Subject: [PATCH 4.2 27/30] net: phy: fixed_phy: handle link-down case

From: Greg Kroah-Hartman <[email-masked]>
Date: Thu, 1 Oct 2015 11:21:49 +0200

4.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Stas Sergeev <[email-masked]>

[ Upstream 868a4215be9a6d80548ccb74763b883dc99d32a2 in net-next tree,
  will be pushed to Linus very soon. ]

fixed_phy_register() currently hardcodes the fixed PHY link to 1, and
expects to find a "speed" parameter to provide correct information
towards the fixed PHY consumer.

In a subsequent change, where we allow "managed" (e.g: (RS)GMII in-band
status auto-negotiation) fixed PHYs, none of these parameters can be
provided since they will be auto-negotiated, hence, we just provide a
zero-initialized fixed_phy_status to fixed_phy_register() which makes it
fail when we call fixed_phy_update_regs() since status.speed = 0 which
makes us hit the "default" label and error out.

Without this change, we would also see potentially inconsistent
speed/duplex parameters for fixed PHYs when the link is DOWN.

CC: [email-masked]
CC: [email-masked]
Signed-off-by: Stas Sergeev <[email-masked]>
[florian: add more background to why this is correct and desirable]
Signed-off-by: Florian Fainelli <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
Signed-off-by: Greg Kroah-Hartman <[email-masked]>
---
 drivers/net/phy/fixed_phy.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/drivers/net/phy/fixed_phy.c
+++ b/drivers/net/phy/fixed_phy.c
@@ -52,6 +52,10 @@ static int fixed_phy_update_regs(struct
 	u16 lpagb = 0;
 	u16 lpa = 0;
 
+	if (!fp->status.link)
+		goto done;
+	bmsr |= BMSR_LSTATUS | BMSR_ANEGCOMPLETE;
+
 	if (fp->status.duplex) {
 		bmcr |= BMCR_FULLDPLX;
 
@@ -96,15 +100,13 @@ static int fixed_phy_update_regs(struct
 		}
 	}
 
-	if (fp->status.link)
-		bmsr |= BMSR_LSTATUS | BMSR_ANEGCOMPLETE;
-
 	if (fp->status.pause)
 		lpa |= LPA_PAUSE_CAP;
 
 	if (fp->status.asym_pause)
 		lpa |= LPA_PAUSE_ASYM;
 
+done:
 	fp->regs[MII_PHYSID1] = 0;
 	fp->regs[MII_PHYSID2] = 0;