[PATCH] net: phy: marvell10g: report if the PHY fails to boot firmware

[Russell King <rmk+kernel@armlinux.org.uk>]

Some boards do not have the PHY firmware programmed in the 3310's flash,
which leads to the PHY not working as expected.  Warn the user when the
PHY fails to boot the firmware and refuse to initialise.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
I think this patch needs testing with the Marvell 88x2110 PHY before
this can be merged into mainline, but I think it should go into -rc
and be back-ported to stable trees to avoid user frustration. I spent
some time last night debugging one such instance, and the user
afterwards indicated that they'd had the problem for a long time, and
had thought of throwing the hardware out the window!  Clearly not a
good user experience.

 drivers/net/phy/marvell10g.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/net/phy/marvell10g.c b/drivers/net/phy/marvell10g.c
index 100b401b1f4a..754cde873dde 100644
--- a/drivers/net/phy/marvell10g.c
+++ b/drivers/net/phy/marvell10g.c
@@ -31,6 +31,9 @@
 #define MV_PHY_ALASKA_NBT_QUIRK_REV	(MARVELL_PHY_ID_88X3310 | 0xa)
 
 enum {
+	MV_PMA_BOOT		= 0xc050,
+	MV_PMA_BOOT_FATAL	= BIT(0),
+
 	MV_PCS_BASE_T		= 0x0000,
 	MV_PCS_BASE_R		= 0x1000,
 	MV_PCS_1000BASEX	= 0x2000,
@@ -211,6 +214,16 @@ static int mv3310_probe(struct phy_device *phydev)
 	    (phydev->c45_ids.devices_in_package & mmd_mask) != mmd_mask)
 		return -ENODEV;
 
+	ret = phy_read_mmd(phydev, MDIO_MMD_PMAPMD, MV_PMA_BOOT);
+	if (ret < 0)
+		return ret;
+
+	if (ret & MV_PMA_BOOT_FATAL) {
+		dev_warn(&phydev->mdio.dev,
+			 "PHY failed to boot firmware, status=%04x\n", ret);
+		return -ENODEV;
+	}
+
 	priv = devm_kzalloc(&phydev->mdio.dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
-- 
2.7.4