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: correct open parenthesis alignment

Fix checkpatch warning in iosm_ipc_mmio.c
- Alignment should match open parenthesis

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: wwan: iosm: Unify IO accessors used in the driver

Currently we have readl()/writel()/ioread*()/iowrite*() APIs in use.
Let's unify to use only ioread*()/iowrite*() variants.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: wwan: iosm: Replace io.*64_lo_hi() with regular accessors

The io.*_lo_hi() variants are not strictly needed on the x86 hardware
and especially the PCI bus. Replace them with regular accessors, but
leave headers in place in case of 32-bit build.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: iosm: mmio scratchpad

1) Initializes the Scratchpad region for Host-Device communication.
2) Exposes device capabilities like chip info and device execution
stages.

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