consoles: polling support, kgdboc
polled console handling support, to access a console in an irq-less way while in debug or irq context. absolutely zero impact as long as CONFIG_CONSOLE_POLL is disabled. (which is the default) [ jan.kiszka@siemens.com: lots of cleanups ] [ mingo@elte.hu: redesign, splitups, cleanups. ] Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jan Kiszka <jan.kiszka@web.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Jason Wessel
Ingo Molnar
parent
dc7d552705
commit
f2d937f3bf
8 changed files with 357 additions and 3 deletions
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@ -1155,6 +1155,48 @@ static struct tty_driver *get_tty_driver(dev_t device, int *index)
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return NULL;
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}
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#ifdef CONFIG_CONSOLE_POLL
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/**
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* tty_find_polling_driver - find device of a polled tty
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* @name: name string to match
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* @line: pointer to resulting tty line nr
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*
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* This routine returns a tty driver structure, given a name
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* and the condition that the tty driver is capable of polled
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* operation.
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*/
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struct tty_driver *tty_find_polling_driver(char *name, int *line)
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{
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struct tty_driver *p, *res = NULL;
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int tty_line = 0;
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char *str;
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mutex_lock(&tty_mutex);
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/* Search through the tty devices to look for a match */
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list_for_each_entry(p, &tty_drivers, tty_drivers) {
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str = name + strlen(p->name);
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tty_line = simple_strtoul(str, &str, 10);
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if (*str == ',')
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str++;
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if (*str == '\0')
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str = 0;
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if (tty_line >= 0 && tty_line <= p->num && p->poll_init &&
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!p->poll_init(p, tty_line, str)) {
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res = p;
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*line = tty_line;
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break;
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}
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}
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mutex_unlock(&tty_mutex);
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return res;
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}
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EXPORT_SYMBOL_GPL(tty_find_polling_driver);
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#endif
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/**
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* tty_check_change - check for POSIX terminal changes
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* @tty: tty to check
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@ -3850,6 +3892,11 @@ void tty_set_operations(struct tty_driver *driver,
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driver->write_proc = op->write_proc;
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driver->tiocmget = op->tiocmget;
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driver->tiocmset = op->tiocmset;
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#ifdef CONFIG_CONSOLE_POLL
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driver->poll_init = op->poll_init;
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driver->poll_get_char = op->poll_get_char;
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driver->poll_put_char = op->poll_put_char;
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#endif
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}
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@ -1740,6 +1740,60 @@ static inline void wait_for_xmitr(struct uart_8250_port *up, int bits)
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}
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}
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#ifdef CONFIG_CONSOLE_POLL
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/*
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* Console polling routines for writing and reading from the uart while
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* in an interrupt or debug context.
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*/
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static int serial8250_get_poll_char(struct uart_port *port)
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{
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struct uart_8250_port *up = (struct uart_8250_port *)port;
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unsigned char lsr = serial_inp(up, UART_LSR);
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while (!(lsr & UART_LSR_DR))
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lsr = serial_inp(up, UART_LSR);
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return serial_inp(up, UART_RX);
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}
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static void serial8250_put_poll_char(struct uart_port *port,
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unsigned char c)
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{
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unsigned int ier;
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struct uart_8250_port *up = (struct uart_8250_port *)port;
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/*
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* First save the IER then disable the interrupts
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*/
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ier = serial_in(up, UART_IER);
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if (up->capabilities & UART_CAP_UUE)
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serial_out(up, UART_IER, UART_IER_UUE);
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else
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serial_out(up, UART_IER, 0);
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wait_for_xmitr(up, BOTH_EMPTY);
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/*
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* Send the character out.
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* If a LF, also do CR...
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*/
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serial_out(up, UART_TX, c);
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if (c == 10) {
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wait_for_xmitr(up, BOTH_EMPTY);
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serial_out(up, UART_TX, 13);
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}
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/*
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* Finally, wait for transmitter to become empty
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* and restore the IER
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*/
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wait_for_xmitr(up, BOTH_EMPTY);
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serial_out(up, UART_IER, ier);
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}
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#endif /* CONFIG_CONSOLE_POLL */
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static int serial8250_startup(struct uart_port *port)
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{
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struct uart_8250_port *up = (struct uart_8250_port *)port;
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@ -2386,6 +2440,10 @@ static struct uart_ops serial8250_pops = {
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.request_port = serial8250_request_port,
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.config_port = serial8250_config_port,
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.verify_port = serial8250_verify_port,
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#ifdef CONFIG_CONSOLE_POLL
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.poll_get_char = serial8250_get_poll_char,
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.poll_put_char = serial8250_put_poll_char,
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#endif
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};
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static struct uart_8250_port serial8250_ports[UART_NR];
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@ -961,6 +961,9 @@ config SERIAL_CORE
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config SERIAL_CORE_CONSOLE
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bool
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config CONSOLE_POLL
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bool
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config SERIAL_68328
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bool "68328 serial support"
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depends on M68328 || M68EZ328 || M68VZ328
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@ -66,4 +66,5 @@ obj-$(CONFIG_SERIAL_UARTLITE) += uartlite.o
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obj-$(CONFIG_SERIAL_NETX) += netx-serial.o
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obj-$(CONFIG_SERIAL_OF_PLATFORM) += of_serial.o
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obj-$(CONFIG_SERIAL_KS8695) += serial_ks8695.o
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obj-$(CONFIG_KGDB_SERIAL_CONSOLE) += kgdboc.o
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obj-$(CONFIG_SERIAL_QE) += ucc_uart.o
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163
drivers/serial/kgdboc.c
Normal file
163
drivers/serial/kgdboc.c
Normal file
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@ -0,0 +1,163 @@
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/*
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* Based on the same principle as kgdboe using the NETPOLL api, this
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* driver uses a console polling api to implement a gdb serial inteface
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* which is multiplexed on a console port.
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*
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* Maintainer: Jason Wessel <jason.wessel@windriver.com>
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*
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* 2007-2008 (c) Jason Wessel - Wind River Systems, Inc.
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*/
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#include <linux/kernel.h>
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#include <linux/ctype.h>
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#include <linux/kgdb.h>
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#include <linux/tty.h>
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#define MAX_CONFIG_LEN 40
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static struct kgdb_io kgdboc_io_ops;
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/* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
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static int configured = -1;
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static char config[MAX_CONFIG_LEN];
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static struct kparam_string kps = {
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.string = config,
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.maxlen = MAX_CONFIG_LEN,
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};
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static struct tty_driver *kgdb_tty_driver;
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static int kgdb_tty_line;
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static int kgdboc_option_setup(char *opt)
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{
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if (strlen(opt) > MAX_CONFIG_LEN) {
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printk(KERN_ERR "kgdboc: config string too long\n");
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return -ENOSPC;
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}
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strcpy(config, opt);
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return 0;
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}
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__setup("kgdboc=", kgdboc_option_setup);
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static int configure_kgdboc(void)
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{
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struct tty_driver *p;
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int tty_line = 0;
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int err;
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err = kgdboc_option_setup(config);
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if (err || !strlen(config) || isspace(config[0]))
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goto noconfig;
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err = -ENODEV;
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p = tty_find_polling_driver(config, &tty_line);
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if (!p)
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goto noconfig;
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kgdb_tty_driver = p;
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kgdb_tty_line = tty_line;
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err = kgdb_register_io_module(&kgdboc_io_ops);
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if (err)
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goto noconfig;
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configured = 1;
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return 0;
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noconfig:
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config[0] = 0;
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configured = 0;
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return err;
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}
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static int __init init_kgdboc(void)
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{
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/* Already configured? */
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if (configured == 1)
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return 0;
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return configure_kgdboc();
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}
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static void cleanup_kgdboc(void)
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{
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if (configured == 1)
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kgdb_unregister_io_module(&kgdboc_io_ops);
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}
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static int kgdboc_get_char(void)
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{
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return kgdb_tty_driver->poll_get_char(kgdb_tty_driver, kgdb_tty_line);
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}
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static void kgdboc_put_char(u8 chr)
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{
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kgdb_tty_driver->poll_put_char(kgdb_tty_driver, kgdb_tty_line, chr);
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}
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static int param_set_kgdboc_var(const char *kmessage, struct kernel_param *kp)
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{
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if (strlen(kmessage) >= MAX_CONFIG_LEN) {
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printk(KERN_ERR "kgdboc: config string too long\n");
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return -ENOSPC;
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}
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/* Only copy in the string if the init function has not run yet */
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if (configured < 0) {
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strcpy(config, kmessage);
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return 0;
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}
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if (kgdb_connected) {
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printk(KERN_ERR
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"kgdboc: Cannot reconfigure while KGDB is connected.\n");
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return -EBUSY;
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}
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strcpy(config, kmessage);
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if (configured == 1)
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cleanup_kgdboc();
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/* Go and configure with the new params. */
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return configure_kgdboc();
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}
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static void kgdboc_pre_exp_handler(void)
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{
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/* Increment the module count when the debugger is active */
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if (!kgdb_connected)
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try_module_get(THIS_MODULE);
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}
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static void kgdboc_post_exp_handler(void)
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{
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/* decrement the module count when the debugger detaches */
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if (!kgdb_connected)
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module_put(THIS_MODULE);
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}
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static struct kgdb_io kgdboc_io_ops = {
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.name = "kgdboc",
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.read_char = kgdboc_get_char,
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.write_char = kgdboc_put_char,
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.pre_exception = kgdboc_pre_exp_handler,
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.post_exception = kgdboc_post_exp_handler,
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};
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module_init(init_kgdboc);
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module_exit(cleanup_kgdboc);
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module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644);
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MODULE_PARM_DESC(kgdboc, "<serial_device>[,baud]");
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MODULE_DESCRIPTION("KGDB Console TTY Driver");
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MODULE_LICENSE("GPL");
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@ -1827,7 +1827,7 @@ uart_get_console(struct uart_port *ports, int nr, struct console *co)
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* options. The format of the string is <baud><parity><bits><flow>,
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* eg: 115200n8r
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*/
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void __init
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void
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uart_parse_options(char *options, int *baud, int *parity, int *bits, int *flow)
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{
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char *s = options;
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@ -1842,6 +1842,7 @@ uart_parse_options(char *options, int *baud, int *parity, int *bits, int *flow)
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if (*s)
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*flow = *s;
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}
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EXPORT_SYMBOL_GPL(uart_parse_options);
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struct baud_rates {
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unsigned int rate;
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@ -1872,7 +1873,7 @@ static const struct baud_rates baud_rates[] = {
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* @bits: number of data bits
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* @flow: flow control character - 'r' (rts)
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*/
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int __init
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int
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uart_set_options(struct uart_port *port, struct console *co,
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int baud, int parity, int bits, int flow)
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{
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@ -1924,10 +1925,16 @@ uart_set_options(struct uart_port *port, struct console *co,
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port->mctrl |= TIOCM_DTR;
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port->ops->set_termios(port, &termios, &dummy);
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co->cflag = termios.c_cflag;
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/*
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* Allow the setting of the UART parameters with a NULL console
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* too:
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*/
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if (co)
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co->cflag = termios.c_cflag;
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return 0;
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}
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EXPORT_SYMBOL_GPL(uart_set_options);
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#endif /* CONFIG_SERIAL_CORE_CONSOLE */
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static void uart_change_pm(struct uart_state *state, int pm_state)
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@ -2182,6 +2189,60 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,
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}
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}
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#ifdef CONFIG_CONSOLE_POLL
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static int uart_poll_init(struct tty_driver *driver, int line, char *options)
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{
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struct uart_driver *drv = driver->driver_state;
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struct uart_state *state = drv->state + line;
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struct uart_port *port;
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int baud = 9600;
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int bits = 8;
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int parity = 'n';
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int flow = 'n';
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if (!state || !state->port)
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return -1;
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port = state->port;
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if (!(port->ops->poll_get_char && port->ops->poll_put_char))
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return -1;
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if (options) {
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uart_parse_options(options, &baud, &parity, &bits, &flow);
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return uart_set_options(port, NULL, baud, parity, bits, flow);
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}
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return 0;
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}
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static int uart_poll_get_char(struct tty_driver *driver, int line)
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{
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struct uart_driver *drv = driver->driver_state;
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struct uart_state *state = drv->state + line;
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struct uart_port *port;
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if (!state || !state->port)
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return -1;
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port = state->port;
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return port->ops->poll_get_char(port);
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}
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static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
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{
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struct uart_driver *drv = driver->driver_state;
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struct uart_state *state = drv->state + line;
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struct uart_port *port;
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if (!state || !state->port)
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return;
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port = state->port;
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port->ops->poll_put_char(port, ch);
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}
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#endif
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static const struct tty_operations uart_ops = {
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.open = uart_open,
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.close = uart_close,
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@ -2206,6 +2267,11 @@ static const struct tty_operations uart_ops = {
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#endif
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.tiocmget = uart_tiocmget,
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.tiocmset = uart_tiocmset,
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#ifdef CONFIG_CONSOLE_POLL
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.poll_init = uart_poll_init,
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.poll_get_char = uart_poll_get_char,
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.poll_put_char = uart_poll_put_char,
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#endif
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};
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/**
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@ -213,6 +213,10 @@ struct uart_ops {
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void (*config_port)(struct uart_port *, int);
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int (*verify_port)(struct uart_port *, struct serial_struct *);
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int (*ioctl)(struct uart_port *, unsigned int, unsigned long);
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#ifdef CONFIG_CONSOLE_POLL
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void (*poll_put_char)(struct uart_port *, unsigned char);
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int (*poll_get_char)(struct uart_port *);
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#endif
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};
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#define UART_CONFIG_TYPE (1 << 0)
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@ -125,6 +125,7 @@
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#include <linux/cdev.h>
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struct tty_struct;
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struct tty_driver;
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struct tty_operations {
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int (*open)(struct tty_struct * tty, struct file * filp);
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@ -157,6 +158,11 @@ struct tty_operations {
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int (*tiocmget)(struct tty_struct *tty, struct file *file);
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int (*tiocmset)(struct tty_struct *tty, struct file *file,
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unsigned int set, unsigned int clear);
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#ifdef CONFIG_CONSOLE_POLL
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int (*poll_init)(struct tty_driver *driver, int line, char *options);
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int (*poll_get_char)(struct tty_driver *driver, int line);
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void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
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#endif
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};
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struct tty_driver {
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|
@ -220,6 +226,11 @@ struct tty_driver {
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int (*tiocmget)(struct tty_struct *tty, struct file *file);
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||||
int (*tiocmset)(struct tty_struct *tty, struct file *file,
|
||||
unsigned int set, unsigned int clear);
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||||
#ifdef CONFIG_CONSOLE_POLL
|
||||
int (*poll_init)(struct tty_driver *driver, int line, char *options);
|
||||
int (*poll_get_char)(struct tty_driver *driver, int line);
|
||||
void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
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#endif
|
||||
|
||||
struct list_head tty_drivers;
|
||||
};
|
||||
|
|
@ -230,6 +241,7 @@ struct tty_driver *alloc_tty_driver(int lines);
|
|||
void put_tty_driver(struct tty_driver *driver);
|
||||
void tty_set_operations(struct tty_driver *driver,
|
||||
const struct tty_operations *op);
|
||||
extern struct tty_driver *tty_find_polling_driver(char *name, int *line);
|
||||
|
||||
/* tty driver magic number */
|
||||
#define TTY_DRIVER_MAGIC 0x5402
|
||||
|
|
|
|||
Loading…
Reference in a new issue