[PATCH 6.18 007/277] tg3: replace placeholder MAC address with device property

Greg Kroah-Hartman
2026-04-08T18:28:48Z

From: Paul SAGE <paul.sage@42.fr>

[ Upstream commit e4c00ba7274b613e3ab19e27eb009f0ec2e28379 ]

On some systems (e.g. iMac 20,1 with BCM57766), the tg3 driver reads
a default placeholder mac address (00:10:18:00:00:00) from the
mailbox. The correct value on those systems are stored in the
'local-mac-address' property.

This patch, detect the default value and tries to retrieve
the correct address from the device_get_mac_address
function instead.

The patch has been tested on two different systems:
- iMac 20,1 (BCM57766) model which use the local-mac-address property
- iMac 13,2 (BCM57766) model which can use the mailbox,
NVRAM or MAC control registers

Tested-by: Rishon Jonathan R <mithicalaviator85@gmail.com>

Co-developed-by: Vincent MORVAN <vinc@42.fr>
Signed-off-by: Vincent MORVAN <vinc@42.fr>
Signed-off-by: Paul SAGE <paul.sage@42.fr>
Signed-off-by: Atharva Tiwari <atharvatiwarilinuxdev@gmail.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Link: https://patch.msgid.link/20260314215432.3589-1-atharvatiwarilinuxdev@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/broadcom/tg3.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index 0397a6ebf20f9..a04b5eb02689d 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -17042,6 +17042,13 @@ static int tg3_get_invariants(struct tg3 *tp, const struct pci_device_id *ent)
return err;
}

+static int tg3_is_default_mac_address(u8 *addr)
+{
+ static const u8 default_mac_address[ETH_ALEN] = { 0x00, 0x10, 0x18, 0x00, 0x00, 0x00 };
+
+ return ether_addr_equal(default_mac_address, addr);
+}
+
static int tg3_get_device_address(struct tg3 *tp, u8 *addr)
{
u32 hi, lo, mac_offset;
@@ -17115,6 +17122,10 @@ static int tg3_get_device_address(struct tg3 *tp, u8 *addr)

if (!is_valid_ether_addr(addr))
return -EINVAL;
+
+ if (tg3_is_default_mac_address(addr))
+ return device_get_mac_address(&tp->pdev->dev, addr);
+
return 0;
}

--
2.53.0