From mISDN.org

Contents 1 Howto write mISDN v2 layer1 drivers 1.1 hwskel 1.1.1 latest git version 1.1.2 compile hwskel 1.1.3 load hwskel 1.1.4 test data loop 1.1.5 function description

Howto write mISDN v2 layer1 drivers

hwskel

• hwskel is a base skeleton implementation of a layer1 mISDN v2 driver.
• It can register several mISDN ports, and act like an S0 interface having a cross connector plugged, so all data layer2 sends down to layer1 are looped back immediately.
• hwskel shows what it takes to register an mISDN v2 interface, and how messaging with layer2 is done.

latest git version

• hwskel.c
• hwskel.h

compile hwskel

uncomment line

 CONFIGS+=CONFIG_MISDN_HWSKEL=m

at mISDN/Makefile and run

 make && make modules_install

load hwskel

modprobe mISDN_hwskel

• with numports=n you can create more than one hwskel interface

test data loop

testlayer1 --d --b1 --b2

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function description

• setup_instance() register mISDN interface at mISDN_core
• release_instance() release mISDN interface at mISDN_core
• ph_state(): handle a physical state change (S0 bus), such as ACTIVATE_INDICATION
  • ph_state_te(): handle state changes for TE (Terminal Equipment)
  • ph_state_nt(): handle state changes for NT (Network Terminator)
• layer2 entry callback entry points:
  • hwskel_dctrl(): device control (open channel, etc)
  • hwskel_bctrl(): Bchannel control (close channel, set PCM settings, etc)
  • hwskel_l2l1D(): main layer2 D-Channel entry point for PH_DATA_REQ, PH_ACTIVATE_REQ, PH_DEACTIVATE_REQ
  • hwskel_l2l1B(): main layer2 B-Channel entry point for PH_DATA_REQ, PH_ACTIVATE_REQ, PH_DEACTIVATE_REQ
• layer1 meta module callback
  • hwskel_l1callback() receives callbacks from the layer1 helper instance created via create_l1(). This instance cares about common layer1 jobs, e.g. Activation Timers (T3/T4), etc.
• hwskel_ph_command(): wraps physical bus commands to perform e.g. S0 bus activation/deactivation