[ethernet] Add MII link status functions from Linux

Signed-off-by: Michael Brown <mcb30@etherboot.org>

src/include/mii.h

@@ -157,4 +157,63 @@ struct mii_if_info {
         void (*mdio_write) (struct net_device *dev, int phy_id, int location, int val);
 };
 
+
+extern int mii_link_ok (struct mii_if_info *mii);
+extern void mii_check_link (struct mii_if_info *mii);
+extern unsigned int mii_check_media (struct mii_if_info *mii,
+                                       unsigned int ok_to_print,
+                                       unsigned int init_media);
+
+
+/**
+ * mii_nway_result
+ * @negotiated: value of MII ANAR and'd with ANLPAR
+ *
+ * Given a set of MII abilities, check each bit and returns the
+ * currently supported media, in the priority order defined by
+ * IEEE 802.3u.  We use LPA_xxx constants but note this is not the
+ * value of LPA solely, as described above.
+ *
+ * The one exception to IEEE 802.3u is that 100baseT4 is placed
+ * between 100T-full and 100T-half.  If your phy does not support
+ * 100T4 this is fine.  If your phy places 100T4 elsewhere in the
+ * priority order, you will need to roll your own function.
+ */
+static inline unsigned int mii_nway_result (unsigned int negotiated)
+{
+        unsigned int ret;
+
+        if (negotiated & LPA_100FULL)
+                ret = LPA_100FULL;
+        else if (negotiated & LPA_100BASE4)
+                ret = LPA_100BASE4;
+        else if (negotiated & LPA_100HALF)
+                ret = LPA_100HALF;
+        else if (negotiated & LPA_10FULL)
+                ret = LPA_10FULL;
+        else
+                ret = LPA_10HALF;
+
+        return ret;
+}
+
+/**
+ * mii_duplex
+ * @duplex_lock: Non-zero if duplex is locked at full
+ * @negotiated: value of MII ANAR and'd with ANLPAR
+ *
+ * A small helper function for a common case.  Returns one
+ * if the media is operating or locked at full duplex, and
+ * returns zero otherwise.
+ */
+static inline unsigned int mii_duplex (unsigned int duplex_lock,
+                                       unsigned int negotiated)
+{
+        if (duplex_lock)
+                return 1;
+        if (mii_nway_result(negotiated) & LPA_DUPLEX)
+                return 1;
+        return 0;
+}
+
 #endif

src/net/mii.c

@@ -0,0 +1,147 @@
+/*
+
+	mii.c: MII interface library
+
+	Ported to gPXE by Daniel Verkamp <daniel@drv.nu>
+	from Linux drivers/net/mii.c
+
+	Maintained by Jeff Garzik <jgarzik@pobox.com>
+	Copyright 2001,2002 Jeff Garzik
+
+	Various code came from myson803.c and other files by
+	Donald Becker.  Copyright:
+
+		Written 1998-2002 by Donald Becker.
+
+		This software may be used and distributed according
+		to the terms of the GNU General Public License (GPL),
+		incorporated herein by reference.  Drivers based on
+		or derived from this code fall under the GPL and must
+		retain the authorship, copyright and license notice.
+		This file is not a complete program and may only be
+		used when the entire operating system is licensed
+		under the GPL.
+
+		The author may be reached as becker@scyld.com, or C/O
+		Scyld Computing Corporation
+		410 Severn Ave., Suite 210
+		Annapolis MD 21403
+
+*/
+
+#include <mii.h>
+
+/**
+ * mii_link_ok - is link status up/ok
+ * @mii: the MII interface
+ *
+ * Returns 1 if the MII reports link status up/ok, 0 otherwise.
+ */
+int
+mii_link_ok ( struct mii_if_info *mii )
+{
+	/* first, a dummy read, needed to latch some MII phys */
+	mii->mdio_read ( mii->dev, mii->phy_id, MII_BMSR );
+	if ( mii->mdio_read ( mii->dev, mii->phy_id, MII_BMSR ) & BMSR_LSTATUS )
+		return 1;
+	return 0;
+}
+
+/**
+ * mii_check_link - check MII link status
+ * @mii: MII interface
+ *
+ * If the link status changed (previous != current), call
+ * netif_carrier_on() if current link status is Up or call
+ * netif_carrier_off() if current link status is Down.
+ */
+void
+mii_check_link ( struct mii_if_info *mii )
+{
+	int cur_link = mii_link_ok ( mii );
+	int prev_link = netdev_link_ok ( mii->dev );
+
+	if ( cur_link && !prev_link )
+		netdev_link_up ( mii->dev );
+	else if (prev_link && !cur_link)
+		netdev_link_down ( mii->dev );
+}
+
+
+/**
+ * mii_check_media - check the MII interface for a duplex change
+ * @mii: the MII interface
+ * @ok_to_print: OK to print link up/down messages
+ * @init_media: OK to save duplex mode in @mii
+ *
+ * Returns 1 if the duplex mode changed, 0 if not.
+ * If the media type is forced, always returns 0.
+ */
+unsigned int
+mii_check_media ( struct mii_if_info *mii,
+                  unsigned int ok_to_print,
+                  unsigned int init_media )
+{
+	unsigned int old_carrier, new_carrier;
+	int advertise, lpa, media, duplex;
+	int lpa2 = 0;
+
+	/* if forced media, go no further */
+	if (mii->force_media)
+		return 0; /* duplex did not change */
+
+	/* check current and old link status */
+	old_carrier = netdev_link_ok ( mii->dev ) ? 1 : 0;
+	new_carrier = (unsigned int) mii_link_ok ( mii );
+
+	/* if carrier state did not change, this is a "bounce",
+	 * just exit as everything is already set correctly
+	 */
+	if ( ( ! init_media ) && ( old_carrier == new_carrier ) )
+		return 0; /* duplex did not change */
+
+	/* no carrier, nothing much to do */
+	if ( ! new_carrier ) {
+		netdev_link_down ( mii->dev );
+		if ( ok_to_print )
+			DBG ( "%s: link down\n", mii->dev->name);
+		return 0; /* duplex did not change */
+	}
+
+	/*
+	 * we have carrier, see who's on the other end
+	 */
+	netdev_link_up ( mii->dev );
+
+	/* get MII advertise and LPA values */
+	if ( ( ! init_media ) && ( mii->advertising ) ) {
+		advertise = mii->advertising;
+	} else {
+		advertise = mii->mdio_read ( mii->dev, mii->phy_id, MII_ADVERTISE );
+		mii->advertising = advertise;
+	}
+	lpa = mii->mdio_read ( mii->dev, mii->phy_id, MII_LPA );
+	if ( mii->supports_gmii )
+		lpa2 = mii->mdio_read ( mii->dev, mii->phy_id, MII_STAT1000 );
+
+	/* figure out media and duplex from advertise and LPA values */
+	media = mii_nway_result ( lpa & advertise );
+	duplex = ( media & ADVERTISE_FULL ) ? 1 : 0;
+	if ( lpa2 & LPA_1000FULL )
+		duplex = 1;
+
+	if ( ok_to_print )
+		DBG ( "%s: link up, %sMbps, %s-duplex, lpa 0x%04X\n",
+		       mii->dev->name,
+		       lpa2 & ( LPA_1000FULL | LPA_1000HALF ) ? "1000" :
+		       media & ( ADVERTISE_100FULL | ADVERTISE_100HALF ) ? "100" : "10",
+		       duplex ? "full" : "half",
+		       lpa);
+
+	if ( ( init_media ) || ( mii->full_duplex != duplex ) ) {
+		mii->full_duplex = duplex;
+		return 1; /* duplex changed */
+	}
+
+	return 0; /* duplex did not change */
+}