net: dsa: qca8k: add support for mib autocast in Ethernet packet

The switch can autocast MIB counter using Ethernet packet.
Add support for this and provide a handler for the tagger.
The switch will send packet with MIB counter for each port, the switch
will use completion API to wait for the correct packet to be received
and will complete the task only when each packet is received.
Although the handler will drop all the other packet, we still have to
consume each MIB packet to complete the request. This is done to prevent
mixed data with concurrent ethtool request.

connect_tag_protocol() is used to add the handler to the tag_qca tagger,
master_state_change() use the MIB lock to make sure no MIB Ethernet is
in progress.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 105 insertions, 1 deletions

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index e3a215f04559..199cf4f761c0 100644
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -830,7 +830,10 @@ qca8k_mib_init(struct qca8k_priv *priv)
 	int ret;
 
 	mutex_lock(&priv->reg_mutex);
-	ret = regmap_set_bits(priv->regmap, QCA8K_REG_MIB, QCA8K_MIB_FLUSH | QCA8K_MIB_BUSY);
+	ret = regmap_update_bits(priv->regmap, QCA8K_REG_MIB,
+				 QCA8K_MIB_FUNC | QCA8K_MIB_BUSY,
+				 FIELD_PREP(QCA8K_MIB_FUNC, QCA8K_MIB_FLUSH) |
+				 QCA8K_MIB_BUSY);
 	if (ret)
 		goto exit;
 
@@ -1901,6 +1904,97 @@ qca8k_get_strings(struct dsa_switch *ds, int port, u32 stringset, uint8_t *data)
 			ETH_GSTRING_LEN);
 }
 
+static void qca8k_mib_autocast_handler(struct dsa_switch *ds, struct sk_buff *skb)
+{
+	const struct qca8k_match_data *match_data;
+	struct qca8k_mib_eth_data *mib_eth_data;
+	struct qca8k_priv *priv = ds->priv;
+	const struct qca8k_mib_desc *mib;
+	struct mib_ethhdr *mib_ethhdr;
+	int i, mib_len, offset = 0;
+	u64 *data;
+	u8 port;
+
+	mib_ethhdr = (struct mib_ethhdr *)skb_mac_header(skb);
+	mib_eth_data = &priv->mib_eth_data;
+
+	/* The switch autocast every port. Ignore other packet and
+	 * parse only the requested one.
+	 */
+	port = FIELD_GET(QCA_HDR_RECV_SOURCE_PORT, ntohs(mib_ethhdr->hdr));
+	if (port != mib_eth_data->req_port)
+		goto exit;
+
+	match_data = device_get_match_data(priv->dev);
+	data = mib_eth_data->data;
+
+	for (i = 0; i < match_data->mib_count; i++) {
+		mib = &ar8327_mib[i];
+
+		/* First 3 mib are present in the skb head */
+		if (i < 3) {
+			data[i] = mib_ethhdr->data[i];
+			continue;
+		}
+
+		mib_len = sizeof(uint32_t);
+
+		/* Some mib are 64 bit wide */
+		if (mib->size == 2)
+			mib_len = sizeof(uint64_t);
+
+		/* Copy the mib value from packet to the */
+		memcpy(data + i, skb->data + offset, mib_len);
+
+		/* Set the offset for the next mib */
+		offset += mib_len;
+	}
+
+exit:
+	/* Complete on receiving all the mib packet */
+	if (refcount_dec_and_test(&mib_eth_data->port_parsed))
+		complete(&mib_eth_data->rw_done);
+}
+
+static int
+qca8k_get_ethtool_stats_eth(struct dsa_switch *ds, int port, u64 *data)
+{
+	struct dsa_port *dp = dsa_to_port(ds, port);
+	struct qca8k_mib_eth_data *mib_eth_data;
+	struct qca8k_priv *priv = ds->priv;
+	int ret;
+
+	mib_eth_data = &priv->mib_eth_data;
+
+	mutex_lock(&mib_eth_data->mutex);
+
+	reinit_completion(&mib_eth_data->rw_done);
+
+	mib_eth_data->req_port = dp->index;
+	mib_eth_data->data = data;
+	refcount_set(&mib_eth_data->port_parsed, QCA8K_NUM_PORTS);
+
+	mutex_lock(&priv->reg_mutex);
+
+	/* Send mib autocast request */
+	ret = regmap_update_bits(priv->regmap, QCA8K_REG_MIB,
+				 QCA8K_MIB_FUNC | QCA8K_MIB_BUSY,
+				 FIELD_PREP(QCA8K_MIB_FUNC, QCA8K_MIB_CAST) |
+				 QCA8K_MIB_BUSY);
+
+	mutex_unlock(&priv->reg_mutex);
+
+	if (ret)
+		goto exit;
+
+	ret = wait_for_completion_timeout(&mib_eth_data->rw_done, QCA8K_ETHERNET_TIMEOUT);
+
+exit:
+	mutex_unlock(&mib_eth_data->mutex);
+
+	return ret;
+}
+
 static void
 qca8k_get_ethtool_stats(struct dsa_switch *ds, int port,
 			uint64_t *data)
@@ -1912,6 +2006,10 @@ qca8k_get_ethtool_stats(struct dsa_switch *ds, int port,
 	u32 hi = 0;
 	int ret;
 
+	if (priv->mgmt_master &&
+	    qca8k_get_ethtool_stats_eth(ds, port, data) > 0)
+		return;
+
 	match_data = of_device_get_match_data(priv->dev);
 
 	for (i = 0; i < match_data->mib_count; i++) {
@@ -2593,9 +2691,11 @@ qca8k_master_change(struct dsa_switch *ds, const struct net_device *master,
 		return;
 
 	mutex_lock(&priv->mgmt_eth_data.mutex);
+	mutex_lock(&priv->mib_eth_data.mutex);
 
 	priv->mgmt_master = operational ? (struct net_device *)master : NULL;
 
+	mutex_unlock(&priv->mib_eth_data.mutex);
 	mutex_unlock(&priv->mgmt_eth_data.mutex);
 }
 
@@ -2609,6 +2709,7 @@ static int qca8k_connect_tag_protocol(struct dsa_switch *ds,
 		tagger_data = ds->tagger_data;
 
 		tagger_data->rw_reg_ack_handler = qca8k_rw_reg_ack_handler;
+		tagger_data->mib_autocast_handler = qca8k_mib_autocast_handler;
 
 		break;
 	default:
@@ -2737,6 +2838,9 @@ qca8k_sw_probe(struct mdio_device *mdiodev)
 	mutex_init(&priv->mgmt_eth_data.mutex);
 	init_completion(&priv->mgmt_eth_data.rw_done);
 
+	mutex_init(&priv->mib_eth_data.mutex);
+	init_completion(&priv->mib_eth_data.rw_done);
+
 	priv->ds->dev = &mdiodev->dev;
 	priv->ds->num_ports = QCA8K_NUM_PORTS;
 	priv->ds->priv = priv;