;
+	stats->rx_packets = pm->rx_frames;
+	stats->tx_packets = pm->tx_frames;
 	stats->rx_bytes = mib->rx_good_bytes - ETH_FCS_LEN * stats->rx_packets;
 	stats->tx_bytes = mib->tx_good_bytes - ETH_FCS_LEN * stats->tx_packets;
 	stats->rx_errors = stats->rx_length_errors + stats->rx_over_errors +
@@ -821,7 +850,12 @@ yt921x_dsa_get_pause_stats(struct dsa_switch *ds, int port,
 {
 	struct yt921x_priv *priv = to_yt921x_priv(ds);
 	struct yt921x_port *pp = &priv->ports[port];
-	struct yt921x_mib_stats *mib = &pp->mib;
+	struct yt921x_mib *pm = pp->mib;
+	struct yt921x_mib_stats *mib;
+
+	if (!pm)
+		return;
+	mib = &pm->stats;
 
 	mutex_lock(&priv->reg_lock);
 	yt921x_mib_read(priv, port);
@@ -3952,11 +3986,14 @@ yt921x_phylink_mac_link_down(struct phylink_config *config, unsigned int mode,
 {
 	struct dsa_port *dp = dsa_phylink_to_port(config);
 	struct yt921x_priv *priv = to_yt921x_priv(dp->ds);
+	struct yt921x_mib *pm;
 	int port = dp->index;
 	int res;
 
 	/* No need to sync; port control block is hold until device remove */
-	cancel_delayed_work(&priv->ports[port].mib_read);
+	pm = priv->ports[port].mib;
+	if (pm)
+		cancel_delayed_work(&pm->work);
 
 	mutex_lock(&priv->reg_lock);
 	res = yt921x_port_down(priv, port);
@@ -3975,6 +4012,7 @@ yt921x_phylink_mac_link_up(struct phylink_config *config,
 {
 	struct dsa_port *dp = dsa_phylink_to_port(config);
 	struct yt921x_priv *priv = to_yt921x_priv(dp->ds);
+	struct yt921x_mib *pm;
 	int port = dp->index;
 	int res;
 
@@ -3987,7 +4025,9 @@ yt921x_phylink_mac_link_up(struct phylink_config *config,
 		dev_err(dp->ds->dev, "Failed to %s port %d: %i\n", "bring up",
 			port, res);
 
-	schedule_delayed_work(&priv->ports[port].mib_read, 0);
+	pm = priv->ports[port].mib;
+	if (pm)
+		schedule_delayed_work(&pm->work, 0);
 }
 
 static void
@@ -4107,11 +4147,40 @@ yt921x_dsa_get_tag_protocol(struct dsa_switch *ds, int port,
 	return DSA_TAG_PROTO_YT921X;
 }
 
+static void yt921x_dsa_port_teardown(struct dsa_switch *ds, int port)
+{
+	struct yt921x_priv *priv = to_yt921x_priv(ds);
+	struct yt921x_port *pp = &priv->ports[port];
+	struct yt921x_mib *pm = pp->mib;
+
+	/* get_stats64() might not be synchronized with port_teardown(), hold
+	 * the MIB block till the device teardown
+	 */
+	if (pm)
+		disable_delayed_work_sync(&pm->work);
+}
+
 static int yt921x_dsa_port_setup(struct dsa_switch *ds, int port)
 {
 	struct yt921x_priv *priv = to_yt921x_priv(ds);
+	struct yt921x_port *pp = &priv->ports[port];
+	struct device *dev = to_device(priv);
+	struct yt921x_mib *pm = pp->mib;
 	int res;
 
+	if (pm) {
+		enable_delayed_work(&pm->work);
+	} else if (BIT(port) & (priv->info->internal_mask |
+				priv->info->external_mask)) {
+		pm = devm_kzalloc(dev, sizeof(*pm), GFP_KERNEL);
+		if (!pm)
+			return -ENOMEM;
+		pp->mib = pm;
+
+		pm->port = pp;
+		INIT_DELAYED_WORK(&pm->work, yt921x_mib_poll);
+	}
+
 	mutex_lock(&priv->reg_lock);
 	res = yt921x_port_setup(priv, port);
 	mutex_unlock(&priv->reg_lock);
@@ -4666,6 +4735,7 @@ static const struct dsa_switch_ops yt921x_dsa_switch_ops = {
 	/* port */
 	.get_tag_protocol	= yt921x_dsa_get_tag_protocol,
 	.phylink_get_caps	= yt921x_dsa_phylink_get_caps,
+	.port_teardown		= yt921x_dsa_port_teardown,
 	.port_setup		= yt921x_dsa_port_setup,
 #if IS_ENABLED(CONFIG_DCB)
 	/* dscp */
@@ -4695,12 +4765,6 @@ static void yt921x_mdio_remove(struct mdio_device *mdiodev)
 	if (!priv)
 		return;
 
-	for (size_t i = ARRAY_SIZE(priv->ports); i-- > 0; ) {
-		struct yt921x_port *pp = &priv->ports[i];
-
-		disable_delayed_work_sync(&pp->mib_read);
-	}
-
 	dsa_unregister_switch(&priv->ds);
 
 	for (unsigned int i = 0; i < ARRAY_SIZE(priv->acl_blks); i++) {
@@ -4748,7 +4812,6 @@ static int yt921x_mdio_probe(struct mdio_device *mdiodev)
 		struct yt921x_port *pp = &priv->ports[i];
 
 		pp->index = i;
-		INIT_DELAYED_WORK(&pp->mib_read, yt921x_mib_poll);
 	}
 
 	ds = &priv->ds;
diff --git a/drivers/net/dsa/motorcomm/chip.h b/drivers/net/dsa/motorcomm/chip.h
index 9205be423e39..9f3c8af4f638 100644
--- a/drivers/net/dsa/motorcomm/chip.h
+++ b/drivers/net/dsa/motorcomm/chip.h
@@ -913,6 +913,15 @@ struct yt921x_mib_stats {
 	u64 tx_oam;
 };
 
+struct yt921x_mib {
+	struct yt921x_port *port;
+
+	struct delayed_work work;
+	struct yt921x_mib_stats stats;
+	u64 rx_frames;
+	u64 tx_frames;
+};
+
 struct yt921x_acl_entry {
 	u32 key[2];
 	u32 mask[2];
@@ -939,11 +948,6 @@ struct yt921x_port {
 	bool hairpin;
 	bool isolated;
 
-	struct delayed_work mib_read;
-	struct yt921x_mib_stats mib;
-	u64 rx_frames;
-	u64 tx_frames;
-
 #if IS_ENABLED(CONFIG_NET_DSA_YT921X_LEDS)
 	unsigned char led_duty;
 	unsigned short led_cycle;
@@ -953,6 +957,8 @@ struct yt921x_port {
 
 	struct yt921x_led *leds[YT921X_LED_GROUP_NUM];
 #endif
+
+	struct yt921x_mib *mib;
 };
 
 struct yt921x_reg_ops {
-- 
2.53.0