Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=279e1dab949d33737557babfe9f74e0b74fbe39a
Commit:     279e1dab949d33737557babfe9f74e0b74fbe39a
Parent:     8cc91677ae027e15654d7d86a735a7ab6f5c2ec1
Author:     Linus Torvalds <[EMAIL PROTECTED]>
AuthorDate: Thu Nov 15 08:44:36 2007 -0800
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Thu Nov 15 08:44:36 2007 -0800

    Revert "skge: fix ram buffer size calculation"
    
    This reverts commit 7fb7ac241162dc51ec0f7644d4a97b2855213c32.
    
    Heikki Orsila reports that it causes a regression:
    
      "Doing
    
        nc host port < /dev/zero
    
       on a sending machine (not skge) to an skge machine that is receiving:
    
        nc -l -p port >/dev/null
    
       with ~60 MiB/s speed, causes the interface go malfunct. A slow
       transfer doesn't cause a problem."
    
    See
    
        http://bugzilla.kernel.org/show_bug.cgi?id=9321
    
    for some more information.
    
    There is a workaround (also reported by Heikki):
    
      "After some fiddling, I noticed that not changing the register write
       order on patch:
    
       +       skge_write32(hw, RB_ADDR(q, RB_END), end);
               skge_write32(hw, RB_ADDR(q, RB_WP), start);
               skge_write32(hw, RB_ADDR(q, RB_RP), start);
       -       skge_write32(hw, RB_ADDR(q, RB_END), end);
    
       fixes the visible effect..  Possibly not the root cause of the
       problem, but changing the order back fixes networking here."
    
    but that has yet to be ack'ed or tested more widely, so the whole
    problem-causing commit gets reverted until this is resolved properly.
    
    Bisected-and-requested-by: Heikki Orsila <[EMAIL PROTECTED]>
    Cc: Stephen Hemminger <[EMAIL PROTECTED]>
    Cc: Jeff Garzik <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
 drivers/net/skge.c |   51 +++++++++++++++++++++++++++------------------------
 1 files changed, 27 insertions(+), 24 deletions(-)

diff --git a/drivers/net/skge.c b/drivers/net/skge.c
index b9961dc..6d62250 100644
--- a/drivers/net/skge.c
+++ b/drivers/net/skge.c
@@ -2512,31 +2512,32 @@ static int skge_ioctl(struct net_device *dev, struct 
ifreq *ifr, int cmd)
        return err;
 }
 
-/* Assign Ram Buffer allocation to queue */
-static void skge_ramset(struct skge_hw *hw, u16 q, u32 start, u32 space)
+static void skge_ramset(struct skge_hw *hw, u16 q, u32 start, size_t len)
 {
        u32 end;
 
-       /* convert from K bytes to qwords used for hw register */
-       start *= 1024/8;
-       space *= 1024/8;
-       end = start + space - 1;
+       start /= 8;
+       len /= 8;
+       end = start + len - 1;
 
        skge_write8(hw, RB_ADDR(q, RB_CTRL), RB_RST_CLR);
        skge_write32(hw, RB_ADDR(q, RB_START), start);
-       skge_write32(hw, RB_ADDR(q, RB_END), end);
        skge_write32(hw, RB_ADDR(q, RB_WP), start);
        skge_write32(hw, RB_ADDR(q, RB_RP), start);
+       skge_write32(hw, RB_ADDR(q, RB_END), end);
 
        if (q == Q_R1 || q == Q_R2) {
-               u32 tp = space - space/4;
-
                /* Set thresholds on receive queue's */
-               skge_write32(hw, RB_ADDR(q, RB_RX_UTPP), tp);
-               skge_write32(hw, RB_ADDR(q, RB_RX_LTPP), space/4);
-       } else if (hw->chip_id != CHIP_ID_GENESIS)
-               /* Genesis Tx Fifo is too small for normal store/forward */
+               skge_write32(hw, RB_ADDR(q, RB_RX_UTPP),
+                            start + (2*len)/3);
+               skge_write32(hw, RB_ADDR(q, RB_RX_LTPP),
+                            start + (len/3));
+       } else {
+               /* Enable store & forward on Tx queue's because
+                * Tx FIFO is only 4K on Genesis and 1K on Yukon
+                */
                skge_write8(hw, RB_ADDR(q, RB_CTRL), RB_ENA_STFWD);
+       }
 
        skge_write8(hw, RB_ADDR(q, RB_CTRL), RB_ENA_OP_MD);
 }
@@ -2564,7 +2565,7 @@ static int skge_up(struct net_device *dev)
        struct skge_port *skge = netdev_priv(dev);
        struct skge_hw *hw = skge->hw;
        int port = skge->port;
-       u32 ramaddr, ramsize, rxspace;
+       u32 chunk, ram_addr;
        size_t rx_size, tx_size;
        int err;
 
@@ -2619,15 +2620,14 @@ static int skge_up(struct net_device *dev)
        spin_unlock_bh(&hw->phy_lock);
 
        /* Configure RAMbuffers */
-       ramsize = (hw->ram_size - hw->ram_offset) / hw->ports;
-       ramaddr = hw->ram_offset + port * ramsize;
-       rxspace = 8 + (2*(ramsize - 16))/3;
-
-       skge_ramset(hw, rxqaddr[port], ramaddr, rxspace);
-       skge_ramset(hw, txqaddr[port], ramaddr + rxspace, ramsize - rxspace);
+       chunk = hw->ram_size / ((hw->ports + 1)*2);
+       ram_addr = hw->ram_offset + 2 * chunk * port;
 
+       skge_ramset(hw, rxqaddr[port], ram_addr, chunk);
        skge_qset(skge, rxqaddr[port], skge->rx_ring.to_clean);
+
        BUG_ON(skge->tx_ring.to_use != skge->tx_ring.to_clean);
+       skge_ramset(hw, txqaddr[port], ram_addr+chunk, chunk);
        skge_qset(skge, txqaddr[port], skge->tx_ring.to_use);
 
        /* Start receiver BMU */
@@ -3591,12 +3591,15 @@ static int skge_reset(struct skge_hw *hw)
        if (hw->chip_id == CHIP_ID_GENESIS) {
                if (t8 == 3) {
                        /* special case: 4 x 64k x 36, offset = 0x80000 */
-                       hw->ram_size = 1024;
-                       hw->ram_offset = 512;
+                       hw->ram_size = 0x100000;
+                       hw->ram_offset = 0x80000;
                } else
                        hw->ram_size = t8 * 512;
-       } else /* Yukon */
-               hw->ram_size = t8 ? t8 * 4 : 128;
+       }
+       else if (t8 == 0)
+               hw->ram_size = 0x20000;
+       else
+               hw->ram_size = t8 * 4096;
 
        hw->intr_mask = IS_HW_ERR;
 
-
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