[00/10] Add QMI Device Service Request Rate-limit Option

Message

Grant Erickson Feb. 12, 2025, 5:52 a.m. UTC

Certain modems, among them the Quectel Wireless Solutions Co.,
Ltd. (2c7c) BG96 CAT-M1/NB-IoT modem (0296), have a firmware issue
where they can lock up and hang (not responding to subsequent
commands) due to high QMI service request arrival rates.

QMI service request rate limiting is achieved by:

1. Adding a new, optional options structure to qmi_qmux_device_new
   that has its rate-limit "quirk" and minimum request period fields
   set when the modem "QMIMinReqPeriodUs" integer property is set.

2. Adding logic to the QMI driver that, when a minimum request period
   is set, limits the QMI service request rate accordingly.

(1) and (2) are used by the udevng and gobi plugins such that when the
modem vendor and model match 2c7c/0296, then the option to rate limit
QMI service requests is set to no more than one every 2,000 us.

Grant Erickson (10):
  qmi: Added minimum service request period property string.
  qmi: Added enumeration for device quirk flags.
  qmi: Added structure for device options.
  qmi: Added device options parameter to 'qmi_qmux_device_new'.
  qmi: Added minimum request period data member to 'qmi_transport'.
  qmi: Added last request time data member to 'qmi_transport'.
  qmi: Handle request rate limit option in 'qmi_qmux_device_new'.
  qmi: Implement QMI service request rate limiting in 'can_write_data'.
  udevng: Set the QMI minimum service request period for Quectel BG96
    modems.
  gobi: Pass QMI qmux device options to 'qmi_qmux_device_new'.

 drivers/qmimodem/qmi.c | 42 +++++++++++++++++++++++++++++++++++++++++-
 drivers/qmimodem/qmi.h | 42 +++++++++++++++++++++++++++++++++++++++++-
 plugins/gobi.c         | 14 +++++++++++++-
 plugins/udevng.c       | 14 ++++++++++++++
 4 files changed, 109 insertions(+), 3 deletions(-)