[PATCH net-next v2 3/3] net: dsa: mxl-gsw1xx: validate chip ID
From: Daniel Golle <daniel@makrotopia.org>
Date: 2026-01-30 00:50:10
Also in:
linux-devicetree, lkml
Subsystem:
lantiq / maxlinear / intel ethernet dsa drivers, networking drivers, networking [dsa], the rest · Maintainers:
Hauke Mehrtens, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Andrew Lunn, Vladimir Oltean, Linus Torvalds
No check for actually present hardware is being performed in the probe function of the mxl-gsw1xx switch driver. So even if the switch isn't present at the configured MDIO bus address the driver wrongly tells the user that a "GSWIP version 0 mod 0" was found, outputting errors about PHY capabilities not matching. Read and validate the chip MANU_ID and PNUM_ID registers and output information while probing, but return an error and abort probing in case the hardware is not actually present. Signed-off-by: Daniel Golle <daniel@makrotopia.org> --- v2: no changes drivers/net/dsa/lantiq/mxl-gsw1xx.c | 27 ++++++++++++++++++++++++++- drivers/net/dsa/lantiq/mxl-gsw1xx.h | 9 +++++++++ 2 files changed, 35 insertions(+), 1 deletion(-)
diff --git a/drivers/net/dsa/lantiq/mxl-gsw1xx.c b/drivers/net/dsa/lantiq/mxl-gsw1xx.c
index df89707dc59e..69858d73245c 100644
--- a/drivers/net/dsa/lantiq/mxl-gsw1xx.c
+++ b/drivers/net/dsa/lantiq/mxl-gsw1xx.c@@ -685,7 +685,9 @@ static int gsw1xx_probe(struct mdio_device *mdiodev) { struct device *dev = &mdiodev->dev; struct gsw1xx_priv *priv; - u32 version; + u32 version, val; + u8 shellver; + u16 pnum; int ret; priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
@@ -733,6 +735,27 @@ static int gsw1xx_probe(struct mdio_device *mdiodev) if (IS_ERR(priv->shell)) return PTR_ERR(priv->shell); + ret = regmap_read(priv->shell, GSW1XX_SHELL_MANU_ID, &val); + if (ret < 0) + return ret; + + /* validate chip ID */ + if (FIELD_GET(GSW1XX_SHELL_MANU_ID_FIX1, val) != 1) + return -ENODEV; + + if (FIELD_GET(GSW1XX_SHELL_MANU_ID_MANID, val) != + GSW1XX_SHELL_MANU_ID_MANID_VAL) + return -ENODEV; + + pnum = FIELD_GET(GSW1XX_SHELL_MANU_ID_PNUML, val); + + ret = regmap_read(priv->shell, GSW1XX_SHELL_PNUM_ID, &val); + if (ret < 0) + return ret; + + pnum |= FIELD_GET(GSW1XX_SHELL_PNUM_ID_PNUMM, val) << 4; + shellver = FIELD_GET(GSW1XX_SHELL_PNUM_ID_VER, val); + ret = gsw1xx_serdes_pcs_init(priv); if (ret < 0) return ret;
@@ -753,6 +776,8 @@ static int gsw1xx_probe(struct mdio_device *mdiodev) if (ret) return ret; + dev_info(dev, "standalone switch part number 0x%x v1.%u\n", pnum, shellver); + dev_set_drvdata(dev, &priv->gswip); return 0;
diff --git a/drivers/net/dsa/lantiq/mxl-gsw1xx.h b/drivers/net/dsa/lantiq/mxl-gsw1xx.h
index d1fded56e967..caa8f1008587 100644
--- a/drivers/net/dsa/lantiq/mxl-gsw1xx.h
+++ b/drivers/net/dsa/lantiq/mxl-gsw1xx.h@@ -110,6 +110,15 @@ #define GSW1XX_SHELL_BASE 0xfa00 #define GSW1XX_SHELL_RST_REQ 0x01 #define GSW1XX_RST_REQ_SGMII_SHELL BIT(5) +#define GSW1XX_SHELL_MANU_ID 0x10 +#define GSW1XX_SHELL_MANU_ID_PNUML GENMASK(15, 12) +#define GSW1XX_SHELL_MANU_ID_MANID GENMASK(11, 1) +#define GSW1XX_SHELL_MANU_ID_MANID_VAL 0x389 +#define GSW1XX_SHELL_MANU_ID_FIX1 BIT(0) +#define GSW1XX_SHELL_PNUM_ID 0x11 +#define GSW1XX_SHELL_PNUM_ID_VER GENMASK(15, 12) +#define GSW1XX_SHELL_PNUM_ID_PNUMM GENMASK(11, 0) + /* RGMII PAD Slew Control Register */ #define GSW1XX_SHELL_RGMII_SLEW_CFG 0x78 #define RGMII_SLEW_CFG_DRV_TXC BIT(2)
--
2.52.0