Daniel Starke 72206cc730 tty: n_gsm: add keep alive support ... n_gsm is based on the 3GPP 07.010 and its newer version is the 3GPP 27.010. See https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1516 The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to the newer 27.010 here. Chapters 5.4.6.3.4 and 5.1.8.1.3 describe the test command which can be used to test the mux connection between both sides. Currently, no algorithm is implemented to make use of this command. This requires that each multiplexed upper layer protocol supervises the underlying muxer connection to handle possible connection losses. Introduce ioctl commands and functions to optionally enable keep alive handling via the test command as described in chapter 5.4.6.3.4. A single incrementing octet "ka_num" is being used for unique identification of each single keep alive packet. Retries will use the same "ka_num" value as the original packet. Retry count and interval are taken from the general parameters N2 and T2. Add usage description and basic example for the new ioctl to the n_gsm documentation. Note that support for the test command is mandatory and already present in the muxer implementation since the very first version. Also note that the previous ioctl structure gsm_config cannot be extended due to missing checks against zero of the field "unused". Signed-off-by: Daniel Starke <daniel.starke@siemens.com> Link: https://lore.kernel.org/r/20230214122737.1976-1-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2023-02-16 13:50:50 +01:00
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index.rst	Documentation: tty: move moxa-smartio.rst to tty	2022-04-14 18:24:24 +02:00
moxa-smartio.rst	Documentation: tty: move moxa-smartio.rst to tty	2022-04-14 18:24:24 +02:00
n_gsm.rst	tty: n_gsm: add keep alive support	2023-02-16 13:50:50 +01:00
n_tty.rst
tty_buffer.rst
tty_driver.rst
tty_internals.rst
tty_ldisc.rst
tty_port.rst
tty_struct.rst