ramips: mt7530: use IS_REACHABLE for swconfig code

Commit 224a967ba113 ("ramips: mt7530: compile swconfig code
conditionally") used IS_ENABLED(CONFIG_SWCONFIG) to guard
swconfig-specific code.

When CONFIG_ALL_KMODS=y is selected, kmod-swconfig's KCONFIG
override forces CONFIG_SWCONFIG=m during the kernel config merge.

An explicit CONFIG_SWCONFIG=y is protected from being downgraded by
the kmod override, but an absent/unset symbol is not, so the
override's =m wins instead.

IS_ENABLED() evaluates to 1 both for built-in (=y) and module (=m),
so the swconfig code is still compiled into the built-in mt7530
driver even though register_switch() lives in the external
swconfig.ko module and is not available during vmlinux linking,
resulting in:

  drivers/net/ethernet/ralink/mt7530.c: undefined reference to `register_switch'

Switch to IS_REACHABLE(CONFIG_SWCONFIG) which returns true only when
the symbol is actually reachable from the current compilation unit.
This correctly handles the case where mt7530 is built-in and
swconfig is a module, while still allowing both to be built as
modules. Also update the diagnostic message in the fallback branch,
since it is now also reached when swconfig is built as an
unreachable module, not only when support is absent entirely.

Fixes: 224a967ba113 ("ramips: mt7530: compile swconfig code conditionally")
Signed-off-by: Mieczyslaw Nalewaj <namiltd@yahoo.com>
Link: https://github.com/openwrt/openwrt/pull/24728
Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>

diff --git a/target/linux/ramips/files/drivers/net/ethernet/ralink/mt7530.c b/target/linux/ramips/files/drivers/net/ethernet/ralink/mt7530.c
index 0c546e1dc79f3e6a095cd334262bd4b2ff736412..328e11f20408c335dcd4c9f737a48556060c28f1 100644 (file)
--- a/target/linux/ramips/files/drivers/net/ethernet/ralink/mt7530.c
+++ b/target/linux/ramips/files/drivers/net/ethernet/ralink/mt7530.c
@@ -160,7 +160,7 @@ enum {
        MT7530_ATTR_ENABLE_VLAN,
 };
 
-#if IS_ENABLED(CONFIG_SWCONFIG)
+#if IS_REACHABLE(CONFIG_SWCONFIG)
 struct mt7530_port_entry {
        u16     pvid;
        bool    mirror_rx;
@@ -177,7 +177,7 @@ struct mt7530_vlan_entry {
 struct mt7530_priv {
        void __iomem            *base;
        struct mii_bus          *bus;
-#if IS_ENABLED(CONFIG_SWCONFIG)
+#if IS_REACHABLE(CONFIG_SWCONFIG)
        struct switch_dev       swdev;
 
        u8                      mirror_dest_port;
@@ -188,7 +188,7 @@ struct mt7530_priv {
 #endif /* CONFIG_SWCONFIG */
 };
 
-#if IS_ENABLED(CONFIG_SWCONFIG)
+#if IS_REACHABLE(CONFIG_SWCONFIG)
 struct mt7530_mapping {
        char    *name;
        u16     pvids[MT7530_NUM_PORTS];
@@ -330,7 +330,7 @@ mt7530_w32(struct mt7530_priv *priv, u32 reg, u32 val)
        iowrite32(val, priv->base + reg);
 }
 
-#if IS_ENABLED(CONFIG_SWCONFIG)
+#if IS_REACHABLE(CONFIG_SWCONFIG)
 static void
 mt7530_vtcr(struct mt7530_priv *priv, u32 cmd, u32 val)
 {
@@ -1019,7 +1019,7 @@ mt7530_probe(struct device *dev, void __iomem *base, struct mii_bus *bus, int vl
        bool swconfig_active = false;
        const char *name = bus ? "mt7530" : "mt7620";
        int i;
-#if IS_ENABLED(CONFIG_SWCONFIG)
+#if IS_REACHABLE(CONFIG_SWCONFIG)
        struct switch_dev *swdev;
        struct mt7530_mapping *map;
        int ret;
@@ -1031,7 +1031,7 @@ mt7530_probe(struct device *dev, void __iomem *base, struct mii_bus *bus, int vl
 
        mt7530->base = base;
        mt7530->bus = bus;
-#if IS_ENABLED(CONFIG_SWCONFIG)
+#if IS_REACHABLE(CONFIG_SWCONFIG)
        mt7530->global_vlan_enable = vlan;
 
        swdev = &mt7530->swdev;
@@ -1058,7 +1058,7 @@ mt7530_probe(struct device *dev, void __iomem *base, struct mii_bus *bus, int vl
                dev_info(dev, "swconfig disabled, MAC learning disabled on all ports\n");
        }
 #else
-       dev_info(dev, "swconfig support not built in, MAC learning disabled on all ports\n");
+       dev_info(dev, "swconfig support not reachable, MAC learning disabled on all ports\n");
 #endif /* CONFIG_SWCONFIG */
 
        if (!swconfig_active) {