Rather than re-initialising the entire completion on every mdio access,
use reinit_completion() which only resets the completion count.  This
avoids possible reinitialisation of the contained spinlock and waitqueue
while they may be in use (eg, mid-completion.)

Such an event could occur if there's a long delay in interrupt handling
causing the mdio accessor to time out, then a second access comes in
while the interrupt handler on a different CPU has called complete().
Another scenario where this has been observed is while locking has
been missing at the phy layer, allowing concurrent attempts to access
the MDIO bus.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is no need to use the IS_ERR_VALUE() macro for checking
the return value from pm_runtime_* functions.

Just do a simple negative test instead.

The semantic patch that makes this change is available
in scripts/coccinelle/api/pm_runtime.cocci.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When we transmit a fragmented skb, we may run into a race like the
following scenario (assume txq->cur_tx is next to txq->dirty_tx):
           cpu 0                                          cpu 1
  fec_enet_txq_submit_skb
    reserve a bdp for the first fragment
    fec_enet_txq_submit_frag_skb
       update the bdp for the other fragment
       update txq->cur_tx
                                                   fec_enet_tx_queue
                                                     bdp = fec_enet_get_nextdesc(txq->dirty_tx, fep, queue_id);
                                                     This bdp is the bdp reserved for the first segment. Given
                                                     that this bdp BD_ENET_TX_READY bit is not set and txq->cur_tx
                                                     is already pointed to a bdp beyond this one. We think this is a
                                                     completed bdp and try to reclaim it.
    update the bdp for the first segment
    update txq->cur_tx

So we shouldn't update the txq->cur_tx until all the update to the
bdps used for fragments are performed. Also add the corresponding
memory barrier to guarantee that the update to the bdps, dirty_tx and
cur_tx performed in the proper order.
Signed-off-by: NKevin Hao <haokexin@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The clocks are initially active and thus the device is marked active.
This still keeps the PM refcount at 0, the pm_runtime_put_autosuspend()
call at the end of probe then leaves us with an invalid refcount of -1,
which in turn leads to the device staying in suspended state even though
netdev open had been called.

Fix this by initializing the refcount to be coherent with the initial
device status.

Fixes:
8fff755e (net: fec: Ensure clocks are enabled while using mdio bus)
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Tested-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When a switch is attached to the mdio bus, the mdio bus can be used
while the interface is not open. If the IPG clock is not enabled, MDIO
reads/writes will simply time out.

Add support for runtime PM to control this clock. Enable/disable this
clock using runtime PM, with open()/close() and mdio read()/write()
function triggering runtime PM operations. Since PM is optional, the
IPG clock is enabled at probe and is no longer modified by
fec_enet_clk_enable(), thus if PM is not enabled in the kernel, it is
guaranteed the clock is running when MDIO operations are performed.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Cc: tyler.baker@linaro.org
Cc: fabio.estevam@freescale.com
Cc: shawn.guo@linaro.org
Tested-by: NFabio Estevam <fabio.estevam@freescale.com>
Tested-by: NTyler Baker <tyler.baker@linaro.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This function frees resources and cancels delayed work item that
have been initialized in fec_ptp_init().

Use this to do proper error handling if something goes wrong in
probe function after fec_ptp_init has been called.
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

So it gets freed when the device is going away.
This fixes a DMA memory leak on driver probe() fail and driver
remove().
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit 6c3e921b.

commit 6c3e921b ("net: fec: Ensure clocks are enabled while using mdio
 bus") prevents the kernel to boot on mx6 boards, so let's revert it.
Reported-by: NTyler Baker <tyler.baker@linaro.org>
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When a switch is attached to the mdio bus, the mdio bus can be used
while the interface is not open. If the IPG clock is not enabled, MDIO
reads/writes will simply time out.

Add support for runtime PM to control this clock. Enable/disable this
clock using runtime PM, with open()/close() and mdio read()/write()
function triggering runtime PM operations. Since PM is optional, the
IPG clock is enabled at probe and is no longer modified by
fec_enet_clk_enable(), thus if PM is not enabled in the kernel, it is
guaranteed the clock is running when MDIO operations are performed.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Not all silicon implementations of the Freescale FEC hardware module
have the RACC (Receive Accelerator Function) register, so we should not
be trying to access it on those that don't. Currently none of the ColdFire
based parts with a FEC have it.

Support for RACC was introduced by commit 4c09eed9 ("net: fec: Enable imx6
enet checksum acceleration"). A fix was introduced in commit d1391930
("net: fec: Fix build for MCF5272") that disables its use on the ColdFire
M5272 part, but it doesn't fix the general case of other ColdFire parts.

To fix we create a quirk flag, FEC_QUIRK_HAS_RACC, and check it before
working with the RACC register.
Signed-off-by: NGreg Ungerer <gerg@uclinux.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Below case causes mii bus probe failed:
ifconfig eth0 down -> suspend/resume with Mega/fax mix off -> ifconfig eth0 up

In i.MX6SX/i.MX7D chip, Mega/fast mix off feature is supported that means most of
SOC power will be off including ENET MAC for power saving. Once ENET MAC power
off, all initialized MAC registers reset to default, so in the case, it must
init MAC prior to mii bus probe.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This enables the ethtool's "-d" and "--register-dump"
options for fec devices.
Signed-off-by: NPhilippe Reynes <tremyfr@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

RGMII-ID uses an internal delay within the transmitter or receiver. This
feature is phy specific. The rest of the communication is normal RGMII.

So the fec driver has to check for all RGMII modes, not only
'PHY_INTERFACE_MODE_RGMII'.
Signed-off-by: NMarkus Pargmann <mpa@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The FEC modules used on i.MX28 and newer have a register to tune the MDIO
output hold time that should be at least 10 ns. Up to now this value was not
explicitly set and so resulted in less hold time if the fec clock was
faster than 100 MHz.

This was noticed on an i.MX28 machine that uses an input clock of ~150
Mhz which resulted in unreliable communication with a Marvell switch.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit 2b995f63.

Панов Андрей reported the following regression:

"Commit 2b995f63 in 4.0.0-rc3 introduces a
nasty bug in transmit, corrupting packets.

To reproduce:

$ dd if=/dev/zero of=zeros bs=1M count=20
$ md5sum -b zeros
8f4e33f3dc3e414ff94e5fb6905cba8c *zeros

This checksum is correct.

Copy file "zeros" to another host with NFS, and it gets corrupted, checksum is
changed.
File should be big, small amounts of transmit isn't affected.

I use an i.MX6 Quad board.

If this commit is reverted, all works fine."
Reported-by: NПанов Андрей <rockford@yandex.ru>
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current driver support receive VLAN CTAG HW acceleration feature
(NETIF_F_HW_VLAN_CTAG_RX) through software simulation. There calls the
api .skb_copy_to_linear_data_offset() to skip the VLAN tag, but there
have overlap between the two memory data point range. The patch just fix
the issue.

V2:
Michael Grzeschik suggest to use memmove() instead of skb_copy_to_linear_data_offset().
Reported-by: NMichael Grzeschik <m.grzeschik@pengutronix.de>
Fixes: 1b7bde6d ("net: fec: implement rx_copybreak to improve rx performance")
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When the driver is removed (e.g. using unbind through sysfs), the
clocks get disabled twice, once on fec_enet_close and once on
fec_drv_remove. Since the clocks are enabled only once, this leads
to a warning:

WARNING: CPU: 0 PID: 402 at drivers/clk/clk.c:992 clk_core_disable+0x64/0x68()

Remove the call to fec_enet_clk_enable in fec_drv_remove to balance
the clock enable/disable calls again. This has been introduce by
e8fcfcd5 ("net: fec: optimize the clock management to save power").
Signed-off-by: NStefan Agner <stefan@agner.ch>
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When do suspend/resume stress test, some log shows "rcv is not +last".
The issue is that enet suspend will disable phy clock, phy link down,
after resume back, enet MAC redo initial and ready to tx/rx packet,
but phy still is not ready which is doing auto-negotiation. When phy
link is not up, don't schdule napi soft irq.

[Peter]
It has fixed kernel panic after long time suspend/resume test
with nfs rootfs.

[ 8864.429458] fec 2188000.ethernet eth0: rcv is not +last
[ 8864.434799] fec 2188000.ethernet eth0: rcv is not +last
[ 8864.440088] fec 2188000.ethernet eth0: rcv is not +last
[ 8864.445424] fec 2188000.ethernet eth0: rcv is not +last
[ 8864.450782] fec 2188000.ethernet eth0: rcv is not +last
[ 8864.456111] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[ 8864.464225] pgd = 80004000
[ 8864.466997] [00000000] *pgd=00000000
[ 8864.470627] Internal error: Oops: 17 [#1] SMP ARM
[ 8864.475353] Modules linked in: evbug
[ 8864.479006] CPU: 0 PID: 3 Comm: ksoftirqd/0 Not tainted 4.0.0-rc1-00044-g7a2a1d2 #234
[ 8864.486854] Hardware name: Freescale i.MX6 SoloX (Device Tree)
[ 8864.492709] task: be069380 ti: be07a000 task.ti: be07a000
[ 8864.498137] PC is at memcpy+0x80/0x330
[ 8864.501919] LR is at gro_pull_from_frag0+0x34/0xa8
[ 8864.506735] pc : [<802bb080>]    lr : [<8057c204>]    psr: 00000113
[ 8864.506735] sp : be07bbd4  ip : 00000010  fp : be07bc0c
[ 8864.518235] r10: 0000000e  r9 : 00000000  r8 : 809c7754
[ 8864.523479] r7 : 809c7754  r6 : bb43c040  r5 : bd280cc0  r4 : 00000012
[ 8864.530025] r3 : 00000804  r2 : fffffff2  r1 : 00000000  r0 : bb43b83c
[ 8864.536575] Flags: nzcv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
[ 8864.543904] Control: 10c5387d  Table: bd14c04a  DAC: 00000015
[ 8864.549669] Process ksoftirqd/0 (pid: 3, stack limit = 0xbe07a210)
[ 8864.555869] Stack: (0xbe07bbd4 to 0xbe07c000)
[ 8864.560250] bbc0:                                              bd280cc0 bb43c040 809c7754
[ 8864.568455] bbe0: 809c7754 bb43b83c 00000012 8057c204 00000000 bd280cc0 bd8a0718 00000003
[ 8864.576658] bc00: be07bc5c be07bc10 8057ebf0 8057c1dc 00000000 00000000 8057ecc4 bef59760
[ 8864.584863] bc20: 00000002 bd8a0000 be07bc64 809c7754 00000000 bd8a0718 bd280cc0 bd8a0000
[ 8864.593066] bc40: 00000000 0000001c 00000000 bd8a0000 be07bc74 be07bc60 8057f148 8057eb90
[ 8864.601268] bc60: bf0810a0 00000000 be07bcf4 be07bc78 8044e7b4 8057f12c 00000000 8007df6c
[ 8864.609470] bc80: bd8a0718 00000040 00000000 bd280a80 00000002 00000019 bd8a0600 bd8a1214
[ 8864.617672] bca0: bd8a0690 bf0810a0 00000000 00000000 bd8a1000 00000000 00000027 bd280cc0
[ 8864.625874] bcc0: 80062708 800625cc 000943db bd8a0718 00000001 000d1166 00000040 be7c1ec0
[ 8864.634077] bce0: 0000012c be07bd00 be07bd3c be07bcf8 8057fc98 8044e3ac 809c2ec0 3ddff000
[ 8864.642280] bd00: be07bd00 be07bd00 be07bd08 be07bd08 00000000 00000020 809c608c 00000003
[ 8864.650481] bd20: 809c6080 40000001 809c6088 00200100 be07bd84 be07bd40 8002e690 8057fac8
[ 8864.658684] bd40: be07bd64 be07bd50 00000001 04208040 000d1165 0000000a be07bd84 809c0d7c
[ 8864.666885] bd60: 00000000 809c6af8 00000000 00000001 be008000 00000000 be07bd9c be07bd88
[ 8864.675087] bd80: 8002eb64 8002e564 00000125 809c0d7c be07bdc4 be07bda0 8006f100 8002eaac
[ 8864.683291] bda0: c080e10c be07bde8 809c6c6c c080e100 00000002 00000000 be07bde4 be07bdc8
[ 8864.691492] bdc0: 800087a0 8006f098 806f2934 20000013 ffffffff be07be1c be07be44 be07bde8
[ 8864.699695] bde0: 800133a4 80008784 00000001 00000001 00000000 00000000 be7c1680 00000000
[ 8864.707896] be00: be0cfe00 bd93eb40 00000002 00000000 00000000 be07be44 be07be00 be07be30
[ 8864.716098] be20: 8006278c 806f2934 20000013 ffffffff be069380 be7c1680 be07be7c be07be48
[ 8864.724300] be40: 80049cfc 806f2910 00000001 00000000 80049cb4 00000000 be07be7c be7c1680
[ 8864.732502] be60: be3289c0 be069380 bd23b600 be0cfe00 be07bebc be07be80 806ed614 80049c68
[ 8864.740706] be80: be07a000 0000020a 809c608c 00000003 00000001 8002e858 be07a000 be035740
[ 8864.748907] bea0: 00000000 00000001 809d4598 00000000 be07bed4 be07bec0 806edd0c 806ed440
[ 8864.757110] bec0: be07a000 be07a000 be07bee4 be07bed8 806edd68 806edcf0 be07bef4 be07bee8
[ 8864.765311] bee0: 8002e860 806edd34 be07bf24 be07bef8 800494b0 8002e828 be069380 00000000
[ 8864.773512] bf00: be035780 be035740 8004938c 00000000 00000000 00000000 be07bfac be07bf28
[ 8864.781715] bf20: 80045928 80049398 be07bf44 00000001 00000000 be035740 00000000 00030003
[ 8864.789917] bf40: dead4ead ffffffff ffffffff 80a2716c 80b59b00 00000000 8088c954 be07bf5c
[ 8864.798120] bf60: be07bf5c 00000000 00000000 dead4ead ffffffff ffffffff 80a2716c 00000000
[ 8864.806320] bf80: 00000000 8088c954 be07bf88 be07bf88 be035780 8004584c 00000000 00000000
[ 8864.814523] bfa0: 00000000 be07bfb0 8000ed10 80045858 00000000 00000000 00000000 00000000
[ 8864.822723] bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 8864.830925] bfe0: 00000000 00000000 00000000 00000000 00000013 00000000 5ffbb5f7 f9fcf5e7
[ 8864.839115] Backtrace:
[ 8864.841631] [<8057c1d0>] (gro_pull_from_frag0) from [<8057ebf0>] (dev_gro_receive+0x6c/0x3f8)
[ 8864.850173]  r6:00000003 r5:bd8a0718 r4:bd280cc0 r3:00000000
[ 8864.855958] [<8057eb84>] (dev_gro_receive) from [<8057f148>] (napi_gro_receive+0x28/0xac)
[ 8864.864152]  r10:bd8a0000 r9:00000000 r8:0000001c r7:00000000 r6:bd8a0000 r5:bd280cc0
[ 8864.872115]  r4:bd8a0718
[ 8864.874713] [<8057f120>] (napi_gro_receive) from [<8044e7b4>] (fec_enet_rx_napi+0x414/0xc74)
[ 8864.883167]  r5:00000000 r4:bf0810a0
[ 8864.886823] [<8044e3a0>] (fec_enet_rx_napi) from [<8057fc98>] (net_rx_action+0x1dc/0x2ec)
[ 8864.895016]  r10:be07bd00 r9:0000012c r8:be7c1ec0 r7:00000040 r6:000d1166 r5:00000001
[ 8864.902982]  r4:bd8a0718
[ 8864.905570] [<8057fabc>] (net_rx_action) from [<8002e690>] (__do_softirq+0x138/0x2c4)
[ 8864.913417]  r10:00200100 r9:809c6088 r8:40000001 r7:809c6080 r6:00000003 r5:809c608c
[ 8864.921382]  r4:00000020
[ 8864.923966] [<8002e558>] (__do_softirq) from [<8002eb64>] (irq_exit+0xc4/0x138)
[ 8864.931289]  r10:00000000 r9:be008000 r8:00000001 r7:00000000 r6:809c6af8 r5:00000000
[ 8864.939252]  r4:809c0d7c
[ 8864.941841] [<8002eaa0>] (irq_exit) from [<8006f100>] (__handle_domain_irq+0x74/0xe8)
[ 8864.949688]  r4:809c0d7c r3:00000125
[ 8864.953342] [<8006f08c>] (__handle_domain_irq) from [<800087a0>] (gic_handle_irq+0x28/0x68)
[ 8864.961707]  r9:00000000 r8:00000002 r7:c080e100 r6:809c6c6c r5:be07bde8 r4:c080e10c
[ 8864.969597] [<80008778>] (gic_handle_irq) from [<800133a4>] (__irq_svc+0x44/0x5c)
[ 8864.977097] Exception stack(0xbe07bde8 to 0xbe07be30)
[ 8864.982173] bde0:                   00000001 00000001 00000000 00000000 be7c1680 00000000
[ 8864.990377] be00: be0cfe00 bd93eb40 00000002 00000000 00000000 be07be44 be07be00 be07be30
[ 8864.998573] be20: 8006278c 806f2934 20000013 ffffffff
[ 8865.003638]  r7:be07be1c r6:ffffffff r5:20000013 r4:806f2934
[ 8865.009447] [<806f2904>] (_raw_spin_unlock_irq) from [<80049cfc>] (finish_task_switch+0xa0/0x160)
[ 8865.018334]  r4:be7c1680 r3:be069380
[ 8865.021993] [<80049c5c>] (finish_task_switch) from [<806ed614>] (__schedule+0x1e0/0x5dc)
[ 8865.030098]  r8:be0cfe00 r7:bd23b600 r6:be069380 r5:be3289c0 r4:be7c1680
[ 8865.036942] [<806ed434>] (__schedule) from [<806edd0c>] (preempt_schedule_common+0x28/0x44)
[ 8865.045307]  r9:00000000 r8:809d4598 r7:00000001 r6:00000000 r5:be035740 r4:be07a000
[ 8865.053197] [<806edce4>] (preempt_schedule_common) from [<806edd68>] (_cond_resched+0x40/0x48)
[ 8865.061822]  r4:be07a000 r3:be07a000
[ 8865.065472] [<806edd28>] (_cond_resched) from [<8002e860>] (run_ksoftirqd+0x44/0x64)
[ 8865.073252] [<8002e81c>] (run_ksoftirqd) from [<800494b0>] (smpboot_thread_fn+0x124/0x190)
[ 8865.081550] [<8004938c>] (smpboot_thread_fn) from [<80045928>] (kthread+0xdc/0xf8)
[ 8865.089133]  r10:00000000 r9:00000000 r8:00000000 r7:8004938c r6:be035740 r5:be035780
[ 8865.097097]  r4:00000000 r3:be069380
[ 8865.100752] [<8004584c>] (kthread) from [<8000ed10>] (ret_from_fork+0x14/0x24)
[ 8865.107990]  r7:00000000 r6:00000000 r5:8004584c r4:be035780
[ 8865.113767] Code: e320f000 e4913004 e4914004 e4915004 (e4916004)
[ 8865.120006] ---[ end trace b0a4c6bd499288ca ]---
[ 8865.124697] Kernel panic - not syncing: Fatal exception in interrupt
[ 8865.131084] ---[ end Kernel panic - not syncing: Fatal exception in interrupt

Cc: [v3.19+] stable@vger.kernel.org
Tested-by: NPeter Chen <peter.chen@freescale.com>
Signed-off-by: NPeter Chen <peter.chen@freescale.com>
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The kfree() function tests whether its argument is NULL and then
returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Enable kernel config "CONFIG_HAVE_DMA_API_DEBUG", FEC have kernel warning:
[    6.650444] fec 2188000.ethernet: DMA-API: device driver tries to free DMA memory it has not allocated
[    6.664289] Modules linked in:
[    6.667378] CPU: 0 PID: 3 Comm: ksoftirqd/0 Not tainted 3.19.0-rc4-00688-g88340160-dirty #150
[    6.675841] Hardware name: Freescale i.MX6 SoloX (Device Tree)
[    6.681698] Backtrace:
[    6.684189] [<80011e3c>] (dump_backtrace) from [<80011fdc>] (show_stack+0x18/0x1c)
[    6.691789]  r6:80890154 r5:00000000 r4:00000000 r3:00000000
[    6.697533] [<80011fc4>] (show_stack) from [<806d2d88>] (dump_stack+0x80/0x9c)
[    6.704799] [<806d2d08>] (dump_stack) from [<8002a4e4>] (warn_slowpath_common+0x7c/0xb4)
[    6.712917]  r5:00000445 r4:00000000
[    6.716544] [<8002a468>] (warn_slowpath_common) from [<8002a5c0>] (warn_slowpath_fmt+0x38/0x40)
[    6.725265]  r8:809a2ee8 r7:00000000 r6:00000000 r5:00000000 r4:00000042
[    6.732087] [<8002a58c>] (warn_slowpath_fmt) from [<802d6268>] (check_unmap+0x86c/0x98c)
[    6.740202]  r3:808c79bc r2:8089060c
[    6.743826] [<802d59fc>] (check_unmap) from [<802d65e4>] (debug_dma_unmap_page+0x80/0x88)
[    6.752029]  r10:00000000 r9:00000000 r8:00000000 r7:00000001 r6:be12a410 r5:00000000
[    6.759967]  r4:00000042
[    6.762538] [<802d6564>] (debug_dma_unmap_page) from [<80440248>] (fec_enet_rx_napi+0x7ec/0xb9c)
[    6.771345]  r7:00000400 r6:be3e4000 r5:bf08fa20 r4:be036000
[    6.777094] [<8043fa5c>] (fec_enet_rx_napi) from [<8056ae24>] (net_rx_action+0x134/0x324)
[    6.785297]  r10:be089e60 r9:80998180 r8:ffff8d68 r7:0000012c r6:00000040 r5:00000001
[    6.793239]  r4:be036718
[    6.795801] [<8056acf0>] (net_rx_action) from [<8002db24>] (__do_softirq+0x138/0x2d0)
[    6.803655]  r10:00000003 r9:00000003 r8:80996378 r7:8099c080 r6:00000100 r5:8099c08c
[    6.811593]  r4:00000000
[    6.814157] [<8002d9ec>] (__do_softirq) from [<8002dd00>] (run_ksoftirqd+0x44/0x5c)
[    6.821836]  r10:00000000 r9:00000000 r8:809b133c r7:00000000 r6:00000001 r5:00000000
[    6.829775]  r4:be027e80
[    6.832346] [<8002dcbc>] (run_ksoftirqd) from [<80048290>] (smpboot_thread_fn+0x154/0x1c4)
[    6.840649] [<8004813c>] (smpboot_thread_fn) from [<80044780>] (kthread+0xdc/0xf8)
[    6.848224]  r10:00000000 r8:00000000 r7:8004813c r6:be027e80 r5:be027ec0 r4:00000000
[    6.856179] [<800446a4>] (kthread) from [<8000ebc8>] (ret_from_fork+0x14/0x2c)
[    6.863425]  r7:00000000 r6:00000000 r5:800446a4 r4:be027ec0
[    6.869156] ---[ end trace 861cf914d2461a8b ]---

There have one bug in .fec_enet_tx_queue() function to unmap the DMA memory:
For SG or TSO, get one buffer descriptor and then unmap the related DMA memory, and then
get the next buffer descriptor, loop to while() to check "TX_READY". If "TX_READY" bit
still __IS__ existed in the BD (The next fraglist or next TSO packet is not transmited
complitely), exit the current clean work. When the next work is triggered, it still repeat
above step with the same BD. The potential issue is that unmap the same DMA memory for
multiple times.

The patch fix the clean work for SG and TSO packet.
Reported-by: NAnand Moon <moon.linux@yahoo.com>
Reported-by: NChristian Gmeiner <christian.gmeiner@gmail.com>
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

On i.MX28, the MDIO bus is shared between the two FEC instances.
The driver makes sure that the second FEC uses the MDIO bus of the
first FEC. This is done conditionally if FEC_QUIRK_ENET_MAC is set.
However, in newer designs, such as Vybrid or i.MX6SX, each FEC MAC
has its own MDIO bus. Simply removing the quirk FEC_QUIRK_ENET_MAC
is not an option since other logic, triggered by this quirk, is
still needed.

Furthermore, there are board designs which use the same MDIO bus
for both PHY's even though the second bus would be available on the
SoC side. Such layout are popular since it saves pins on SoC side.
Due to the above quirk, those boards currently do work fine. The
boards in the mainline tree with such a layout are:
- Freescale Vybrid Tower with TWR-SER2 (vf610-twr.dts)
- Freescale i.MX6 SoloX SDB Board (imx6sx-sdb.dts)

This patch adds a new quirk FEC_QUIRK_SINGLE_MDIO for i.MX28, which
makes sure that the MDIO bus of the first FEC is used in any case.

However, the boards above do have a SoC with a MDIO bus for each FEC
instance. But the PHY's are not connected in a 1:1 configuration. A
proper device tree description is needed to allow the driver to
figure out where to find its PHY. This patch fixes that shortcoming
by adding a MDIO bus child node to the first FEC instance, along
with the two PHY's on that bus, and making use of the phy-handle
property to add a reference to the PHY's.
Acked-by: NSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NStefan Agner <stefan@agner.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch initialises the fep->netdev pointer. This pointer was not
initialised at all, but is used in fec_enet_timeout_work and in some
error paths.
Signed-off-by: NHubert Feurstein <h.feurstein@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Support for Wake-on-LAN using Magic Packet. ENET IP supports sleep mode
in low power status, when system enter suspend status, Magic packet can
wake up system even if all SOC clocks are gate. The patch doing below things:
- flagging the device as a wakeup source for the system, as well as
  its Wake-on-LAN interrupt
- prepare the hardware for entering WoL mode
- add standard ethtool WOL interface
- enable the ENET interrupt to wake us

Tested on i.MX6q/dl sabresd, sabreauto boards, i.MX6SX arm2 boards.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Do camera capture test on i.MX6q sabresd board, and save the capture data to
nfs rootfs. The command is:
gst-launch-1.0 -e imxv4l2src device=/dev/video1 num-buffers=2592000 ! tee name=t !
queue ! imxv4l2sink sync=false t. ! queue ! vpuenc ! queue ! mux. pulsesrc num-buffers=3720937
blocksize=4096 ! 'audio/x-raw, rate=44100, channels=2' ! queue ! imxmp3enc ! mpegaudioparse !
queue ! mux. qtmux name=mux ! filesink location=video_recording_long.mov

After about 10 hours running, there have net watchdog timeout kernel dump:
...
WARNING: CPU: 0 PID: 0 at net/sched/sch_generic.c:264 dev_watchdog+0x2b4/0x2d8()
NETDEV WATCHDOG: eth0 (fec): transmit queue 0 timed out
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.14.24-01051-gdb840b7 #440
[<80014e6c>] (unwind_backtrace) from [<800118ac>] (show_stack+0x10/0x14)
[<800118ac>] (show_stack) from [<806ae3f0>] (dump_stack+0x78/0xc0)
[<806ae3f0>] (dump_stack) from [<8002b504>] (warn_slowpath_common+0x68/0x8c)
[<8002b504>] (warn_slowpath_common) from [<8002b558>] (warn_slowpath_fmt+0x30/0x40)
[<8002b558>] (warn_slowpath_fmt) from [<8055e0d4>] (dev_watchdog+0x2b4/0x2d8)
[<8055e0d4>] (dev_watchdog) from [<800352d8>] (call_timer_fn.isra.33+0x24/0x8c)
[<800352d8>] (call_timer_fn.isra.33) from [<800354c4>] (run_timer_softirq+0x184/0x220)
[<800354c4>] (run_timer_softirq) from [<8002f420>] (__do_softirq+0xc0/0x22c)
[<8002f420>] (__do_softirq) from [<8002f804>] (irq_exit+0xa8/0xf4)
[<8002f804>] (irq_exit) from [<8000ee5c>] (handle_IRQ+0x54/0xb4)
[<8000ee5c>] (handle_IRQ) from [<80008598>] (gic_handle_irq+0x28/0x5c)
[<80008598>] (gic_handle_irq) from [<800123c0>] (__irq_svc+0x40/0x74)
Exception stack(0x80d27f18 to 0x80d27f60)
7f00:                                                       80d27f60 0000014c
7f20: 8858c60e 0000004d 884e4540 0000004d ab7250d0 80d34348 00000000 00000000
7f40: 00000001 00000000 00000017 80d27f60 800702a4 80476e6c 600f0013 ffffffff
[<800123c0>] (__irq_svc) from [<80476e6c>] (cpuidle_enter_state+0x50/0xe0)
[<80476e6c>] (cpuidle_enter_state) from [<80476fa8>] (cpuidle_idle_call+0xac/0x154)
[<80476fa8>] (cpuidle_idle_call) from [<8000f174>] (arch_cpu_idle+0x8/0x44)
[<8000f174>] (arch_cpu_idle) from [<80064c54>] (cpu_startup_entry+0x100/0x158)
[<80064c54>] (cpu_startup_entry) from [<80cd8a9c>] (start_kernel+0x304/0x368)
---[ end trace 09ebd32fb032f86d ]---
...

There might have a race in napi_schedule(), leaving interrupts disabled forever.
After these patch, the case still work more than 40 hours running.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Before phy device link up, we only enable FEC mdio interrupt, which
is more reasonable.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For i.MX6SX FEC controller, there have interrupt mask and event
field extension. To support all SOCs FEC, we clear all interrupt
events during MAVC initial process.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

On some i.MX6 serial boards, phy power and refrence clock are supplied
or controlled by SOC. When do suspend/resume test, the power and clock
are disabled, so phy device link down.

For current driver, fep->link is still up status, which cause extra operation
like below code. To avoid the dumy operation, we set fep->link to down when
phy device is real down.
...
if (fep->link) {
	napi_disable(&fep->napi);
	netif_tx_lock_bh(ndev);
	fec_stop(ndev);
	netif_tx_unlock_bh(ndev);
	napi_enable(&fep->napi);
	fep->link = phy_dev->link;
	status_change = 1;
}
...
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

On i.MX6SX sabreauto board, when there have no phy daughter board connection,
there have kernel crash by NULL pointer:

fec 2188000.ethernet eth0: could not attach to PHY
Unable to handle kernel NULL pointer dereference at virtual address 00000220
pgd = 80004000
[00000220] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.14.24-01042-g27eaeea-dirty #405
task: d8078000 ti: d8076000 task.ti: d8076000
PC is at mutex_lock+0x10/0x54
LR is at phy_start+0x14/0x68
pc : [<806ad4e4>]    lr : [<803b0f90>]    psr: 60000113
sp : d8077d80  ip : 00000000  fp : d83cc000
r10: 0000100c  r9 : d83cc800  r8 : 00000000
r7 : d83bcd0c  r6 : 00000200  r5 : 00000220  r4 : 00000220
r3 : 00000000  r2 : 00000000  r1 : d83bcd90  r0 : 00000220
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
Control: 10c5387d  Table: 8000404a  DAC: 00000015
Process swapper/0 (pid: 1, stack limit = 0xd8076240)
Stack: (0xd8077d80 to 0xd8078000)
7d80: 00000000 803b0f90 00000001 00000000 d83bc800 803be034 00000007 805c3fb4
7da0: 00000003 80d4e0bc 805efcb8 fffffff1 fffffff0 00000000 00000000 d8077dfc
7dc0: 0000000d 80d6ce80 80d126b0 800499c8 d83bc800 d83bc800 806f0f40 d83bc82c
7de0: 00000000 00000000 80d6ce80 80d126b0 0000016b 80540250 d8076008 d83bc800
7e00: 0000016b d83bc800 00001003 00000001 00001002 805404d4 d83bc800 00000120
7e20: 00001002 00001002 00000000 805405d4 d83bc800 00000001 80d126c0 00001002
7e40: 80dbc5dc 80d02024 00000000 806ae360 00000002 d6128420 d6127198 12400000
7e60: 00000000 00000000 00000002 d61271e8 00000000 12400000 d801674c 800e49f0
7e80: d6127198 d6124e58 00000000 80238848 d61271c4 00000000 00000001 d8016700
7ea0: 80dd2e00 80d752c0 80d752c0 80cfdaec 0000010c 80239430 806c2e90 d800f080
7ec0: d800f380 804e46b4 ffffffbc 80d15cb0 00000007 80d752c0 80d752c0 80d01e94
7ee0: 0000010c d8076030 00000000 800088cc 80dbaba4 80bd411c d80a6f00 806b1e04
7f00: 00000000 00000000 00000000 80125b84 00000000 80d2c56c 60000113 00000001
7f20: ef7ff9df 806c80cc 0000010c 80043f5c 80c95eb8 00000007 ef7ffa1d 00000007
7f40: 80d2c55c 80d15cb0 00000007 80d752c0 80d752c0 80ccc50c 0000010c 80d0a114
7f60: 80d0a10c 80cccc04 00000007 00000007 80ccc50c 806ae410 00000000 8004cb84
7f80: 80d17bc0 00000000 806a4bd4 00000000 00000000 00000000 00000000 00000000
7fa0: 00000000 806a4bdc 00000000 8000e5f8 00000000 00000000 00000000 00000000
7fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
7fe0: 00000000 00000000 00000000 00000000 00000013 00000000 1e79a7bb e5337f77
[<806ad4e4>] (mutex_lock) from [<803b0f90>] (phy_start+0x14/0x68)
[<803b0f90>] (phy_start) from [<803be034>] (fec_enet_open+0x448/0x5dc)
[<803be034>] (fec_enet_open) from [<80540250>] (__dev_open+0xa8/0x110)
[<80540250>] (__dev_open) from [<805404d4>] (__dev_change_flags+0x88/0x170)
[<805404d4>] (__dev_change_flags) from [<805405d4>] (dev_change_flags+0x18/0x48)
[<805405d4>] (dev_change_flags) from [<80d02024>] (ip_auto_config+0x190/0xf94)
[<80d02024>] (ip_auto_config) from [<800088cc>] (do_one_initcall+0xe8/0x144)
[<800088cc>] (do_one_initcall) from [<80cccc04>] (kernel_init_freeable+0x104/0x1c8)
[<80cccc04>] (kernel_init_freeable) from [<806a4bdc>] (kernel_init+0x8/0xec)
[<806a4bdc>] (kernel_init) from [<8000e5f8>] (ret_from_fork+0x14/0x3c)
Code: e92d4010 e3a03000 e1a04000 ee073fba (e1903f9f)

Add phydev check to fix the issue.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

i.MX6SX fec support three rx ring1, the current driver lost to init
ring1 and ring2 maximum receive buffer size, that cause receving
frame date length error. The driver reports "rcv is not +last" error
log in user case.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The return value of swap_buffer() is not used by any caller, thus
remove it.
Signed-off-by: NLothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Eliminate the DIV_ROUND_UP() and change the loop counter increment to
4 instead. This results in saving 6 instructions in the functions
assembly code.
Signed-off-by: NLothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

when swap_buffer() is being called, we know for sure, that we need to
byte swap the data. Furthermore, this function is called for swapping
data in both directions. Thus cpu_to_be32() is semantically not
correct for all use cases. Use swab32s() to reflect this.
Signed-off-by: NLothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NLothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fep->bufdesc_ex is treated as a boolean value, thus declare it as
such.
Signed-off-by: NLothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

commit 1b7bde6d ("net: fec: implement rx_copybreak to improve rx performance")
introduced a regression for i.MX28. The swap_buffer() function doing
the endian conversion of the received data on i.MX28 may access memory
beyond the actual packet size in the DMA buffer. fec_enet_copybreak()
does not copy those bytes, so that the last bytes of a packet may be
filled with invalid data after swapping.
This will likely lead to checksum errors on received packets.
E.g. when trying to mount an NFS rootfs:
UDP: bad checksum. From 192.168.1.225:111 to 192.168.100.73:44662 ulen 36

Do the byte swapping and copying to the new skb in one go if
necessary.
Signed-off-by: NLothar Waßmann <LW@KARO-electronics.de>
Tested-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

On i.MX6SX sdb platform, there has two same enet MACs, after system up,
just eth0 is up, and then do suspend/resume test:

[   50.437967] PM: Syncing filesystems ... done.
[   50.476924] Freezing user space processes ... (elapsed 0.005 seconds) done.
[   50.490093] Freezing remaining freezable tasks ... (elapsed 0.004 seconds) done.
[   50.559771] ------------[ cut here ]------------
[   50.564453] WARNING: CPU: 0 PID: 575 at drivers/clk/clk.c:851 __clk_disable+0x60/0x6c()
[   50.572475] Modules linked in:
[   50.575578] CPU: 0 PID: 575 Comm: sh Not tainted 3.18.0-rc2-next-20141031-00007-gf61135b #21
[   50.584031] Backtrace:
[   50.586550] [<80011ecc>] (dump_backtrace) from [<8001206c>] (show_stack+0x18/0x1c)
[   50.594136]  r6:808a7a54 r5:00000000 r4:00000000 r3:00000000
[   50.599920] [<80012054>] (show_stack) from [<806ab3c0>] (dump_stack+0x80/0x9c)
[   50.607187] [<806ab340>] (dump_stack) from [<8002a3e8>] (warn_slowpath_common+0x6c/0x8c)
[   50.615294]  r5:00000353 r4:00000000
[   50.618940] [<8002a37c>] (warn_slowpath_common) from [<8002a42c>] (warn_slowpath_null+0x24/0x2c)
[   50.627738]  r8:00000000 r7:be144c44 r6:be015600 r5:80070013 r4:be015600
[   50.634573] [<8002a408>] (warn_slowpath_null) from [<804f8d4c>] (__clk_disable+0x60/0x6c)
[   50.642777] [<804f8cec>] (__clk_disable) from [<804f8e5c>] (clk_disable+0x2c/0x38)
[   50.650359]  r4:be015600 r3:00000000
[   50.654006] [<804f8e30>] (clk_disable) from [<80420ab4>] (fec_enet_clk_enable+0xc4/0x258)
[   50.662196]  r5:be3cb620 r4:be3cb000
[   50.665838] [<804209f0>] (fec_enet_clk_enable) from [<80421178>] (fec_suspend+0x30/0x180)
[   50.674026]  r7:be144c44 r6:be144c10 r5:8037f5a4 r4:be3cb000
[   50.679802] [<80421148>] (fec_suspend) from [<8037f5d8>] (platform_pm_suspend+0x34/0x64)
[   50.687906]  r10:00000000 r9:00000000 r8:00000000 r7:be144c44 r6:be144c10 r5:8037f5a4
[   50.695852]  r4:be144c10 r3:80421148
[   50.699511] [<8037f5a4>] (platform_pm_suspend) from [<8038784c>] (dpm_run_callback.isra.14+0x34/0x6c)
[   50.708764] [<80387818>] (dpm_run_callback.isra.14) from [<80387f00>] (__device_suspend+0x12c/0x2a4)
[   50.717909]  r9:8098ec8c r8:80973bec r6:00000002 r5:811c7038 r4:be144c10
[   50.724746] [<80387dd4>] (__device_suspend) from [<803894fc>] (dpm_suspend+0x64/0x224)
[   50.732675]  r8:80973bec r7:be144c10 r6:8098ec24 r5:811c7038 r4:be144cc4
[   50.739509] [<80389498>] (dpm_suspend) from [<8038999c>] (dpm_suspend_start+0x60/0x68)
[   50.747438]  r10:8082fa24 r9:00000000 r8:00000004 r7:00000003 r6:00000000 r5:8116ec80
[   50.755386]  r4:00000002
[   50.757969] [<8038993c>] (dpm_suspend_start) from [<800679d8>] (suspend_devices_and_enter+0x90/0x3ec)
[   50.767202]  r4:00000003 r3:8116eca0
[   50.770843] [<80067948>] (suspend_devices_and_enter) from [<80067f40>] (pm_suspend+0x20c/0x2a4)
[   50.779553]  r8:00000004 r7:00000003 r6:00000000 r5:8116ec8c r4:00000003
[   50.786394] [<80067d34>] (pm_suspend) from [<80066858>] (state_store+0x70/0xc0)
[   50.793718]  r6:8116ec90 r5:00000003 r4:bd88a800 r3:0000006d
[   50.799496] [<800667e8>] (state_store) from [<802b0384>] (kobj_attr_store+0x1c/0x28)
[   50.807251]  r10:bd399f78 r8:00000000 r7:bd88a800 r6:bd88a800 r5:00000004 r4:bd085680
[   50.815219] [<802b0368>] (kobj_attr_store) from [<80153090>] (sysfs_kf_write+0x54/0x58)
[   50.823252] [<8015303c>] (sysfs_kf_write) from [<80151fd8>] (kernfs_fop_write+0xd0/0x194)
[   50.831441]  r6:00000004 r5:bd08568c r4:bd085680 r3:8015303c
[   50.837220] [<80151f08>] (kernfs_fop_write) from [<800eddb4>] (vfs_write+0xb8/0x1a8)
[   50.844975]  r10:00000000 r9:00000000 r8:00000000 r7:bd399f78 r6:01336408 r5:00000004
[   50.852924]  r4:bc584dc0
[   50.855505] [<800edcfc>] (vfs_write) from [<800ee0b8>] (SyS_write+0x48/0x88)
[   50.862567]  r10:00000000 r8:00000000 r7:01336408 r6:00000004 r5:bc584dc0 r4:bc584dc0
[   50.870537] [<800ee070>] (SyS_write) from [<8000eb00>] (ret_fast_syscall+0x0/0x48)
[   50.878120]  r9:bd398000 r8:8000ecc4 r7:00000004 r6:76f42b48 r5:01336408 r4:00000004
[   50.885983] ---[ end trace 7545115d752a316a ]---
[   50.890765] ------------[ cut here ]------------

The root cause is that eth1 is not opened and clock is not enabled, and .suspend() still
call .fec_enet_clk_enable() to disable clock.

To avoid the broken, let it check network device up status by calling .netif_running()
before disable/enable clocks.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since commit 278d2404 (net: fec: ptp: Enable PPS output based on ptp clock)
fec_enet_interrupt calls fec_ptp_check_pps_event unconditionally, which calls
into ptp_clock_event. If fep->ptp_clock is NULL, ptp_clock_event tries to
dereference the NULL pointer.
Since on i.MX53 fep->bufdesc_ex is not set, fec_ptp_init is never called,
and fep->ptp_clock is NULL, which reliably causes a kernel panic.

This patch adds a check for fep->ptp_clock == NULL in fec_enet_interrupt.
Signed-off-by: NPhilipp Zabel <p.zabel@pengutronix.de>
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>

iMX6SX IEEE 1588 module has one hw issue in capturing the ATVR register.
The current SW flow is:
		ENET0->ATCR |= ENET_ATCR_CAPTURE_MASK;
		ts_counter_ns = ENET0->ATVR;
The ATVR value is not expected value that cause LinuxPTP stack cannot be convergent.

ENET Block Guide/ Chapter for the iMX6SX (PELE) address the issue:
After set ENET_ATCR[Capture], there need some time cycles before the counter
value is capture in the register clock domain. The wait-time-cycles is at least
6 clock cycles of the slower clock between the register clock and the 1588 clock.
So need something like:
		ENET0->ATCR |= ENET_ATCR_CAPTURE_MASK;
		wait();
		ts_counter_ns = ENET0->ATVR;

For iMX6SX, the 1588 ts_clk is fixed to 25Mhz, register clock is 66Mhz, so the
wait-time-cycles must be greater than 240ns (40ns * 6). The patch add 1us delay
before cpu read ATVR register.

Changes V2:
Modify the commit/comments log to describe the issue clearly.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Acked-by: NRichard Cochran <richardcochran@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

FEC ptp timer has 4 channel compare/trigger function. It can be used to
enable pps output.
The pulse would be ouput high exactly on N second. The pulse ouput high
on compare event mode is used to produce pulse per second.  The pulse
width would be one cycle based on ptp timer clock source.Since 31-bit
ptp hardware timer is used, the timer will wrap more than 2 seconds. We
need to reload the compare compare event about every 1 second.
Signed-off-by: NLuwei Zhou <b45643@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>