The mv643xx_eth mii bus implementation uses wait_event_timeout() to
wait for SMI completion interrupts.

If wait_event_timeout() would return zero, mv643xx_eth would conclude
that the SMI access timed out, but this is not necessarily true --
wait_event_timeout() can also return zero in the case where the SMI
completion interrupt did happen in time but where it took longer than
the requested timeout for the process performing the SMI access to be
scheduled again.  This would lead to occasional SMI access timeouts
when the system would be under heavy load.

The fix is to ignore the return value of wait_event_timeout(), and
to re-check the SMI done bit after wait_event_timeout() returns to
determine whether or not the SMI access timed out.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>
Signed-off-by: NJeff Garzik <jgarzik@redhat.com>

mv643xx_eth uses ip_hdr() (defined in linux/ip.h), but relied on
another header file to include the needed header file indirectly.
In latest net-next this indirect include chain is gone, so the
driver fails to build.  Include linux/ip.h explicitly to fix this.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch introduces mdiobus_alloc() and mdiobus_free(), and
makes all mdio bus drivers use these functions to allocate their
struct mii_bus'es dynamically.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NAndy Fleming <afleming@freescale.com>

In preparation of giving mii_bus objects a device tree presence of
their own, rename struct mii_bus's ->dev argument to ->parent, since
having a 'struct device *dev' that points to our parent device
conflicts with introducing a 'struct device dev' representing our own
device.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NAndy Fleming <afleming@freescale.com>

This gives a nice increase in the maximum loss-free packet forwarding
rate in routing workloads.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

Switch mv643xx_eth from using drivers/net/mii.c to using phylib.

Since the mv643xx_eth hardware does all the link state handling and
PHY polling, the driver will use phylib in the "Doing it all yourself"
mode described in the phylib documentation.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>
Acked-by: NAndy Fleming <afleming@freescale.com>

If we don't poll the hardware statistics counters at least once every
~34 seconds, overflow might occur without us noticing.  So, set up a
timer to poll the statistics counters at least once every 30 seconds.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

When the IP header doesn't start 14, 18, 22 or 26 bytes into the packet
(which are the only four cases that the hardware can deal with if asked
to do IP checksumming on transmit), invoke the software checksum helper
instead of letting the packet go out with a corrupt checksum inserted
into the packet in the wrong place.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

We have to explicitly tell the hardware to include the pseudo-header
when doing receive checksumming, otherwise hardware checksumming will
fail for every received packet and we'll end up setting CHECKSUM_NONE
on every received packet.

While we're at it, when skb->ip_summed is set to CHECKSUM_UNNECESSARY
on received packets, skb->csum is supposed to be undefined, and thus
there is no need to set it.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

Add support for mv643xx_eth versions that have no transmit bandwidth
control registers at all, such as the ethernet block found in the
Marvell 88F6183 ARM SoC.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

Currently, the receive processing reads ->byte_cnt twice (once to
update interface statistics and once to properly size the data area
of the received skb), but since receive descriptors live in uncached
memory, caching this value in a local variable saves one uncached
access, and increases routing performance a tiny little bit more.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

Since the size of the receive queue is directly related to the data
cache footprint of the driver (between refilling a receive ring entry
with a fresh skb and receiving a packet in that entry, queue_size - 1
other skbs will have been touched), shrink the default receive queue
size to a saner number of entries, as 400 is definite overkill for
almost all workloads.

While we are at it, trim the default transmit queue size a bit as well.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

Get rid of the skb pointer array that we currently use for transmit
reclaim, and replace it with an skb queue, to which skbuffs are appended
when they are passed to the xmit function, and removed from the front
and freed when we do transmit queue reclaim and hit a descriptor with
the 'owned by device' bit clear and 'last descriptor' bit set.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

By moving DMA unmapping during transmit reclaim back under the netif
tx lock, we avoid the situation where we read the DMA address and buffer
length from the descriptor under the lock and then not do anything with
that data after dropping the lock on platforms where the DMA unmapping
routines are all NOPs (which is the case on all ARM platforms that
mv643xx_eth is used on at least).

This saves two uncached reads, which makes a small but measurable
performance difference in routing benchmarks.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

Since our ->hard_start_xmit() method is already called under spinlock
protection (the netif tx queue lock), we can simply make that lock
cover the private transmit state (descriptor ring indexes et al.) as
well, which avoids having to use a private lock to protect that state.

Since this was the last user of the driver-private spinlock, it can
be killed off.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

Move link status handling, transmit reclaim and TX_END handling from
the interrupt handler to the napi poll handler.  This allows switching
->lock over to a non-IRQ-safe lock and removes all explicit interrupt
disabling from the driver.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

As all the infrastructure for multiple transmit queues already exists
in the driver, this patch is entirely trivial.

The individual transmit queues are still serialised by the driver's
per-port private spinlock, but that will disappear (i.e. be replaced
by the per-subqueue ->_xmit_lock) in a subsequent patch.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

Delete a couple of unused and uninteresting interrupt source mask bits:
- The receive resource underrun interrupt sources are uninteresting
  because if we are in out-of-memory mode, we are already dealing with
  the issue, and we don't need the hardware to remind us again that we
  are out of memory.
- The LINK and PHY interrupt sources can be coalesced into one define,
  since we always use them together.
- The transmit resource underrun interrupt source can be disabled since
  we never activate the head descriptor of a paged skb until the
  fragments are all activated, so transmit underrun during a packet
  should never happen.
- The INT_EXT_TX_0 define is never used.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

There is no need to call netif_{stop,wake}_queue() when the link goes
down/up, as the networking already takes care of this internally.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

Currently, there are two different fields in the
mv643xx_eth_platform_data struct that together describe the PHY
address -- one field (phy_addr) has the address of the PHY, but if
that address is zero, a second field (force_phy_addr) needs to be
set to distinguish the actual address zero from a zero due to not
having filled in the PHY address explicitly (which should mean
'use the default PHY address').

If we are a bit smarter about the encoding of the phy_addr field,
we can avoid the need for a second field -- this patch does that.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

Which top-level unit's SMI interface to use should be a property of
the top-level unit, not of the individual ports.  This patch moves the
->shared_smi pointer from the per-port platform data to the global
platform data.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

Simplify receive and transmit queue handling by requiring the set
of queue numbers to be contiguous starting from zero.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

Get rid of the mv643xx_eth-internal MV643XX_ETH_CHECKSUM_OFFLOAD_TX
compile-time option.  Using transmit checksumming is the sane default,
and anyone wanting to disable it should use ethtool(8) instead of
recompiling their kernels.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

By having the receive out-of-memory handling timer schedule the napi
poll handler and then doing oom processing from the napi poll handler,
all code that touches receive state moves to napi context, letting us
get rid of all explicit locking in the receive paths since the only
mutual exclusion we need anymore at that point is protection against
reentering ourselves, which is provided by napi synchronisation.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

Make napi unconditional on the receive side, so that we can get rid
of all the locking and local interrupt disabling in the receive path.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

If the platform code has passed us the IRQ number of the mv643xx_eth
top-level error interrupt, use the error interrupt to wait for SMI
access completion instead of polling the SMI busy bit, since SMI bus
accesses can take up to tens of milliseconds.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

Since commit 81600eea ("mv643xx_eth:
use auto phy polling for configuring (R)(G)MII interface"),
mv643xx_eth no longer does SMI accesses from interrupt context.  The
only other callers that do SMI accesses all do them from process
context, which means we can switch the PHY lock from a spinlock to a
mutex, and get rid of the extra locking in some ethtool methods.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

Get rid of the modulo operations that are currently used for
computing successive TX/RX descriptor ring indexes.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

Using IRQF_SAMPLE_RANDOM for the mv643xx_eth interrupt handler
significantly increases interrupt processing overhead, so get rid
of it.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

When tearing down a DMA mapping for a receive buffer, we should pass
dma_unmap_single() the exact same address that dma_map_single() gave
us when we originally set up the mapping.
Signed-off-by: NLennert Buytenhek <buytenh@marvell.com>

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

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

Commit 12e4ab79 ("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: NLennert 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: NLennert Buytenhek <buytenh@marvell.com>

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