[PATCH net-next 3/8] net: mdio: realtek-rtl9300: Add page tracking
From: Markus Stockhausen <hidden>
Date: 2026-06-13 11:30:15
Also in:
linux-devicetree
Subsystem:
ethernet phy library, networking drivers, the rest · Maintainers:
Andrew Lunn, Heiner Kallweit, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
The hardware polling unit of the Realtek switches has a very special handling for PHY register 31 (aka Realtek page register) in place. - On the RTL838x it is permanently reset to zero. - On other devices there is some magic saving/restoring (aka parking) in the background in place. This makes access to PHYs a gamble. As of now all known existing hardware designs have Realtek based 1G PHYs. Otherwise the polling engine and the MAC status update will not work at all and the vendor SDK would fail totally. This driver differentiates clearly between c22 and c45 buses. During probing it enables only one of the protocols for a bus. So it is safe to assume that any c22 access will only target a Realtek based 1G PHY. Intercept access to register 31 and store the desired value for each port in the driver. When issuing access to other registers add the saved page. This given, the hardware will run two consecutive c22 commands that are not interrupted by polling. ... hardware poll ... phy_write(phy, 31, page) phy_write(phy, reg, value) ... hardware poll ... Remark! To keep this simple, writes to register 31 are only accepted if they are lower than the device specific raw page - 0..4094/8190. Otherwise -EINVAL is returned. Under the above assumption (Only 1G Realtek PHYs on c22 bus) this is no limitation. Signed-off-by: Markus Stockhausen <redacted> --- drivers/net/mdio/mdio-realtek-rtl9300.c | 32 +++++++++++++++++-------- 1 file changed, 22 insertions(+), 10 deletions(-)
diff --git a/drivers/net/mdio/mdio-realtek-rtl9300.c b/drivers/net/mdio/mdio-realtek-rtl9300.c
index da2864c94d2c..c3a9eeca3154 100644
--- a/drivers/net/mdio/mdio-realtek-rtl9300.c
+++ b/drivers/net/mdio/mdio-realtek-rtl9300.c@@ -193,6 +193,7 @@ struct otto_emdio_priv { struct regmap *regmap; struct mutex lock; /* protect HW access */ DECLARE_BITMAP(valid_ports, MAX_PORTS); + u16 page[MAX_PORTS]; u8 smi_bus[MAX_PORTS]; u8 smi_addr[MAX_PORTS]; bool smi_bus_is_c45[MAX_SMI_BUSSES];
@@ -337,7 +338,7 @@ static int otto_emdio_9300_read_c22(struct mii_bus *bus, int port, int regnum, u struct otto_emdio_cmd_regs cmd_data = { .c22_data = FIELD_PREP(RTL9300_PHY_CTRL_REG_ADDR, regnum) | FIELD_PREP(RTL9300_PHY_CTRL_PARK_PAGE, 0x1f) | - FIELD_PREP(RTL9300_PHY_CTRL_MAIN_PAGE, RAW_PAGE(priv)), + FIELD_PREP(RTL9300_PHY_CTRL_MAIN_PAGE, priv->page[port]), .io_data = FIELD_PREP(RTL9300_PHY_CTRL_INDATA, port), };
@@ -351,7 +352,7 @@ static int otto_emdio_9300_write_c22(struct mii_bus *bus, int port, int regnum, struct otto_emdio_cmd_regs cmd_data = { .c22_data = FIELD_PREP(RTL9300_PHY_CTRL_REG_ADDR, regnum) | FIELD_PREP(RTL9300_PHY_CTRL_PARK_PAGE, 0x1f) | - FIELD_PREP(RTL9300_PHY_CTRL_MAIN_PAGE, RAW_PAGE(priv)), + FIELD_PREP(RTL9300_PHY_CTRL_MAIN_PAGE, priv->page[port]), .io_data = FIELD_PREP(RTL9300_PHY_CTRL_INDATA, value), .port_mask_low = BIT(port), };
@@ -391,7 +392,7 @@ static int otto_emdio_9310_read_c22(struct mii_bus *bus, int port, int regnum, u struct otto_emdio_cmd_regs cmd_data = { .broadcast = FIELD_PREP(RTL9310_BC_PORT_ID, port), .c22_data = FIELD_PREP(RTL9310_PHY_CTRL_REG_ADDR, regnum) | - FIELD_PREP(RTL9310_PHY_CTRL_MAIN_PAGE, RAW_PAGE(priv)), + FIELD_PREP(RTL9310_PHY_CTRL_MAIN_PAGE, priv->page[port]), }; return otto_emdio_read_cmd(bus, RTL9310_PHY_CTRL_TYPE_C22, &cmd_data,
@@ -403,7 +404,7 @@ static int otto_emdio_9310_write_c22(struct mii_bus *bus, int port, int regnum, struct otto_emdio_priv *priv = otto_emdio_bus_to_priv(bus); struct otto_emdio_cmd_regs cmd_data = { .c22_data = FIELD_PREP(RTL9310_PHY_CTRL_REG_ADDR, regnum) | - FIELD_PREP(RTL9310_PHY_CTRL_MAIN_PAGE, RAW_PAGE(priv)), + FIELD_PREP(RTL9310_PHY_CTRL_MAIN_PAGE, priv->page[port]), .io_data = FIELD_PREP(RTL9310_PHY_CTRL_INDATA, value), .port_mask_high = (u32)(BIT_ULL(port) >> 32), .port_mask_low = (u32)(BIT_ULL(port)),
@@ -442,15 +443,19 @@ static int otto_emdio_9310_write_c45(struct mii_bus *bus, int port, static int otto_emdio_read_c22(struct mii_bus *bus, int phy_id, int regnum) { struct otto_emdio_priv *priv = otto_emdio_bus_to_priv(bus); - int ret, port; + int port, ret = 0; u32 value; port = otto_emdio_phy_to_port(bus, phy_id); if (port < 0) return port; - scoped_guard(mutex, &priv->lock) + scoped_guard(mutex, &priv->lock) { + if (regnum == 31) + return priv->page[port]; + ret = priv->info->read_c22(bus, port, regnum, &value); + } return ret ? ret : value; }
@@ -458,16 +463,23 @@ static int otto_emdio_read_c22(struct mii_bus *bus, int phy_id, int regnum) static int otto_emdio_write_c22(struct mii_bus *bus, int phy_id, int regnum, u16 value) { struct otto_emdio_priv *priv = otto_emdio_bus_to_priv(bus); - int ret, port; + int port; port = otto_emdio_phy_to_port(bus, phy_id); if (port < 0) return port; - scoped_guard(mutex, &priv->lock) - ret = priv->info->write_c22(bus, port, regnum, value); + scoped_guard(mutex, &priv->lock) { + if (regnum == 31) { + if (value >= RAW_PAGE(priv)) + return -EINVAL; - return ret; + priv->page[port] = value; + return 0; + } + + return priv->info->write_c22(bus, port, regnum, value); + } } static int otto_emdio_read_c45(struct mii_bus *bus, int phy_id, int dev_addr, int regnum)
--
2.54.0