[openwrt/openwrt] realtek: 6.12: harden the mdio bus even more

[LEDE Commits]

robimarko pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/65cf5b74c5c1cfd73e3315228fbac175fab5549c

commit 65cf5b74c5c1cfd73e3315228fbac175fab5549c
Author: Markus Stockhausen <markus.stockhausen at gmx.de>
AuthorDate: Tue Jun 3 10:41:47 2025 -0400

    realtek: 6.12: harden the mdio bus even more
    
    With the follow up EEE patches the mdio bus will run c22 and c45
    accesses during initial scan. Especially when accessing addresses
    beyond the CPU port phy requests might fail in a way that cannot
    be handled gratefully. Do two things
    
    - do not allow access to addresses starting from cpu port
    - set the scan disable bitmask to ports starting from cpu port
    
    Signed-off-by: Markus Stockhausen <markus.stockhausen at gmx.de>
    Link: https://github.com/openwrt/openwrt/pull/18935
    Signed-off-by: Robert Marko <robimarko at gmail.com>
---
 .../files-6.12/drivers/net/ethernet/rtl838x_eth.c      | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.c b/target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.c
index 460038db0f..afeac29d64 100644
--- a/target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.c
+++ b/target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.c
@@ -1651,6 +1651,7 @@ struct rtmdio_bus_priv {
 	u16 family_id;
 	int extaddr;
 	int rawpage;
+	int cpu_port;
 	int page[RTMDIO_MAX_PORT];
 	bool raw[RTMDIO_MAX_PORT];
 	int smi_bus[RTMDIO_MAX_PORT];
@@ -1784,7 +1785,7 @@ static int rtmdio_read_c45(struct mii_bus *bus, int addr, int devnum, int regnum
 	if (priv->extaddr >= 0)
 		addr = priv->extaddr;
 
-	if (addr >= RTMDIO_MAX_PORT)
+	if (addr >= priv->cpu_port)
 		return -ENODEV;
 
 	err = (*priv->read_mmd_phy)(addr, devnum, regnum, &val);
@@ -1801,7 +1802,7 @@ static int rtmdio_83xx_read(struct mii_bus *bus, int addr, int regnum)
 	if (priv->extaddr >= 0)
 		addr = priv->extaddr;
 
-	if (addr >= RTMDIO_MAX_PORT)
+	if (addr >= priv->cpu_port)
 		return -ENODEV;
 
 	if (addr >= 24 && addr <= 27 && priv->id == 0x8380)
@@ -1828,7 +1829,7 @@ static int rtmdio_93xx_read(struct mii_bus *bus, int addr, int regnum)
 	if (priv->extaddr >= 0)
 		addr = priv->extaddr;
 
-	if (addr >= RTMDIO_MAX_PORT)
+	if (addr >= priv->cpu_port)
 		return -ENODEV;
 
 	if (regnum == RTMDIO_PAGE_SELECT && priv->page[addr] != priv->rawpage)
@@ -1858,7 +1859,7 @@ static int rtmdio_write_c45(struct mii_bus *bus, int addr, int devnum, int regnu
 	if (priv->extaddr >= 0)
 		addr = priv->extaddr;
 
-	if (addr >= RTMDIO_MAX_PORT)
+	if (addr >= priv->cpu_port)
 		return -ENODEV;
 
 	err = (*priv->write_mmd_phy)(addr, devnum, regnum, val);
@@ -1880,7 +1881,7 @@ static int rtmdio_83xx_write(struct mii_bus *bus, int addr, int regnum, u16 val)
 	if (priv->extaddr >= 0)
 		addr = priv->extaddr;
 
-	if (addr >= RTMDIO_MAX_PORT)
+	if (addr >= priv->cpu_port)
 		return -ENODEV;
 
 	page = priv->page[addr];
@@ -1919,7 +1920,7 @@ static int rtmdio_93xx_write(struct mii_bus *bus, int addr, int regnum, u16 val)
 	if (priv->extaddr >= 0)
 		addr = priv->extaddr;
 
-	if (addr >= RTMDIO_MAX_PORT)
+	if (addr >= priv->cpu_port)
 		return -ENODEV;
 
 	page = priv->page[addr];
@@ -2227,6 +2228,7 @@ static int rtl838x_mdio_init(struct rtl838x_eth_priv *priv)
 		bus_priv->write_mmd_phy = rtl838x_write_mmd_phy;
 		bus_priv->read_phy = rtl838x_read_phy;
 		bus_priv->write_phy = rtl838x_write_phy;
+		bus_priv->cpu_port = RTL838X_CPU_PORT;
 		bus_priv->rawpage = 0xfff;
 		break;
 	case RTL8390_FAMILY_ID:
@@ -2238,6 +2240,7 @@ static int rtl838x_mdio_init(struct rtl838x_eth_priv *priv)
 		bus_priv->write_mmd_phy = rtl839x_write_mmd_phy;
 		bus_priv->read_phy = rtl839x_read_phy;
 		bus_priv->write_phy = rtl839x_write_phy;
+		bus_priv->cpu_port = RTL839X_CPU_PORT;
 		bus_priv->rawpage = 0x1fff;
 		break;
 	case RTL9300_FAMILY_ID:
@@ -2249,6 +2252,7 @@ static int rtl838x_mdio_init(struct rtl838x_eth_priv *priv)
 		bus_priv->write_mmd_phy = rtl930x_write_mmd_phy;
 		bus_priv->read_phy = rtl930x_read_phy;
 		bus_priv->write_phy = rtl930x_write_phy;
+		bus_priv->cpu_port = RTL930X_CPU_PORT;
 		bus_priv->rawpage = 0xfff;
 		break;
 	case RTL9310_FAMILY_ID:
@@ -2260,12 +2264,14 @@ static int rtl838x_mdio_init(struct rtl838x_eth_priv *priv)
 		bus_priv->write_mmd_phy = rtl931x_write_mmd_phy;
 		bus_priv->read_phy = rtl931x_read_phy;
 		bus_priv->write_phy = rtl931x_write_phy;
+		bus_priv->cpu_port = RTL931X_CPU_PORT;
 		bus_priv->rawpage = 0x1fff;
 		break;
 	}
 	priv->mii_bus->read_c45 = rtmdio_read_c45;
 	priv->mii_bus->write_c45 = rtmdio_write_c45;
 	priv->mii_bus->parent = &priv->pdev->dev;
+	priv->mii_bus->phy_mask = ~(BIT_ULL(bus_priv->cpu_port) - 1ULL);
 
 	for_each_node_by_name(dn, "ethernet-phy") {
 		u32 smi_addr[2];