Changing the features (receive checksumming) requires the hardware to be
reprogrammed, and also changes the checks in the receive packet
processing.

The current implementation has a race - fec_set_features() changes the
flags which alter the receive packet processing while the adapter is
active, and potentially receiving frames.  Only after we've modified
the software flag do we shutdown and reconfigure the hardware.

This can lead to packets being received and marked with a valid checksum
(via CHECKSUM_UNNECESSARY) when the hardware checksum validation has not
yet been enabled.

We must quiesce the device, then change the software configuration for
this feature, and then resume the device if it was previously running.

The resulting code structure also allows us to add other configuration
features in this path without having to quiesce and resume the network
interface and device.
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fec_set_features() calls fec_stop() to stop the transmit ring while the
transmit queue is still active.  This can lead to the transmit ring
being restarted by an intervening packet queued for transmission, or
by the tx quirk timer expiring.

Fix this by disabling NAPI (which ensures that the NAPI handlers are
not running), and then take the transmit lock while we stop and
restart the adapter (which prevents new packets being queued).
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fec_suspend() calls fec_stop() to stop the transmit ring while the
transmit packet processing is still active.  This can lead to the
transmit queue being restarted by an intervening packet queued for
transmission, or by the tx quirk timer expiring.

Fix this by disabling NAPI first, which will ensure that the NAPI
handlers are not running.  Then, take the transmit lock before
detaching the netif device.  This ensures that there are no races
with the transmit path - and also ensures that the watchdog won't
fire.

We can then safely stop the ethernet device itself, knowing that the
rest of the driver is safely shut down.

On resume, we bring the device back up in reverse order - we restart
the device, reattach the device (under the tx lock), and then enable
the NAPI handlers.

We also need to adjust the close function to cope with this new
sequence, so that it's possible to cleanly close down the driver
after the hardware fails to resume (eg, due to the regulator_enable()
or pinctrl calls in the resume path returning an error.)
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is the second stage to "move calls to quiesce/resume packet
processing out of fec_restart()", where we remove calls which are not
appropriate to the call site.

In the majority of cases, there is no need to detach and reattach the
interface as we are holding the queue xmit lock across the reset.  The
exception to that is in fec_resume(), where we are already detached by
the suspend function.  Here, we can remove the call to detach the
interface.

We also do not need to stop the transmit queue.  Holding the xmit lock
is enough to ensure that the transmit packet processing is not running
while we perform our task.  However, since fec_restart() always cleans
the rings, we call netif_wake_queue() (or netif_device_attach() in the
case of resume) just before dropping the xmit lock.  This prevents the
watchdog firing.

Lastly, always call napi_enable() after the device has been reattached
in the resume path so that we know that the transmit packet processing
is already in an enabled state, so we don't call netif_wake_queue()
while detached.
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move the calls to quiesce and resume packet processing out of
fec_restart() to its call sites.  This is the first step in a two stage
clean up of this code, where we just move the calls out of fec_restart()
without changing them.  Not everywhere needs to issue these calls, and
not everywhere needs all of these calls to be issued.
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Avoid calling fec_restart() or fec_stop() while the device is down
or not present (iow suspended.)

Although the ndo_timeout method will only be called if the device is
present and running, we defer this to a work queue.  The work queue
can run independently, and so needs to repeat these checks to ensure
that a restart doesn't occur after the device has been taken down or
detached for suspend.  In this case, we call fec_restart() in the
resume path, so nothing is lost.

For fec_set_features, we add a call to fec_restart() in fec_enet_open()
to ensure that the hardware is appropriate programmed when the interface
is opened.  fec_set_features() call should not occur while we're
suspended, so we don't have to worry about that case.

The adjust_link needs similar treatment - this also is called from a
work queue, which may be run independently after we have taken the
device down and detached it.  In this case, we just mark the link
down and take no further action.  We will reset things appropriately
once the device is up and running again, at which point we will receive
another adjust_link callback.
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When the FEC is suspended, the device is detached.  Upon resume failure,
the device is left in detached mode, possibly with some of the required
clocks not running.  We don't want to be poking the device in that state
because as it may cause bus errors.

If the device is marked detached, avoid calling fec_stop().

This depends upon: "net:fec: improve safety of suspend/resume paths"
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We should hold the rtnl lock while suspending, resuming or processing
the transmit timeout to ensure that nothing will interfere while we
bring up, take down or restart the hardware.  The transmit timeout
could run if we're preempted during suspend.
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fec_enet_alloc_buffers() assumes that kmalloc() will never fail, which
is an invalid assumption.  Fix this by implementing a common error
cleanup path, and use it to also clean up after failed bounce buffer
allocation.
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Ensure that we do not double-free any allocations, and that any transmit
skbuffs are properly freed when we clean up the rings.
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Avoid writing any state until we're certain we can proceed with the
transmission: this avoids writing mapping error address values to the
descriptors, or setting the skbuff pointer until we have successfully
mapped the skb.
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Allocate, and then map the receive skb before writing any data to the
ring descriptor or storing the skb.  When freeing the receive ring
entries, unmap and free the skb, and then clear the stored skb pointer.

This means we have ring data and skb pointer in one of two states:
either both fully setup, or nothing setup.

This simplifies the cleanup, as we can use just the skb pointer to
indicate whether the descriptor is setup, and thus avoids potentially
calling dma_unmap_single() on a DMA error value.
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

napi_disable() waits until the NAPI processing has completed, and then
prevents any further polls.  At this point, the driver then clears
fep->opened.  The NAPI poll function uses this to stop processing in
the receive path.  Hence, it will never see this variable cleared,
because the NAPI poll has to complete before it will be cleared.

Therefore, this variable serves no purpose, so let's remove it.
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When the network interface goes down, stop the phy to prevent further
link up status changes before taking the MAC or netif sections down.
This prevents further reception of link up events which could
potentially call fec_restart().

Since phy_stop() takes the mutex which adjust_link() runs under, we
also ensure that adjust_link() will not already be processing a link
up event.

We also need to do this when suspending as well - we don't want a
mis-timed phy state change to restart the MAC after we have stopped
it for suspend, and thus need to restart the phy when resuming.
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When we disconnect from a phy, we should forget our pointer to it so we
don't accidentally try to configure it.  We handle a NULL phy pointer
correctly in most places, except fec_enet_set_pauseparam().  Fix this
too.
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fep->phy_dev can not be NULL here for two reasons:
- fec_enet_open() will have successfully connected the phy, or will have
  failed.
- fec_enet_open() will have called phy_start(fep->phy_dev), which
  unconditionally dereferences this pointer.

If it were to be NULL here, then fec_enet_open() will have already
oopsed.
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We use netif_stop_queue() in several places where we want to ensure that
the start_xmit function is not running.  netif_stop_queue() is not
sufficient to achieve that - it merely sets a flag to indicate that the
transmit queue(s) should not be run.

netif_tx_disable() gives this guarantee, since it takes the transmit
queue lock while marking the queue stopped.  This will wait for the
transmit function to complete before returning.
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

While running: while :; do iperf -c <HOST> -P 4; done, transmit timeouts
are regularly reported.  With the tx ring dumping in place, we can see
that all entries are in use, and the hardware has finished transmitting
these packets.  However, the driver has not reclaimed these ring
entries.

This can occur if the interrupt handler is invoked at the wrong moment -
eg:

	CPU0				CPU1
	fec_enet_tx()
					interrupt, IEVENT = FEC_ENET_TXF
					FEC_ENET_TXF cleared
					napi_schedule_prep()
	napi_complete()

The result is that we clear the transmit interrupt, but we don't trigger
any cleaning of the transmit ring.  Instead, use a different strategy:

- When receiving a transmit or receive interrupt, disable both tx and rx
  interrupts, but do not acknowledge them.  Schedule a napi poll.  Don't
  loop.

- When we are polled, read IEVENT, acknowledging the pending transmit
  and receive interrupts, before then going on to process the
  appropriate rings.

This allows us to avoid the race, and has a number of other advantages:
- we cut down on the number of transmit interrupts we have to process.
- we only look at the rings which have pending events.
- we gain additional throughput: the iperf total bandwidth increases
  from about 180Mbps to 240Mbps:

[  3]  0.0-10.0 sec  68.1 MBytes  57.0 Mbits/sec
[  5]  0.0-10.0 sec  72.4 MBytes  60.5 Mbits/sec
[  4]  0.0-10.1 sec  76.1 MBytes  63.5 Mbits/sec
[  6]  0.0-10.1 sec  71.9 MBytes  59.9 Mbits/sec
[SUM]  0.0-10.1 sec   288 MBytes   241 Mbits/sec
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Setting the pause parameters causes a running network interface to be
restarted.  However, the restart forces the FEC into half-duplex mode,
whether or not the remote end is in half-duplex mode.  Misconfigured
duplex mode is a known source of problems on a link.

Fix this by always preserving the duplex mode on configuration changes.
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The iMX6 gigabit FEC does not support half-duplex gigabit operation.
Phys attacked to the FEC may support this, and we currently do nothing
to disable this feature.  This may result in an invalid configuration.
Mask out phy support for gigabit half-duplex operation.
Acked-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The commit 96c50caa (net: fec: Enable IP header hardware checksum)
enable HW IP header checksum for IPV4 and IPV6, which causes IPV6 TCP/UDP
cannot work. (The issue is reported by Russell King)

For FEC IP header checksum function: Insert IP header checksum. This "IINS"
bit is written by the user. If set, IP accelerator calculates the IP header
checksum and overwrites the IINS corresponding header field with the calculated
value. The checksum field must be cleared by user, otherwise the checksum
always is 0xFFFF.

So the previous patch clear IP header checksum field regardless of IP frame
type.

In fact, IP HW detect the packet as IPV6 type, even if the "IINS" bit is set,
the IP accelerator is not triggered to calculates IPV6 header checksum because
IPV6 frame format don't have checksum.

So this results in the IPV6 frame being corrupted.

The patch just add software detect the current packet type, if it is IPV6
frame, it don't clear IP header checksum field.

Cc: Russell King <linux@arm.linux.org.uk>
Reported-and-tested-by: NRussell King <linux@arm.linux.org.uk>
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add software TSO support for FEC.
This feature allows to improve outbound throughput performance.

Tested on imx6dl sabresd board, running iperf tcp tests shows:
- 16.2% improvement comparing with FEC SG patch
- 82% improvement comparing with NO SG & TSO patch

$ ethtool -K eth0 tso on
$ iperf -c 10.192.242.167 -t 3 &
[  3] local 10.192.242.108 port 35388 connected with 10.192.242.167 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0- 3.0 sec   181 MBytes   506 Mbits/sec

During the testing, CPU loading is 30%.
Since imx6dl FEC Bandwidth is limited to SOC system bus bandwidth, the
performance with SW TSO is a milestone.

CC: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: David Laight <David.Laight@ACULAB.COM>
CC: Li Frank <B20596@freescale.com>
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add Scatter/gather support for FEC.
This feature allows to improve outbound throughput performance.

Tested on imx6dl sabresd board:
Running iperf tests shows a 55.4% improvement.

$ ethtool -K eth0 sg off
$ iperf -c 10.192.242.167 -t 3 &
[  3] local 10.192.242.108 port 52618 connected with 10.192.242.167 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0- 3.0 sec  99.5 MBytes   278 Mbits/sec

$ ethtool -K eth0 sg on
$ iperf -c 10.192.242.167 -t 3 &
[  3] local 10.192.242.108 port 52617 connected with 10.192.242.167 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0- 3.0 sec   154 MBytes   432 Mbits/sec

CC: Li Frank <B20596@freescale.com>
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In order to support SG, software TSO, let's increase BD entry number.

CC: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: David Laight <David.Laight@ACULAB.COM>
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In order to enhance the code readable, let's factorize the
feature list.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

IP header checksum is calcalated by network layer in default.
To support software TSO, it is better to use HW calculate the
IP header checksum.

FEC hw checksum feature request the checksum field in frame
is zero, otherwise the calculative CRC is not correct.

For segmentated TCP packet, HW calculate the IP header checksum again,
it doesn't bring any impact. For SW TSO, HW calculated checksum bring
better performance.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Make the code more readable and easy to support other features like
SG, TSO, moving the common transmit function to one api.

And the patch also factorize the getting BD index to it own function.

CC: David Laight <David.Laight@ACULAB.COM>
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 5bbde4d2 ("net: fec: use pinctrl PM helpers") caused the following
build error on m68k:

drivers/net/ethernet/freescale/fec_main.c: In function 'fec_enet_open':
drivers/net/ethernet/freescale/fec_main.c:1819:2: error: implicit declaration of function 'pinctrl_pm_select_default_state' [-Werror=implicit-function-declaration]
drivers/net/ethernet/freescale/fec_main.c: In function 'fec_enet_close':
drivers/net/ethernet/freescale/fec_main.c:1863:2: error: implicit declaration of function 'pinctrl_pm_select_sleep_state' [-Werror=implicit-function-declaration]

In order to fix the build error, include the linux/pinctrl/consumer.h header
file.
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

when system suspend, need to set pins to low power state to
save IO power consumption, there are three states of pinctrl:
"default", "idle" and "sleep". Currently enet supports default
and sleep state.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since imx serials FEC/ENET MDIO clock source is internal ipg clock,
and "ahb" clock is defined as FEC/ENET bus clock, so the patch just
correct the fec driver MDIO clock source.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Acked-by: NFrank Li <frank.li@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add below clock management to save fec power:
- After probe, disable all clocks incluing ipg, ahb, enet_out, ptp clock.
- Open ethx interface enable necessary clocks.
  Close ethx interface disable all clocks.

The patch also encapsulates the all enet clocks enable/disable to
.fec_enet_clk_enable(), which can reduce the repetitional code in
driver.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Acked-by: NFrank Li <Frank.li@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Though we made sure to acquire a valid MAC for
the netdevice we never actually programmed it
into the hardware.
So if the bootloader did not set the MAC,
network operation would only work if userspace
explicitly asked to transfer the MAC to hardware.
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

fec_enet_mdio_reset() does nothing useful and is optional for the MDIO
bus code, so let's just remove it.
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Replace kfree_skb with dev_kfree_skb_any in fec_enet_start_xmit that
can be called in hard irq and other contexts, when the packet is
dropped.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

If the Freescale fec is in promiscuous mode and network cable is
reconnected then the promiscuous mode get lost. The problem is caused
by a too soon call of set_multicast_list to re-enable promisc mode.
The FEC_R_CNTRL register changes are overwritten by fec_restart.

This patch fixes this by moving the call behind the init of FEC_R_CNTRL
register in fec_restart.

Successful tested on a i.MX28 board.
Signed-off-by: NStefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The current flow: Set TX BD ready, and then set "INT" and "PINS" bit to
enable tx interrupt generation and crc checksum.

There has potential issue like as:
CPU			fec uDMA
Set tx ready bit
			uDMA start the BD transmission
Set "INT" bit
Set "PINS" bit
...

Above situation cause fec tx interrupt lost and fec MAC don't do
CRC checksum. The patch fix the potential issue.
Signed-off-by: NFugang Duan <B38611@freescale.com>
Acked-by: NFrank Li <Frank.li@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If napi is left enabled after a failed attempt to bring the interface
up, we BUG:

fec 2188000.ethernet eth0: no PHY, assuming direct connection to switch
libphy: PHY fixed-0:00 not found
fec 2188000.ethernet eth0: could not attach to PHY
------------[ cut here ]------------
kernel BUG at include/linux/netdevice.h:502!
Internal error: Oops - BUG: 0 [#1] SMP ARM
...
PC is at fec_enet_open+0x4d0/0x500
LR is at __dev_open+0xa4/0xfc

Only enable napi after we are past all the failure paths.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

None of these files are actually using any __init type directives
and hence don't need to include <linux/init.h>.   Most are just a
left over from __devinit and __cpuinit removal, or simply due to
code getting copied from one driver to the next.

This covers everything under drivers/net except for wireless, which
has been submitted separately.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In order to keep DT compatibility we need to revert this, otherwise the original
dts files will no longer work with this driver change.

This reverts commit 7a399e3a.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We should not assume that the PHY reset is always active low.

Retrieve this information from the device tree instead, so that the PHY reset
can work on both cases.
Reported-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>