arch/um/drivers/chan_kern.c - kernel/msm-5.4 - Gitiles

 /*
  * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
  * Licensed under the GPL
  */

 #include <linux/stddef.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/tty.h>
 #include <linux/string.h>
 #include <linux/tty_flip.h>
 #include <asm/irq.h>
 #include "chan_kern.h"
 #include "user_util.h"
 #include "kern.h"
 #include "irq_user.h"
 #include "sigio.h"
 #include "line.h"
 #include "os.h"

 /* XXX: could well be moved to somewhere else, if needed. */
 static int my_printf(const char * fmt, ...)
 	__attribute__ ((format (printf, 1, 2)));

 static int my_printf(const char * fmt, ...)
 {
 	/* Yes, can be called on atomic context.*/
 	char *buf = kmalloc(4096, GFP_ATOMIC);
 	va_list args;
 	int r;

 	if (!buf) {
 		/* We print directly fmt.
 		 * Yes, yes, yes, feel free to complain. */
 		r = strlen(fmt);
 	} else {
 		va_start(args, fmt);
 		r = vsprintf(buf, fmt, args);
 		va_end(args);
 		fmt = buf;
 	}

 	if (r)
 		r = os_write_file(1, fmt, r);
 	return r;

 }

 #ifdef CONFIG_NOCONFIG_CHAN
 /* Despite its name, there's no added trailing newline. */
 static int my_puts(const char * buf)
 {
 	return os_write_file(1, buf, strlen(buf));
 }

 static void *not_configged_init(char *str, int device, struct chan_opts *opts)
 {
 	my_puts("Using a channel type which is configured out of "
 	       "UML\n");
 	return NULL;
 }

 static int not_configged_open(int input, int output, int primary, void *data,
 			      char **dev_out)
 {
 	my_puts("Using a channel type which is configured out of "
 	       "UML\n");
 	return -ENODEV;
 }

 static void not_configged_close(int fd, void *data)
 {
 	my_puts("Using a channel type which is configured out of "
 	       "UML\n");
 }

 static int not_configged_read(int fd, char *c_out, void *data)
 {
 	my_puts("Using a channel type which is configured out of "
 	       "UML\n");
 	return -EIO;
 }

 static int not_configged_write(int fd, const char *buf, int len, void *data)
 {
 	my_puts("Using a channel type which is configured out of "
 	       "UML\n");
 	return -EIO;
 }

 static int not_configged_console_write(int fd, const char *buf, int len)
 {
 	my_puts("Using a channel type which is configured out of "
 	       "UML\n");
 	return -EIO;
 }

 static int not_configged_window_size(int fd, void *data, unsigned short *rows,
 				     unsigned short *cols)
 {
 	my_puts("Using a channel type which is configured out of "
 	       "UML\n");
 	return -ENODEV;
 }

 static void not_configged_free(void *data)
 {
 	my_puts("Using a channel type which is configured out of "
 	       "UML\n");
 }

 static struct chan_ops not_configged_ops = {
 	.init		= not_configged_init,
 	.open		= not_configged_open,
 	.close		= not_configged_close,
 	.read		= not_configged_read,
 	.write		= not_configged_write,
 	.console_write	= not_configged_console_write,
 	.window_size	= not_configged_window_size,
 	.free		= not_configged_free,
 	.winch		= 0,
 };
 #endif /* CONFIG_NOCONFIG_CHAN */

 void generic_close(int fd, void *unused)
 {
 	os_close_file(fd);
 }

 int generic_read(int fd, char *c_out, void *unused)
 {
 	int n;

 	n = os_read_file(fd, c_out, sizeof(*c_out));

 	if(n == -EAGAIN)
 		return 0;
 	else if(n == 0)
 		return -EIO;
 	return n;
 }

 /* XXX Trivial wrapper around os_write_file */

 int generic_write(int fd, const char *buf, int n, void *unused)
 {
 	return os_write_file(fd, buf, n);
 }

 int generic_window_size(int fd, void *unused, unsigned short *rows_out,
 			unsigned short *cols_out)
 {
 	int rows, cols;
 	int ret;

 	ret = os_window_size(fd, &rows, &cols);
 	if(ret < 0)
 		return ret;

 	ret = ((*rows_out != rows) || (*cols_out != cols));

 	*rows_out = rows;
 	*cols_out = cols;

 	return ret;
 }

 void generic_free(void *data)
 {
 	kfree(data);
 }

 static void tty_receive_char(struct tty_struct *tty, char ch)
 {
 	if(tty == NULL) return;

 	if(I_IXON(tty) && !I_IXOFF(tty) && !tty->raw) {
 		if(ch == STOP_CHAR(tty)){
 			stop_tty(tty);
 			return;
 		}
 		else if(ch == START_CHAR(tty)){
 			start_tty(tty);
 			return;
 		}
 	}

 	tty_insert_flip_char(tty, ch, TTY_NORMAL);
 }

 static int open_one_chan(struct chan *chan)
 {
 	int fd;

 	if(chan->opened)
 		return 0;

 	if(chan->ops->open == NULL)
 		fd = 0;
 	else fd = (*chan->ops->open)(chan->input, chan->output, chan->primary,
 				     chan->data, &chan->dev);
 	if(fd < 0)
 		return fd;
 	chan->fd = fd;

 	chan->opened = 1;
 	return 0;
 }

 int open_chan(struct list_head *chans)
 {
 	struct list_head *ele;
 	struct chan *chan;
 	int ret, err = 0;

 	list_for_each(ele, chans){
 		chan = list_entry(ele, struct chan, list);
 		ret = open_one_chan(chan);
 		if(chan->primary)
 			err = ret;
 	}
 	return err;
 }

 void chan_enable_winch(struct list_head *chans, struct tty_struct *tty)
 {
 	struct list_head *ele;
 	struct chan *chan;

 	list_for_each(ele, chans){
 		chan = list_entry(ele, struct chan, list);
 		if(chan->primary && chan->output && chan->ops->winch){
 			register_winch(chan->fd, tty);
 			return;
 		}
 	}
 }

 void enable_chan(struct line *line)
 {
 	struct list_head *ele;
 	struct chan *chan;

 	list_for_each(ele, &line->chan_list){
 		chan = list_entry(ele, struct chan, list);
 		if(open_one_chan(chan))
 			continue;

 		if(chan->enabled)
 			continue;
 		line_setup_irq(chan->fd, chan->input, chan->output, line,
 			       chan);
 		chan->enabled = 1;
 	}
 }

 static LIST_HEAD(irqs_to_free);

 void free_irqs(void)
 {
 	struct chan *chan;

 	while(!list_empty(&irqs_to_free)){
 		chan = list_entry(irqs_to_free.next, struct chan, free_list);
 		list_del(&chan->free_list);

 		if(chan->input)
 			free_irq(chan->line->driver->read_irq, chan);
 		if(chan->output)
 			free_irq(chan->line->driver->write_irq, chan);
 		chan->enabled = 0;
 	}
 }

 static void close_one_chan(struct chan *chan, int delay_free_irq)
 {
 	if(!chan->opened)
 		return;

 	if(delay_free_irq){
 		list_add(&chan->free_list, &irqs_to_free);
 	}
 	else {
 		if(chan->input)
 			free_irq(chan->line->driver->read_irq, chan);
 		if(chan->output)
 			free_irq(chan->line->driver->write_irq, chan);
 		chan->enabled = 0;
 	}
 	if(chan->ops->close != NULL)
 		(*chan->ops->close)(chan->fd, chan->data);

 	chan->opened = 0;
 	chan->fd = -1;
 }

 void close_chan(struct list_head *chans, int delay_free_irq)
 {
 	struct chan *chan;

 	/* Close in reverse order as open in case more than one of them
 	 * refers to the same device and they save and restore that device's
 	 * state.  Then, the first one opened will have the original state,
 	 * so it must be the last closed.
 	 */
 	list_for_each_entry_reverse(chan, chans, list) {
 		close_one_chan(chan, delay_free_irq);
 	}
 }

 void deactivate_chan(struct list_head *chans, int irq)
 {
 	struct list_head *ele;

 	struct chan *chan;
 	list_for_each(ele, chans) {
 		chan = list_entry(ele, struct chan, list);

 		if(chan->enabled && chan->input)
 			deactivate_fd(chan->fd, irq);
 	}
 }

 void reactivate_chan(struct list_head *chans, int irq)
 {
 	struct list_head *ele;
 	struct chan *chan;

 	list_for_each(ele, chans) {
 		chan = list_entry(ele, struct chan, list);

 		if(chan->enabled && chan->input)
 			reactivate_fd(chan->fd, irq);
 	}
 }

 int write_chan(struct list_head *chans, const char *buf, int len,
 	       int write_irq)
 {
 	struct list_head *ele;
 	struct chan *chan = NULL;
 	int n, ret = 0;

 	list_for_each(ele, chans) {
 		chan = list_entry(ele, struct chan, list);
 		if (!chan->output || (chan->ops->write == NULL))
 			continue;
 		n = chan->ops->write(chan->fd, buf, len, chan->data);
 		if (chan->primary) {
 			ret = n;
 			if ((ret == -EAGAIN) || ((ret >= 0) && (ret < len)))
 				reactivate_fd(chan->fd, write_irq);
 		}
 	}
 	return ret;
 }

 int console_write_chan(struct list_head *chans, const char *buf, int len)
 {
 	struct list_head *ele;
 	struct chan *chan;
 	int n, ret = 0;

 	list_for_each(ele, chans){
 		chan = list_entry(ele, struct chan, list);
 		if(!chan->output || (chan->ops->console_write == NULL))
 			continue;
 		n = chan->ops->console_write(chan->fd, buf, len);
 		if(chan->primary) ret = n;
 	}
 	return ret;
 }

 int console_open_chan(struct line *line, struct console *co,
 		      struct chan_opts *opts)
 {
 	int err;

 	err = open_chan(&line->chan_list);
 	if(err)
 		return err;

 	printk("Console initialized on /dev/%s%d\n",co->name,co->index);
 	return 0;
 }

 int chan_window_size(struct list_head *chans, unsigned short *rows_out,
 		      unsigned short *cols_out)
 {
 	struct list_head *ele;
 	struct chan *chan;

 	list_for_each(ele, chans){
 		chan = list_entry(ele, struct chan, list);
 		if(chan->primary){
 			if(chan->ops->window_size == NULL)
 				return 0;
 			return chan->ops->window_size(chan->fd, chan->data,
 						      rows_out, cols_out);
 		}
 	}
 	return 0;
 }

 static void free_one_chan(struct chan *chan, int delay_free_irq)
 {
 	list_del(&chan->list);

 	close_one_chan(chan, delay_free_irq);

 	if(chan->ops->free != NULL)
 		(*chan->ops->free)(chan->data);

 	if(chan->primary && chan->output) ignore_sigio_fd(chan->fd);
 	kfree(chan);
 }

 static void free_chan(struct list_head *chans, int delay_free_irq)
 {
 	struct list_head *ele, *next;
 	struct chan *chan;

 	list_for_each_safe(ele, next, chans){
 		chan = list_entry(ele, struct chan, list);
 		free_one_chan(chan, delay_free_irq);
 	}
 }

 static int one_chan_config_string(struct chan *chan, char *str, int size,
 				  char **error_out)
 {
 	int n = 0;

 	if(chan == NULL){
 		CONFIG_CHUNK(str, size, n, "none", 1);
 		return n;
 	}

 	CONFIG_CHUNK(str, size, n, chan->ops->type, 0);

 	if(chan->dev == NULL){
 		CONFIG_CHUNK(str, size, n, "", 1);
 		return n;
 	}

 	CONFIG_CHUNK(str, size, n, ":", 0);
 	CONFIG_CHUNK(str, size, n, chan->dev, 0);

 	return n;
 }

 static int chan_pair_config_string(struct chan *in, struct chan *out,
 				   char *str, int size, char **error_out)
 {
 	int n;

 	n = one_chan_config_string(in, str, size, error_out);
 	str += n;
 	size -= n;

 	if(in == out){
 		CONFIG_CHUNK(str, size, n, "", 1);
 		return n;
 	}

 	CONFIG_CHUNK(str, size, n, ",", 1);
 	n = one_chan_config_string(out, str, size, error_out);
 	str += n;
 	size -= n;
 	CONFIG_CHUNK(str, size, n, "", 1);

 	return n;
 }

 int chan_config_string(struct list_head *chans, char *str, int size,
 		       char **error_out)
 {
 	struct list_head *ele;
 	struct chan *chan, *in = NULL, *out = NULL;

 	list_for_each(ele, chans){
 		chan = list_entry(ele, struct chan, list);
 		if(!chan->primary)
 			continue;
 		if(chan->input)
 			in = chan;
 		if(chan->output)
 			out = chan;
 	}

 	return chan_pair_config_string(in, out, str, size, error_out);
 }

 struct chan_type {
 	char *key;
 	struct chan_ops *ops;
 };

 static struct chan_type chan_table[] = {
 	{ "fd", &fd_ops },

 #ifdef CONFIG_NULL_CHAN
 	{ "null", &null_ops },
 #else
 	{ "null", &not_configged_ops },
 #endif

 #ifdef CONFIG_PORT_CHAN
 	{ "port", &port_ops },
 #else
 	{ "port", &not_configged_ops },
 #endif

 #ifdef CONFIG_PTY_CHAN
 	{ "pty", &pty_ops },
 	{ "pts", &pts_ops },
 #else
 	{ "pty", &not_configged_ops },
 	{ "pts", &not_configged_ops },
 #endif

 #ifdef CONFIG_TTY_CHAN
 	{ "tty", &tty_ops },
 #else
 	{ "tty", &not_configged_ops },
 #endif

 #ifdef CONFIG_XTERM_CHAN
 	{ "xterm", &xterm_ops },
 #else
 	{ "xterm", &not_configged_ops },
 #endif
 };

 static struct chan *parse_chan(struct line *line, char *str, int device,
 			       struct chan_opts *opts)
 {
 	struct chan_type *entry;
 	struct chan_ops *ops;
 	struct chan *chan;
 	void *data;
 	int i;

 	ops = NULL;
 	data = NULL;
 	for(i = 0; i < sizeof(chan_table)/sizeof(chan_table[0]); i++){
 		entry = &chan_table[i];
 		if(!strncmp(str, entry->key, strlen(entry->key))){
 			ops = entry->ops;
 			str += strlen(entry->key);
 			break;
 		}
 	}
 	if(ops == NULL){
 		my_printf("parse_chan couldn't parse \"%s\"\n",
 		       str);
 		return NULL;
 	}
 	if(ops->init == NULL)
 		return NULL;
 	data = (*ops->init)(str, device, opts);
 	if(data == NULL)
 		return NULL;

 	chan = kmalloc(sizeof(*chan), GFP_ATOMIC);
 	if(chan == NULL)
 		return NULL;
 	*chan = ((struct chan) { .list	 	= LIST_HEAD_INIT(chan->list),
 				 .free_list 	=
 				 	LIST_HEAD_INIT(chan->free_list),
 				 .line		= line,
 				 .primary	= 1,
 				 .input		= 0,
 				 .output 	= 0,
 				 .opened  	= 0,
 				 .enabled  	= 0,
 				 .fd 		= -1,
 				 .ops 		= ops,
 				 .data 		= data });
 	return chan;
 }

 int parse_chan_pair(char *str, struct line *line, int device,
 		    struct chan_opts *opts)
 {
 	struct list_head *chans = &line->chan_list;
 	struct chan *new, *chan;
 	char *in, *out;

 	if(!list_empty(chans)){
 		chan = list_entry(chans->next, struct chan, list);
 		free_chan(chans, 0);
 		INIT_LIST_HEAD(chans);
 	}

 	out = strchr(str, ',');
 	if(out != NULL){
 		in = str;
 		*out = '\0';
 		out++;
 		new = parse_chan(line, in, device, opts);
 		if(new == NULL)
 			return -1;

 		new->input = 1;
 		list_add(&new->list, chans);

 		new = parse_chan(line, out, device, opts);
 		if(new == NULL)
 			return -1;

 		list_add(&new->list, chans);
 		new->output = 1;
 	}
 	else {
 		new = parse_chan(line, str, device, opts);
 		if(new == NULL)
 			return -1;

 		list_add(&new->list, chans);
 		new->input = 1;
 		new->output = 1;
 	}
 	return 0;
 }

 int chan_out_fd(struct list_head *chans)
 {
 	struct list_head *ele;
 	struct chan *chan;

 	list_for_each(ele, chans){
 		chan = list_entry(ele, struct chan, list);
 		if(chan->primary && chan->output)
 			return chan->fd;
 	}
 	return -1;
 }

 void chan_interrupt(struct list_head *chans, struct work_struct *task,
 		    struct tty_struct *tty, int irq)
 {
 	struct list_head *ele, *next;
 	struct chan *chan;
 	int err;
 	char c;

 	list_for_each_safe(ele, next, chans){
 		chan = list_entry(ele, struct chan, list);
 		if(!chan->input || (chan->ops->read == NULL)) continue;
 		do {
 			if (tty && !tty_buffer_request_room(tty, 1)) {
 				schedule_delayed_work(task, 1);
 				goto out;
 			}
 			err = chan->ops->read(chan->fd, &c, chan->data);
 			if(err > 0)
 				tty_receive_char(tty, c);
 		} while(err > 0);

 		if(err == 0) reactivate_fd(chan->fd, irq);
 		if(err == -EIO){
 			if(chan->primary){
 				if(tty != NULL)
 					tty_hangup(tty);
 				close_chan(chans, 1);
 				return;
 			}
 			else close_one_chan(chan, 1);
 		}
 	}
  out:
 	if(tty) tty_flip_buffer_push(tty);
 }
	/*
	* Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
	* Licensed under the GPL
	*/

	#include <linux/stddef.h>
	#include <linux/kernel.h>
	#include <linux/list.h>
	#include <linux/slab.h>
	#include <linux/tty.h>
	#include <linux/string.h>
	#include <linux/tty_flip.h>
	#include <asm/irq.h>
	#include "chan_kern.h"
	#include "user_util.h"
	#include "kern.h"
	#include "irq_user.h"
	#include "sigio.h"
	#include "line.h"
	#include "os.h"

	/* XXX: could well be moved to somewhere else, if needed. */
	static int my_printf(const char * fmt, ...)
	__attribute__ ((format (printf, 1, 2)));

	static int my_printf(const char * fmt, ...)
	{
	/* Yes, can be called on atomic context.*/
	char *buf = kmalloc(4096, GFP_ATOMIC);
	va_list args;
	int r;

	if (!buf) {
	/* We print directly fmt.
	* Yes, yes, yes, feel free to complain. */
	r = strlen(fmt);
	} else {
	va_start(args, fmt);
	r = vsprintf(buf, fmt, args);
	va_end(args);
	fmt = buf;
	}

	if (r)
	r = os_write_file(1, fmt, r);
	return r;

	}

	#ifdef CONFIG_NOCONFIG_CHAN
	/* Despite its name, there's no added trailing newline. */
	static int my_puts(const char * buf)
	{
	return os_write_file(1, buf, strlen(buf));
	}

	static void not_configged_init(char str, int device, struct chan_opts *opts)
	{
	my_puts("Using a channel type which is configured out of "
	"UML\n");
	return NULL;
	}

	static int not_configged_open(int input, int output, int primary, void *data,
	char **dev_out)
	{
	my_puts("Using a channel type which is configured out of "
	"UML\n");
	return -ENODEV;
	}

	static void not_configged_close(int fd, void *data)
	{
	my_puts("Using a channel type which is configured out of "
	"UML\n");
	}

	static int not_configged_read(int fd, char c_out, void data)
	{
	my_puts("Using a channel type which is configured out of "
	"UML\n");
	return -EIO;
	}

	static int not_configged_write(int fd, const char buf, int len, void data)
	{
	my_puts("Using a channel type which is configured out of "
	"UML\n");
	return -EIO;
	}

	static int not_configged_console_write(int fd, const char *buf, int len)
	{
	my_puts("Using a channel type which is configured out of "
	"UML\n");
	return -EIO;
	}

	static int not_configged_window_size(int fd, void data, unsigned short rows,
	unsigned short *cols)
	{
	my_puts("Using a channel type which is configured out of "
	"UML\n");
	return -ENODEV;
	}

	static void not_configged_free(void *data)
	{
	my_puts("Using a channel type which is configured out of "
	"UML\n");
	}

	static struct chan_ops not_configged_ops = {
	.init = not_configged_init,
	.open = not_configged_open,
	.close = not_configged_close,
	.read = not_configged_read,
	.write = not_configged_write,
	.console_write = not_configged_console_write,
	.window_size = not_configged_window_size,
	.free = not_configged_free,
	.winch = 0,
	};
	#endif /* CONFIG_NOCONFIG_CHAN */

	void generic_close(int fd, void *unused)
	{
	os_close_file(fd);
	}

	int generic_read(int fd, char c_out, void unused)
	{
	int n;

	n = os_read_file(fd, c_out, sizeof(*c_out));

	if(n == -EAGAIN)
	return 0;
	else if(n == 0)
	return -EIO;
	return n;
	}

	/* XXX Trivial wrapper around os_write_file */

	int generic_write(int fd, const char buf, int n, void unused)
	{
	return os_write_file(fd, buf, n);
	}

	int generic_window_size(int fd, void unused, unsigned short rows_out,
	unsigned short *cols_out)
	{
	int rows, cols;
	int ret;

	ret = os_window_size(fd, &rows, &cols);
	if(ret < 0)
	return ret;

	ret = ((rows_out != rows) \|\| (cols_out != cols));

	*rows_out = rows;
	*cols_out = cols;

	return ret;
	}

	void generic_free(void *data)
	{
	kfree(data);
	}

	static void tty_receive_char(struct tty_struct *tty, char ch)
	{
	if(tty == NULL) return;

	if(I_IXON(tty) && !I_IXOFF(tty) && !tty->raw) {
	if(ch == STOP_CHAR(tty)){
	stop_tty(tty);
	return;
	}
	else if(ch == START_CHAR(tty)){
	start_tty(tty);
	return;
	}
	}

	tty_insert_flip_char(tty, ch, TTY_NORMAL);
	}

	static int open_one_chan(struct chan *chan)
	{
	int fd;

	if(chan->opened)
	return 0;

	if(chan->ops->open == NULL)
	fd = 0;
	else fd = (*chan->ops->open)(chan->input, chan->output, chan->primary,
	chan->data, &chan->dev);
	if(fd < 0)
	return fd;
	chan->fd = fd;

	chan->opened = 1;
	return 0;
	}

	int open_chan(struct list_head *chans)
	{
	struct list_head *ele;
	struct chan *chan;
	int ret, err = 0;

	list_for_each(ele, chans){
	chan = list_entry(ele, struct chan, list);
	ret = open_one_chan(chan);
	if(chan->primary)
	err = ret;
	}
	return err;
	}

	void chan_enable_winch(struct list_head chans, struct tty_struct tty)
	{
	struct list_head *ele;
	struct chan *chan;

	list_for_each(ele, chans){
	chan = list_entry(ele, struct chan, list);
	if(chan->primary && chan->output && chan->ops->winch){
	register_winch(chan->fd, tty);
	return;
	}
	}
	}

	void enable_chan(struct line *line)
	{
	struct list_head *ele;
	struct chan *chan;

	list_for_each(ele, &line->chan_list){
	chan = list_entry(ele, struct chan, list);
	if(open_one_chan(chan))
	continue;

	if(chan->enabled)
	continue;
	line_setup_irq(chan->fd, chan->input, chan->output, line,
	chan);
	chan->enabled = 1;
	}
	}

	static LIST_HEAD(irqs_to_free);

	void free_irqs(void)
	{
	struct chan *chan;

	while(!list_empty(&irqs_to_free)){
	chan = list_entry(irqs_to_free.next, struct chan, free_list);
	list_del(&chan->free_list);

	if(chan->input)
	free_irq(chan->line->driver->read_irq, chan);
	if(chan->output)
	free_irq(chan->line->driver->write_irq, chan);
	chan->enabled = 0;
	}
	}

	static void close_one_chan(struct chan *chan, int delay_free_irq)
	{
	if(!chan->opened)
	return;

	if(delay_free_irq){
	list_add(&chan->free_list, &irqs_to_free);
	}
	else {
	if(chan->input)
	free_irq(chan->line->driver->read_irq, chan);
	if(chan->output)
	free_irq(chan->line->driver->write_irq, chan);
	chan->enabled = 0;
	}
	if(chan->ops->close != NULL)
	(*chan->ops->close)(chan->fd, chan->data);

	chan->opened = 0;
	chan->fd = -1;
	}

	void close_chan(struct list_head *chans, int delay_free_irq)
	{
	struct chan *chan;

	/* Close in reverse order as open in case more than one of them
	* refers to the same device and they save and restore that device's
	* state. Then, the first one opened will have the original state,
	* so it must be the last closed.
	*/
	list_for_each_entry_reverse(chan, chans, list) {
	close_one_chan(chan, delay_free_irq);
	}
	}

	void deactivate_chan(struct list_head *chans, int irq)
	{
	struct list_head *ele;

	struct chan *chan;
	list_for_each(ele, chans) {
	chan = list_entry(ele, struct chan, list);

	if(chan->enabled && chan->input)
	deactivate_fd(chan->fd, irq);
	}
	}

	void reactivate_chan(struct list_head *chans, int irq)
	{
	struct list_head *ele;
	struct chan *chan;

	list_for_each(ele, chans) {
	chan = list_entry(ele, struct chan, list);

	if(chan->enabled && chan->input)
	reactivate_fd(chan->fd, irq);
	}
	}

	int write_chan(struct list_head chans, const char buf, int len,
	int write_irq)
	{
	struct list_head *ele;
	struct chan *chan = NULL;
	int n, ret = 0;

	list_for_each(ele, chans) {
	chan = list_entry(ele, struct chan, list);
	if (!chan->output \|\| (chan->ops->write == NULL))
	continue;
	n = chan->ops->write(chan->fd, buf, len, chan->data);
	if (chan->primary) {
	ret = n;
	if ((ret == -EAGAIN) \|\| ((ret >= 0) && (ret < len)))
	reactivate_fd(chan->fd, write_irq);
	}
	}
	return ret;
	}

	int console_write_chan(struct list_head chans, const char buf, int len)
	{
	struct list_head *ele;
	struct chan *chan;
	int n, ret = 0;

	list_for_each(ele, chans){
	chan = list_entry(ele, struct chan, list);
	if(!chan->output \|\| (chan->ops->console_write == NULL))
	continue;
	n = chan->ops->console_write(chan->fd, buf, len);
	if(chan->primary) ret = n;
	}
	return ret;
	}

	int console_open_chan(struct line line, struct console co,
	struct chan_opts *opts)
	{
	int err;

	err = open_chan(&line->chan_list);
	if(err)
	return err;

	printk("Console initialized on /dev/%s%d\n",co->name,co->index);
	return 0;
	}

	int chan_window_size(struct list_head chans, unsigned short rows_out,
	unsigned short *cols_out)
	{
	struct list_head *ele;
	struct chan *chan;

	list_for_each(ele, chans){
	chan = list_entry(ele, struct chan, list);
	if(chan->primary){
	if(chan->ops->window_size == NULL)
	return 0;
	return chan->ops->window_size(chan->fd, chan->data,
	rows_out, cols_out);
	}
	}
	return 0;
	}

	static void free_one_chan(struct chan *chan, int delay_free_irq)
	{
	list_del(&chan->list);

	close_one_chan(chan, delay_free_irq);

	if(chan->ops->free != NULL)
	(*chan->ops->free)(chan->data);

	if(chan->primary && chan->output) ignore_sigio_fd(chan->fd);
	kfree(chan);
	}

	static void free_chan(struct list_head *chans, int delay_free_irq)
	{
	struct list_head ele, next;
	struct chan *chan;

	list_for_each_safe(ele, next, chans){
	chan = list_entry(ele, struct chan, list);
	free_one_chan(chan, delay_free_irq);
	}
	}

	static int one_chan_config_string(struct chan chan, char str, int size,
	char **error_out)
	{
	int n = 0;

	if(chan == NULL){
	CONFIG_CHUNK(str, size, n, "none", 1);
	return n;
	}

	CONFIG_CHUNK(str, size, n, chan->ops->type, 0);

	if(chan->dev == NULL){
	CONFIG_CHUNK(str, size, n, "", 1);
	return n;
	}

	CONFIG_CHUNK(str, size, n, ":", 0);
	CONFIG_CHUNK(str, size, n, chan->dev, 0);

	return n;
	}

	static int chan_pair_config_string(struct chan in, struct chan out,
	char str, int size, char *error_out)
	{
	int n;

	n = one_chan_config_string(in, str, size, error_out);
	str += n;
	size -= n;

	if(in == out){
	CONFIG_CHUNK(str, size, n, "", 1);
	return n;
	}

	CONFIG_CHUNK(str, size, n, ",", 1);
	n = one_chan_config_string(out, str, size, error_out);
	str += n;
	size -= n;
	CONFIG_CHUNK(str, size, n, "", 1);

	return n;
	}

	int chan_config_string(struct list_head chans, char str, int size,
	char **error_out)
	{
	struct list_head *ele;
	struct chan chan, in = NULL, *out = NULL;

	list_for_each(ele, chans){
	chan = list_entry(ele, struct chan, list);
	if(!chan->primary)
	continue;
	if(chan->input)
	in = chan;
	if(chan->output)
	out = chan;
	}

	return chan_pair_config_string(in, out, str, size, error_out);
	}

	struct chan_type {
	char *key;
	struct chan_ops *ops;
	};

	static struct chan_type chan_table[] = {
	{ "fd", &fd_ops },

	#ifdef CONFIG_NULL_CHAN
	{ "null", &null_ops },
	#else
	{ "null", &not_configged_ops },
	#endif

	#ifdef CONFIG_PORT_CHAN
	{ "port", &port_ops },
	#else
	{ "port", &not_configged_ops },
	#endif

	#ifdef CONFIG_PTY_CHAN
	{ "pty", &pty_ops },
	{ "pts", &pts_ops },
	#else
	{ "pty", &not_configged_ops },
	{ "pts", &not_configged_ops },
	#endif

	#ifdef CONFIG_TTY_CHAN
	{ "tty", &tty_ops },
	#else
	{ "tty", &not_configged_ops },
	#endif

	#ifdef CONFIG_XTERM_CHAN
	{ "xterm", &xterm_ops },
	#else
	{ "xterm", &not_configged_ops },
	#endif
	};

	static struct chan parse_chan(struct line line, char *str, int device,
	struct chan_opts *opts)
	{
	struct chan_type *entry;
	struct chan_ops *ops;
	struct chan *chan;
	void *data;
	int i;

	ops = NULL;
	data = NULL;
	for(i = 0; i < sizeof(chan_table)/sizeof(chan_table[0]); i++){
	entry = &chan_table[i];
	if(!strncmp(str, entry->key, strlen(entry->key))){
	ops = entry->ops;
	str += strlen(entry->key);
	break;
	}
	}
	if(ops == NULL){
	my_printf("parse_chan couldn't parse \"%s\"\n",
	str);
	return NULL;
	}
	if(ops->init == NULL)
	return NULL;
	data = (*ops->init)(str, device, opts);
	if(data == NULL)
	return NULL;

	chan = kmalloc(sizeof(*chan), GFP_ATOMIC);
	if(chan == NULL)
	return NULL;
	*chan = ((struct chan) { .list = LIST_HEAD_INIT(chan->list),
	.free_list =
	LIST_HEAD_INIT(chan->free_list),
	.line = line,
	.primary = 1,
	.input = 0,
	.output = 0,
	.opened = 0,
	.enabled = 0,
	.fd = -1,
	.ops = ops,
	.data = data });
	return chan;
	}

	int parse_chan_pair(char str, struct line line, int device,
	struct chan_opts *opts)
	{
	struct list_head *chans = &line->chan_list;
	struct chan new, chan;
	char in, out;

	if(!list_empty(chans)){
	chan = list_entry(chans->next, struct chan, list);
	free_chan(chans, 0);
	INIT_LIST_HEAD(chans);
	}

	out = strchr(str, ',');
	if(out != NULL){
	in = str;
	*out = '\0';
	out++;
	new = parse_chan(line, in, device, opts);
	if(new == NULL)
	return -1;

	new->input = 1;
	list_add(&new->list, chans);

	new = parse_chan(line, out, device, opts);
	if(new == NULL)
	return -1;

	list_add(&new->list, chans);
	new->output = 1;
	}
	else {
	new = parse_chan(line, str, device, opts);
	if(new == NULL)
	return -1;

	list_add(&new->list, chans);
	new->input = 1;
	new->output = 1;
	}
	return 0;
	}

	int chan_out_fd(struct list_head *chans)
	{
	struct list_head *ele;
	struct chan *chan;

	list_for_each(ele, chans){
	chan = list_entry(ele, struct chan, list);
	if(chan->primary && chan->output)
	return chan->fd;
	}
	return -1;
	}

	void chan_interrupt(struct list_head chans, struct work_struct task,
	struct tty_struct *tty, int irq)
	{
	struct list_head ele, next;
	struct chan *chan;
	int err;
	char c;

	list_for_each_safe(ele, next, chans){
	chan = list_entry(ele, struct chan, list);
	if(!chan->input \|\| (chan->ops->read == NULL)) continue;
	do {
	if (tty && !tty_buffer_request_room(tty, 1)) {
	schedule_delayed_work(task, 1);
	goto out;
	}
	err = chan->ops->read(chan->fd, &c, chan->data);
	if(err > 0)
	tty_receive_char(tty, c);
	} while(err > 0);

	if(err == 0) reactivate_fd(chan->fd, irq);
	if(err == -EIO){
	if(chan->primary){
	if(tty != NULL)
	tty_hangup(tty);
	close_chan(chans, 1);
	return;
	}
	else close_one_chan(chan, 1);
	}
	}
	out:
	if(tty) tty_flip_buffer_push(tty);
	}