-
Alexandre Bailon authored
Explain that the cport number is stored in greybus header. That particullary important because other controller like TPC/IP can open one communication channel per cport, and doesn't need to keep it in the header. Signed-off-by:Alexandre Bailon <abailon@baylibre.com>
Alexandre Bailon authoredExplain that the cport number is stored in greybus header. That particullary important because other controller like TPC/IP can open one communication channel per cport, and doesn't need to keep it in the header. Signed-off-by:
README 1.72 KiB
GBridge (Greybus Bridge) Greybus is a protocol layer for UniPro bus. It was supposed to be used by modular phones to control modules. GBridge is an application that can be used to support other bus / network, such as TCP/IP or bluetooth. I) SVC The SVC take a central piece in Greybus. It is in charge of module hot plug / hot unplug detection, create / destroy connections, etc. In modular phones, the SVC is a micro-controller but here, we don't have a micro-controller to detect modules, so we have to simulate it. SVC protocol has been made for UniPro. Most of the SVC operations are useless or not adapted for non UniPro modules. The current implementation of SVC protocol only implements the mandatory operations though some of them are not correctly implemented (such as DME operations). II) Netlink GBridge is using netlink to communicate with Greybus. Currently, netlink is only used to transmit Greybus operations, but it's planned to use it to control Greybus when SVC protocol is not adapted. II) Controller The controller is actually the link between the SVC, netlink and all the modules. The controller is actually handling some operations made by SVC in phones, such as modules detection and connection. a) Bluetooth controller The Bluetooth controller scans continuously to detect new bluetooth module. When a Bluetooth module with the "GREYBUS" string in its name show up, the controller will generate an hotplug event and create a connection. Currently, the controller open a RFCOMM socket that is not available for BLE. It's planned to use L2CAP instead of RFCOMM to support both Bluetooth and BLE. Because RFCOMM doesn't have any notion of channel, the controller use the padding bytes in operation header to store the cport number.