Add 'modem ussd' commands.

This CL adds the following modem commands for modems supported by
ModemManager, which are exposed via crosh:

  modem ussd status             - Show the status of any ongoing USSD session
  modem ussd initiate <command> - Initiate a USSD session
  modem ussd respond <response> - Respond to a USSD request
  modme ussd cancel             - Cancel any ongoing USSD session

TEST=Tested the crosh commands below with a Y3400 modem connected to T-Mobile:

  modem ussd
  modem ussd status
  modem ussd initiate
  modem ussd initiate #686#
  modem ussd respond
  modem ussd cancel
  modem ussd bogus-command

Change-Id: I92e0cee193d5c2f383394644d9954df85a204d18
Reviewed-by: Arman Uguray <>
Commit-Queue: Ben Chan <>
Tested-by: Ben Chan <>
1 file changed