net: wwan: iosm: fix memory leak in ipc_mux_init()

When failed to alloc ipc_mux->ul_adb.pp_qlt in ipc_mux_init(), ipc_mux
is not released.

Fixes: 1f52d7b62285 ("net: wwan: iosm: Enable M.2 7360 WWAN card support")
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Reviewed-by: M Chetan Kumar <m.chetan.kumar@intel.com>
Link: https://lore.kernel.org/r/20221203020903.383235-1-shaozhengchao@huawei.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

net: wwan: iosm: Enable M.2 7360 WWAN card support

This patch enables Intel M.2 7360 WWAN card support on
IOSM Driver.

Control path implementation is a reuse whereas data path
implementation it uses a different protocol called as MUX
Aggregation. The major portion of this patch covers the MUX
Aggregation protocol implementation used for IP traffic
communication.

For M.2 7360 WWAN card, driver exposes 2 wwan AT ports for
control communication. The user space application or the
modem manager to use wwan AT port for data path establishment.

During probe, driver reads the mux protocol device capability
register to know the mux protocol version supported by device.
Base on which the right mux protocol is initialized for data
path communication.

An overview of an Aggregation Protocol
1> An IP packet is encapsulated with 16 octet padding header
to form a Datagram & the start offset of the Datagram is
indexed into Datagram Header (DH).
2> Multiple such Datagrams are composed & the start offset of
each DH is indexed into Datagram Table Header (DTH).
3> The Datagram Table (DT) is IP session specific & table_length
item in DTH holds the number of composed datagram pertaining
to that particular IP session.
4> And finally the offset of first DTH is indexed into DBH (Datagram
Block Header).

So in TX/RX flow Datagram Block (Datagram Block Header + Payload)is
exchanged between driver & device.

Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: wwan: iosm: release data channel in case no active IP session

If there is no active IP session (interface up & running) then
release the data channel.

Use nr_sessions variable to track current active IP sessions.
If the count drops to 0, then send pipe close ctrl message to
release the data channel.

Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Reviewed-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: iosm: multiplex IP sessions

Establish IP session between host-device & session management.

Signed-off-by: M Chetan Kumar <m.chetan.kumar@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>