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/*
* 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");
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