[PATCH] net: fsl_enetc: fix all interfaces getting named enetc-0 on LS1028A

enetc_bind() names each interface by calling enetc_dev_id(), which for
LS1028A is supposed to return PCI_FUNC(pci_get_devfn(dev)) - the PCI
function number of each port, giving "enetc-0", "enetc-1", "enetc-2"
(and "enetc-6", if enabled).

The guard that selects this path is enetc_is_ls1028a(), which checks
pplat->vendor == PCI_VENDOR_ID_FREESCALE.  However, pplat->vendor is
not yet populated when enetc_bind() runs. It was thought this extra
check would not introduce a functional change, but it did.

The bind sequence in device_bind() calls uclass_bind_device() first,
which invokes pci_uclass_child_post_bind().  That callback tries to
parse the vendor ID from a "pciVVVV,DDDD"-format compatible string via
ofnode_read_pci_vendev(), but the LS1028A ENETC DT nodes carry
"fsl,enetc", not a PCI compatible - so pplat->vendor stays 0.

The actual PCI config-space read that sets pplat->vendor = 0x1957
happens only after device_bind() returns, when the PCI bus enumerator
processes the scanned BDF.  By that point enetc_bind() has already run
and named all three ports "enetc-0".

pci_get_devfn() is not affected by this ordering problem: it reads the
"reg" property of the DT node directly via ofnode_read_pci_addr(), and
is called by the same pci_uclass_child_post_bind() to populate
pplat->devfn before enetc_bind() is invoked.

Remove the enetc_is_ls1028a() guard from enetc_dev_id() and call
pci_get_devfn() unconditionally for the LS1028A path.  This is safe
because enetc_dev_id() is only reached from the ofnode_valid() branch
of enetc_bind(), and the iMX95 case is already handled above by
enetc_dev_id_imx() (which also reads the "reg" property directly).

Fixes: 4eb5ef73a956 ("net: fsl_enetc: Introduce enetc_dev_id()")
Signed-off-by: Vladimir Oltean <[email protected]>
---
 drivers/net/fsl_enetc.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/net/fsl_enetc.c b/drivers/net/fsl_enetc.c
index f393af40e275..0bff1cca4a6e 100644
--- a/drivers/net/fsl_enetc.c
+++ b/drivers/net/fsl_enetc.c
@@ -105,10 +105,8 @@ static int enetc_dev_id(struct udevice *dev)
 {
 	if (enetc_is_imx95(dev))
 		return enetc_dev_id_imx(dev);
-	if (enetc_is_ls1028a(dev))
-		return PCI_FUNC(pci_get_devfn(dev));
 
-	return 0;
+	return PCI_FUNC(pci_get_devfn(dev));
 }
 
 static void enetc_inval_rxbd(struct udevice *dev)
-- 
2.34.1