Release 4.14 arch/alpha/kernel/srmcons.c

// SPDX-License-Identifier: GPL-2.0
/*
 *      linux/arch/alpha/kernel/srmcons.c
 *
 * Callback based driver for SRM Console console device.
 * (TTY driver and console driver)
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/delay.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>

#include <asm/console.h>
#include <linux/uaccess.h>


static DEFINE_SPINLOCK(srmcons_callback_lock);

static int srm_is_registered_console = 0;

/* 
 * The TTY driver
 */

#define MAX_SRM_CONSOLE_DEVICES 1	
/* only support 1 console device */


struct srmcons_private {
	
struct tty_port port;
	
struct timer_list timer;

} srmcons_singleton;


typedef union _srmcons_result {
	struct {
		
unsigned long c :61;
		
unsigned long status :3;
	
} bits;
	
long as_long;

} srmcons_result;

/* called with callback_lock held */

static int

srmcons_do_receive_chars(struct tty_port *port)
{
	srmcons_result result;
	int count = 0, loops = 0;

	do {
		result.as_long = callback_getc(0);
		if (result.bits.status < 2) {
			tty_insert_flip_char(port, (char)result.bits.c, 0);
			count++;
		}
	} while((result.bits.status & 1) && (++loops < 10));

	if (count)
		tty_schedule_flip(port);

	return count;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Richard Henderson
91
92.86%
1
33.33%
Jiri Slaby
7
7.14%
2
66.67%
Total
98
100.00%
3
100.00%


static void

srmcons_receive_chars(unsigned long data)
{
	struct srmcons_private *srmconsp = (struct srmcons_private *)data;
	struct tty_port *port = &srmconsp->port;
	unsigned long flags;
	int incr = 10;

	local_irq_save(flags);
	if (spin_trylock(&srmcons_callback_lock)) {
		if (!srmcons_do_receive_chars(port))
			incr = 100;
		spin_unlock(&srmcons_callback_lock);
	} 

	spin_lock(&port->lock);
	if (port->tty)
		mod_timer(&srmconsp->timer, jiffies + incr);
	spin_unlock(&port->lock);

	local_irq_restore(flags);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Richard Henderson
95
84.07%
1
33.33%
Jiri Slaby
18
15.93%
2
66.67%
Total
113
100.00%
3
100.00%

/* called with callback_lock held */

static int

srmcons_do_write(struct tty_port *port, const char *buf, int count)
{
	static char str_cr[1] = "\r";
	long c, remaining = count;
	srmcons_result result;
	char *cur;
	int need_cr;

	for (cur = (char *)buf; remaining > 0; ) {
		need_cr = 0;
		/* 
                 * Break it up into reasonable size chunks to allow a chance
                 * for input to get in
                 */
		for (c = 0; c < min_t(long, 128L, remaining) && !need_cr; c++)
			if (cur[c] == '\n')
				need_cr = 1;
		
		while (c > 0) {
			result.as_long = callback_puts(0, cur, c);
			c -= result.bits.c;
			remaining -= result.bits.c;
			cur += result.bits.c;

			/*
                         * Check for pending input iff a tty port was provided
                         */
			if (port)
				srmcons_do_receive_chars(port);
		}

		while (need_cr) {
			result.as_long = callback_puts(0, str_cr, 1);
			if (result.bits.c > 0)
				need_cr = 0;
		}
	}
	return count;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Richard Henderson
189
97.42%
2
66.67%
Jiri Slaby
5
2.58%
1
33.33%
Total
194
100.00%
3
100.00%


static int

srmcons_write(struct tty_struct *tty,
	      const unsigned char *buf, int count)
{
	unsigned long flags;

	spin_lock_irqsave(&srmcons_callback_lock, flags);
	srmcons_do_write(tty->port, (const char *) buf, count);
	spin_unlock_irqrestore(&srmcons_callback_lock, flags);

	return count;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Richard Henderson
57
96.61%
2
66.67%
Jiri Slaby
2
3.39%
1
33.33%
Total
59
100.00%
3
100.00%


static int

srmcons_write_room(struct tty_struct *tty)
{
	return 512;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Richard Henderson
14
100.00%
1
100.00%
Total
14
100.00%
1
100.00%


static int

srmcons_chars_in_buffer(struct tty_struct *tty)
{
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Richard Henderson
14
100.00%
1
100.00%
Total
14
100.00%
1
100.00%


static int

srmcons_open(struct tty_struct *tty, struct file *filp)
{
	struct srmcons_private *srmconsp = &srmcons_singleton;
	struct tty_port *port = &srmconsp->port;
	unsigned long flags;

	spin_lock_irqsave(&port->lock, flags);

	if (!port->tty) {
		tty->driver_data = srmconsp;
		tty->port = port;
		port->tty = tty; /* XXX proper refcounting */
		mod_timer(&srmconsp->timer, jiffies + 10);
	}

	spin_unlock_irqrestore(&port->lock, flags);

	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Richard Henderson
73
72.28%
1
25.00%
Jiri Slaby
28
27.72%
3
75.00%
Total
101
100.00%
4
100.00%


static void

srmcons_close(struct tty_struct *tty, struct file *filp)
{
	struct srmcons_private *srmconsp = tty->driver_data;
	struct tty_port *port = &srmconsp->port;
	unsigned long flags;

	spin_lock_irqsave(&port->lock, flags);

	if (tty->count == 1) {
		port->tty = NULL;
		del_timer(&srmconsp->timer);
	}

	spin_unlock_irqrestore(&port->lock, flags);
}


Contributors
Person
Tokens
Prop
Commits
CommitProp
Richard Henderson
70
84.34%
1
50.00%
Jiri Slaby
13
15.66%
1
50.00%
Total
83
100.00%
2
100.00%


static struct tty_driver *srmcons_driver;


static const struct tty_operations srmcons_ops = {
	.open		= srmcons_open,
	.close		= srmcons_close,
	.write		= srmcons_write,
	.write_room	= srmcons_write_room,
	.chars_in_buffer= srmcons_chars_in_buffer,
};


static int __init

srmcons_init(void)
{
	setup_timer(&srmcons_singleton.timer, srmcons_receive_chars,
			(unsigned long)&srmcons_singleton);
	if (srm_is_registered_console) {
		struct tty_driver *driver;
		int err;

		driver = alloc_tty_driver(MAX_SRM_CONSOLE_DEVICES);
		if (!driver)
			return -ENOMEM;

		tty_port_init(&srmcons_singleton.port);

		driver->driver_name = "srm";
		driver->name = "srm";
		driver->major = 0; 	/* dynamic */
		driver->minor_start = 0;
		driver->type = TTY_DRIVER_TYPE_SYSTEM;
		driver->subtype = SYSTEM_TYPE_SYSCONS;
		driver->init_termios = tty_std_termios;
		tty_set_operations(driver, &srmcons_ops);
		tty_port_link_device(&srmcons_singleton.port, driver, 0);
		err = tty_register_driver(driver);
		if (err) {
			put_tty_driver(driver);
			tty_port_destroy(&srmcons_singleton.port);
			return err;
		}
		srmcons_driver = driver;
	}

	return -ENODEV;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Al Viro
84
51.22%
1
16.67%
Jiri Slaby
45
27.44%
3
50.00%
Richard Henderson
27
16.46%
1
16.67%
Ivan Kokshaysky
8
4.88%
1
16.67%
Total
164
100.00%
6
100.00%


device_initcall(srmcons_init);


/*
 * The console driver
 */

static void

srm_console_write(struct console *co, const char *s, unsigned count)
{
	unsigned long flags;

	spin_lock_irqsave(&srmcons_callback_lock, flags);
	srmcons_do_write(NULL, s, count);
	spin_unlock_irqrestore(&srmcons_callback_lock, flags);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Richard Henderson
48
100.00%
1
100.00%
Total
48
100.00%
1
100.00%


static struct tty_driver *

srm_console_device(struct console *co, int *index)
{
	*index = co->index;
	return srmcons_driver;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Richard Henderson
14
51.85%
1
50.00%
Al Viro
13
48.15%
1
50.00%
Total
27
100.00%
2
100.00%


static int

srm_console_setup(struct console *co, char *options)
{
	return 0;
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Richard Henderson
18
100.00%
1
100.00%
Total
18
100.00%
1
100.00%


static struct console srmcons = {
	.name		= "srm",
	.write		= srm_console_write,
	.device		= srm_console_device,
	.setup		= srm_console_setup,
	.flags		= CON_PRINTBUFFER | CON_BOOT,
	.index		= -1,
};


void __init

register_srm_console(void)
{
	if (!srm_is_registered_console) {
		callback_open_console();
		register_console(&srmcons);
		srm_is_registered_console = 1;
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Richard Henderson
28
100.00%
1
100.00%
Total
28
100.00%
1
100.00%


void __init

unregister_srm_console(void)
{
	if (srm_is_registered_console) {
		callback_close_console();
		unregister_console(&srmcons);
		srm_is_registered_console = 0;
	}
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Richard Henderson
27
100.00%
1
100.00%
Total
27
100.00%
1
100.00%

Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Richard Henderson
933
79.40%
2
11.11%
Jiri Slaby
121
10.30%
7
38.89%
Al Viro
103
8.77%
2
11.11%
Ivan Kokshaysky
8
0.68%
1
5.56%
Thomas Gleixner
4
0.34%
1
5.56%
Gerd Hoffmann
2
0.17%
1
5.56%
Paul Gortmaker
1
0.09%
1
5.56%
Greg Kroah-Hartman
1
0.09%
1
5.56%
Jeff Dike
1
0.09%
1
5.56%
Linus Torvalds
1
0.09%
1
5.56%
Total
1175
100.00%
18
100.00%
Directory: arch/alpha/kernel

Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.