Author: yongari
Date: Wed May 23 01:20:25 2012
New Revision: 235816
URL: http://svn.freebsd.org/changeset/base/235816

Log:
  Make IPMI work in the bce driver even when the interface is
  configured down.  Formerly, IPMI communication was lost whenever the
  interface was not up.  The reason was that the BCE_EMAC_MODE
  register was not configured with the correct media settings.  There
  are two parts to the fix.
  
  First, resetting the chip in bce_reset() causes the BCE_EMAC_MODE
  register to be initialized to a default value that does not
  necessarily correspond to the actual media settings.  The fix
  implemented here is a bit of a hack.  Ideally, at the end of
  bce_reset() we would poll the PHY to determine the negotiated media,
  and then we would set the BCE_EMAC_MODE register accordingly.  That
  is difficult, since the PHY is abstracted behind the MII layer and is
  not supposed to be queried directly from the MAC driver.  Instead,
  we read the BCE_EMAC_MODE register at the beginning of bce_reset()
  and then restore its media bits to their original values before
  returning.  If IPMI is up and running, then the link is already
  established and the BCE_EMAC_MODE register is already set appropriately
  when bce_reset() is called.  If IPMI is not running, no harm is
  done by preserving the BCE_EMAC_MODE settings.  The driver will set
  the register properly once the interface is configured up and link
  is established.
  
  Second, bce_miibus_statchg() is sometimes called when the link is
  down.  In that case, the reported media settings are invalid.
  Formerly, the driver used them anyway to setup the BCE_EMAC_MODE
  register.  We now avoid changing any MAC registers unless link is
  active and the reported media settings are valid.
  
  Submitted by: jdp
  Tested by:    jdp
  MFC after:    5 days

Modified:
  head/sys/dev/bce/if_bce.c

Modified: head/sys/dev/bce/if_bce.c
==============================================================================
--- head/sys/dev/bce/if_bce.c   Wed May 23 00:46:19 2012        (r235815)
+++ head/sys/dev/bce/if_bce.c   Wed May 23 01:20:25 2012        (r235816)
@@ -2062,6 +2062,11 @@ bce_miibus_statchg(device_t dev)
                media_status = mii->mii_media_status;
        }
 
+       /* Ignore invalid media status. */
+       if ((media_status & (IFM_ACTIVE | IFM_AVALID)) !=
+           (IFM_ACTIVE | IFM_AVALID))
+               goto bce_miibus_statchg_exit;
+
        val = REG_RD(sc, BCE_EMAC_MODE);
        val &= ~(BCE_EMAC_MODE_PORT | BCE_EMAC_MODE_HALF_DUPLEX |
            BCE_EMAC_MODE_MAC_LOOP | BCE_EMAC_MODE_FORCE_LINK |
@@ -2131,6 +2136,7 @@ bce_miibus_statchg(device_t dev)
 
        /* ToDo: Update watermarks in bce_init_rx_context(). */
 
+bce_miibus_statchg_exit:
        DBEXIT(BCE_VERBOSE_PHY);
 }
 
@@ -4997,14 +5003,25 @@ bce_stop(struct bce_softc *sc)
 static int
 bce_reset(struct bce_softc *sc, u32 reset_code)
 {
-       u32 val;
+       u32 emac_mode_save, val;
        int i, rc = 0;
+       static const u32 emac_mode_mask = BCE_EMAC_MODE_PORT |
+           BCE_EMAC_MODE_HALF_DUPLEX | BCE_EMAC_MODE_25G;
 
        DBENTER(BCE_VERBOSE_RESET);
 
        DBPRINT(sc, BCE_VERBOSE_RESET, "%s(): reset_code = 0x%08X\n",
            __FUNCTION__, reset_code);
 
+       /*
+        * If ASF/IPMI is operational, then the EMAC Mode register already
+        * contains appropriate values for the link settings that have
+        * been auto-negotiated.  Resetting the chip will clobber those
+        * values.  Save the important bits so we can restore them after
+        * the reset.
+        */
+       emac_mode_save = REG_RD(sc, BCE_EMAC_MODE) & emac_mode_mask;
+
        /* Wait for pending PCI transactions to complete. */
        REG_WR(sc, BCE_MISC_ENABLE_CLR_BITS,
            BCE_MISC_ENABLE_CLR_BITS_TX_DMA_ENABLE |
@@ -5094,6 +5111,11 @@ bce_reset(struct bce_softc *sc, u32 rese
        bce_fw_cap_init(sc);
 
 bce_reset_exit:
+       /* Restore EMAC Mode bits needed to keep ASF/IPMI running. */
+       val = REG_RD(sc, BCE_EMAC_MODE);
+       val = (val & ~emac_mode_mask) | emac_mode_save;
+       REG_WR(sc, BCE_EMAC_MODE, val);
+
        DBEXIT(BCE_VERBOSE_RESET);
        return (rc);
 }
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