Using multiple serial drivers from yaml environment

[mitchellostler]

For our labgrid configuration, we are running tests and hoping to use two serial connections on a remote lab host.
We would like to be able to run shell commands via the ShellDriver on each of these serial ports.
Our configuration is specified in our environment yaml file:

targets:
  resources:
    RemotePlace: 
      name: remote1
  drivers:
    SerialDriver:
      name: 's1'
    SerialDriver:
      name: 's2'
    ...

Reading through the documentation, it seems that labgrid supports multiple drivers with the same type, via the name parameter, and the target.get_driver('SerialDriver', name=name) method can be used to get them individually.

However, it is not stated how the underlying resources should be configured. We currently export two USBSerialPort resources with different paths from our RemotePlace, but when our Target is initialized, the second SerialDriver overwrites the first. We could also initialize these drivers in our code, as opposed to our yaml file, but there doesn't seem to be a way to distinguish between the resources they are using.

What should the configuration be to access two serial drivers on different ports from the same project?

[Emantor]

This is unfortunately not very clear from the documentation, but each driver supports a bindings attribute where the name bindings can be specified. This means that for a RemotePlace with two serial ports named i.e. default and second, the driver configuration would look like this:

targets:
  resources:
    RemotePlace: 
      name: remote1
  drivers:
    SerialDriver:
      name: 's1'
      bindings:
        port: default
    SerialDriver:
      name: 's2'
      bindings:
        port: second

Where the named SerialDriver s1 now binds to the SerialPort default and SerialDriver s2 binds to the port second. To create the explicit names for the RemotePlace, add-named-match needs to be used instead of add-match.

My example already contains a recent change to labgrid, namely that if labgrid-client -p remote1 console is called, labgrid will use the port named default by default, instead of requiring an explicit name. If the other port is required, it can still be passed explicitly.

Futher information for binding and driver activation is available inside the docs here.

[yianchen-2023]

Hi Emantor,

I followed your comment and used "add-named-match" to add two named NetworkSerialPort. But, the target.get_driver(‘SerialDriver’, name=name) still could not find the first named SerialDriver in the project yaml file.

We have labgrid version 23.0.3

The resource “show" command output looks as follows:

matches:
    L711/L711/NetworkSerialPort/a_uart -> a_uart
    L711/L711/NetworkSerialPort/b_uart -> b_uart
  acquired: None
  acquired resources:
  created: 2023-08-23 15:47:20.114902
  changed: 2023-08-23 15:49:50.730250
Matching resource 'a_uart' (L711/L711/NetworkSerialPort/a_uart):
  {'acquired': None,
   'avail': True,
   'cls': 'NetworkSerialPort',
   'params': {'extra': {'path': '/dev/ttyUSB3',
                        'proxy': 'l711',
                        'proxy_required': True},
              'host': 'L711',
              'port': None,
              'speed': 115200}}
Matching resource ‘b_uart' (L711/L711/NetworkSerialPort/b_uart):
  {'acquired': None,
   'avail': True,
   'cls': 'NetworkSerialPort',
   'params': {'extra': {'path': '/dev/ttyUSB2',
                        'proxy': 'l711',
                        'proxy_required': True},
              'host': 'L711',
              'port': None,
              'speed': 115200}}

My project yaml file looks as follows:

      SerialDriver:
	name: ‘a_uart_driver'
        bindings:
	  port: ‘a_uart'
      SerialDriver:
	name: ‘b_uart_driver'
        bindings:
	  port: ‘b_uart’

[Bastian-Krause]

@Emantor's configuration is incorrect. You need to specify the drivers as a yaml list, not as a yaml dictionary (the second SerialDriver would overwrite the first, due to duplicate keys). See the documentation about Environment configuration. It contains an example with multiple SerialDrivers.

[yianchen-2023]

@Bastian-Krause: Thanks for your help.

I am following up on the configuration discussion for using one project YAML file for two serial port configurations.

I did some more experiments.

Labgrid accepts the project YAML file as follows (only for experiment purposes)

targets:
  main:
    resources:
    - RawSerialPort:
        name: 'ca55_uart'
        port: '/dev/ttys001'
    - RawSerialPort:
        name: 'cr5_uart'
        port: '/dev/ttys002'
    drivers:
    - SerialDriver:
        name: 'ca55_uart_driver'
        bindings:
          port: 'ca55_uart'
    - SerialDriver:
        name: 'cr5_uart_driver'
        bindings:
          port: 'cr5_uart'

However, Labgrid would not take it if I add a ShellDriver entry in the file (it doesn’t matter if it is a list type or dictionary type):

targets:
  main:
    resources:
    - RawSerialPort:
        name: 'ca55_uart'
        port: '/dev/ttys001'
    - RawSerialPort:
        name: 'cr5_uart'
        port: '/dev/ttys002'
    drivers:
    - SerialDriver:
        name: 'ca55_uart_driver'
        bindings:
          port: 'ca55_uart'
    - SerialDriver:
        name: 'cr5_uart_driver'
        bindings:
          port: ‘cr5_uart'	
      ShellDriver:
        prompt: '# '
        login_prompt: ' login: '
        username: 'root'
        login_timeout: 30

———————
NOTE: Labgrid doesn’t seem to take the list type of ShellDriver entry either, as follows

     - ShellDriver:
        prompt: '# '
        login_prompt: ' login: '
        username: 'root'
        login_timeout: 30

My questions are as follows (Please correct me if I did not ask the right questions):

For project YAML:

1. How can I extend the list to include more drivers in the project YAML for both resources and drivers?
2. As to ShellDriver, do you think there's a need to bind it to a specific serial port?
3. While using YAML list to specify drivers, do I always need to use YAML list to specify the resources partially or all?

For exporter yaml

1. If yes, for the (3) in project YAML, do we need to export remote resources as a YAML list in the exporter config? Since our remote resources are all exported via labgrid exporter as follows, it doesn't seem to work with the YAML list in the project YAML’s drivers section (NOTE: I used add-named-match to add the resources to L711 one by one, and resource show command was in my previous post last week)

Project YAML

    resources:
      RemotePlace:
        name: L711
    drivers:
    - SerialDriver:
        name: 'ca55_uart_driver'
        bindings:
          port: 'ca55_uart'
    - SerialDriver:
        name: 'cr5_uart_driver'
        bindings:
          port: 'cr5_uart'

Exporter YAML file

L711:
  location: lab
  ca55_uart:
    cls: USBSerialPort
    match:
      ID_SERIAL_SHORT: FT4XSQFX
  cr5_uart:
    cls: USBSerialPort
    match:
      ID_SERIAL_SHORT: FT55R8PX

  < some other resources>

Please let me know and correct me if there are any missing setups on the exporter or project side.

[yianchen-2023]

Sorry, somehow the format of YAML was changed after clicking on the reply.

[cruise-bryan-murdock]

I think the real question we have is just this. If this is our exporter config:

SFO3-HIL-LT-711:
  location: sunnyvale-lab
  ca55_uart:
    cls: USBSerialPort
    match:
      ID_SERIAL_SHORT: FT4XSQFX
  cr5_uart:
    cls: USBSerialPort
    match:
      ID_SERIAL_SHORT: FT55R8PX

And our place is:

Place 'lt711_test':
  matches:
    SFO3-HIL-LT-711/SFO3-HIL-LT-711/NetworkSerialPort/ca55_uart -> ca55_uart
    SFO3-HIL-LT-711/SFO3-HIL-LT-711/NetworkSerialPort/cr5_uart -> cr5_uart

And our test target yaml is:

targets:
  main:
    resources:
      RemotePlace:
        name: lt711_user
    drivers:
    - SerialDriver:
        name: 'ca55_uart_driver'
        bindings:
          port: 'ca55_uart'
    - SerialDriver:
        name: 'cr5_uart_driver'
        bindings:
          port: 'cr5_uart'
    - APCDriver: {}
    - LauterbachDriver: {}
    - ShellDriver:
        console: 'ca55_uart_driver'
        prompt: '# '
        login_prompt: ' buildroot login: '
        username: 'root'
        login_timeout: 30

The console line isn't working how I think it should. I just get this error:

abgrid.exceptions.NoDriverFoundError: multiple drivers matching <class 'labgrid.protocol.consoleprotocol.ConsoleProtocol'> found in Target(name='main', env=Environment(config_file='ca55-working.yaml')) with the same priorities

How do we bind the ShellDriver to the ca55_uart_driver?

[cruise-bryan-murdock]

After much stepping through the labgrid code, I figured it out. The Strategy has both a console and a serial binding that are needed. This is the target yaml that works for the strategy now:

    - LinuxBootStrategy:
        bindings:
          console: 'ca55_uart_driver'
          serial: 'ca55_uart_driver'

It would sure be nice if the error messages from labgrid made this more clear!

[Bastian-Krause]

Could you please provide a way to reproduce the error message that should be improved?

[cruise-bryan-murdock]

I guess to reproduce it you'd need a target env that has two SerialDrivers, and a driver or strategy that binds to a serial protocol. Then make sure you don't add bindings for the driver or strategy. You should get an error message like this:

ERROR ss_cr5_test.py::test_ss - labgrid.exceptions.NoDriverFoundError: multiple drivers matching <class 'labgrid.driver.serialdriver.SerialDriver'> found in Target(name='main', env=Environment(config_file='ca55-working.yaml')) with ...

It would be nice if it told me which driver or strategy is looking for the SerialDriver.

Knowing what to look for now, I can see the strategy in the middle of the big traceback that is shown before the above message, but that was not obvious to me when first looking at this.

[Bastian-Krause]

See #1270 for improved target error messages.

[cruise-bryan-murdock]

That looks like it will much more helpful, thanks!