3aef852fc0
The implementation uses the system workqueue and a callback provided and registered by the application. The application callback is called in the context of the workqueue. Notification messages are stored in a queue and delivered to the callback in sequence. We cannot call application callback directly from the USB device stack thread because the behavior of arbitrary code provided by the application is unpredictable, and we do not want it to be executed in the same context where all events from the device controller are handled. Nor can we use the ZBUS subsystem directly. ZBUS offloads responsibility for defined behavior to the observers and application, and does not provide any way for the publisher to enforce defined behavior and execution context. ZBUS listener would be called from the USB thread context and is not acceptable. ZBUS subscriber does not provide delivery guarantee and cached message can be overwritten. ZBUS message subscriber has cumbersome global configuration and buffers that are too complicated to handle from USB configuration, and even if we would use it, defined behavior is not possible because of how listener and subscriber are handled. Signed-off-by: Johann Fischer <johann.fischer@nordicsemi.no> |
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| .. | ||
| device | ||
| device_next | ||
| host | ||
| usb_c | ||
| CMakeLists.txt | ||