1 // SPDX-License-Identifier: GPL-2.0
3  * Based on the same principle as kgdboe using the NETPOLL api, this
5  * which is multiplexed on a console port.
9  * 2007-2008 (c) Jason Wessel - Wind River Systems, Inc.
31 /* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
32 static int configured		= -1;
53  * When we leave the debug trap handler we need to reset the keyboard status
57  * The path to deliver the reset is somewhat circuitous.
59  * To deliver the reset we register an input handler, reset the keyboard and
65  * all its NMI and/or NMI-like oddities. To solve this the kgdboc trap exit code
66  * (the "post_exception" callback) uses irq_work_queue(), which is NMI-safe, to
78 	/* Return an error - we do not want to bind, just to reset */  in kgdboc_reset_connect()
79 	return -ENODEV;  in kgdboc_reset_connect()
109 	 * this work running on different CPUs so they don't try  in kgdboc_restore_input_helper()
157 			kdb_poll_idx--;  in kgdboc_unregister_kbd()
160 			i--;  in kgdboc_unregister_kbd()
199 	int err = -ENODEV;  in configure_kgdboc()
235 		if (cons->device && cons->device(cons, &idx) == p &&  in configure_kgdboc()
278 		/* Convert "no device" to "defer" so we'll keep trying */  in kgdboc_probe()
279 		if (ret == -ENODEV)  in kgdboc_probe()
280 			ret = -EPROBE_DEFER;  in kgdboc_probe()
305 	 * kernel's mechanisms (like -EPROBE_DEFER) to call us when our  in init_kgdboc()
306 	 * underlying tty is ready.  Here we init our platform driver and  in init_kgdboc()
315 		ret = -ENOMEM;  in init_kgdboc()
343 		return -1;  in kgdboc_get_char()
344 	return kgdb_tty_driver->ops->poll_get_char(kgdb_tty_driver,  in kgdboc_get_char()
352 	kgdb_tty_driver->ops->poll_put_char(kgdb_tty_driver,  in kgdboc_put_char()
364 		return -ENOSPC;  in param_set_kgdboc_var()
369 		return -EBUSY;  in param_set_kgdboc_var()
376 	if (len && config[len - 1] == '\n')  in param_set_kgdboc_var()
377 		config[len - 1] = '\0';  in param_set_kgdboc_var()
383 	 * Configure with the new params as long as init already ran.  in param_set_kgdboc_var()
384 	 * Note that we can get called before init if someone loads us  in param_set_kgdboc_var()
386 	 * the odd syntax of "kgdboc.kgdboc=..." on the kernel command.  in param_set_kgdboc_var()
393 	 * specifying an invalid config on the kernel command line vs.  in param_set_kgdboc_var()
395 	 * to configure what was specified on the kernel command line  in param_set_kgdboc_var()
396 	 * we'll leave it in the 'config' and return -EPROBE_DEFER from  in param_set_kgdboc_var()
475 	if (!kgdboc_earlycon_io_ops.cons->read(kgdboc_earlycon_io_ops.cons,  in kgdboc_earlycon_get_char()
484 	kgdboc_earlycon_io_ops.cons->write(kgdboc_earlycon_io_ops.cons, &chr,  in kgdboc_earlycon_put_char()
501 	 * we have no other choice so we keep using it.  Since not all  in kgdboc_earlycon_pre_exp_handler()
527 	con->exit = earlycon_orig_exit;  in kgdboc_earlycon_deferred_exit()
537 	if (kgdboc_earlycon_io_ops.cons->exit == kgdboc_earlycon_deferred_exit)  in kgdboc_earlycon_deinit()
543 		kgdboc_earlycon_io_ops.cons->exit = earlycon_orig_exit;  in kgdboc_earlycon_deinit()
544 	else if (kgdboc_earlycon_io_ops.cons->exit)  in kgdboc_earlycon_deinit()
550 		kgdboc_earlycon_io_ops.cons->exit(kgdboc_earlycon_io_ops.cons);  in kgdboc_earlycon_deinit()
563 #define MAX_CONSOLE_NAME_LEN (sizeof((struct console *) 0)->name)
579 	 * Hold the console_list_lock to guarantee that no consoles are  in kgdboc_earlycon_init()
581 	 * Trapping the exit() callback relies on exit() not being  in kgdboc_earlycon_init()
583 	 * traversal of the console list and race-free reading of @flags.  in kgdboc_earlycon_init()
587 		if (con->write && con->read &&  in kgdboc_earlycon_init()
588 		    (con->flags & (CON_BOOT | CON_ENABLED)) &&  in kgdboc_earlycon_init()
589 		    (!opt || !opt[0] || strcmp(con->name, opt) == 0))  in kgdboc_earlycon_init()
597 		 * in first and, in any case, on ACPI systems earlycon may  in kgdboc_earlycon_init()
604 			pr_info("No suitable earlycon yet, will try later\n");  in kgdboc_earlycon_init()
616 	pr_info("Going to register kgdb with earlycon '%s'\n", con->name);  in kgdboc_earlycon_init()
622 		earlycon_orig_exit = con->exit;  in kgdboc_earlycon_init()
623 		con->exit = kgdboc_earlycon_deferred_exit;  in kgdboc_earlycon_init()
629 	/* Non-zero means malformed option so we always return zero */  in kgdboc_earlycon_init()