r221812 reveals that at least some Broadcom PHYs default to being not only

isolated but also powered down after a reset and while they just work fine
[sic] when both is the case they don't if they are only deisolate but still
powered down. So in order to put PHYs in an overall normal operation mode
for the common case, ensure in mii_phy_reset() that they are not powered
down after a reset. Unfortunately, this only helps in case of BCM5421,
while BCM5709S apparently only work when they remain isolated and powered
down after a reset. So don't call mii_phy_reset() in brgphy_reset() and
implement the reset locally leaving the problematic bits alone. Effectively
this bypasses r221812 for brgphy(4).
Thanks to Justin Hibbits for doing a binary search in order to identify
the problematic commit.

PR:		157405, 158156
Reviewed by:	yongari (mii_phy_reset() part)
Approved by:	re (kib)
MFC after:	3 days

2 files changed, 17 insertions, 5 deletions

diff --git a/sys/dev/mii/brgphy.c b/sys/dev/mii/brgphy.c
index 8e3986a..88090b7 100644
--- a/sys/dev/mii/brgphy.c
+++ b/sys/dev/mii/brgphy.c
@@ -876,10 +876,22 @@ brgphy_reset(struct mii_softc *sc)
 	struct bge_softc *bge_sc = NULL;
 	struct bce_softc *bce_sc = NULL;
 	struct ifnet *ifp;
-	int val;
+	int i, val;
+
+	/*
+	 * Perform a reset.  Note that at least some Broadcom PHYs default to
+	 * being powered down as well as isolated after a reset but don't work
+	 * if one or both of these bits are cleared.  However, they just work
+	 * fine if both bits remain set, so we don't use mii_phy_reset() here.
+	 */
+	PHY_WRITE(sc, BRGPHY_MII_BMCR, BRGPHY_BMCR_RESET);
 
-	/* Perform a standard PHY reset. */
-	mii_phy_reset(sc);
+	/* Wait 100ms for it to complete. */
+	for (i = 0; i < 100; i++) {
+		if ((PHY_READ(sc, BRGPHY_MII_BMCR) & BRGPHY_BMCR_RESET) == 0)
+			break;
+		DELAY(1000);
+	}
 
 	/* Handle any PHY specific procedures following the reset. */
 	switch (sc->mii_mpd_oui) {
diff --git a/sys/dev/mii/mii_physubr.c b/sys/dev/mii/mii_physubr.c
index be66505..8e1476a 100644
--- a/sys/dev/mii/mii_physubr.c
+++ b/sys/dev/mii/mii_physubr.c
@@ -273,8 +273,8 @@ mii_phy_reset(struct mii_softc *sc)
 		DELAY(1000);
 	}
 
-	/* NB: a PHY may default to isolation. */
-	reg &= ~BMCR_ISO;
+	/* NB: a PHY may default to being powered down and/or isolated. */
+	reg &= ~(BMCR_PDOWN | BMCR_ISO);
 	if ((sc->mii_flags & MIIF_NOISOLATE) == 0 &&
 	    ((ife == NULL && sc->mii_inst != 0) ||
 	    (ife != NULL && IFM_INST(ife->ifm_media) != sc->mii_inst)))