There are several (long standing) problems about how the status
field of the rx buffer descriptor (rxbd) is currently handled on
the error path:
- too many unnecessary 16bit reads of the two halves of the rxbd
status field (32bit), also resulting in overuse of endianness
convesion macros;
- "bdp->status = RXBD_LARGE" makes no sense, since the "large"
flag is read only (only eTSEC can write it), and trying to clear
the other status bits is also error prone in this context
(most of the rx status bits are read only anyway).

This is fixed with a single 32bit read of the "status" field,
and then the appropriate 16bit shifting is applied to access
the various status bits or the rx frame length. Also corrected
the use of the RXBD_LARGE flag.

Additional fix:
"rx_over_errors" stat is incremented instead of "rx_crc_errors"
in case of RXBD_OVERRUN occurrence.
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use a more common consumer/ producer index design to improve
rx buffer allocation.  Instead of allocating a single new buffer
(skb) on each iteration, bundle the allocation of several rx
buffers at a time.  This also opens the path for further memory
optimizations.

Remove useless check of rxq->rfbptr, since this patch touches
rx pause frame handling code as well.  rxq->rfbptr is always
initialized as part of Rx BD ring init.
Remove redundant (and misleading) 'amount_pull' parameter.
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use device flag IFF_LIVE_ADDR_CHANGE to signal that
the device supports changing the hardware address when
the device is running.
This allows eth_mac_addr() to change the mac address
also when the network device's interface is open.
This capability is required by certain applications,
like bonding mode 6 (Adaptive Load Balancing).
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Handle TxFIFO underrun exceptions outside the fast path.
A controller reset is more reliable in this exceptional
case, as opposed to re-enabling on-the-fly the Tx DMA.

As the controller reset is handled outside the fast path
by the reset_gfar() workqueue handler, the locking
scheme on the Tx path is significantly simplified.
Because the Tx processing (xmit queues and tx napi) is
disabled during controller reset, tstat access from xmit
does not require locking.  So the scope of the txlock on
the processing path is now reduced to num_txbdfree, which
is shared only between process context (xmit) and softirq
(clean_tx_ring).  As a result, the txlock must not guard
against interrupt context, and the spin_lock_irqsave()
from xmit can be replaced by spin_lock_bh().  Likewise,
the locking has been downgraded for clean_tx_ring().
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

of_device_id is always used as const.
(See driver.of_match_table and open firmware functions)
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use of_property_read*() to get arch endian consistent
property values. Do some refactoring in the process.
Signed-off-by: NJingchang Lu <jingchang.lu@freescale.com>
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use conversion macros to correctly access the BE
fields of the Rx and Tx Frame Control Block on LE CPUs.
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use conversion macros to correctly access the BE
fields of the Rx and Tx Buffer Descriptors on LE CPUs.
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

eTSEC of-nodes may have children which are not queue-group nodes. For
example new-style fixed-phy declarations. These where incorrectly
assumed to be additional queue-groups.

Change the search to filter out any nodes which are not queue-groups,
or have been disabled.
Signed-off-by: NTobias Waldekranz <tobias@waldekranz.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 6ce29b0e ("gianfar: Avoid unnecessary reg accesses in adjust_link()")
eliminates unnecessary calls to adjust_link for phy devices which don't support
interrupts and need polling. As part of that work, the 'new_state' local flag,
which was used to reduce logging noise on the console, was eliminated.

Unfortunately, that means that a 'Link is Down' log message will now be
issued continuously if a link is configured as UP, the link state is down,
and the associated phy requires polling. This occurs because priv->oldduplex
is -1 in this case, which always differs from phydev->duplex. In addition,
phydev->speed may also differ from priv->oldspeed.  gfar_update_link_state()
is therefore called each time a phy is polled, even if the link state did not
change.

Cc: Claudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Reviewed-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since commit cd1e6504 ("of/device: Don't register disabled
devices"), the disabled device will not be registered at all. So we
don't need to do the check again in the platform device driver.
Signed-off-by: NKevin Hao <haokexin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The same macros are used for rx as well. So rename it.
Signed-off-by: NJiri Pirko <jiri@resnulli.us>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix the following spare warning:
drivers/net/ethernet/freescale/gianfar.c:3521:60: warning: incorrect type in argument 1 (different address spaces)
drivers/net/ethernet/freescale/gianfar.c:3521:60:    expected unsigned int [noderef] <asn:2>*addr
drivers/net/ethernet/freescale/gianfar.c:3521:60:    got unsigned int [usertype] *rfbptr
drivers/net/ethernet/freescale/gianfar.c:205:16: warning: incorrect type in assignment (different address spaces)
drivers/net/ethernet/freescale/gianfar.c:205:16:    expected unsigned int [usertype] *rfbptr
drivers/net/ethernet/freescale/gianfar.c:205:16:    got unsigned int [noderef] <asn:2>*<noident>
drivers/net/ethernet/freescale/gianfar.c:2918:44: warning: incorrect type in argument 1 (different address spaces)
drivers/net/ethernet/freescale/gianfar.c:2918:44:    expected unsigned int [noderef] <asn:2>*addr
drivers/net/ethernet/freescale/gianfar.c:2918:44:    got unsigned int [usertype] *rfbptr
Signed-off-by: NKevin Hao <haokexin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NKevin Hao <haokexin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We need to use dma_mapping_error() to check the dma address returned
by dma_map_single/page(). Otherwise we would get warning like this:
  WARNING: at lib/dma-debug.c:1140
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.18.0-rc2-next-20141029 #196
  task: c0834300 ti: effe6000 task.ti: c0874000
  NIP: c02b2c98 LR: c02b2c98 CTR: c030abc4
  REGS: effe7d70 TRAP: 0700   Not tainted  (3.18.0-rc2-next-20141029)
  MSR: 00021000 <CE,ME>  CR: 22044022  XER: 20000000

  GPR00: c02b2c98 effe7e20 c0834300 00000098 00021000 00000000 c030b898 00000003
  GPR08: 00000001 00000000 00000001 749eec9d 22044022 1001abe0 00000020 ef278678
  GPR16: ef278670 ef278668 ef278660 070a8040 c087f99c c08cdc60 00029000 c0840d44
  GPR24: c08be6e8 c0840000 effe7e78 ef041340 00000600 ef114e10 00000000 c08be6e0
  NIP [c02b2c98] check_unmap+0x51c/0x9e4
  LR [c02b2c98] check_unmap+0x51c/0x9e4
  Call Trace:
  [effe7e20] [c02b2c98] check_unmap+0x51c/0x9e4 (unreliable)
  [effe7e70] [c02b31d8] debug_dma_unmap_page+0x78/0x8c
  [effe7ed0] [c03d1640] gfar_clean_rx_ring+0x208/0x488
  [effe7f40] [c03d1a9c] gfar_poll_rx_sq+0x3c/0xa8
  [effe7f60] [c04f8714] net_rx_action+0xc0/0x178
  [effe7f90] [c00435a0] __do_softirq+0x100/0x1fc
  [effe7fe0] [c0043958] irq_exit+0xa4/0xc8
  [effe7ff0] [c000d14c] call_do_irq+0x24/0x3c
  [c0875e90] [c00048a0] do_IRQ+0x8c/0xf8
  [c0875eb0] [c000ed10] ret_from_except+0x0/0x18

For TX, we need to unmap the pages which has already been mapped and
free the skb before return.

For RX, move the dma mapping and error check to gfar_new_skb(). We
would reuse the original skb in the rx ring when either allocating
skb failure or dma mapping error.
Signed-off-by: NKevin Hao <haokexin@gmail.com>
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Reviewed-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The hardware can automatically generate pause frames when the number
of free buffers drops under a certain threshold, but in order to do this,
the address of the last free buffer needs to be written to a specific
register for each RX queue.

This has to be done in 'gfar_clean_rx_ring' which is called for each
RX queue. In order not to impact performance, by adding a register write
for each incoming packet, this operation is done only when the PAUSE frame
transmission is enabled.

Whenever the link is readjusted, this capability is turned on or off.
Signed-off-by: NMatei Pavaluca <matei.pavaluca@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Local flow control options needed in order to resolve the negotiation
are incorrectly calculated.

Previously 'mii_advertise_flowctrl' was called to determine the local advertising
options, but these were determined based on FLOW_CTRL_RX/TX flags which are
never set through ethtool.
The patch simply translates from ethtool flow options to mii flow options.
Signed-off-by: NPavaluca Matei <matei.pavaluca@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The phy device supports 802.3x flow control, but the specific flags are not set
in the phy initialisation code. Flow control flags need to be added to the
supported capabilities of the phydev by the driver.

This is needed in order for ethtool to work ('ethtool -A' code checks for these
flags)
Signed-off-by: NPavaluca Matei <matei.pavaluca@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A platform_driver does not need to set an owner, it will be populated by the
driver core.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

For each Rx frame the eTSEC writes its FCS (Frame Check Sequence)
to the Rx buffer.

The eTSEC h/w manual states in the "Receive Buffer Descriptor Field
Descriptions" table:
"Data length is the number of octets written by the eTSEC into this BD's
data buffer if L is cleared (the value is equal to MRBLR), or, if L is
set, the length of the frame including *CRC*, FCB (if RCTRL[PRSDEP > 00),
preamble (if MACCFG2[PreAmRxEn]=1), time stamp (if RCTRL[TS] = 1) and
any padding (RCTRL[PAL])."

Though the FCS bytes are removed by the driver before passing the skb
to the net stack, the Rx buffer size computation does not currently
take into account the FCS bytes (4 bytes).
Because the Rx buffer size is multiple of 512 bytes, leaving out the
FCS is not a problem for the default MTU of 1500, as the Rx buffer size
is 1536 in this case.  However, for custom MTUs, where the difference
between the MTU size and the Rx buffer size is less, this can be a
problem as the computed Rx buffer size won't be enough to accomodate
the FCS for a received frame that is big enough (close to MTU size).
In such case the received frame is considered to be incomplete (L flag
not set in the RxBD status) and silently dropped.

Note that the driver does not currently support S/G on Rx, so it has to
compute its Rx buffer size based on the MTU of the device.
Reported-by: NKristian Otnes <kotnes@cisco.com>
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Replace PPC specific eieio() with arch independent wmb()
for other architectures, i.e. ARM.
The eieio() macro is not defined on ARM and generates
build error.
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use arch independent code to replace the powerpc dependent
spin_event_timeout() from gfar_halt_nodisable().
Added GRS/GTS read accessors to clean-up the implementation
of gfar_halt_nodisable().
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix the 32-bit memory access that is not endian safe,
i.e. not giving the desired byte layout for a LE CPU:
tempval = *((u32 *) (tmpbuf + 4)), where 'char tmpbuf[]'.

Get rid of rendundant local vars (tmpbuf[] and idx) and
forced casts.  Cleanup comments.
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This excludes the PPC specific instructions for PPC based SoC
(MPC85xx family) version identification from ARM builds.
The PPC specific macro mfspr() from asm/reg.h is not defined
by the ARM architecture.
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Include linux/of_address.h for of_iomap() and linux/of_irq.h
for irq_of_parse_and_map().

This wasn't an issue for PPC, because these were implicitly
included from asm/prom.h (via linux/of.h) for PPC builds only.
ARM builds need these includes explicitly.
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The line before the changed if condition is:

	priv->phy_node = of_parse_phandle(np, "phy-handle", 0);

. If this call succeeds priv->phy_node must not be overwritten in the if
block; otherwise the reference to the node returned by of_parse_phandle
is lost. So add a check that the if block isn't executed in this case.

Furthermore in the fixed phy case no reference is aquired for phy_node
resulting in an of_node_put without holding a reference. To fix that,
get a reference on the MAC dt node.

Fixes: be403645 ("gianfar: use the new fixed PHY helpers")
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

of_node_put is a noop when being called with NULL.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Quoting David Miller:
"At the moment you call register_netdev() the device is visible, notifications
are sent to userspace, and userland tools can try to bring the interface up
and see the incorrect link state, before you do the netif_carrier_off().

Said another way, between the register_netdev() and netif_carrier_off() call,
userspace can see the device in an inconsistent state."

So call netif_carrier_off() prior to register_netdev().
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Building with CONFIG_DEBUG_SECTION_MISMATCH enabled, the following
WARNING is occured:

  LD      drivers/net/built-in.o
WARNING: drivers/net/built-in.o(.text+0xcd4c): Section mismatch in
reference from the function gfar_probe() to the function
.init.text:gfar_init_addr_hash_table()
The function gfar_probe() references
the function __init gfar_init_addr_hash_table().
This is often because gfar_probe lacks a __init
annotation or the annotation of gfar_init_addr_hash_table is wrong.
Signed-off-by: NXiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

of_phy_connect_fixed_link() is becoming obsolete, and also required
platform code to register the fixed PHYs at the specified addresses for
those to be usable. Get rid of it and use the new of_phy_is_fixed_link()
plus of_phy_register_fixed_link() helpers to transition over the new
scheme.
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For phy devices that don't issue interrupts upon link
state changes, phylib polls the link state resulting in
repeated calls to adjust_link(), even if the link state
didn't change.  As a result, some mac registers are
repeatedly read and written with the same values, which
is not ok.

To fix this, adjust_link() has been refactored to check
first whether the link state has changed and to take action
only if needed, updating mac registers and local state
variables.  The 'new_state' local flag, set if one of the
link params changed (link, speed or duplex), has been
rendered useless and removed by this refactoring.
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Mostly scripted conversion of the smp_mb__* barriers.
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-55dhyhocezdw1dg7u19hmh1u@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

The P1010 device tree restricts the number of
supported interrupt groups to 1, although the eth
controller can support 2 interrupt groups and the
driver assumes the Multi-Group mode ("fsl,etsec2" model).

So, in this case the assumption that the Multi-Group
mode (MQ_MG_MODE) devices always support 2 interrupt
groups is false.  To fix this, a check for the actual
number of interrupt groups enabled in the board's
device tree has been added in gfar_probe for the
"fsl,etsec2" devices.

Without this fix, P1010 based boards claim support for
2 Tx queues to the net stack but only one is actually
allocated, leading to NULL access in xmit.  This issue
was introduced by enabling Single-Queue polling for
the P1010 devices.
(71ff9e3d gianfar: Use Single-Queue polling for
"fsl,etsec2")

Fixes: 71ff9e3dSigned-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

netpoll can call functions in hard irq context that are ordinarily
called in lesser contexts.  For those functions use dev_kfree_skb_any
and dev_consume_skb_any so skbs are freed safely from hard irq
context.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

priv is not instantiated at gfar_of_init() time, when
parsing the DT for info on supported HW queues.  Before
the netdev can be allocated, the number of supported
queues must be known.  Because the number of supported
queues depends on device type, move the compatibility
checks before netdev allocation.  Local vars are used
to hold the operation mode info before netdev allocation.
This fixes the null accesses for priv->.., in gfar_of_init.
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For the "fsl,etsec2" compatible models the driver currently
supports 8 Tx and Rx DMA rings (aka HW queues).  However, there
are only 2 pairs of Rx/Tx interrupt lines, as these controllers
are integrated in low power SoCs with 2 CPUs at most.  As a result,
there are at most 2 NAPI instances that have to service multiple
Tx and Rx queues for these devices.  This complicates the NAPI
polling routine having to iterate over the mutiple Rx/Tx queues
hooked to the same interrupt lines.  And there's also an overhead
at HW level, as the controller needs to service all the 8 Tx rings
in a round robin manner.  The combined overhead shows up for multi
parallel Tx flows transmitted by the kernel stack, when the driver
usually starts returning NETDEV_TX_BUSY leading to NETDEV WATCHDOG
Tx timeout triggering if the Tx path is congested for too long.

As an alternative, this patch makes the driver support only one
Tx/Rx DMA ring per NAPI instance (per interrupt group or pair
of Tx/Rx interrupt lines) by default.  The simplified single queue
polling routine (gfar_poll_sq) will be the default napi poll routine
for the etsec2 devices too.  Some adjustments needed to be made to
link the Tx/Rx HW queues with each NAPI instance (2 in this case).
The gfar_poll_sq() is already successfully used by older SQ_SG_MODE
(single interrupt group) controllers.
This patch fixes Tx timeout triggering under heavy Tx traffic load
(i.e. iperf -c -P 8) for the "fsl,etsec2" (currently the only
MQ_MG_MODE devices).  There's also a significant memory footprint
reduction by supporting 2 Rx/Tx DMA rings (at most), instead of 8,
for these devices.
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There are some concurrency issues on devices w/ 2 CPUs related
to the handling of Rx and Tx interrupts.  eTSEC has separate
interrupt lines for Rx and Tx but a single imask register
to mask these interrupts and a single NAPI instance to handle
both Rx and Tx work.  As a result, the Rx and Tx ISRs are
identical, both are invoking gfar_schedule_cleanup(), however
both handlers can be entered at the same time when the Rx and
Tx interrupts are taken by different CPUs.  In this case
spurrious interrupts (SPU) show up (in /proc/interrupts)
indicating a concurrency issue.  Also, Tx overruns followed
by Tx timeout have been observed under heavy Tx traffic load.

To address these issues, the schedule cleanup ISR part has
been changed to handle the Rx and Tx interrupts independently.
The patch adds a separate NAPI poll routine for Tx cleanup to
be triggerred independently by the Tx confirmation interrupts
only.  Existing poll functions are modified to handle only
the Rx path processing.  The Tx poll routine does not need a
budget, since Tx processing doesn't consume NAPI budget, and
hence it is registered with minimum NAPI weight.
NAPI scheduling does not require locking since there are
different NAPI instances between the Rx and Tx confirmation
paths now.
So, the patch fixes the occurence of spurrious Rx/Tx interrupts.
Tx overruns also occur less frequently now.
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Programming the interrupt coalescing (IC) registers while
the controller/DMA is on may incur the loss of one Tx
confirmation interrupt, under certain conditions.  This is
a subtle hw race because it does not occur during a burst
of Tx packets.  It has been observed on p2020 devices that,
if just one packet is being xmit'ed, the Tx confirmation
doesn't trigger and BQL evetually blocks the Tx queues,
followed by Tx timeout and an un-responsive device.
This issue was not apparent prior to introducing BQL
support, as a late Tx confirmation was not an issue back then
and the next burst of Tx frames would have triggered the
Tx confirmation/ Tx ring cleanup anyway.

Bottom line, the hw specifications state that the IC registers
should not be programmed while the Rx/Tx blocks (the DMA) are
enabled. Further more, these registers are currently re-written
with the same values on the processing path, over and over again.
To fix this, rewriting the IC registers has been removed from
the processing path (napi poll).  A complete MAC reset procedure
has been implemented for the ethtool -c option instead, to
reliably update these registers while the controller is stopped.
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The device reset procedure, stop_gfar()/startup_gfar(), has
concurrency issues.
"Kernel access of bad area" oopses show up during Tx timeout
device reset or other reset cases (like changing MTU) that
happen while the interface still has traffic. The oopses
happen in start_xmit and clean_tx_ring when accessing tx_queue->
tx_skbuff which is NULL. The race comes from de-allocating the
tx_skbuff while transmission and napi processing are still
active. Though the Tx queues get temoprarily stopped when Tx
timeout occurs, they get re-enabled as a result of Tx congestion
handling inside the napi context (see clean_tx_ring()). Not
disabling the napi during reset is also a bug, because
clean_tx_ring() will try to access tx_skbuff while it is being
de-alloc'ed and re-alloc'ed.

To fix this, stop_gfar() needs to disable napi processing
after stopping the Tx queues. However, in order to prevent
clean_tx_ring() to re-enable the Tx queue before the napi
gets disabled, the device state DOWN has been introduced.
It prevents the Tx congestion management from re-enabling the
de-congested Tx queue while the device is brought down.
An additional locking state, RESETTING, has been introduced
to prevent simultaneous resets or to prevent configuring the
device while it is resetting.
The bogus 'rxlock's (for each Rx queue) have been removed since
their purpose is not justified, as they don't prevent nor are
suited to prevent device reset/reconfig races (such as this one).
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Resetting the device (stop_gfar()/startup_gfar()) should
be fast and to the point, in order to timely recover
from an error condition (like Tx timeout) or during
device reconfig.  The irq free/ request routines are just
redundant here, and they should be part of the device
close/ open routines instead.
Signed-off-by: NClaudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>