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Miller" , Eric Dumazet , Paolo Abeni , Lad Prabhakar , Romain Gantois , Russell King , Heiko Stuebner , netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-rockchip@lists.infradead.org, Coia Prant Subject: [PATCH net-next] net: stmmac: move XPCS lifetime management to platform drivers Date: Tue, 6 Oct 2026 06:17:49 +0800 Message-ID: <20261005221749.1104430-1-coiaprant@gmail.com> X-Mailer: git-send-email 2.47.3 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The current XPCS creation logic in stmmac_pcs_setup() is problematic for several reasons. First, if a device tree specifies a "pcs-handle" but no select_pcs() callback is provided by the platform driver, the created XPCS cannot be used by phylink for PCS operations. The framework requires select_pcs() to return the PCS to the core, so the pcs-handle property becomes effectively useless for link management without the matching callback. The XPCS is still consulted by stmmac_phylink_setup() and stmmac_init_phy(), which makes the configuration silently half-working rather than clearly broken. Second, and more critically, when a platform driver sets pcs_init() and creates an XPCS inside that callback, the common code afterwards still runs unconditionally and overwrites priv->hw->xpcs with the local xpcs variable, which stays NULL. The platform driver has no way to prevent this override because the common code runs after the platform-specific initialization. After commit 93f84152e4ae ("net: stmmac: clean up stmmac_mac_select_pcs()"), the common code no longer falls back to priv->hw->phylink_pcs if select_pcs() is not set. This change reinforces that each platform must manage its own PCS life cycle explicitly, but the XPCS creation code in stmmac_pcs_setup() was not updated to match this new expectation, leaving a gap where platform drivers have no clean way to take control of XPCS creation. Address all of these issues by simplifying the existing pcs_init() and pcs_exit() dispatch in stmmac_pcs_setup() and stmmac_pcs_clean(). The common stmmac_pcs_setup() now calls plat->pcs_init() if present, and stmmac_pcs_clean() calls plat->pcs_exit() if present, removing the confusing and error-prone XPCS creation logic from the common code. Platforms that do not need an XPCS simply leave the callbacks as NULL and no change in behavior occurs. Platforms that do need an XPCS can now create it with the exact configuration they require, including wrapping it with custom phylink_pcs_ops when necessary. Note that this also removes the generic "pcs-handle" parsing from the common code. A glue that does not set pcs_init() now leaves priv->hw->xpcs as NULL, and "pcs-handle" becomes a no-op for it. No in-tree platform relies on this path: every DTS that pairs a dwmac node with a PCS goes through a glue that sets pcs_init() (Intel, Renesas, RZ/N1, SoCFPGA, Rockchip). The Intel mGbE glue is updated to create its XPCS inside its own pcs_init() implementation, and the renesas-gbeth, rzn1 and socfpga pcs_exit() callbacks now explicitly clear priv->hw->phylink_pcs after destroying the PCS to avoid dangling pointer references. Reviewed-by: Maxime Chevallier Signed-off-by: Coia Prant --- .../net/ethernet/stmicro/stmmac/dwmac-intel.c | 44 +++++++++++++++++-- .../stmicro/stmmac/dwmac-renesas-gbeth.c | 7 ++- .../net/ethernet/stmicro/stmmac/dwmac-rzn1.c | 7 ++- .../ethernet/stmicro/stmmac/dwmac-socfpga.c | 7 ++- .../net/ethernet/stmicro/stmmac/stmmac_mdio.c | 39 +++------------- 5 files changed, 62 insertions(+), 42 deletions(-) diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c index f5f9fa67ecd77..4308dccbf2570 100644 --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c @@ -603,13 +603,47 @@ static void common_default_data(struct plat_stmmacenet_data *plat) plat->mdio_bus_data->needs_reset = true; } +static int intel_mgbe_pcs_init(struct stmmac_priv *priv) +{ + struct fwnode_handle *devnode, *pcsnode; + struct dw_xpcs *xpcs; + int addr; + + devnode = dev_fwnode(priv->device); + + if (fwnode_property_present(devnode, "pcs-handle")) { + pcsnode = fwnode_find_reference(devnode, "pcs-handle", 0); + xpcs = xpcs_create_fwnode(pcsnode); + fwnode_handle_put(pcsnode); + } else { + addr = ffs(priv->plat->mdio_bus_data->pcs_mask) - 1; + xpcs = xpcs_create_mdiodev(priv->mii, addr); + } + + if (IS_ERR(xpcs)) + return PTR_ERR(xpcs); + + xpcs_config_eee_mult_fact(xpcs, priv->plat->mult_fact_100ns); + + priv->hw->xpcs = xpcs; + return 0; +} + +static void intel_mgbe_pcs_exit(struct stmmac_priv *priv) +{ + if (!priv->hw->xpcs) + return; + + xpcs_destroy(priv->hw->xpcs); + priv->hw->xpcs = NULL; +} + static struct phylink_pcs *intel_mgbe_select_pcs(struct stmmac_priv *priv, phy_interface_t interface) { - /* plat->mdio_bus_data->has_xpcs has been set true, so there - * should always be an XPCS. The original code would always - * return this if present. - */ + if (!priv->hw->xpcs) + return NULL; + return xpcs_to_phylink_pcs(priv->hw->xpcs); } @@ -733,6 +767,8 @@ static int intel_mgbe_common_data(struct pci_dev *pdev, plat->phy_interface == PHY_INTERFACE_MODE_1000BASEX) { plat->mdio_bus_data->pcs_mask = BIT_U32(INTEL_MGBE_XPCS_ADDR); plat->default_an_inband = true; + plat->pcs_init = intel_mgbe_pcs_init; + plat->pcs_exit = intel_mgbe_pcs_exit; plat->select_pcs = intel_mgbe_select_pcs; } diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-renesas-gbeth.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-renesas-gbeth.c index 19f34e18bfef2..9af32c26f9c14 100644 --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-renesas-gbeth.c +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-renesas-gbeth.c @@ -81,8 +81,11 @@ static int renesas_gmac_pcs_init(struct stmmac_priv *priv) static void renesas_gmac_pcs_exit(struct stmmac_priv *priv) { - if (priv->hw->phylink_pcs) - miic_destroy(priv->hw->phylink_pcs); + if (!priv->hw->phylink_pcs) + return; + + miic_destroy(priv->hw->phylink_pcs); + priv->hw->phylink_pcs = NULL; } static struct phylink_pcs *renesas_gmac_select_pcs(struct stmmac_priv *priv, diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-rzn1.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-rzn1.c index 13634965bc19a..01df4776edb3f 100644 --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-rzn1.c +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-rzn1.c @@ -35,8 +35,11 @@ static int rzn1_dwmac_pcs_init(struct stmmac_priv *priv) static void rzn1_dwmac_pcs_exit(struct stmmac_priv *priv) { - if (priv->hw->phylink_pcs) - miic_destroy(priv->hw->phylink_pcs); + if (!priv->hw->phylink_pcs) + return; + + miic_destroy(priv->hw->phylink_pcs); + priv->hw->phylink_pcs = NULL; } static struct phylink_pcs *rzn1_dwmac_select_pcs(struct stmmac_priv *priv, diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c index 1d7f0a57d2889..6d4bc1fe8f751 100644 --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c @@ -539,8 +539,11 @@ static int socfpga_dwmac_pcs_init(struct stmmac_priv *priv) static void socfpga_dwmac_pcs_exit(struct stmmac_priv *priv) { - if (priv->hw->phylink_pcs) - lynx_pcs_destroy(priv->hw->phylink_pcs); + if (!priv->hw->phylink_pcs) + return; + + lynx_pcs_destroy(priv->hw->phylink_pcs); + priv->hw->phylink_pcs = NULL; } static struct phylink_pcs *socfpga_dwmac_select_pcs(struct stmmac_priv *priv, diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c index afe98ff5bdcb0..7396b68899c66 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c @@ -426,35 +426,14 @@ int stmmac_mdio_reset(struct mii_bus *bus) int stmmac_pcs_setup(struct net_device *ndev) { struct stmmac_priv *priv = netdev_priv(ndev); - struct fwnode_handle *devnode, *pcsnode; - struct dw_xpcs *xpcs = NULL; - int addr, ret; - - devnode = dev_fwnode(priv->device); - - if (priv->plat->pcs_init) { - ret = priv->plat->pcs_init(priv); - } else if (fwnode_property_present(devnode, "pcs-handle")) { - pcsnode = fwnode_find_reference(devnode, "pcs-handle", 0); - xpcs = xpcs_create_fwnode(pcsnode); - fwnode_handle_put(pcsnode); - ret = PTR_ERR_OR_ZERO(xpcs); - } else if (priv->plat->mdio_bus_data && - priv->plat->mdio_bus_data->pcs_mask) { - addr = ffs(priv->plat->mdio_bus_data->pcs_mask) - 1; - xpcs = xpcs_create_mdiodev(priv->mii, addr); - ret = PTR_ERR_OR_ZERO(xpcs); - } else { + int ret; + + if (!priv->plat->pcs_init) return 0; - } + ret = priv->plat->pcs_init(priv); if (ret) - return dev_err_probe(priv->device, ret, "No xPCS found\n"); - - if (xpcs) - xpcs_config_eee_mult_fact(xpcs, priv->plat->mult_fact_100ns); - - priv->hw->xpcs = xpcs; + return dev_err_probe(priv->device, ret, "Failed to initialize PCS\n"); return 0; } @@ -463,14 +442,10 @@ void stmmac_pcs_clean(struct net_device *ndev) { struct stmmac_priv *priv = netdev_priv(ndev); - if (priv->plat->pcs_exit) - priv->plat->pcs_exit(priv); - - if (!priv->hw->xpcs) + if (!priv->plat->pcs_exit) return; - xpcs_destroy(priv->hw->xpcs); - priv->hw->xpcs = NULL; + priv->plat->pcs_exit(priv); } struct stmmac_clk_rate { -- 2.47.3