net: wwan: t7xx: Infrastructure for early port configuration

To support cases such as FW update or Core dump, the t7xx
device is capable of signaling the host that a special port
needs to be created before the handshake phase.

Adds the infrastructure required to create the early ports
which also requires a different configuration of CLDMA queues.

Base on the v5 patch version of follow series:
'net: wwan: t7xx: fw flashing & coredump support'
(https://patchwork.kernel.org/project/netdevbpf/patch/3777bb382f4b0395cb594a602c5c79dbab86c9e0.1674307425.git.m.chetan.kumar@linux.intel.com/)

Signed-off-by: Jinjian Song <jinjian.song@fibocom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: wwan: t7xx: Add sysfs attribute for device state machine

Add support for userspace to get/set the device mode, device's state
machine changes between (unknown/ready/reset/fastboot).

Get the device state mode:
- 'cat /sys/bus/pci/devices/${bdf}/t7xx_mode'

Set the device state mode:
- reset(cold reset): 'echo reset > /sys/bus/pci/devices/${bdf}/t7xx_mode'
- fastboot: 'echo fastboot_switching > /sys/bus/pci/devices/${bdf}/t7xx_mode'
Reload driver to get the new device state after setting operation.

Signed-off-by: Jinjian Song <jinjian.song@fibocom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: wwan: t7xx: Add AP CLDMA

At this moment with the current status, t7xx is not functional due to
problems like this after connection, if there is no activity:
[ 57.370534] mtk_t7xx 0000:72:00.0: [PM] SAP suspend error: -110
[ 57.370581] mtk_t7xx 0000:72:00.0: can't suspend
(t7xx_pci_pm_runtime_suspend [mtk_t7xx] returned -110)
because after this, the traffic no longer works.

The complete series 'net: wwan: t7xx: fw flashing & coredump support'
was reverted because of issues with the pci implementation.
In order to have at least the modem working, it would be enough if just
the first commit of the series is re-applied:
d20ef656f994 net: wwan: t7xx: Add AP CLDMA
With that, the Application Processor would be controlled, correctly
suspended and the commented problems would be fixed (I am testing here
like this with no related issue).

This commit is independent of the others and not related to the
commented pci implementation for the new features: fw flashing and
coredump collection.

Use v2 patch version of d20ef656f994 as JinJian Song suggests
(https://patchwork.kernel.org/project/netdevbpf/patch/20230105154215.198828-1-m.chetan.kumar@linux.intel.com/).

Original text from the commit that would be re-applied:

d20ef656f994 net: wwan: t7xx: Add AP CLDMA
Author: Haijun Liu <haijun.liu@mediatek.com>
Date: Tue Aug 16 09:53:28 2022 +0530

The t7xx device contains two Cross Layer DMA (CLDMA) interfaces to
communicate with AP and Modem processors respectively. So far only
MD-CLDMA was being used, this patch enables AP-CLDMA.

Rename small Application Processor (sAP) to AP.

Signed-off-by: Haijun Liu <haijun.liu@mediatek.com>
Co-developed-by: Madhusmita Sahu <madhusmita.sahu@intel.com>
Signed-off-by: Madhusmita Sahu <madhusmita.sahu@intel.com>
Signed-off-by: Moises Veleta <moises.veleta@linux.intel.com>
Signed-off-by: Devegowda Chandrashekar <chandrashekar.devegowda@intel.com>
Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>

Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm@redhat.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20230711062817.6108-1-jtornosm@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: wwan: t7xx: Fix the ACPI memory leak

The ACPI buffer memory (buffer.pointer) should be freed as the
buffer is not used after acpi_evaluate_object(), free it to
prevent memory leak.

Fixes: 13e920d93e37 ("net: wwan: t7xx: Add core components")
Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
Link: https://lore.kernel.org/r/1669119580-28977-1-git-send-email-guohanjun@huawei.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Revert "Merge branch 'wwan-t7xx-fw-flashing-and-coredump-support'"

This reverts commit 5417197dd516a8e115aa69f62a7b7554b0c3829c, reversing
changes made to 0630f64d25a0f0a8c6a9ce9fde8750b3b561e6f5.

Reverting to allow addressing review comments.

Link: https://lore.kernel.org/all/4c5dbea0-52a9-1c3d-7547-00ea54c90550@linux.intel.com/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: wwan: t7xx: PCIe reset rescan

PCI rescan module implements "rescan work queue". In firmware flashing
or coredump collection procedure WWAN device is programmed to boot in
fastboot mode and a work item is scheduled for removal & detection.
The WWAN device is reset using APCI call as part driver removal flow.
Work queue rescans pci bus at fixed interval for device detection,
later when device is detect work queue exits.

Signed-off-by: Haijun Liu <haijun.liu@mediatek.com>
Co-developed-by: Madhusmita Sahu <madhusmita.sahu@intel.com>
Signed-off-by: Madhusmita Sahu <madhusmita.sahu@intel.com>
Signed-off-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Signed-off-by: Devegowda Chandrashekar <chandrashekar.devegowda@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: wwan: t7xx: Infrastructure for early port configuration

To support cases such as FW update or Core dump, the t7xx device
is capable of signaling the host that a special port needs
to be created before the handshake phase.

This patch adds the infrastructure required to create the
early ports which also requires a different configuration of
CLDMA queues.

Signed-off-by: Haijun Liu <haijun.liu@mediatek.com>
Co-developed-by: Madhusmita Sahu <madhusmita.sahu@intel.com>
Signed-off-by: Madhusmita Sahu <madhusmita.sahu@intel.com>
Signed-off-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
Signed-off-by: Devegowda Chandrashekar <chandrashekar.devegowda@intel.com>
Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: wwan: t7xx: Add AP CLDMA

The t7xx device contains two Cross Layer DMA (CLDMA) interfaces to
communicate with AP and Modem processors respectively. So far only
MD-CLDMA was being used, this patch enables AP-CLDMA.

Rename small Application Processor (sAP) to AP.

Signed-off-by: Haijun Liu <haijun.liu@mediatek.com>
Co-developed-by: Madhusmita Sahu <madhusmita.sahu@intel.com>
Signed-off-by: Madhusmita Sahu <madhusmita.sahu@intel.com>
Signed-off-by: Moises Veleta <moises.veleta@linux.intel.com>
Signed-off-by: Devegowda Chandrashekar <chandrashekar.devegowda@intel.com>
Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: wwan: t7xx: Fix smatch errors

t7xx_request_irq() error: uninitialized symbol 'ret'.

t7xx_core_hk_handler() error: potentially dereferencing uninitialized 'event'.
If the condition to enter the loop that waits for the handshake event
is false on the first iteration then the uninitialized 'event' will be
dereferenced, fix this by initializing 'event' to NULL.

t7xx_port_proxy_recv_skb() warn: variable dereferenced before check 'skb'.
No need to check skb at t7xx_port_proxy_recv_skb() since we know it
is always called with a valid skb by t7xx_cldma_gpd_rx_from_q().

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
Link: https://lore.kernel.org/r/20220518195529.126246-1-ricardo.martinez@linux.intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: wwan: t7xx: Add WWAN network interface

Creates the Cross Core Modem Network Interface (CCMNI) which implements
the wwan_ops for registration with the WWAN framework, CCMNI also
implements the net_device_ops functions used by the network device.
Network device operations include open, close, start transmission, TX
timeout and change MTU.

Signed-off-by: Haijun Liu <haijun.liu@mediatek.com>
Co-developed-by: Chandrashekar Devegowda <chandrashekar.devegowda@intel.com>
Signed-off-by: Chandrashekar Devegowda <chandrashekar.devegowda@intel.com>
Co-developed-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
Signed-off-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: wwan: t7xx: Add control port

Control Port implements driver control messages such as modem-host
handshaking, controls port enumeration, and handles exception messages.

The handshaking process between the driver and the modem happens during
the init sequence. The process involves the exchange of a list of
supported runtime features to make sure that modem and host are ready
to provide proper feature lists including port enumeration. Further
features can be enabled and controlled in this handshaking process.

Signed-off-by: Haijun Liu <haijun.liu@mediatek.com>
Signed-off-by: Chandrashekar Devegowda <chandrashekar.devegowda@intel.com>
Co-developed-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
Signed-off-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: wwan: t7xx: Add port proxy infrastructure

Port-proxy provides a common interface to interact with different types
of ports. Ports export their configuration via `struct t7xx_port` and
operate as defined by `struct port_ops`.

Signed-off-by: Haijun Liu <haijun.liu@mediatek.com>
Co-developed-by: Chandrashekar Devegowda <chandrashekar.devegowda@intel.com>
Signed-off-by: Chandrashekar Devegowda <chandrashekar.devegowda@intel.com>
Co-developed-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
Signed-off-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: wwan: t7xx: Add core components

Registers the t7xx device driver with the kernel. Setup all the core
components: PCIe layer, Modem Host Cross Core Interface (MHCCIF),
modem control operations, modem state machine, and build
infrastructure.

* PCIe layer code implements driver probe and removal.
* MHCCIF provides interrupt channels to communicate events
such as handshake, PM and port enumeration.
* Modem control implements the entry point for modem init,
reset and exit.
* The modem status monitor is a state machine used by modem control
to complete initialization and stop. It is used also to propagate
exception events reported by other components.

Signed-off-by: Haijun Liu <haijun.liu@mediatek.com>
Signed-off-by: Chandrashekar Devegowda <chandrashekar.devegowda@intel.com>
Co-developed-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
Signed-off-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>