From 426f04684b30ced3632b29b41cb5c97dca500dca Mon Sep 17 00:00:00 2001 From: Martin Roth Date: Sun, 24 Jan 2016 00:56:19 +0200 Subject: [PATCH] 82xx: FCC: Fixing a bug causing to FCC port lock-up (second try) This is an additional patch to the one already submitted recently. The previous patch was not complete, and the FCC port lock-up scenario has been reproduced in lab. I had an opportunity to check the current patch in lab and the FCC port lock no longer freezes, while the previous patch still locks-up the FCC port. The current patch fixes a pointer arithmetic bug (second bug in the same line), which leads FCC port lock-up during underrun/collision handling. Within the tx_startup() function in mac-fcc.c, the address of last BD is not calculated correctly. As a result of wrong calculation of the last BD address, the next transmitted BD may be set to an area out of the transmit BD ring. This actually causes to port lock-up and it is not recoverable. Signed-off-by: Martin Roth Signed-off-by: David S. Miller --- drivers/net/ethernet/freescale/fs_enet/mac-fcc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/freescale/fs_enet/mac-fcc.c b/drivers/net/ethernet/freescale/fs_enet/mac-fcc.c index 52e0091b4fb2..1ba359f17ec6 100644 --- a/drivers/net/ethernet/freescale/fs_enet/mac-fcc.c +++ b/drivers/net/ethernet/freescale/fs_enet/mac-fcc.c @@ -552,7 +552,7 @@ static void tx_restart(struct net_device *dev) cbd_t __iomem *prev_bd; cbd_t __iomem *last_tx_bd; - last_tx_bd = fep->tx_bd_base + ((fpi->tx_ring - 1) * sizeof(cbd_t)); + last_tx_bd = fep->tx_bd_base + (fpi->tx_ring - 1); /* get the current bd held in TBPTR and scan back from this point */ recheck_bd = curr_tbptr = (cbd_t __iomem *) -- 2.20.1