With some PHYs, when the link goes away, the EMAC reset fails due
to the loss of the RX clock I believe.

The old EMAC driver worked around that using some internal chip-specific
clock force bits that are different on various 44x implementations.

This is an attempt at doing it differently, by avoiding the reset when
there is no link, but forcing loopback mode instead. It seems to work
on my Taishan 440GX based board so far.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: NStefan Roese <sr@denx.de>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

It's a bad idea to call flush_scheduled_work from within a
netdev->stop because the linkwatch will occasionally take the
rtnl lock from a workqueue context, and thus that can deadlock.

This reworks things a bit in that area to avoid the problem.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

... since that sucker is not 32bit-only and on 64bit skb->tail is an
offset, not a pointer.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NRoland Dreier <rolandd@cisco.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Fix an obvious typo in emac_xmit_finish.
Signed-off-by: NValentine Barshak <vbarshak@ru.mvista.com>
Signed-off-by: NJeff Garzik <jeff@garzik.org>

Based on BenH's earlier work, this is a new version of the EMAC driver
for the built-in ethernet found on PowerPC 4xx embedded CPUs.  The
same ASIC is also found in the Axon bridge chip.  This new version is
designed to work in the arch/powerpc tree, using the device tree to
probe the device, rather than the old and ugly arch/ppc OCP layer.

This driver is designed to sit alongside the old driver (that lies in
drivers/net/ibm_emac and this one in drivers/net/ibm_newemac).  The
old driver is left in place to support arch/ppc until arch/ppc itself
reaches its final demise (not too long now, with luck).

This driver still has a number of things that could do with cleaning
up, but I think they can be fixed up after merging.  Specifically:
	- Should be adjusted to properly use the dma mapping API.
Axon needs this.
	- Probe logic needs reworking, in conjuction with the general
probing code for of_platform devices.  The dependencies here between
EMAC, MAL, ZMII etc. make this complicated.  At present, it usually
works, because we initialize and register the sub-drivers before the
EMAC driver itself, and (being in driver code) runs after the devices
themselves have been instantiated from the device tree.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NJeff Garzik <jeff@garzik.org>