commit 93af7aca44f0e82e67bda10a0fb73d383edcc8bd upstream.

On several mv643xx_eth hardware versions, the two 64bit mib counters
for 'good octets received' and 'good octets sent' are actually 32bit
counters, and reading from the upper half of the register has the same
effect as reading from the lower half of the register: an atomic
read-and-clear of the entire 32bit counter value.  This can under heavy
traffic occasionally lead to small numbers being added to the upper
half of the 64bit mib counter even though no 32bit wrap has occured.

Since we poll the mib counters at least every 30 seconds anyway, we
might as well just skip the reads of the upper halves of the hardware
counters without breaking the stats, which this patch does.

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
Cc: stable@kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>

The mv643xx_eth hardware ignores the lower three bits of the buffer
size field in receive descriptors, causing the reception of full-sized
packets to fail at some MTUs.  Fix this by rounding the size of
allocated receive buffers up to a multiple of eight bytes.

While we are at it, add a bit of extra space to each receive buffer so
that we can handle multiple vlan tags on ingress.

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>

When we are low on memory, the assumption that every descriptor in the
receive ring will have an skbuff associated with it does not hold.

rxq_process() was assuming that if the receive descriptor it is working
on is not owned by the hardware, it can safely be processed and handed
to the networking stack.  But a descriptor in the receive ring not being
owned by the hardware can also happen when we are low on memory and did
not manage to refill the receive ring fully.

This patch changes rxq_process()'s bailout condition from "the first
receive descriptor to be processed is owned by the hardware" to "the
first receive descriptor to be processed is owned by the hardware OR
the number of valid receive descriptors in the ring is zero".

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>

Nicolas Pitre noted that mv643xx_eth_poll was incorrectly using
non-IRQ-safe locks while checking whether to wake up the netdevice's
transmit queue.  Convert the locking to *_irq() variants, since we
are running from softirq context where interrupts are enabled.

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>

Commit 12e4ab79cd828563dc090d2117dc8626b344bc8f ("mv643xx_eth: be
more agressive about RX refill") changed the condition for the receive
out-of-memory timer to be scheduled from "the receive ring is empty"
to "the receive ring is not full".

This can lead to a situation where the receive out-of-memory timer is
pending because a previous rxq_refill() didn't manage to refill the
receive ring entirely as a result of being out of memory, and
rxq_refill() is then called again as a side effect of a packet receive
interrupt, and that rxq_refill() call then again does not succeed to
refill the entire receive ring with fresh empty skbuffs because we are
still out of memory, and then tries to call add_timer() on the already
scheduled out-of-memory timer.

This patch fixes this issue by changing the add_timer() call in
rxq_refill() to a mod_timer() call.  If the OOM timer was not already
scheduled, this will behave as before, whereas if it was already
scheduled, this patch will push back its firing time a bit, which is
safe because we've (unsuccessfully) attempted to refill the receive
ring just before we do this.

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>

When a receive interrupt occurs, mv643xx_eth would first process the
receive descriptors and then ACK the receive interrupt, instead of the
other way round.

This would leave a small race window between processing the last
receive descriptor and clearing the receive interrupt status in which
a new packet could come in, which would then 'rot' in the receive
ring until the next receive interrupt would come in.

Fix this by ACKing (clearing) the receive interrupt condition before
processing the receive descriptors.

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>

Although mv643xx_eth has no hardware support for inserting a vlan
tag by twiddling some bits in the TX descriptor, it does support
hardware TX checksumming on packets where the IP header starts {a
limited set of values other than 14} bytes into the packet.

This patch sets mv643xx_eth's ->vlan_features to NETIF_F_SG |
NETIF_F_IP_CSUM, which prevents the stack from checksumming vlan'ed
packets in software, and if vlan tags are present on a transmitted
packet, notifies the hardware of this fact by toggling the right
bits in the TX descriptor.

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>

When there is a link status change (link or phy status interrupt),
print a message notifying the user of the new link status.

Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>