Revert "net: wwan: iosm: enable runtime pm support for 7560"

Runtime power management support breaks Intel LTE modem where dmesg dump
showes timeout errors:

```
[ 72.027442] iosm 0000:01:00.0: msg timeout
[ 72.531638] iosm 0000:01:00.0: msg timeout
[ 73.035414] iosm 0000:01:00.0: msg timeout
[ 73.540359] iosm 0000:01:00.0: msg timeout
```

Furthermore, when shutting down with `poweroff` and modem attached, the
system rebooted instead of powering down as expected. The modem works
again only after power cycling.

Revert runtime power management support for IOSM driver as introduced by
commit e4f5073d53be6c ("net: wwan: iosm: enable runtime pm support for
7560").

Fixes: e4f5073d53be ("net: wwan: iosm: enable runtime pm support for 7560")
Reported-by: Martin <mwolf@adiumentum.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217996
Link: https://lore.kernel.org/r/267abf02-4b60-4a2e-92cd-709e3da6f7d3@gmail.com/
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: wwan: iosm: enable runtime pm support for 7560

Adds runtime pm support for 7560.

As part of probe procedure auto suspend is enabled and auto suspend
delay is set to 5000 ms for runtime pm use. Later auto flag is set
to power manage the device at run time.

On successful communication establishment between host and device the
device usage counter is dropped and request to put the device into
sleep state (suspend).

In TX path, the device usage counter is raised and device is moved out
of sleep(resume) for data transmission. In RX path, if the device has
some data to be sent it request host platform to change the power state
by giving PCI PME message.

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

wwan: core: Support slicing in port TX flow of WWAN subsystem

wwan_port_fops_write inputs the SKB parameter to the TX callback of
the WWAN device driver. However, the WWAN device (e.g., t7xx) may
have an MTU less than the size of SKB, causing the TX buffer to be
sliced and copied once more in the WWAN device driver.

This patch implements the slicing in the WWAN subsystem and gives
the WWAN devices driver the option to slice(by frag_len) or not. By
doing so, the additional memory copy is reduced.

Meanwhile, this patch gives WWAN devices driver the option to reserve
headroom in fragments for the device-specific metadata.

Signed-off-by: haozhe chang <haozhe.chang@mediatek.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Link: https://lore.kernel.org/r/20230316095826.181904-1-haozhe.chang@mediatek.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: wwan: iosm: device trace collection using relayfs

This patch brings in support for device trace collection.
It implements relayfs interface for pushing device trace
from kernel space to user space.

Driver gets the debugfs base directory associated to WWAN
Device and creates trace_control and trace debugfs for
device tracing. Both trace_control & trace debugfs are
created under /sys/kernel/debug/wwan/wwan0/.

In order to collect device trace on trace0 interface, user
need to write 1 to trace_ctl interface.

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

net: iosm: wwan port control device

Implements wwan port for MBIM & AT protocol communication

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