eth: mpnic: add a netdevice and basic Tx handling

Register the network interface and let it transmit skbs.

The typical TWQ descriptor sequence for an skb is: 1 primary metadata,
followed by 0 or mo

eth: mpnic: add a netdevice and basic Tx handling

Register the network interface and let it transmit skbs.

The typical TWQ descriptor sequence for an skb is: 1 primary metadata,
followed by 0 or more non-last address + length (A/L) descriptors,
terminated by an always present last A/L descriptor.

The device does not write a Tx completion unless it is requested in the
primary metadata desc. The xmit path sets this bit when the stack does
not report netdev_xmit_more(). This can create a problem if the last
packet in a burst is dropped by the driver. To deal with that case, the
driver latches the last metadata for which a completion was not
requested, and uses this to request a completion and flush queued
packets when one is dropped.

There is no link state yet, so carrier follows the administrative
state.

Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
Link: https://patch.msgid.link/20260924-linux-mpnic-v2-6-4badc9b58b9e@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

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eth: mpnic: implement Tx queue allocation and cleanup

Queues come in triads of two work queues and one completion queue. The
Tx triad only uses the first work queue for now, the second one will be
u

eth: mpnic: implement Tx queue allocation and cleanup

Queues come in triads of two work queues and one completion queue. The
Tx triad only uses the first work queue for now, the second one will be
used for the XDP ring later.

Add the ring structures, the per NAPI vector allocation of triads,
descriptor memory and interrupts, and the completion processing. The
completion queue does not report one entry per packet, it reports a
work queue head, so a single completion can release many packets.

Nothing enables the queues in hardware or submits anything to them yet,
that comes with the next two changes.

Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
Link: https://patch.msgid.link/20260924-linux-mpnic-v2-4-4badc9b58b9e@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

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eth: mpnic: allocate MSI-X vectors

Request one vector for FW generated interrupts and then one vector per
CPU to use for the completion queues. Nothing requests a handler yet,
that comes with the NA

eth: mpnic: allocate MSI-X vectors

Request one vector for FW generated interrupts and then one vector per
CPU to use for the completion queues. Nothing requests a handler yet,
that comes with the NAPI vectors.

Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
Link: https://patch.msgid.link/20260924-linux-mpnic-v2-3-4badc9b58b9e@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

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eth: mpnic: add register init for the device

Perform one time register initialization during mpnic_probe(). These CSR
settings are either static configs that only need to be set once, or
pulses for

eth: mpnic: add register init for the device

Perform one time register initialization during mpnic_probe(). These CSR
settings are either static configs that only need to be set once, or
pulses for zeroizing on chip SRAMs, which also only need to be done
once.

This initialization is idempotent and does not require any matching
deinitialization in the remove path. We can unbind and re-bind the
driver and perform the same initialization without problems.

Signed-off-by: Mohsin Bashir <mohsin.bashr@gmail.com>
Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
Link: https://patch.msgid.link/20260924-linux-mpnic-v2-2-4badc9b58b9e@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

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eth: mpnic: add scaffolding for Meta Platforms NIC

MPNIC is the next network interface controller designed by Meta. Create
a bare PCI driver for it. Subsequent changes will flesh it out.

Registers

eth: mpnic: add scaffolding for Meta Platforms NIC

MPNIC is the next network interface controller designed by Meta. Create
a bare PCI driver for it. Subsequent changes will flesh it out.

Registers live in BAR0 and are addressed as an array of 32 bit words,
which is why the CSR indices are a quarter of the byte offset. Most of
the register file is only accessible as 64 bit, so that is the only
accessor added here.

If a read returns all ones, a second read to an unused register with
reset value 0 is performed to determine if the device is gone. If the
device is gone, the mapped BAR0 pointer is cleared, so no further
accesses reach the bus.

For now, if mpnic_mmio_err() clears mpd->uc_addr0, nothing will
reassign it. The user will have to unbind and rebind the driver. Future
series will reset uc_addr0 from pci error handlers.

In addition to being used as a 0 value reference CSR, MPNIC_BDQ_SPARE is
also used to perform write flushes, because it can be read without
producing side effects.

Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>
Link: https://patch.msgid.link/20260924-linux-mpnic-v2-1-4badc9b58b9e@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

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