Plugins

Current & Default Plugins

The current plugin is a concept that comes into play whenever a plugin provides pattern and test program sources to a parent application.

The current plugin is selected in a similar way to the current target, either at runtime to set the current plugin for a given job only:

origen g atd_ramp --plugin atd_test

or the workspace default can be set via the origen pl command:

origen pl atd_test

Identifying a current plugin performs two main functions:

• Limits the search scope when dynamically searching for pattern sources and avoids ambiguity over which pattern is being requested
• Selects which application callbacks and configuration context should be enabled

The first function is fairly self explanatory and means that Origen will search for the requested pattern only within the subset of all available patterns that are owned by the current plugin. The second function warrants some more discussion…

Application instances (as defined in config/application.rb) are automatically registered as listeners into Origen’s callback system and this is often used to implement pattern generation features like sourceless pattern generation.

That works fine when an application is running standalone, but once it starts to incorporate many plugin instances who can all synthesize pattern sources then we have a problem over which one to choose to fulfill a given request. Similarly there could be issues when a 3rd party callback listener kicks in when generating a completely unrelated pattern.

The selection of the current plugin therefore gives Origen some help by specifying what area of the wider application should be enabled when generating a particular pattern. Ideally a more automated system would be developed for this, and it may be in future, but for now the current plugin concept solves the problem and doesn’t seem to be much of an hindrance to use in practice.

Aside from callbacks, the current plugin selection also selects which plugin’s configuration overrides should be applied to a given generation job, see the plugin configuration guide for some more discussion on this.

The current plugin can be set in Ruby code using the below API.

Origen.app.plugins.current   = :atd_test    # Sets the default plugin
Origen.app.plugins.temporary = :atd_test    # Temporarily sets the current plugin (for this thread only)
Origen.app.plugins.temporary = nil          # Discard the temp plugin and set it back to the default
Origen.app.plugins.current.name             # Returns current plugin name

A common usage pattern for modern ‘BOM’ style applications is to have a target corresponding to each main pattern type, which typically will correspond to the main plugins that are providing pattern sources to the application.

The current plugin can therefore be set in the target and then forgotten about, such that it will automatically be set to the correct thing based on the current target:

# target/atd.rb
load "#{Origen.root}/target/dut.rb"  # Load and instantiate the DUT
Origen.app.plugins.temporary = :atd_test

# target/nvm.rb
load "#{Origen.root}/target/dut.rb"  # Load and instantiate the DUT
Origen.app.plugins.temporary = :nvm_test

Applications can denote a default plugin, to be used when populated in a new workspace, by setting the configuration attribute default_plugin. This points to the name of the plugin which should be loaded in the absence of any user intervention:

# Set the default plugin to OrigenTesters
config.default_plugin = :origen_testers

Plugins can be set and reset as normal. Once the current plugin is reset, the default plugin will not be assessed again.