net: wwan: t7xx: Add debug ports

Add support for userspace to enable/disable the debug ports(ADB,MIPC).
 - ADB port: /dev/wwan0adb0
 - MIPC port: /dev/wwan0mipc0

Application can use ADB (Android Debug Bridge) port to implement
functions (shell, pull, push ...) by ADB protocol commands.
E.g., ADB commands:
 - A_OPEN: OPEN(local-id, 0, "destination")
 - A_WRTE: WRITE(local-id, remote-id, "data")
 - A_OKEY: READY(local-id, remote-id, "")
 - A_CLSE: CLOSE(local-id, remote-id, "")

Link: https://android.googlesource.com/platform/packages/modules/adb/+/refs/heads/main/README.md

Application can use MIPC (Modem Information Process Center) port
to debug antenna tuner or noise profiling through this MTK modem
diagnostic interface.

By default, debug ports are not exposed, so using the command
to enable or disable debug ports.

Enable debug ports:
 - enable: 'echo 1 > /sys/bus/pci/devices/${bdf}/t7xx_debug_ports

Disable debug ports:
 - disable: 'echo 0 > /sys/bus/pci/devices/${bdf}/t7xx_debug_ports

Signed-off-by: Jinjian Song <jinjian.song@fibocom.com>
Reviewed-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

1 files changed, 47 insertions, 0 deletions

diff --git a/Documentation/networking/device_drivers/wwan/t7xx.rst b/Documentation/networking/device_drivers/wwan/t7xx.rst
index f346f5f85f15..4cf777c341cd 100644
--- a/Documentation/networking/device_drivers/wwan/t7xx.rst
+++ b/Documentation/networking/device_drivers/wwan/t7xx.rst
@@ -67,6 +67,28 @@ Write from userspace to set the device mode.
 ::
   $ echo fastboot_switching > /sys/bus/pci/devices/${bdf}/t7xx_mode
 
+t7xx_debug_ports
+----------------
+The sysfs interface provides userspace with access to enable/disable the debug
+ports, this interface supports read and write operations.
+
+Debug port status:
+
+- ``1`` represents enable debug ports
+- ``0`` represents disable debug ports
+
+Currently supported debug ports (ADB/MIPC).
+
+Read from userspace to get the current debug ports status.
+
+::
+  $ cat /sys/bus/pci/devices/${bdf}/t7xx_debug_ports
+
+Write from userspace to set the debug ports status.
+
+::
+  $ echo 1 > /sys/bus/pci/devices/${bdf}/t7xx_debug_ports
+
 Management application development
 ==================================
 The driver and userspace interfaces are described below. The MBIM protocol is
@@ -139,6 +161,25 @@ Please note that driver needs to be reloaded to export /dev/wwan0fastboot0
 port, because device needs a cold reset after enter ``fastboot_switching``
 mode.
 
+ADB port userspace ABI
+----------------------
+
+/dev/wwan0adb0 character device
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The driver exposes a ADB protocol interface by implementing ADB WWAN Port.
+The userspace end of the ADB channel pipe is a /dev/wwan0adb0 character device.
+Application shall use this interface for ADB protocol communication.
+
+MIPC port userspace ABI
+-----------------------
+
+/dev/wwan0mipc0 character device
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The driver exposes a diagnostic interface by implementing MIPC (Modem
+Information Process Center) WWAN Port. The userspace end of the MIPC channel
+pipe is a /dev/wwan0mipc0 character device.
+Application shall use this interface for MTK modem diagnostic communication.
+
 The MediaTek's T700 modem supports the 3GPP TS 27.007 [4] specification.
 
 References
@@ -164,3 +205,9 @@ speak the Mobile Interface Broadband Model (MBIM) protocol"*
 [5] *fastboot "a mechanism for communicating with bootloaders"*
 
 - https://android.googlesource.com/platform/system/core/+/refs/heads/main/fastboot/README.md
+
+[6] *ADB (Android Debug Bridge) "a mechanism to keep track of Android devices
+and emulators instances connected to or running on a given host developer
+machine with ADB protocol"*
+
+- https://android.googlesource.com/platform/packages/modules/adb/+/refs/heads/main/README.md