[PATCH 5.2 049/162] net: stmmac: manage errors returned by of_get_mac_address()

From: Greg Kroah-Hartman
Date: Tue Aug 27 2019 - 04:11:09 EST

[ Upstream commit 195b2919ccd7ffcaf6b6bbcb39444a53ab8308c7 ]

Commit d01f449c008a ("of_net: add NVMEM support to of_get_mac_address")
added support for reading the MAC address from an nvmem-cell. This
required changing the logic to return an error pointer upon failure.

If stmmac is loaded before the nvmem provider driver then
of_get_mac_address() return an error pointer with -EPROBE_DEFER.

Propagate this error so the stmmac driver will be probed again after the
nvmem provider driver is loaded.
Default to a random generated MAC address in case of any other error,
instead of using the error pointer as MAC address.

Fixes: d01f449c008a ("of_net: add NVMEM support to of_get_mac_address")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
Reviewed-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index 0f0f4b31eb7ec..9b5218a8c15bc 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -385,6 +385,13 @@ stmmac_probe_config_dt(struct platform_device *pdev, const char **mac)
return ERR_PTR(-ENOMEM);

*mac = of_get_mac_address(np);
+ if (IS_ERR(*mac)) {
+ if (PTR_ERR(*mac) == -EPROBE_DEFER)
+ return ERR_CAST(*mac);
+ *mac = NULL;
+ }
plat->interface = of_get_phy_mode(np);

/* Get max speed of operation from device tree */