[dpu_tty]: Add a DPU TTY console utility (#3535)

* [dpu_tty]: Add a DPU TTY console utility

* Add dpu_tty.py
* Add dpu_tty.py to scripts

Signed-off-by: Wenchung Wang [email protected]

What I did

Add DPU TTY console utility.

How I did it

* Read platform.json to retrieve TTY settings in DPUS section. Set up TTY
console according to TTY device name and baud rate.
* Also provide options to overwrite default TTY device and baud rate.

'''
"DPUS": {
    "dpu0": {
        "serial-console": {
            "device": "ttyS4",
            "baud-rate": "115200"
        }
    },
    "dpu1": {
        "serial-console": {
            "device": "ttyS5",
            "baud-rate": "115200"
        }
    }
},
'''

How to verify it

Run the utility on a smart switch that provides DPU UART console via
ttyS device. The test plan is at
https://github.com/sonic-net/sonic-mgmt/pull/12701/files section 1.4.

* Correct SA errors

* Correct SA errors

* Correct SA error

* Fix a SA error

* Update Command-Reference.md

Add DPU serial console utility.

* Address review comments

Author: wenchungw

doc/Command-Reference.md

@@ -43,6 +43,7 @@
   * [Console config commands](#console-config-commands)
   * [Console connect commands](#console-connect-commands)
   * [Console clear commands](#console-clear-commands)
+  * [DPU serial console utility](#dpu-serial-console-utility)
 * [CMIS firmware upgrade](#cmis-firmware-upgrade)
   * [CMIS firmware version show commands](#cmis-firmware-version-show-commands)
   * [CMIS firmware upgrade commands](#cmis-firmware-upgrade-commands)
@@ -229,6 +230,7 @@
 
 | Version | Modification Date | Details |
 | --- | --- | --- |
+| v9 | Sep-19-2024 | Add DPU serial console utility |
 | v8 | Oct-09-2023 | Add CMIS firmware upgrade commands |
 | v7 | Jun-22-2023 | Add static DNS show and config commands |
 | v6 | May-06-2021 | Add SNMP show and config commands |
@@ -2825,7 +2827,7 @@ Optionally, you can display configured console ports only by specifying the `-b`
        1    9600         Enabled      -             -   switch1
   ```
 
-## Console config commands
+### Console config commands
 
 This sub-section explains the list of configuration options available for console management module.
 
@@ -3001,6 +3003,88 @@ Optionally, you can clear with a remote device name by specifying the `-d` or `-
 
 Go Back To [Beginning of the document](#) or [Beginning of this section](#console)
 
+### DPU serial console utility
+
+**dpu-tty.py**
+
+This command allows user to connect to a DPU serial console via TTY device with
+interactive CLI program: picocom. The configuration is from platform.json. The
+utility works only on smart switch that provides DPU UART connections through
+/dev/ttyS* devices.
+
+- Usage:
+  ```
+  dpu-tty.py (-n|--name) <DPU_NAME> [(-b|-baud) <BAUD_RATE>] [(-t|-tty) <TTY>]
+  ```
+
+- Example:
+  ```
+  root@MtFuji:/home/cisco# dpu-tty.py -n dpu0
+  picocom v3.1
+
+  port is        : /dev/ttyS4
+  flowcontrol    : none
+  baudrate is    : 115200
+  parity is      : none
+  databits are   : 8
+  stopbits are   : 1
+  escape is      : C-a
+  local echo is  : no
+  noinit is      : no
+  noreset is     : no
+  hangup is      : no
+  nolock is      : no
+  send_cmd is    : sz -vv
+  receive_cmd is : rz -vv -E
+  imap is        : 
+  omap is        : 
+  emap is        : crcrlf,delbs,
+  logfile is     : none
+  initstring     : none
+  exit_after is  : not set
+  exit is        : no
+
+  Type [C-a] [C-h] to see available commands
+  Terminal ready
+
+  sonic login: admin
+  Password: 
+  Linux sonic 6.1.0-11-2-arm64 #1 SMP Debian 6.1.38-4 (2023-08-08) aarch64
+  You are on
+    ____   ___  _   _ _  ____
+   / ___| / _ \| \ | (_)/ ___|
+   \___ \| | | |  \| | | |
+    ___) | |_| | |\  | | |___
+   |____/ \___/|_| \_|_|\____|
+
+  -- Software for Open Networking in the Cloud --
+
+  Unauthorized access and/or use are prohibited.
+  All access and/or use are subject to monitoring.
+
+  Help:    https://sonic-net.github.io/SONiC/
+
+  Last login: Mon Sep  9 21:39:44 UTC 2024 on ttyS0
+  admin@sonic:~$ 
+  Terminating...
+  Thanks for using picocom
+  root@MtFuji:/home/cisco#
+  ```
+
+Optionally, user may overwrite baud rate for experiment.
+
+- Example:
+  ```
+  root@MtFuji:/home/cisco# dpu-tty.py -n dpu1 -b 9600
+  ```
+
+Optionally, user may overwrite TTY device for experiment.
+
+- Example:
+  ```
+  root@MtFuji:/home/cisco# dpu-tty.py -n dpu2 -t ttyS4
+  ```
+
 ## CMIS firmware upgrade
 
 ### CMIS firmware version show commands

scripts/dpu-tty.py

@@ -0,0 +1,73 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) 2024 Cisco Systems, Inc.
+#
+
+import argparse
+import json
+import os
+import subprocess
+from sonic_py_common import device_info
+
+UART_CON = '/usr/bin/picocom'
+
+
+def get_dpu_tty(dpu, tty, baud):
+
+    platform = device_info.get_platform()
+    if not platform:
+        print("No platform")
+        return None
+
+    # Get platform path.
+    platform_path = device_info.get_path_to_platform_dir()
+
+    if os.path.isfile(os.path.join(platform_path, device_info.PLATFORM_JSON_FILE)):
+        json_file = os.path.join(platform_path, device_info.PLATFORM_JSON_FILE)
+
+        try:
+            with open(json_file, 'r') as file:
+                platform_data = json.load(file)
+        except (json.JSONDecodeError, IOError, TypeError, ValueError):
+            print("No platform.json")
+            return None
+
+    dpus = platform_data.get('DPUS', None)
+    if dpus is None:
+        print("No DPUs in platform.json")
+        return None
+
+    if tty is None:
+        dev = dpus[dpu]["serial-console"]["device"]
+    else:
+        # overwrite tty device in platform.json
+        dev = tty
+
+    if baud is None:
+        baud = dpus[dpu]["serial-console"]["baud-rate"]
+    return dev, baud
+
+
+def main():
+
+    parser = argparse.ArgumentParser(description='DPU TTY Console Utility')
+    parser.add_argument('-n', '--name', required=True)
+    parser.add_argument('-t', '--tty')
+    parser.add_argument('-b', '--baud')
+    args = parser.parse_args()
+
+    dpu_tty, dpu_baud = get_dpu_tty(args.name, args.tty, args.baud)
+    # Use UART console utility for error checking of dpu_tty and dpu_baud.
+
+    p = subprocess.run([UART_CON, '-b', dpu_baud, '/dev/%s' % dpu_tty])
+    if p.returncode:
+        print('{} failed'.format(p.args))
+        if p.stdout:
+            print(p.stdout)
+        if p.stderr:
+            print(p.stderr)
+    return p.returncode
+
+
+if __name__ == "__main__":
+    exit(main())

setup.py

@@ -120,6 +120,7 @@
         'scripts/decode-syseeprom',
         'scripts/dropcheck',
         'scripts/disk_check.py',
+        'scripts/dpu-tty.py',
         'scripts/dropconfig',
         'scripts/dropstat',
         'scripts/dualtor_neighbor_check.py',