[RFC PATCH v7 12/16] net: dsa: qca8k: add support for phy read/write with mgmt Ethernet

Ansuel Smith
2022-01-23T01:34:16Z

Use mgmt Ethernet also for phy read/write if availabale. Use a different
seq number to make sure we receive the correct packet.
On any error, we fallback to the legacy mdio read/write.

Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
---
drivers/net/dsa/qca8k.c | 191 ++++++++++++++++++++++++++++++++++++++++
drivers/net/dsa/qca8k.h | 1 +
2 files changed, 192 insertions(+)

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index f51a6d8993ff..e7bc0770bae9 100644
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -848,6 +848,166 @@ qca8k_port_set_status(struct qca8k_priv *priv, int port, int enable)
regmap_clear_bits(priv->regmap, QCA8K_REG_PORT_STATUS(port), mask);
}

+static int
+qca8k_phy_eth_busy_wait(struct qca8k_mgmt_hdr_data *phy_hdr_data,
+ struct sk_buff *read_skb, u32 *val)
+{
+ struct sk_buff *skb = skb_copy(read_skb, GFP_KERNEL);
+ bool ack;
+ int ret;
+
+ reinit_completion(&phy_hdr_data->rw_done);
+ phy_hdr_data->seq = 400;
+ phy_hdr_data->ack = false;
+
+ dev_queue_xmit(skb);
+
+ ret = wait_for_completion_timeout(&phy_hdr_data->rw_done,
+ QCA8K_ETHERNET_TIMEOUT);
+
+ ack = phy_hdr_data->ack;
+
+ if (ret <= 0)
+ return -ETIMEDOUT;
+
+ if (!ack)
+ return -EINVAL;
+
+ *val = phy_hdr_data->data[0];
+
+ return 0;
+}
+
+static int
+qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy,
+ int regnum, u16 data)
+{
+ struct sk_buff *write_skb, *clear_skb, *read_skb;
+ struct qca8k_mgmt_hdr_data *phy_hdr_data;
+ const struct net_device *mgmt_master;
+ u32 write_val, clear_val = 0, val;
+ int seq_num = 400;
+ int ret, ret1;
+ bool ack;
+
+ if (regnum >= QCA8K_MDIO_MASTER_MAX_REG)
+ return -EINVAL;
+
+ phy_hdr_data = &priv->mgmt_hdr_data;
+
+ write_val = QCA8K_MDIO_MASTER_BUSY | QCA8K_MDIO_MASTER_EN |
+ QCA8K_MDIO_MASTER_PHY_ADDR(phy) |
+ QCA8K_MDIO_MASTER_REG_ADDR(regnum);
+
+ if (read) {
+ write_val |= QCA8K_MDIO_MASTER_READ;
+ } else {
+ write_val |= QCA8K_MDIO_MASTER_WRITE;
+ write_val |= QCA8K_MDIO_MASTER_DATA(data);
+ }
+
+ /* Prealloc all the needed skb before the lock */
+ write_skb = qca8k_alloc_mdio_header(MDIO_WRITE, QCA8K_MDIO_MASTER_CTRL,
+ &write_val, seq_num, QCA8K_ETHERNET_PHY_PRIORITY);
+ if (!write_skb)
+ return -ENOMEM;
+
+ clear_skb = qca8k_alloc_mdio_header(MDIO_WRITE, QCA8K_MDIO_MASTER_CTRL,
+ &clear_val, seq_num, QCA8K_ETHERNET_PHY_PRIORITY);
+ if (!write_skb)
+ return -ENOMEM;
+
+ read_skb = qca8k_alloc_mdio_header(MDIO_READ, QCA8K_MDIO_MASTER_CTRL,
+ &clear_val, seq_num, QCA8K_ETHERNET_PHY_PRIORITY);
+ if (!write_skb)
+ return -ENOMEM;
+
+ /* Actually start the request:
+ * 1. Send mdio master packet
+ * 2. Busy Wait for mdio master command
+ * 3. Get the data if we are reading
+ * 4. Reset the mdio master (even with error)
+ */
+ mutex_lock(&phy_hdr_data->mutex);
+
+ /* Recheck mgmt_master under lock to make sure it's operational */
+ mgmt_master = priv->mgmt_master;
+ if (!mgmt_master)
+ return -EINVAL;
+
+ read_skb->dev = (struct net_device *)mgmt_master;
+ clear_skb->dev = (struct net_device *)mgmt_master;
+ write_skb->dev = (struct net_device *)mgmt_master;
+
+ reinit_completion(&phy_hdr_data->rw_done);
+ phy_hdr_data->ack = false;
+ phy_hdr_data->seq = seq_num;
+
+ dev_queue_xmit(write_skb);
+
+ ret = wait_for_completion_timeout(&phy_hdr_data->rw_done,
+ QCA8K_ETHERNET_TIMEOUT);
+
+ ack = phy_hdr_data->ack;
+
+ if (ret <= 0) {
+ ret = -ETIMEDOUT;
+ goto exit;
+ }
+
+ if (!ack) {
+ ret = -EINVAL;
+ goto exit;
+ }
+
+ ret = read_poll_timeout(qca8k_phy_eth_busy_wait, ret1,
+ !(val & QCA8K_MDIO_MASTER_BUSY), 0,
+ QCA8K_BUSY_WAIT_TIMEOUT * USEC_PER_MSEC, false,
+ phy_hdr_data, read_skb, &val);
+
+ if (ret < 0 && ret1 < 0) {
+ ret = ret1;
+ goto exit;
+ }
+
+ if (read) {
+ reinit_completion(&phy_hdr_data->rw_done);
+ phy_hdr_data->ack = false;
+
+ dev_queue_xmit(read_skb);
+
+ ret = wait_for_completion_timeout(&phy_hdr_data->rw_done,
+ QCA8K_ETHERNET_TIMEOUT);
+
+ ack = phy_hdr_data->ack;
+
+ if (ret <= 0) {
+ ret = -ETIMEDOUT;
+ goto exit;
+ }
+
+ if (!ack) {
+ ret = -EINVAL;
+ goto exit;
+ }
+
+ ret = phy_hdr_data->data[0] & QCA8K_MDIO_MASTER_DATA_MASK;
+ }
+
+exit:
+ reinit_completion(&phy_hdr_data->rw_done);
+ phy_hdr_data->ack = false;
+
+ dev_queue_xmit(clear_skb);
+
+ wait_for_completion_timeout(&phy_hdr_data->rw_done,
+ QCA8K_ETHERNET_TIMEOUT);
+
+ mutex_unlock(&phy_hdr_data->mutex);
+
+ return ret;
+}
+
static u32
qca8k_port_to_phy(int port)
{
@@ -970,6 +1130,14 @@ qca8k_internal_mdio_write(struct mii_bus *slave_bus, int phy, int regnum, u16 da
{
struct qca8k_priv *priv = slave_bus->priv;
struct mii_bus *bus = priv->bus;
+ int ret;
+
+ /* Use mdio Ethernet when available, fallback to legacy one on error */
+ if (priv->mgmt_master) {
+ ret = qca8k_phy_eth_command(priv, false, phy, regnum, data);
+ if (!ret)
+ return 0;
+ }

return qca8k_mdio_write(bus, phy, regnum, data);
}
@@ -979,6 +1147,14 @@ qca8k_internal_mdio_read(struct mii_bus *slave_bus, int phy, int regnum)
{
struct qca8k_priv *priv = slave_bus->priv;
struct mii_bus *bus = priv->bus;
+ int ret;
+
+ /* Use mdio Ethernet when available, fallback to legacy one on error */
+ if (priv->mgmt_master) {
+ ret = qca8k_phy_eth_command(priv, true, phy, regnum, 0);
+ if (ret >= 0)
+ return ret;
+ }

return qca8k_mdio_read(bus, phy, regnum);
}
@@ -987,6 +1163,7 @@ static int
qca8k_phy_write(struct dsa_switch *ds, int port, int regnum, u16 data)
{
struct qca8k_priv *priv = ds->priv;
+ int ret;

/* Check if the legacy mapping should be used and the
* port is not correctly mapped to the right PHY in the
@@ -995,6 +1172,13 @@ qca8k_phy_write(struct dsa_switch *ds, int port, int regnum, u16 data)
if (priv->legacy_phy_port_mapping)
port = qca8k_port_to_phy(port) % PHY_MAX_ADDR;

+ /* Use mdio Ethernet when available, fallback to legacy one on error */
+ if (priv->mgmt_master) {
+ ret = qca8k_phy_eth_command(priv, true, port, regnum, 0);
+ if (!ret)
+ return ret;
+ }
+
return qca8k_mdio_write(priv->bus, port, regnum, data);
}

@@ -1011,6 +1195,13 @@ qca8k_phy_read(struct dsa_switch *ds, int port, int regnum)
if (priv->legacy_phy_port_mapping)
port = qca8k_port_to_phy(port) % PHY_MAX_ADDR;

+ /* Use mdio Ethernet when available, fallback to legacy one on error */
+ if (priv->mgmt_master) {
+ ret = qca8k_phy_eth_command(priv, true, port, regnum, 0);
+ if (ret >= 0)
+ return ret;
+ }
+
ret = qca8k_mdio_read(priv->bus, port, regnum);

if (ret < 0)
diff --git a/drivers/net/dsa/qca8k.h b/drivers/net/dsa/qca8k.h
index dc1365542aa3..952217db2047 100644
--- a/drivers/net/dsa/qca8k.h
+++ b/drivers/net/dsa/qca8k.h
@@ -14,6 +14,7 @@
#include <linux/dsa/tag_qca.h>

#define QCA8K_ETHERNET_MDIO_PRIORITY 7
+#define QCA8K_ETHERNET_PHY_PRIORITY 6
#define QCA8K_ETHERNET_TIMEOUT 100

#define QCA8K_NUM_PORTS 7
--
2.33.1