From 9e62bed6e105f2f522e360a024fc93c64c58a207 Mon Sep 17 00:00:00 2001 From: Oleksij Rempel Date: Wed, 24 Jan 2024 13:33:14 +0100 Subject: [PATCH] net: dsa: microchip: implement PHY loopback configuration for KSZ8794 and KSZ8873 Correct the PHY loopback bit handling in the ksz8_w_phy_bmcr and ksz8_r_phy_bmcr functions for KSZ8794 and KSZ8873 variants in the ksz8795 driver. Previously, the code erroneously used Bit 7 of port register 0xD for both chip variants, which is actually for LED configuration. This update ensures the correct registers and bits are used for the PHY loopback feature: - For KSZ8794: Use 0xF / Bit 7. - For KSZ8873: Use 0xD / Bit 0. The lack of loopback support was seen on KSZ8873 system by using "ethtool -t lanX". After this patch, the ethtool selftest will work, but only if port is not part of a bridge. Signed-off-by: Oleksij Rempel Reviewed-by: Vladimir Oltean Acked-by: Arun Ramadoss Link: https://lore.kernel.org/r/20240124123314.734815-4-o.rempel@pengutronix.de Signed-off-by: Jakub Kicinski --- drivers/net/dsa/microchip/ksz8795.c | 76 ++++++++++++++++++++++--- drivers/net/dsa/microchip/ksz8795_reg.h | 1 + 2 files changed, 70 insertions(+), 7 deletions(-) diff --git a/drivers/net/dsa/microchip/ksz8795.c b/drivers/net/dsa/microchip/ksz8795.c index 51e0194453df..50351cef6ca5 100644 --- a/drivers/net/dsa/microchip/ksz8795.c +++ b/drivers/net/dsa/microchip/ksz8795.c @@ -632,6 +632,57 @@ static void ksz8_w_vlan_table(struct ksz_device *dev, u16 vid, u16 vlan) ksz8_w_table(dev, TABLE_VLAN, addr, buf); } +/** + * ksz879x_get_loopback - KSZ879x specific function to get loopback + * configuration status for a specific port + * @dev: Pointer to the device structure + * @port: Port number to query + * @val: Pointer to store the result + * + * This function reads the SMI registers to determine whether loopback mode + * is enabled for a specific port. + * + * Return: 0 on success, error code on failure. + */ +static int ksz879x_get_loopback(struct ksz_device *dev, u16 port, + u16 *val) +{ + u8 stat3; + int ret; + + ret = ksz_pread8(dev, port, REG_PORT_STATUS_3, &stat3); + if (ret) + return ret; + + if (stat3 & PORT_PHY_LOOPBACK) + *val |= BMCR_LOOPBACK; + + return 0; +} + +/** + * ksz879x_set_loopback - KSZ879x specific function to set loopback mode for + * a specific port + * @dev: Pointer to the device structure. + * @port: Port number to modify. + * @val: Value indicating whether to enable or disable loopback mode. + * + * This function translates loopback bit of the BMCR register into the + * corresponding hardware register bit value and writes it to the SMI interface. + * + * Return: 0 on success, error code on failure. + */ +static int ksz879x_set_loopback(struct ksz_device *dev, u16 port, u16 val) +{ + u8 stat3 = 0; + + if (val & BMCR_LOOPBACK) + stat3 |= PORT_PHY_LOOPBACK; + + return ksz_prmw8(dev, port, REG_PORT_STATUS_3, PORT_PHY_LOOPBACK, + stat3); +} + /** * ksz8_r_phy_ctrl - Translates and reads from the SMI interface to a MIIM PHY * Control register (Reg. 31). @@ -731,16 +782,20 @@ static int ksz8_r_phy_bmcr(struct ksz_device *dev, u16 port, u16 *val) if (ret) return ret; - if (restart & PORT_PHY_LOOPBACK) - *val |= BMCR_LOOPBACK; - if (ctrl & PORT_FORCE_100_MBIT) *val |= BMCR_SPEED100; if (ksz_is_ksz88x3(dev)) { + if (restart & KSZ8873_PORT_PHY_LOOPBACK) + *val |= BMCR_LOOPBACK; + if ((ctrl & PORT_AUTO_NEG_ENABLE)) *val |= BMCR_ANENABLE; } else { + ret = ksz879x_get_loopback(dev, port, val); + if (ret) + return ret; + if (!(ctrl & PORT_AUTO_NEG_DISABLE)) *val |= BMCR_ANENABLE; } @@ -1001,8 +1056,7 @@ static int ksz8_w_phy_bmcr(struct ksz_device *dev, u16 port, u16 val) restart = 0; restart_mask = PORT_LED_OFF | PORT_TX_DISABLE | PORT_AUTO_NEG_RESTART | - PORT_POWER_DOWN | PORT_AUTO_MDIX_DISABLE | PORT_FORCE_MDIX | - PORT_PHY_LOOPBACK; + PORT_POWER_DOWN | PORT_AUTO_MDIX_DISABLE | PORT_FORCE_MDIX; if (val & KSZ886X_BMCR_DISABLE_LED) restart |= PORT_LED_OFF; @@ -1022,8 +1076,16 @@ static int ksz8_w_phy_bmcr(struct ksz_device *dev, u16 port, u16 val) if (val & KSZ886X_BMCR_FORCE_MDI) restart |= PORT_FORCE_MDIX; - if (val & BMCR_LOOPBACK) - restart |= PORT_PHY_LOOPBACK; + if (ksz_is_ksz88x3(dev)) { + restart_mask |= KSZ8873_PORT_PHY_LOOPBACK; + + if (val & BMCR_LOOPBACK) + restart |= KSZ8873_PORT_PHY_LOOPBACK; + } else { + ret = ksz879x_set_loopback(dev, port, val); + if (ret) + return ret; + } return ksz_prmw8(dev, port, regs[P_NEG_RESTART_CTRL], restart_mask, restart); diff --git a/drivers/net/dsa/microchip/ksz8795_reg.h b/drivers/net/dsa/microchip/ksz8795_reg.h index beca974e0171..7c9341ef73b0 100644 --- a/drivers/net/dsa/microchip/ksz8795_reg.h +++ b/drivers/net/dsa/microchip/ksz8795_reg.h @@ -265,6 +265,7 @@ #define PORT_AUTO_MDIX_DISABLE BIT(2) #define PORT_FORCE_MDIX BIT(1) #define PORT_MAC_LOOPBACK BIT(0) +#define KSZ8873_PORT_PHY_LOOPBACK BIT(0) #define REG_PORT_1_STATUS_2 0x1E #define REG_PORT_2_STATUS_2 0x2E -- 2.25.1