We add the support of XDP ZC TX submission and cleaning into
stmmac_tx_clean(). The function is made to clean as many TX complete
frames as possible, i.e. limit by priv->dma_tx_size instead of NAPI
budget. For TX ring that is associated with XSK pool, the function
stmmac_xdp_xmit_zc() is introduced to TX frame buffers from XSK pool by
using xsk_tx_peek_desc(). To make stmmac_tx_clean() support the cleaning
of XSK TX frames, STMMAC_TXBUF_T_XSK_TX TX buffer type is introduced.

As stmmac_tx_clean() uses the return value to cue whether NAPI function
should continue to poll, we augment the caller of stmmac_tx_clean() to
pass NAPI budget instead of priv->dma_tx_size through 'budget' input and
made stmmac_tx_clean() to always clean up-to the TX ring size instead.
This allows us to use the return boolean status of stmmac_xdp_xmit_zc()
to decide if XSK TX work is done or not: If true, set 'xmits' to return
'budget - 1' so that NAPI poll may exit. Else, set 'xmits' to return
'budget' to make NAPI poll continue to poll since XSK TX work is not
done. Finally, at the end of stmmac_tx_clean(), the function now take
a maximum value between 'count' and 'xmits' so that status from both
TX cleaning and XSK TX (only for XDP ZC) is considered.

This patch adds a new NAPI poll called stmmac_napi_poll_rxtx() that is
meant to be enabled/disabled for RX and TX ring that are bound to XSK
pool. This NAPI poll function starts with cleaning TX ring, then submits
XSK TX frames to TX ring before proceed to perform RX operations, i.e.
, receiving RX frames and replenishing RX ring with RX free buffers
obtained from XSK pool. Therefore, during XSK RX and TX setup, the driver
enables stmmac_napi_poll_rxtx() for RX and TX operations, then during
XSK RX and TX pool tear-down, the driver reenables the exisiting
independent NAPI poll functions accordingly: stmmac_napi_poll_rx() and
stmmac_napi_poll_tx().
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch adds the support for receiving packet via AF_XDP zero-copy
mechanism.

XDP ZC uses 1:1 mapping of XDP buffer to receive packet, therefore the
use of split header is not used currently. The 'xdp_buff' is declared as
union together with a struct that contains 'page', 'addr' and
'page_offset' that are associated with primary buffer.

RX buffers are now allocated either via page_pool or xsk pool. For RX
buffers from xsk_pool they are allocated and deallocated using below
functions:

 * stmmac_alloc_rx_buffers_zc(struct stmmac_priv *priv, u32 queue)
 * dma_free_rx_xskbufs(struct stmmac_priv *priv, u32 queue)

With above functions now available, we then extend the following driver
functions to support XDP ZC:
 * stmmac_reinit_rx_buffers()
 * __init_dma_rx_desc_rings()
 * init_dma_rx_desc_rings()
 * __free_dma_rx_desc_resources()

Note: stmmac_alloc_rx_buffers_zc() may return -ENOMEM due to RX XDP
buffer pool is not allocated (e.g. samples/bpf/xdpsock TX-only). But,
it is still ok to let TX XDP ZC to continue, therefore, the -ENOMEM
is silently ignored to let the driver succcessfully transition to XDP
ZC mode for the said RX and TX queue.

As XDP ZC buffer size is different, the DMA buffer size is required
to be reprogrammed accordingly for RX DMA/Queue that is populated with
XDP buffer from XSK pool.

Next, to add or remove per-queue XSK pool, stmmac_xdp_setup_pool()
will call stmmac_xdp_enable_pool() or stmmac_xdp_disable_pool()
that in-turn coordinates the tearing down and setting up RX ring via
RX buffers and descriptors removal and reallocation through
stmmac_disable_rx_queue() and stmmac_enable_rx_queue(). In addition,
stmmac_xsk_wakeup() is added to initiate XDP RX buffer replenishing
by signalling user application to add available XDP frames back to
FILL queue.

For RX processing using XDP zero-copy buffer, stmmac_rx_zc() is
introduced which is implemented with the assumption that RX split
header is disabled. For XDP verdict is XDP_PASS, the XDP buffer is
copied into a sk_buff allocated through stmmac_construct_skb_zc()
and sent to Linux network GRO inside stmmac_dispatch_skb_zc(). Free RX
buffers are then replenished using stmmac_rx_refill_zc()

v2: introduce __stmmac_disable_all_queues() to contain the original code
    that does napi_disable() and then make stmmac_setup_tc_block_cb()
    to use it. Move synchronize_rcu() into stmmac_disable_all_queues()
    that eventually calls __stmmac_disable_all_queues(). Then,
    make both stmmac_release() and stmmac_suspend() to use
    stmmac_disable_all_queues(). Thanks David Miller for spotting the
    synchronize_rcu() issue in v1 patch.
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Prepare stmmac_xdp_run_prog() for AF_XDP zero-copy support which will be
added by upcoming patches by splitting out the XDP verdict processing
into __stmmac_xdp_run_prog() and it callable for XDP ZC path which does
not need to verify bpf_prog is not NULL.

The stmmac_xdp_run_prog() is used for regular XDP Rx path which requires
bpf_prog to be verified.
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Below functions are made to be per-queue in preparation of XDP ZC:

 __init_dma_rx_desc_rings(struct stmmac_priv *priv, u32 queue, gfp_t flags)
 __init_dma_tx_desc_rings(struct stmmac_priv *priv, u32 queue)

The original functions below are stay maintained for all queue usage:

 init_dma_rx_desc_rings(struct net_device *dev, gfp_t flags)
 init_dma_tx_desc_rings(struct net_device *dev)
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The per-queue RX buffer allocation in stmmac_reinit_rx_buffers() can be
made to use stmmac_alloc_rx_buffers() by merging the page_pool alloc
checks for "buf->page" and "buf->sec_page" in stmmac_init_rx_buffers().

This is in preparation for XSK pool allocation later.
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Rearrange RX buffer page_pool recycling logics into dma_recycle_rx_skbufs,
so that we prepare stmmac_reinit_rx_buffers() for XSK pool expansion.
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch restructures the per RX queue buffer allocation from page_pool
to stmmac_alloc_rx_buffers().

We also rearrange dma_free_rx_skbufs() so that it can be used in
init_dma_rx_desc_rings() during freeing of RX buffer in the event of
page_pool allocation failure to replace the more efficient method earlier.
The replacement is needed to make the RX buffer alloc and free method
scalable to XDP ZC xsk_pool alloc and free later.
Signed-off-by: Ong Boon Leong <boon.leong.ong@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Alex Elder says:

====================
net: ipa: add support for the SM8350 SoC

This small series adds IPA driver support for the Qualcomm SM8350
SoC, which implements IPA v4.9.

The first patch updates the DT binding, and depends on a previous
patch that has already been accepted into net-next.

The second just defines the IPA v4.9 configuration data file.

(Device Tree files to support this SoC will be sent separately and
will go through the Qualcomm tree.)
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Add support for the SM8350 SoC, which includes IPA version 4.9.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add support for "qcom,sm8350-ipa", which uses IPA v4.9.

Use "enum" rather than "oneOf/const ..." to specify compatible
strings, as suggested by Rob Herring.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

All the uses of HWTSTAMP_FILTER_* values need to be
bit shifters, not straight values.

v2: fixed subject and added Cc Dan and SoB Allen

Fixes: f8ba81da ("ionic: add ethtool support for PTP")
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: Allen Hubbe <allenbh@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

The reset process for ibmvnic commonly takes multiple seconds, clearly
making it inappropriate for schedule_work/system_wq. The reason to make
this change is that ibmvnic's use of the default system-wide workqueue
for a relatively long-running work item can negatively affect other
workqueue users. So, queue the relatively slow reset job to the
system_long_wq.
Suggested-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Lijun Pan <lijunp213@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Merge tag 'linux-can-next-for-5.13-20210413' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next

Marc Kleine-Budde says:

====================
pull-request: can-next 2021-04-13

this is a pull request of 14 patches for net-next/master.

The first patch is by Yoshihiro Shimoda and updates the DT bindings
for the rcar_can driver.

Vincent Mailhol contributes 3 patches that add support for several
ETAS USB CAN adapters.

The final 10 patches are by me and clean up the peak_usb CAN driver.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Fix the following versioncheck warning:
./drivers/net/wireless/rsi/rsi_91x_ps.c: 19 linux/version.h not needed.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

in st_nci_spi_write function, first assign a value to a variable then
goto exit label. return statement just follow the label and exit label
just used once, so we should directly return and remove exit label.
Signed-off-by: wengjianfeng <wengjianfeng@yulong.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The current implementation relies on H_IOCTL call to issue a
H_SESSION_ERR_DETECTED command to let the hypervisor to send a failover
signal. However, it may not work if there is no backup device or if
the vnic is already in error state,
e.g., "ibmvnic 30000003 env3: rx buffer returned with rc 6".
Add a last resort, that is to schedule a failover reset via CRQ command.
Signed-off-by: Lijun Pan <lijunp213@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The current icmp_rcv function drops all unknown ICMP types, including
ICMP_EXT_ECHOREPLY (type 43). In order to parse Extended Echo Reply messages, we have
to pass these packets to the ping_rcv function, which does not do any
other filtering and passes the packet to the designated socket.

Pass incoming RFC 8335 ICMP Extended Echo Reply packets to the ping_rcv
handler instead of discarding the packet.
Signed-off-by: Andreas Roeseler <andreas.a.roeseler@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Michael Walle says:

====================
of: net: support non-platform devices in of_get_mac_address()

of_get_mac_address() is commonly used to fetch the MAC address
from the device tree. It also supports reading it from a NVMEM
provider. But the latter is only possible for platform devices,
because only platform devices are searched for a matching device
node.

Add a second method to fetch the NVMEM cell by a device tree node
instead of a "struct device".

Moreover, the NVMEM subsystem will return dynamically allocated
data which has to be freed after use. Currently, this is handled
by allocating a device resource manged buffer to store the MAC
address. of_get_mac_address() then returns a pointer to this
buffer. Without a device, this trick is not possible anymore.
Thus, change the of_get_mac_address() API to have the caller
supply a buffer.

It was considered to use the network device to attach the buffer
to, but then the order matters and netdev_register() has to be
called before of_get_mac_address(). No driver does it this way.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

of_get_mac_address() already supports fetching the MAC address by an
nvmem provider. But until now, it was just working for platform devices.
Esp. it was not working for DSA ports and PCI devices. It gets more
common that PCI devices have a device tree binding since SoCs contain
integrated root complexes.

Use the nvmem of_* binding to fetch the nvmem cells by a struct
device_node. We still have to try to read the cell by device first
because there might be a nvmem_cell_lookup associated with that device.
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

of_get_mac_address() returns a "const void*" pointer to a MAC address.
Lately, support to fetch the MAC address by an NVMEM provider was added.
But this will only work with platform devices. It will not work with
PCI devices (e.g. of an integrated root complex) and esp. not with DSA
ports.

There is an of_* variant of the nvmem binding which works without
devices. The returned data of a nvmem_cell_read() has to be freed after
use. On the other hand the return of_get_mac_address() points to some
static data without a lifetime. The trick for now, was to allocate a
device resource managed buffer which is then returned. This will only
work if we have an actual device.

Change it, so that the caller of of_get_mac_address() has to supply a
buffer where the MAC address is written to. Unfortunately, this will
touch all drivers which use the of_get_mac_address().

Usually the code looks like:

  const char *addr;
  addr = of_get_mac_address(np);
  if (!IS_ERR(addr))
    ether_addr_copy(ndev->dev_addr, addr);

This can then be simply rewritten as:

  of_get_mac_address(np, ndev->dev_addr);

Sometimes is_valid_ether_addr() is used to test the MAC address.
of_get_mac_address() already makes sure, it just returns a valid MAC
address. Thus we can just test its return code. But we have to be
careful if there are still other sources for the MAC address before the
of_get_mac_address(). In this case we have to keep the
is_valid_ether_addr() call.

The following coccinelle patch was used to convert common cases to the
new style. Afterwards, I've manually gone over the drivers and fixed the
return code variable: either used a new one or if one was already
available use that. Mansour Moufid, thanks for that coccinelle patch!

<spml>
@A@
identifier x;
expression y, z;
@@
- x = of_get_mac_address(y);
+ x = of_get_mac_address(y, z);
  <...
- ether_addr_copy(z, x);
  ...>

@@
identifier a.x;
@@
- if (<+... x ...+>) {}

@@
identifier a.x;
@@
  if (<+... x ...+>) {
      ...
  }
- else {}

@@
identifier a.x;
expression e;
@@
- if (<+... x ...+>@e)
-     {}
- else
+ if (!(e))
      {...}

@@
expression x, y, z;
@@
- x = of_get_mac_address(y, z);
+ of_get_mac_address(y, z);
  ... when != x
</spml>

All drivers, except drivers/net/ethernet/aeroflex/greth.c, were
compile-time tested.
Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch adds EEE support.
Signed-off-by: René van Dorst <opensource@vdorst.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Merge tag 'wireless-drivers-next-2021-04-13' of git://git.kernel.org/pub/scm/linux/kernel/git/kvalo/wireless-drivers-next

Kalle Valo says:

====================
wireless-drivers-next patches for v5.13

First set of patches for v5.13. I have been offline for a couple of
and I have a smaller pull request this time. The next one will be
bigger. Nothing really special standing out.

ath11k

* add initial support for QCN9074, but not enabled yet due to firmware problems

* enable radar detection for 160MHz secondary segment

* handle beacon misses in station mode

rtw88

* 8822c: support firmware crash dump

mt7601u

* enable TDLS support
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch replaces the open coded endianness conversion of unaligned
data by the appropriate get/put_unaligned_leXX() variants.

Link: https://lore.kernel.org/r/20210406111622.1874957-11-mkl@pengutronix.deAcked-by: Stephane Grosjean <s.grosjean@peak-system.com>
Tested-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

The function serial_number is only called from one location with a
valid serial_number pointer. Remove not needed NULL pointer check.

Link: https://lore.kernel.org/r/20210406111622.1874957-10-mkl@pengutronix.deAcked-by: Stephane Grosjean <s.grosjean@peak-system.com>
Tested-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

This patch replaces the memcpy() + le32_to_cpu() by le32_to_cpup().

Link: https://lore.kernel.org/r/20210406111622.1874957-9-mkl@pengutronix.deAcked-by: Stephane Grosjean <s.grosjean@peak-system.com>
Tested-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

The caller of pcan_usb_get_serial() already prints an error message,
so remove this one and return immediately.

Link: https://lore.kernel.org/r/20210406111622.1874957-8-mkl@pengutronix.deAcked-by: Stephane Grosjean <s.grosjean@peak-system.com>
Tested-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

The callback struct peak_usb_adapter::dev_get_device_id, which is
implemented by the functions pcan_usb_{,pro}_get_device_id() is only
ever called with a valid device_id pointer.

This patch removes the unneeded check if the device_id pointer is
valid.

Link: https://lore.kernel.org/r/20210406111622.1874957-7-mkl@pengutronix.deAcked-by: Stephane Grosjean <s.grosjean@peak-system.com>
Tested-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

There's no need to iterate over all supported adapters to find the
struct peak_usb_adapter that describes the currently probed devices's
capabilities. The driver core gives us the information for free, if we
assign it to the struct usb_device_id::driver_info.

This patch assigns the usb_device_id::driver_info and converts
peak_usb_probe() to make use of it. This reduces the driver size by
100 bytes on ARCH=arm.

| add/remove: 0/1 grow/shrink: 0/1 up/down: 0/-124 (-124)
| Function                                     old     new   delta
| peak_usb_adapters_list                        24       -     -24
| peak_usb_probe                               236     136    -100
| Total: Before=25263, After=25139, chg -0.49%

Link: https://lore.kernel.org/r/20210406111622.1874957-6-mkl@pengutronix.deAcked-by: Stephane Grosjean <s.grosjean@peak-system.com>
Tested-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

The variable struct peak_usb_adapter::ts_period is only ever written
to. This patch removes it from the driver.

Link: https://lore.kernel.org/r/20210406111622.1874957-5-mkl@pengutronix.deAcked-by: Stephane Grosjean <s.grosjean@peak-system.com>
Tested-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

This patch removes the unused variables struct
peak_usb_device::echo_skb and struct peak_usb_device::bus_load from
the driver.

Link: https://lore.kernel.org/r/20210406111622.1874957-4-mkl@pengutronix.deAcked-by: Stephane Grosjean <s.grosjean@peak-system.com>
Tested-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

This patch replaces the double space indention after the u8 with a
single space in pcan_usb_pro.h.

Link: https://lore.kernel.org/r/20210406111622.1874957-3-mkl@pengutronix.deAcked-by: Stephane Grosjean <s.grosjean@peak-system.com>
Tested-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

This patch cleans several checkpatch warnings in the peak_usb driver.

Link: https://lore.kernel.org/r/20210406111622.1874957-2-mkl@pengutronix.deAcked-by: Stephane Grosjean <s.grosjean@peak-system.com>
Tested-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

This patch add support for the ES582.1 and ES584.1 interfaces from
ETAS GmbH (https://www.etas.com/en/products/es58x.php).

Link: https://lore.kernel.org/r/20210410095948.233305-4-mailhol.vincent@wanadoo.frCo-developed-by: Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>
Signed-off-by: Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

This patch adds support for the ES581.4 interface from ETAS
GmbH (https://www.etas.com/en/products/es58x.php).

Link: https://lore.kernel.org/r/20210410095948.233305-3-mailhol.vincent@wanadoo.frCo-developed-by: Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>
Signed-off-by: Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

This patch adds the core support for various USB CAN interfaces from
ETAS GmbH (https://www.etas.com/en/products/es58x.php). The next
patches add the glue code drivers for the individual interfaces.

Link: https://lore.kernel.org/r/20210410095948.233305-2-mailhol.vincent@wanadoo.frCo-developed-by: Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>
Signed-off-by: Arunachalam Santhanam <arunachalam.santhanam@in.bosch.com>
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Document SoC specific bindings for R-Car M3-W+ (r8a77961) SoC.

Also as R8A7796 is now called R8A77960 so that update those
references.

Link: https://lore.kernel.org/r/20210409000020.2317696-1-yoshihiro.shimoda.uh@renesas.comSigned-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

For devices that use a programmable clock for the AVB reference clock,
the driver may need to enable them.  Add code to find the optional clock
and enable it when available.
Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

The AVB driver assumes there is an external crystal, but it could
be clocked by other means.  In order to enable a programmable
clock, it needs to be added to the clocks list and enabled in the
driver.  Since there currently only one clock, there is no
clock-names list either.

Update bindings to add the additional optional clock, and explicitly
name both of them.
Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Yangbo Lu says:

====================
enetc: support PTP Sync packet one-step timestamping

This patch-set is to add support for PTP Sync packet one-step timestamping.
Since ENETC single-step register has to be configured dynamically per
packet for correctionField offeset and UDP checksum update, current
one-step timestamping packet has to be sent only when the last one
completes transmitting on hardware. So, on the TX, this patch handles
one-step timestamping packet as below:

- Trasmit packet immediately if no other one in transfer, or queue to
  skb queue if there is already one in transfer.
  The test_and_set_bit_lock() is used here to lock and check state.
- Start a work when complete transfer on hardware, to release the bit
  lock and to send one skb in skb queue if has.

Changes for v2:
	- Rebased.
	- Fixed issues from patchwork checks.
	- netif_tx_lock for one-step timestamping packet sending.
Changes for v3:
	- Used system workqueue.
	- Set bit lock when transmitted one-step packet, and scheduled
	  work when completed. The worker cleared the bit lock, and
	  transmitted one skb in skb queue if has, instead of a loop.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch is to add support for PTP Sync packet one-step timestamping.
Since ENETC single-step register has to be configured dynamically per
packet for correctionField offeset and UDP checksum update, current
one-step timestamping packet has to be sent only when the last one
completes transmitting on hardware. So, on the TX, this patch handles
one-step timestamping packet as below:

- Trasmit packet immediately if no other one in transfer, or queue to
  skb queue if there is already one in transfer.
  The test_and_set_bit_lock() is used here to lock and check state.
- Start a work when complete transfer on hardware, to release the bit
  lock and to send one skb in skb queue if has.

And the configuration for one-step timestamping on ENETC before
transmitting is,

- Set one-step timestamping flag in extension BD.
- Write 30 bits current timestamp in tstamp field of extension BD.
- Update PTP Sync packet originTimestamp field with current timestamp.
- Configure single-step register for correctionField offeset and UDP
  checksum update.
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Reviewed-by: Claudiu Manoil <claudiu.manoil@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>