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[e100 2.5] ICH 10/H Tx hang fix

To: jgarzik@xxxxxxxxx
Subject: [e100 2.5] ICH 10/H Tx hang fix
From: Scott Feldman <scott.feldman@xxxxxxxxx>
Date: Fri, 23 Apr 2004 22:25:41 -0700 (PDT)
Cc: netdev@xxxxxxxxxxx, scott.feldman@xxxxxxxxx
Replyto: "Scott Feldman" <scott.feldman@intel.com>
Sender: netdev-bounce@xxxxxxxxxxx
* Need to carry forward this workaround from old e100 driver to
  avoid a Tx hang on ICH systems linked at 10/Half.  Workaround
  adds a stall before each Tx command queued by issuing a NOP
  command followed by 1us delay.  Yuck!  Otherwise HW locks hard.
  (Probably needed for eepro100 also ;-).

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


--- linux-2.5/drivers/net/e100.c        2004-04-20 15:52:24.000000000 -0700
+++ linux-2.5/drivers/net/e100.c.mod    2004-04-20 15:55:32.000000000 -0700
@@ -287,6 +287,7 @@ enum scb_cmd_hi {
 };

 enum scb_cmd_lo {
+       cuc_nop        = 0x00,
        ruc_start      = 0x01,
        ruc_load_base  = 0x06,
        cuc_start      = 0x10,
@@ -514,10 +515,11 @@ struct nic {
        /* End: frequently used values: keep adjacent for cache effect */

        enum {
-               ich           = (1 << 0),
-               promiscuous   = (1 << 1),
-               multicast_all = (1 << 2),
-               wol_magic     = (1 << 3),
+               ich                = (1 << 0),
+               promiscuous        = (1 << 1),
+               multicast_all      = (1 << 2),
+               wol_magic          = (1 << 3),
+               ich_10h_workaround = (1 << 4),
        } flags                                 ____cacheline_aligned;

        enum mac mac;
@@ -1225,6 +1227,12 @@ static void e100_watchdog(unsigned long
                /* Issue a multicast command to workaround a 557 lock up */
                e100_set_multicast_list(nic->netdev);

+       if(nic->flags & ich && cmd.speed==SPEED_10 && cmd.duplex==DUPLEX_HALF)
+               /* Need SW workaround for ICH[x] 10Mbps/half duplex Tx hang. */
+               nic->flags |= ich_10h_workaround;
+       else
+               nic->flags &= ~ich_10h_workaround;
+
        mod_timer(&nic->watchdog, jiffies + E100_WATCHDOG_PERIOD);
 }

@@ -1244,7 +1252,17 @@ static inline void e100_xmit_prepare(str
 static int e100_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
 {
        struct nic *nic = netdev->priv;
-       int err = e100_exec_cb(nic, skb, e100_xmit_prepare);
+       int err;
+
+       if(nic->flags & ich_10h_workaround) {
+               /* SW workaround for ICH[x] 10Mbps/half duplex Tx hang.
+                  Issue a NOP command followed by a 1us delay before
+                  issuing the Tx command. */
+               e100_exec_cmd(nic, cuc_nop, 0);
+               udelay(1);
+       }
+
+       err = e100_exec_cb(nic, skb, e100_xmit_prepare);

        switch(err) {
        case -ENOSPC:

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