From 78aa09754d69ba19a55c59f490788ec1c85f41f0 Mon Sep 17 00:00:00 2001 From: Alexander Kochetkov Date: Tue, 19 Dec 2017 14:03:57 +0300 Subject: net: arc_emac: restart stalled EMAC Under certain conditions EMAC stop reception of incoming packets and continuously increment R_MISS register instead of saving data into provided buffer. The commit implement workaround for such situation. Then the stall detected EMAC will be restarted. On device the stall looks like the device lost it's dynamic IP address. ifconfig shows that interface error counter rapidly increments. At the same time on the DHCP server we can see continues DHCP-requests from device. In real network stalls happen really rarely. To make them frequent the broadcast storm[1] should be simulated. For simulation it is necessary to make following connections: 1. connect radxarock to 1st port of switch 2. connect some PC to 2nd port of switch 3. connect two other free ports together using standard ethernet cable, in order to make a switching loop. After that, is necessary to make a broadcast storm. For example, running on PC 'ping' to some IP address triggers ARP-request storm. After some time (~10sec), EMAC on rk3188 will stall. Observed and tested on rk3188 radxarock. [1] https://en.wikipedia.org/wiki/Broadcast_radiation Signed-off-by: Alexander Kochetkov Signed-off-by: David S. Miller --- drivers/net/ethernet/arc/emac.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/net/ethernet/arc/emac.h') diff --git a/drivers/net/ethernet/arc/emac.h b/drivers/net/ethernet/arc/emac.h index 3c63b16d485f..d9efbc8d783b 100644 --- a/drivers/net/ethernet/arc/emac.h +++ b/drivers/net/ethernet/arc/emac.h @@ -159,6 +159,8 @@ struct arc_emac_priv { unsigned int link; unsigned int duplex; unsigned int speed; + + unsigned int rx_missed_errors; }; /** -- cgit v1.2.3