diff options
| -rw-r--r-- | drivers/net/phy/mdio-bcm-unimac.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/drivers/net/phy/mdio-bcm-unimac.c b/drivers/net/phy/mdio-bcm-unimac.c index fc7abc50b4f1..6a52a7f0fa0d 100644 --- a/drivers/net/phy/mdio-bcm-unimac.c +++ b/drivers/net/phy/mdio-bcm-unimac.c @@ -120,6 +120,48 @@ static int unimac_mdio_write(struct mii_bus *bus, int phy_id, return 0; } +/* Workaround for integrated BCM7xxx Gigabit PHYs which have a problem with + * their internal MDIO management controller making them fail to successfully + * be read from or written to for the first transaction. We insert a dummy + * BMSR read here to make sure that phy_get_device() and get_phy_id() can + * correctly read the PHY MII_PHYSID1/2 registers and successfully register a + * PHY device for this peripheral. + * + * Once the PHY driver is registered, we can workaround subsequent reads from + * there (e.g: during system-wide power management). + * + * bus->reset is invoked before mdiobus_scan during mdiobus_register and is + * therefore the right location to stick that workaround. Since we do not want + * to read from non-existing PHYs, we either use bus->phy_mask or do a manual + * Device Tree scan to limit the search area. + */ +static int unimac_mdio_reset(struct mii_bus *bus) +{ + struct device_node *np = bus->dev.of_node; + struct device_node *child; + u32 read_mask = 0; + int addr; + + if (!np) { + read_mask = ~bus->phy_mask; + } else { + for_each_available_child_of_node(np, child) { + addr = of_mdio_parse_addr(&bus->dev, child); + if (addr < 0) + continue; + + read_mask |= 1 << addr; + } + } + + for (addr = 0; addr < PHY_MAX_ADDR; addr++) { + if (read_mask & 1 << addr) + mdiobus_read(bus, addr, MII_BMSR); + } + + return 0; +} + static int unimac_mdio_probe(struct platform_device *pdev) { struct unimac_mdio_priv *priv; @@ -155,6 +197,7 @@ static int unimac_mdio_probe(struct platform_device *pdev) bus->parent = &pdev->dev; bus->read = unimac_mdio_read; bus->write = unimac_mdio_write; + bus->reset = unimac_mdio_reset; snprintf(bus->id, MII_BUS_ID_SIZE, "%s", pdev->name); bus->irq = kcalloc(PHY_MAX_ADDR, sizeof(int), GFP_KERNEL); |