net: partial revert of the "Make timestamping selectable: series

Revert following commits:

commit acec05fb78ab ("net_tstamp: Add TIMESTAMPING SOFTWARE and HARDWARE mask")
commit 11d55be06df0 ("net: ethtool: Add a command to expose current time stamping layer")
commit bb8645b00ced ("netlink: specs: Introduce new netlink command to get current timestamp")
commit d905f9c75329 ("net: ethtool: Add a command to list available time stamping layers")
commit aed5004ee7a0 ("netlink: specs: Introduce new netlink command to list available time stamping layers")
commit 51bdf3165f01 ("net: Replace hwtstamp_source by timestamping layer")
commit 0f7f463d4821 ("net: Change the API of PHY default timestamp to MAC")
commit 091fab122869 ("net: ethtool: ts: Update GET_TS to reply the current selected timestamp")
commit 152c75e1d002 ("net: ethtool: ts: Let the active time stamping layer be selectable")
commit ee60ea6be0d3 ("netlink: specs: Introduce time stamping set command")

They need more time for reviews.

Link: https://lore.kernel.org/all/20231118183529.6e67100c@kernel.org/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: Replace hwtstamp_source by timestamping layer

Replace hwtstamp_source which is only used by the kernel_hwtstamp_config
structure by the more widely use timestamp_layer structure. This is done
to prepare the support of selectable timestamping source.

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: remove phy_has_hwtstamp() -> phy_mii_ioctl() decision from converted drivers

It is desirable that the new .ndo_hwtstamp_set() API gives more
uniformity, less overhead and future flexibility w.r.t. the PHY
timestamping behavior.

Currently there are some drivers which allow PHY timestamping through
the procedure mentioned in Documentation/networking/timestamping.rst.
They don't do anything locally if phy_has_hwtstamp() is set, except for
lan966x which installs PTP packet traps.

Centralize that behavior in a new dev_set_hwtstamp_phylib() code
function, which calls either phy_mii_ioctl() for the phylib PHY,
or .ndo_hwtstamp_set() of the netdev, based on a single policy
(currently simplistic: phy_has_hwtstamp()).

Any driver converted to .ndo_hwtstamp_set() will automatically opt into
the centralized phylib timestamping policy. Unconverted drivers still
get to choose whether they let the PHY handle timestamping or not.

Netdev drivers with integrated PHY drivers that don't use phylib
presumably don't set dev->phydev, and those will always see
HWTSTAMP_SOURCE_NETDEV requests even when converted. The timestamping
policy will remain 100% up to them.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Link: https://lore.kernel.org/r/20230801142824.1772134-13-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: add hwtstamping helpers for stackable net devices

The stackable net devices with hwtstamping support (vlan, macvlan,
bonding) only pass the hwtstamping ops to the lower (real) device.

These drivers are the first that need to be converted to the new
timestamping API, because if they aren't prepared to handle that,
then no real device driver cannot be converted to the new API either.

After studying what vlan_dev_ioctl(), macvlan_eth_ioctl() and
bond_eth_ioctl() have in common, here we propose two generic
implementations of ndo_hwtstamp_get() and ndo_hwtstamp_set() which
can be called by those 3 drivers, with "dev" being their lower device.

These helpers cover both cases, when the lower driver is converted to
the new API or unconverted.

We need some hacks in case of an unconverted driver, namely to stuff
some pointers in struct kernel_hwtstamp_config which shouldn't have
been there (since the new API isn't supposed to need it). These will
be removed when all drivers will have been converted to the new API.

Signed-off-by: Maxim Georgiev <glipus@gmail.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://lore.kernel.org/r/20230801142824.1772134-3-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: add NDOs for configuring hardware timestamping

Current hardware timestamping API for NICs requires implementing
.ndo_eth_ioctl() for SIOCGHWTSTAMP and SIOCSHWTSTAMP.

That API has some boilerplate such as request parameter translation
between user and kernel address spaces, handling possible translation
failures correctly, etc. Since it is the same all across the board, it
would be desirable to handle it through generic code.

Here we introduce .ndo_hwtstamp_get() and .ndo_hwtstamp_set(), which
implement that boilerplate and allow drivers to just act upon requests.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Maxim Georgiev <glipus@gmail.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Link: https://lore.kernel.org/r/20230801142824.1772134-2-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: add struct kernel_hwtstamp_config and make net_hwtstamp_validate() use it

Jakub Kicinski suggested that we may want to add new UAPI for
controlling hardware timestamping through netlink in the future, and in
that case, we will be limited to the struct hwtstamp_config that is
currently passed in fixed binary format through the SIOCGHWTSTAMP and
SIOCSHWTSTAMP ioctls. It would be good if new kernel code already
started operating on an extensible kernel variant of that structure,
similar in concept to struct kernel_ethtool_coalesce vs struct
ethtool_coalesce.

Since struct hwtstamp_config is in include/uapi/linux/net_tstamp.h, here
we introduce include/linux/net_tstamp.h which shadows that other header,
but also includes it, so that existing includers of this header work as
before. In addition to that, we add the definition for the kernel-only
structure, and a helper which translates all fields by manual copying.
I am doing a manual copy in order to not force the alignment (or type)
of the fields of struct kernel_hwtstamp_config to be the same as of
struct hwtstamp_config, even though now, they are the same.

Link: https://lore.kernel.org/netdev/20230330223519.36ce7d23@kernel.org/
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>