[2/2] net: stmmac: support shared MDIO
Commit Message
From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
When two MACs share the MDIO lines to their respective PHYs, one is
considered the logical "owner" of the bus. The secondary controller must
wait until the MDIO bus is registered before trying to attach to the
PHY.
If the mdio node is not defined for given MAC, try to read the
"snps,shared-mdio" property on its node. If it exists, parse the phandle
and store the result as the MAC's mdio device-tree node.
When registering the MDIO bus: if we know that we share it with another
MAC, lookup the MDIO bus and if it's not up yet, defer probe until it
is.
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c | 8 ++++++++
drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c | 6 ++++++
include/linux/stmmac.h | 1 +
3 files changed, 15 insertions(+)
@@ -543,6 +543,14 @@ int stmmac_mdio_register(struct net_device *ndev)
if (!mdio_bus_data)
return 0;
+ if (priv->plat->flags & STMMAC_FLAG_SHARED_MDIO) {
+ new_bus = of_mdio_find_bus(mdio_node);
+ if (!new_bus)
+ return -EPROBE_DEFER;
+
+ goto bus_register_done;
+ }
+
new_bus = mdiobus_alloc();
if (!new_bus)
return -ENOMEM;
@@ -340,6 +340,12 @@ static int stmmac_dt_phy(struct plat_stmmacenet_data *plat,
}
}
+ if (!plat->mdio_node) {
+ plat->mdio_node = of_parse_phandle(np, "snps,shared-mdio", 0);
+ if (plat->mdio_node)
+ plat->flags |= STMMAC_FLAG_SHARED_MDIO;
+ }
+
if (plat->mdio_node) {
dev_dbg(dev, "Found MDIO subnode\n");
mdio = true;
@@ -218,6 +218,7 @@ struct dwmac4_addrs {
#define STMMAC_FLAG_INT_SNAPSHOT_EN BIT(9)
#define STMMAC_FLAG_RX_CLK_RUNS_IN_LPI BIT(10)
#define STMMAC_FLAG_EN_TX_LPI_CLOCKGATING BIT(11)
+#define STMMAC_FLAG_SHARED_MDIO BIT(12)
struct plat_stmmacenet_data {
int bus_id;