/* * Based on the same principle as kgdboe using the NETPOLL api, this * driver uses a console polling api to implement a gdb serial inteface * which is multiplexed on a console port. * * Maintainer: Jason Wessel <jason.wessel@windriver.com> * * 2007-2008 (c) Jason Wessel - Wind River Systems, Inc. * * This file is licensed under the terms of the GNU General Public * License version 2. This program is licensed "as is" without any * warranty of any kind, whether express or implied. */ #include <linux/kernel.h> #include <linux/ctype.h> #include <linux/kgdb.h> #include <linux/tty.h> #define MAX_CONFIG_LEN 40 static struct kgdb_io kgdboc_io_ops; /* -1 = init not run yet, 0 = unconfigured, 1 = configured. */ static int configured = -1; static char config[MAX_CONFIG_LEN]; static struct kparam_string kps = { .string = config, .maxlen = MAX_CONFIG_LEN, }; static struct tty_driver *kgdb_tty_driver; static int kgdb_tty_line; static int kgdboc_option_setup(char *opt) { if (strlen(opt) > MAX_CONFIG_LEN) { printk(KERN_ERR "kgdboc: config string too long\n"); return -ENOSPC; } strcpy(config, opt); return 0; } __setup("kgdboc=", kgdboc_option_setup); static int configure_kgdboc(void) { struct tty_driver *p; int tty_line = 0; int err; err = kgdboc_option_setup(config); if (err || !strlen(config) || isspace(config[0])) goto noconfig; err = -ENODEV; p = tty_find_polling_driver(config, &tty_line); if (!p) goto noconfig; kgdb_tty_driver = p; kgdb_tty_line = tty_line; err = kgdb_register_io_module(&kgdboc_io_ops); if (err) goto noconfig; configured = 1; return 0; noconfig: config[0] = 0; configured = 0; return err; } static int __init init_kgdboc(void) { /* Already configured? */ if (configured == 1) return 0; return configure_kgdboc(); } static void cleanup_kgdboc(void) { if (configured == 1) kgdb_unregister_io_module(&kgdboc_io_ops); } static int kgdboc_get_char(void) { return kgdb_tty_driver->ops->poll_get_char(kgdb_tty_driver, kgdb_tty_line); } static void kgdboc_put_char(u8 chr) { kgdb_tty_driver->ops->poll_put_char(kgdb_tty_driver, kgdb_tty_line, chr); } static int param_set_kgdboc_var(const char *kmessage, struct kernel_param *kp) { int len = strlen(kmessage); if (len >= MAX_CONFIG_LEN) { printk(KERN_ERR "kgdboc: config string too long\n"); return -ENOSPC; } /* Only copy in the string if the init function has not run yet */ if (configured < 0) { strcpy(config, kmessage); return 0; } if (kgdb_connected) { printk(KERN_ERR "kgdboc: Cannot reconfigure while KGDB is connected.\n"); return -EBUSY; } strcpy(config, kmessage); /* Chop out \n char as a result of echo */ if (config[len - 1] == '\n') config[len - 1] = '\0'; if (configured == 1) cleanup_kgdboc(); /* Go and configure with the new params. */ return configure_kgdboc(); } static void kgdboc_pre_exp_handler(void) { /* Increment the module count when the debugger is active */ if (!kgdb_connected) try_module_get(THIS_MODULE); } static void kgdboc_post_exp_handler(void) { /* decrement the module count when the debugger detaches */ if (!kgdb_connected) module_put(THIS_MODULE); } static struct kgdb_io kgdboc_io_ops = { .name = "kgdboc", .read_char = kgdboc_get_char, .write_char = kgdboc_put_char, .pre_exception = kgdboc_pre_exp_handler, .post_exception = kgdboc_post_exp_handler, }; module_init(init_kgdboc); module_exit(cleanup_kgdboc); module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644); MODULE_PARM_DESC(kgdboc, "<serial_device>[,baud]"); MODULE_DESCRIPTION("KGDB Console TTY Driver"); MODULE_LICENSE("GPL");