gsm_fcs_add(9)

💅 NAME 💅

okay so bestie, this is gsm_fcs_add(9) straight out of the Kernel API Manual, and its whole name vibe is literally gsm_fcs_add - update FCS. No cap. 🫶

✨ SYNOPSIS ✨

The signature is exactly this, bestie — do not freestyle it:

u8 gsm_fcs_add (u8 fcs , u8 c );

🎀 ARGUMENTS 🎀

• fcs — Current FCS. Like, the FCS you’re holding right now 💅
• c — Next data. The next data that’s about to get included, periodt.

🦋 DESCRIPTION 🦋

So the move is: update the FCS to include c. That’s it. It uses the algorithm in the specification notes — iconic, lowkey mysterious, but that’s what the page says. ✨

🌈 SEE ALSO 🌈

Kernel file: ./drivers/tty/n_gsm.c — that’s the home base, bestie. The whole squad is:

• gsm_fcs_add_block(9), gsm_read_ea(9), gsm_read_ea_val(9), gsm_encode_modem(9), gsm_encode_params(9), gsm_register_devices(9), gsm_unregister_devices(9), gsm_print_packet(9), gsm_stuff_frame(9), gsm_send(9)
• gsm_dlci_clear_queues(9), gsm_response(9), gsm_command(9), gsm_data_alloc(9), gsm_send_packet(9), gsm_is_flow_ctrl_msg(9), gsm_data_kick(9), __gsm_data_queue(9), gsm_data_queue(9), gsm_dlci_data_output(9)
• gsm_dlci_data_output_framed(9), gsm_dlci_modem_output(9), gsm_dlci_data_sweep(9), gsm_dlci_data_kick(9), gsm_control_command(9), gsm_control_reply(9), gsm_process_modem(9), gsm_process_negotiation(9), gsm_control_modem(9), gsm_control_negotiation(9)
• gsm_control_rls(9), gsm_control_message(9), gsm_control_response(9), gsm_control_keep_alive(9), gsm_control_transmit(9), gsm_control_retransmit(9), gsm_control_send(9), gsm_control_wait(9), gsm_dlci_close(9), gsm_dlci_open(9)
• gsm_dlci_negotiate(9), gsm_dlci_t1(9), gsm_dlci_begin_open(9), gsm_dlci_set_opening(9), gsm_dlci_set_wait_config(9), gsm_dlci_begin_close(9), gsm_dlci_data(9), gsm_dlci_command(9), gsm_kick_timer(9), gsm_dlci_copy_config_values(9)
• gsm_dlci_config(9), gsm_dlci_alloc(9), gsm_dlci_free(9), gsm_dlci_release(9), gsm_queue(9), gsm0_receive_state_check_and_fix(9), gsm0_receive(9), gsm1_receive_state_check_and_fix(9), gsm1_receive(9), gsm_error(9)
• gsm_cleanup_mux(9), gsm_activate_mux(9), gsm_free_mux(9), gsm_free_muxr(9), gsm_alloc_mux(9), gsmld_output(9), gsmld_write_trigger(9), gsmld_write_task(9), gsmld_attach_gsm(9), gsmld_detach_gsm(9)
• gsmld_flush_buffer(9), gsmld_close(9), gsmld_open(9), gsmld_write_wakeup(9), gsmld_read(9), gsmld_write(9), gsmld_poll(9), gsm_modem_upd_via_data(9), gsm_modem_upd_via_msc(9), gsm_modem_update(9), gsm_wait_modem_change(9)

okay that’s the whole page, bestie — short and slay. The source/version is ./drivers/tty, the date is October 2026, and this is literally gsm_fcs_add(9). Bye bestie, mwah 💋✨🎀