net: dsa: mxl-gsw1xx: validate chip ID

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>
Link: https://patch.msgid.link/3194d3d3bb0b51f08755d392e1fdf7bb6dc49608.1769916962.git.daniel@makrotopia.org
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/dsa/lantiq/mxl-gsw1xx.c b/drivers/net/dsa/lantiq/mxl-gsw1xx.c
index 61220b5fe5afabed175c53a4f5ea35cee6b35be3..a1104b2f92a92d44def08664f3536377adea2363 100644 (file)
--- a/drivers/net/dsa/lantiq/mxl-gsw1xx.c
+++ b/drivers/net/dsa/lantiq/mxl-gsw1xx.c
@@ -688,7 +688,9 @@ 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);
@@ -736,6 +738,27 @@ 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;
@@ -756,6 +779,8 @@ 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 d1fded56e96782929fd3dd65c156c42f9c1d04e0..caa8f1008587a80f54bc7449719cf45458308edc 100644 (file)
--- 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)