Similar to Eric's IPv6 BIG TCP, this patch is to enable IPv4 BIG TCP.

Firstly, allow sk->sk_gso_max_size to be set to a value greater than
GSO_LEGACY_MAX_SIZE by not trimming gso_max_size in sk_trim_gso_size()
for IPv4 TCP sockets.

Then on TX path, set IP header tot_len to 0 when skb->len > IP_MAX_MTU
in __ip_local_out() to allow to send BIG TCP packets, and this implies
that skb->len is the length of a IPv4 packet; On RX path, use skb->len
as the length of the IPv4 packet when the IP header tot_len is 0 and
skb->len > IP_MAX_MTU in ip_rcv_core(). As the API iph_set_totlen() and
skb_ip_totlen() are used in __ip_local_out() and ip_rcv_core(), we only
need to update these APIs.

Also in GRO receive, add the check for ETH_P_IP/IPPROTO_TCP, and allows
the merged packet size >= GRO_LEGACY_MAX_SIZE in skb_gro_receive(). In
GRO complete, set IP header tot_len to 0 when the merged packet size
greater than IP_MAX_MTU in iph_set_totlen() so that it can be processed
on RX path.

Note that by checking skb_is_gso_tcp() in API iph_totlen(), it makes
this implementation safe to use iph->len == 0 indicates IPv4 BIG TCP
packets.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This patch introduces gso_ipv4_max_size and gro_ipv4_max_size
per device and adds netlink attributes for them, so that IPV4
BIG TCP can be guarded by a separate tunable in the next patch.

To not break the old application using "gso/gro_max_size" for
IPv4 GSO packets, this patch updates "gso/gro_ipv4_max_size"
in netif_set_gso/gro_max_size() if the new size isn't greater
than GSO_LEGACY_MAX_SIZE, so that nothing will change even if
userspace doesn't realize the new netlink attributes.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Introduce TP_STATUS_GSO_TCP tp_status flag to tell the af_packet user
that this is a TCP GSO packet. When parsing IPv4 BIG TCP packets in
tcpdump/libpcap, it can use tp_len as the IPv4 packet len when this
flag is set, as iph tot_len is set to 0 for IPv4 BIG TCP packets.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

ipvlan devices calls netif_inherit_tso_max() to get the tso_max_size/segs
from the lower device, so when lower device supports BIG TCP, the ipvlan
devices support it too. We also should consider its iph tot_len accessing.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

It may process IPv4 TCP GSO packets in cipso_v4_skbuff_setattr(), so
the iph->tot_len update should use iph_set_totlen().

Note that for these non GSO packets, the new iph tot_len with extra
iph option len added may become greater than 65535, the old process
will cast it and set iph->tot_len to it, which is a bug. In theory,
iph options shouldn't be added for these big packets in here, a fix
may be needed here in the future. For now this patch is only to set
iph->tot_len to 0 when it happens.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

There are also quite some places in netfilter that may process IPv4 TCP
GSO packets, we need to replace them too.

In length_mt(), we have to use u_int32_t/int to accept skb_ip_totlen()
return value, otherwise it may overflow and mismatch. This change will
also help us add selftest for IPv4 BIG TCP in the following patch.

Note that we don't need to replace the one in tcpmss_tg4(), as it will
return if there is data after tcphdr in tcpmss_mangle_packet(). The
same in mangle_contents() in nf_nat_helper.c, it returns false when
skb->len + extra > 65535 in enlarge_skb().
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

There are 1 action and 1 qdisc that may process IPv4 TCP GSO packets
and access iph->tot_len, replace them with skb_ip_totlen() and
iph_totlen() accordingly.

Note that we don't need to replace the one in tcf_csum_ipv4(), as it
will return for TCP GSO packets in tcf_csum_ipv4_tcp().
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

IPv4 GSO packets may get processed in ovs_skb_network_trim(),
and we need to use skb_ip_totlen() to get iph totlen.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Aaron Conole <aconole@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

These 3 places in bridge netfilter are called on RX path after GRO
and IPv4 TCP GSO packets may come through, so replace iph tot_len
accessing with skb_ip_totlen() in there.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This patch adds three APIs to replace the iph->tot_len setting
and getting in all places where IPv4 BIG TCP packets may reach,
they will be used in the following patches.

Note that iph_totlen() will be used when iph is not in linear
data of the skb.
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Laurent Vivier says:

====================
virtio_net: vdpa: update MAC address when it is generated by virtio-net

When the MAC address is not provided by the vdpa device virtio_net
driver assigns a random one without notifying the device.
The consequence, in the case of mlx5_vdpa, is the internal routing
tables of the device are not updated and this can block the
communication between two namespaces.

To fix this problem, use virtnet_send_command(VIRTIO_NET_CTRL_MAC)
to set the address from virtnet_probe() when the MAC address is
not provided by the device.
====================

Link: https://lore.kernel.org/r/20230127204500.51930-1-lvivier@redhat.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

In virtnet_probe(), if the device doesn't provide a MAC address the
driver assigns a random one.
As we modify the MAC address we need to notify the device to allow it
to update all the related information.

The problem can be seen with vDPA and mlx5_vdpa driver as it doesn't
assign a MAC address by default. The virtio_net device uses a random
MAC address (we can see it with "ip link"), but we can't ping a net
namespace from another one using the virtio-vdpa device because the
new MAC address has not been provided to the hardware:
RX packets are dropped since they don't go through the receive filters,
TX packets go through unaffected.
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

failover relies on the MAC address to pair the primary and the standby
devices:

  "[...] the hypervisor needs to enable VIRTIO_NET_F_STANDBY
   feature on the virtio-net interface and assign the same MAC address
   to both virtio-net and VF interfaces."

  Documentation/networking/net_failover.rst

This patch disables the STANDBY feature if the MAC address is not
provided by the hypervisor.
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

This patch corrects two oversights relating to releasing resources
and DCB initialisation.

1. If mapping of the dcbcfg_tbl area fails: an error should be
   propagated, allowing partial initialisation (probe) to be unwound.

2. Conversely, if where dcbcfg_tbl is successfully mapped: it should
   be unmapped in nfp_nic_dcb_clean() which is called via various error
   cleanup paths, and shutdown or removal of the PCIE device.

Fixes: 9b7fe804 ("nfp: add DCB IEEE support")
Signed-off-by: Huayu Chen <huayu.chen@corigine.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Link: https://lore.kernel.org/r/20230131163033.981937-1-simon.horman@corigine.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Swap is a function interface that provides exchange function. To avoid
code duplication, we can use swap function.

./net/ipv6/icmp.c:344:25-26: WARNING opportunity for swap().
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=3896Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20230131063456.76302-1-jiapeng.chong@linux.alibaba.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Jiri Pirko says:

====================
devlink: trivial names cleanup

This is a follow-up to Jakub's devlink code split and dump iteration
helper patchset. No functional changes, just couple of renames to makes
things consistent and perhaps easier to follow.
====================

Link: https://lore.kernel.org/r/20230131090613.2131740-1-jiri@resnulli.usSigned-off-by: Jakub Kicinski <kuba@kernel.org>

In order to maintain naming consistency, rename and reorder all usages
of struct struct devlink_cmd in the following way:
1) Remove "gen" and replace it with "cmd" to match the struct name
2) Order devl_cmds[] and the header file to match the order
   of enum devlink_command
3) Move devl_cmd_rate_get among the peers
4) Remove "inst" for DEVLINK_CMD_GET
5) Add "_get" suffix to all to match DEVLINK_CMD_*_GET (only rate had it
   done correctly)
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

No need to have "gen" inside name of the structure for devlink commands.
Remove it.
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

To have the name of the function consistent with the struct cb name,
rename devlink_nl_instance_iter_dump() to
devlink_nl_instance_iter_dumpit().
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Alex Elder says:

====================
net: ipa: remaining IPA v5.0 support

This series includes almost all remaining IPA code changes required
to support IPA v5.0.  IPA register definitions and configuration
data for IPA v5.0 will be sent later (soon).  Note that the GSI
register definitions still require work.  GSI for IPA v5.0 supports
up to 256 (rather than 32) channels, and this changes the way GSI
register offsets are calculated.  A few GSI register fields also
change.

The first patch in this series increases the number of IPA endpoints
supported by the driver, from 32 to 36.  The next updates the width
of the destination field for the IP_PACKET_INIT immediate command so
it can represent up to 256 endpoints rather than just 32.  The next
adds a few definitions of some IPA registers and fields that are
first available in IPA v5.0.

The next two patches update the code that handles router and filter
table caches.  Previously these were referred to as "hashed" tables,
and the IPv4 and IPv6 tables are now combined into one "unified"
table.  The sixth and seventh patches add support for a new pulse
generator, which allows time periods to be specified with a wider
range of clock resolution.  And the last patch just defines two new
memory regions that were not previously used.
====================

Link: https://lore.kernel.org/r/20230130210158.4126129-1-elder@linaro.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

IPA v5.0 uses two memory regions not previously used.  Define them
and treat them as valid only for IPA v5.0.
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

The AP has third pulse generator available starting with IPA v5.0.
Redefine ipa_qtime_val() to support that possibility.  Pass the IPA
pointer as an argument so the version can be determined.  And stop
using the sign of the returned tick count to indicate which of two
pulse generators to use.

Instead, have the caller provide the address of a variable that will
hold the selected pulse generator for the Qtime value.  And for
version 5.0, check whether the third pulse generator best represents
the time period.

Add code in ipa_qtime_config() to configure the fourth pulse
generator for IPA v5.0+; in that case configure both the third and
fourth pulse generators to use 10 msec granularity.

Consistently use "ticks" for local variables that represent a tick
count.
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Starting with IPA v5.0, the head-of-line blocking timer has more
than two pulse generators available to define timer granularity.
To prepare for that, change the way the field value is encoded
to use ipa_reg_encode() rather than ipa_reg_bit().

The aggregation granularity selection could (in principle) also use
an additional pulse generator starting with IPA v5.0.  Encode the
AGGR_GRAN_SEL field differently to allow that as well.
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

IPA v5.0+ separates the configuration of entries in the cached
(previously "hashed") routing and filtering tables into distinct
registers.  Previously a single "filter and router" register updated
entries in both tables at once; now the routing and filter table
caches have separate registers that define their content.

This patch updates the code that zeroes entries in the cached filter
and router tables to support IPA versions including v5.0+.
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Update the code that causes filter and router table caches to be
flushed so that it supports IPA versions 5.0+.  It adds a comment in
ipa_hardware_config_hashing() that explains that cacheing does not
need to be enabled, just as before, because it's enabled by default.
(For the record, the FILT_ROUT_CACHE_CFG register would have been
used if we wanted to explicitly enable these.)
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Define some new registers that appear starting with IPA v5.0, along
with enumerated types identifying their fields.  Code that uses
these will be added by upcoming patches.

Most of the new registers are related to filter and routing tables,
and in particular, their "hashed" variant.  These tables are better
described as "cached", where a hash value determines which entries
are cached.  From now on, naming related to this functionality will
use "cache" instead of "hash", and that is reflected in these new
register names.  Some registers for managing these caches and their
contents have changed as well.

A few other new field definitions for registers (unrelated to table
caches) are also defined.
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

The IP_PACKET_INIT immediate command defines the destination
endpoint to which a packet should be sent.  Prior to IPA v5.0, a
5 bit field in that command represents the endpoint, but starting
with IPA v5.0, the field is extended to 8 bits to support more than
32 endpoints.
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Increase the number of endpoints supported by the driver to 36,
which IPA v5.0 supports.  This makes it impossible to check at build
time whether the supported number is too big to fit within the
(5-bit) PACKET_INIT destination endpoint field.  Instead, convert
the build time check to compare against what fits in 8 bits.

Add a check in ipa_endpoint_config() to also ensure the hardware
reports an endpoint count that's in the expected range.  Just
open-code 32 as the limit (the PACKET_INIT field mask is not
available where we'd want to use it).
Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Saeed Mahameed says:

====================
mlx5-updates-2023-01-30

Add fast update encryption key

Jianbo Liu Says:
================

Data encryption keys (DEKs) are the keys used for data encryption and
decryption operations. Starting from version 22.33.0783, firmware is
optimized to accelerate the update of user keys into DEK object in
hardware. The support for bulk allocation and destruction of DEK
objects is added, and the bulk allocated DEKs are uninitialized, as
the bulk creation requires no input key. When offload
encryption/decryption, user gets one object from a bulk, and updates
key by a new "modify DEK" command. This command is the same as create
DEK object, but requires no heavy context memory allocation in
firmware, which consumes most cpu cycles of the create DEK command.

DEKs are cached internally by the NIC, so invalidating internal NIC
caches is required before reusing DEKs. The SYNC_CRYPTO command is
added to support it. DEK object can be reused, the keys in it can be
updated after this command is executed.

This patchset enhances the key creation and destruction flow, to get
use of this new feature. Any user, for example, ktls, ipsec and
macsec, can use it to offload keys. But, only ktls uses it, as others
don't need many keys, and caching two many DEKs in pool is wasteful.

There are two new data struts added:
    a. DEK pool. One pool is created for each key type. The bulks by
the type, are placed in the pool's different bulk lists, according to
the number of available and in_used DEKs in the bulk.
    b. DEK bulk. All DEKs in one bulk allocation are store here. There
are two bitmaps to indicate the state of each DEK.

New APIs are then added. When user need a DEK object,
    a. Fetch one bulk with avail DEKs, from the partial_list or
avail_list, otherwise create new one.
    b. Pick one DEK, and set its need_sync and in_used bits to 1.
Move the bulk to full_list if no more available keys, or put it to
partial_list if the bulk is newly created.
    c. Update DEK object's key with user key, by the "modify DEK"
command.
    d. Return DEK struct to user, then it gets the object id and fills
it into the offload commands.
When user free a DEK,
    a. Set in_use bit to 0. If all need_sync bits are 1 and all in_use
bits of this bulk are 0, move it to sync_list.
    b. If the number of DEKs, which are freed by users, is over the
threshold (128), schedule a workqueue to do the sync process.

For the sync process, the SYNC_CRYPTO command is executed first. Then,
for each bulks in partial_list, full_list and sync_list, reset
need_sync bits of the freed DEK objects. If all need_sync bits in one
bulk are zero, move it to avail_list.

We already supported TIS pool to recycle the TISes. With this series
and TIS pool, TLS CPS performance is improved greatly.
And we tested https on the system:
    CPU: dual AMD EPYC 7763 64-Core processors
    RAM: 512G
    DEV: ConnectX-6 DX, with FW ver 22.33.0838 and TLS_OPTIMISE=true
TLS CPS performance numbers are:
    Before: 11k connections/sec
    After: 101 connections/sec

================

* tag 'mlx5-updates-2023-01-30' of git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux:
  net/mlx5e: kTLS, Improve connection rate by using fast update encryption key
  net/mlx5: Keep only one bulk of full available DEKs
  net/mlx5: Add async garbage collector for DEK bulk
  net/mlx5: Reuse DEKs after executing SYNC_CRYPTO command
  net/mlx5: Use bulk allocation for fast update encryption key
  net/mlx5: Add bulk allocation and modify_dek operation
  net/mlx5: Add support SYNC_CRYPTO command
  net/mlx5: Add new APIs for fast update encryption key
  net/mlx5: Refactor the encryption key creation
  net/mlx5: Add const to the key pointer of encryption key creation
  net/mlx5: Prepare for fast crypto key update if hardware supports it
  net/mlx5: Change key type to key purpose
  net/mlx5: Add IFC bits and enums for crypto key
  net/mlx5: Add IFC bits for general obj create param
  net/mlx5: Header file for crypto
====================

Link: https://lore.kernel.org/r/20230131031201.35336-1-saeed@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Tony Nguyen says:

====================
Intel Wired LAN: Remove redundant Device Control Error Reporting Enable

Bjorn Helgaas says:

Since f26e58bf ("PCI/AER: Enable error reporting when AER is native"),
the PCI core sets the Device Control bits that enable error reporting for
PCIe devices.

This series removes redundant calls to pci_enable_pcie_error_reporting()
that do the same thing from several NIC drivers.

There are several more drivers where this should be removed; I started with
just the Intel drivers here.

* '10GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/next-queue:
  ixgbe: Remove redundant pci_enable_pcie_error_reporting()
  igc: Remove redundant pci_enable_pcie_error_reporting()
  igb: Remove redundant pci_enable_pcie_error_reporting()
  ice: Remove redundant pci_enable_pcie_error_reporting()
  iavf: Remove redundant pci_enable_pcie_error_reporting()
  i40e: Remove redundant pci_enable_pcie_error_reporting()
  fm10k: Remove redundant pci_enable_pcie_error_reporting()
  e1000e: Remove redundant pci_enable_pcie_error_reporting()
====================

Link: https://lore.kernel.org/r/20230130192519.686446-1-anthony.l.nguyen@intel.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Petr Machata says:

====================
selftests: mlxsw: Convert to iproute2 dcb

There is a dedicated tool for configuration of DCB in iproute2. Use it
in the selftests instead of lldpad.

Patches #1-#3 convert three tests. Patch #4 drops the now-unnecessary
lldpad helpers.
====================

Link: https://lore.kernel.org/r/cover.1675096231.git.petrm@nvidia.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

The existing users of these helpers have been converted to iproute2 dcb.
Drop the helpers.
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Set up default port priority through the iproute2 dcb tool, which is easier
to understand and manage.
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Set up DSCP prioritization through the iproute2 dcb tool, which is easier
to understand and manage.
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Set up DSCP prioritization through the iproute2 dcb tool, which is easier
to understand and manage.
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Jerome Brunet says:

====================
net: mdio: add amlogic gxl mdio mux support

Add support for the MDIO multiplexer found in the Amlogic GXL SoC family.
This multiplexer allows to choose between the external (SoC pins) MDIO bus,
or the internal one leading to the integrated 10/100M PHY.

This multiplexer has been handled with the mdio-mux-mmioreg generic driver
so far. When it was added, it was thought the logic was handled by a
single register.

It turns out more than a single register need to be properly set.
As long as the device is using the Amlogic vendor bootloader, or upstream
u-boot with net support, it is working fine since the kernel is inheriting
the bootloader settings. Without net support in the bootloader, this glue
comes unset in the kernel and only the external path may operate properly.

With this driver (and the associated change in
arch/arm64/boot/dts/amlogic/meson-gxl.dtsi), the kernel no longer relies
on the bootloader to set things up, fixing the problem.
====================

Link: https://lore.kernel.org/r/20230130151616.375168-1-jbrunet@baylibre.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Add support for the mdio mux and internal phy glue of the GXL SoC
family
Reported-by: Da Xue <da@lessconfused.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Add documentation for the MDIO bus multiplexer found on the Amlogic GXL
SoC family
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Jakub Kicinski says:

====================
tools: ynl: more docs and basic ethtool support

I got discouraged from supporting ethtool in specs, because
generating the user space C code seems a little tricky.
The messages are ID'ed in a "directional" way (to and from
kernel are separate ID "spaces"). There is value, however,
in having the spec and being able to for example use it
in Python.

After paying off some technical debt - add a partial
ethtool spec. Partial because the header for ethtool is almost
a 1000 LoC, so converting in one sitting is tough. But adding
new commands should be trivial now.

Last but not least I add more docs, I realized that I've been
sending a similar "instructions" email to people working on
new families. It's now intro-specs.rst.
====================

Link: https://lore.kernel.org/r/20230131023354.1732677-1-kuba@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

The scripts require Python 3 and some distros are dropping
Python 2 support.
Reported-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>