[mirror_ubuntu-jammy-kernel.git] / arch / parisc / kernel / pdc_cons.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* 
 *    PDC Console support - ie use firmware to dump text via boot console
 *
 *    Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
 *    Copyright (C) 2000 Martin K Petersen <mkp at mkp.net>
 *    Copyright (C) 2000 John Marvin <jsm at parisc-linux.org>
 *    Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
 *    Copyright (C) 2000 Philipp Rumpf <prumpf with tux.org>
 *    Copyright (C) 2000 Michael Ang <mang with subcarrier.org>
 *    Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
 *    Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
 *    Copyright (C) 2001 Helge Deller <deller at parisc-linux.org>
 *    Copyright (C) 2001 Thomas Bogendoerfer <tsbogend at parisc-linux.org>
 *    Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
 *    Copyright (C) 2010 Guy Martin <gmsoft at tuxicoman.be>
 */

/*
 *  The PDC console is a simple console, which can be used for debugging 
 *  boot related problems on HP PA-RISC machines. It is also useful when no
 *  other console works.
 *
 *  This code uses the ROM (=PDC) based functions to read and write characters
 *  from and to PDC's boot path.
 */

/* Define EARLY_BOOTUP_DEBUG to debug kernel related boot problems. 
 * On production kernels EARLY_BOOTUP_DEBUG should be undefined. */
#define EARLY_BOOTUP_DEBUG


#include <linux/kernel.h>
#include <linux/console.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/major.h>
#include <linux/tty.h>
#include <asm/page.h>		/* for PAGE0 */
#include <asm/pdc.h>		/* for iodc_call() proto and friends */

static DEFINE_SPINLOCK(pdc_console_lock);
static struct console pdc_cons;

static void pdc_console_write(struct console *co, const char *s, unsigned count)
{
	int i = 0;
	unsigned long flags;

	spin_lock_irqsave(&pdc_console_lock, flags);
	do {
		i += pdc_iodc_print(s + i, count - i);
	} while (i < count);
	spin_unlock_irqrestore(&pdc_console_lock, flags);
}

int pdc_console_poll_key(struct console *co)
{
	int c;
	unsigned long flags;

	spin_lock_irqsave(&pdc_console_lock, flags);
	c = pdc_iodc_getc();
	spin_unlock_irqrestore(&pdc_console_lock, flags);

	return c;
}

static int pdc_console_setup(struct console *co, char *options)
{
	return 0;
}

#if defined(CONFIG_PDC_CONSOLE)
#include <linux/vt_kern.h>
#include <linux/tty_flip.h>

#define PDC_CONS_POLL_DELAY (30 * HZ / 1000)

static void pdc_console_poll(struct timer_list *unused);
static DEFINE_TIMER(pdc_console_timer, pdc_console_poll);
static struct tty_port tty_port;

static int pdc_console_tty_open(struct tty_struct *tty, struct file *filp)
{
	tty_port_tty_set(&tty_port, tty);
	mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);

	return 0;
}

static void pdc_console_tty_close(struct tty_struct *tty, struct file *filp)
{
	if (tty->count == 1) {
		del_timer_sync(&pdc_console_timer);
		tty_port_tty_set(&tty_port, NULL);
	}
}

static int pdc_console_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
{
	pdc_console_write(NULL, buf, count);
	return count;
}

static unsigned int pdc_console_tty_write_room(struct tty_struct *tty)
{
	return 32768; /* no limit, no buffer used */
}

static const struct tty_operations pdc_console_tty_ops = {
	.open = pdc_console_tty_open,
	.close = pdc_console_tty_close,
	.write = pdc_console_tty_write,
	.write_room = pdc_console_tty_write_room,
};

static void pdc_console_poll(struct timer_list *unused)
{
	int data, count = 0;

	while (1) {
		data = pdc_console_poll_key(NULL);
		if (data == -1)
			break;
		tty_insert_flip_char(&tty_port, data & 0xFF, TTY_NORMAL);
		count ++;
	}

	if (count)
		tty_flip_buffer_push(&tty_port);

	if (pdc_cons.flags & CON_ENABLED)
		mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
}

static struct tty_driver *pdc_console_tty_driver;

static int __init pdc_console_tty_driver_init(void)
{
	struct tty_driver *driver;
	int err;

	/* Check if the console driver is still registered.
	 * It is unregistered if the pdc console was not selected as the
	 * primary console. */

	struct console *tmp;

	console_lock();
	for_each_console(tmp)
		if (tmp == &pdc_cons)
			break;
	console_unlock();

	if (!tmp) {
		printk(KERN_INFO "PDC console driver not registered anymore, not creating %s\n", pdc_cons.name);
		return -ENODEV;
	}

	printk(KERN_INFO "The PDC console driver is still registered, removing CON_BOOT flag\n");
	pdc_cons.flags &= ~CON_BOOT;

	driver = tty_alloc_driver(1, TTY_DRIVER_REAL_RAW |
			TTY_DRIVER_RESET_TERMIOS);
	if (IS_ERR(driver))
		return PTR_ERR(driver);

	tty_port_init(&tty_port);

	driver->driver_name = "pdc_cons";
	driver->name = "ttyB";
	driver->major = MUX_MAJOR;
	driver->minor_start = 0;
	driver->type = TTY_DRIVER_TYPE_SYSTEM;
	driver->init_termios = tty_std_termios;
	tty_set_operations(driver, &pdc_console_tty_ops);
	tty_port_link_device(&tty_port, driver, 0);

	err = tty_register_driver(driver);
	if (err) {
		printk(KERN_ERR "Unable to register the PDC console TTY driver\n");
		tty_port_destroy(&tty_port);
		tty_driver_kref_put(driver);
		return err;
	}

	pdc_console_tty_driver = driver;

	return 0;
}
device_initcall(pdc_console_tty_driver_init);

static struct tty_driver * pdc_console_device (struct console *c, int *index)
{
	*index = c->index;
	return pdc_console_tty_driver;
}
#else
#define pdc_console_device NULL
#endif

static struct console pdc_cons = {
	.name =		"ttyB",
	.write =	pdc_console_write,
	.device =	pdc_console_device,
	.setup =	pdc_console_setup,
	.flags =	CON_BOOT | CON_PRINTBUFFER,
	.index =	-1,
};

static int pdc_console_initialized;

static void pdc_console_init_force(void)
{
	if (pdc_console_initialized)
		return;
	++pdc_console_initialized;
	
	/* If the console is duplex then copy the COUT parameters to CIN. */
	if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
		memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));

	/* register the pdc console */
	register_console(&pdc_cons);
}

void __init pdc_console_init(void)
{
#if defined(EARLY_BOOTUP_DEBUG) || defined(CONFIG_PDC_CONSOLE)
	pdc_console_init_force();
#endif
#ifdef EARLY_BOOTUP_DEBUG
	printk(KERN_INFO "Initialized PDC Console for debugging.\n");
#endif
}


/*
 * Used for emergencies. Currently only used if an HPMC occurs. If an
 * HPMC occurs, it is possible that the current console may not be
 * properly initialised after the PDC IO reset. This routine unregisters
 * all of the current consoles, reinitializes the pdc console and
 * registers it.
 */

void pdc_console_restart(void)
{
	struct console *console;

	if (pdc_console_initialized)
		return;

	/* If we've already seen the output, don't bother to print it again */
	if (console_drivers != NULL)
		pdc_cons.flags &= ~CON_PRINTBUFFER;

	while ((console = console_drivers) != NULL)
		unregister_console(console_drivers);

	/* force registering the pdc console */
	pdc_console_init_force();
}
Commit	Line	Data
1a59d1b8	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4 LT	2	/*
	3	* PDC Console support - ie use firmware to dump text via boot console
	4	*
	5	* Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
	6	* Copyright (C) 2000 Martin K Petersen <mkp at mkp.net>
	7	* Copyright (C) 2000 John Marvin <jsm at parisc-linux.org>
	8	* Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
	9	* Copyright (C) 2000 Philipp Rumpf <prumpf with tux.org>
	10	* Copyright (C) 2000 Michael Ang <mang with subcarrier.org>
	11	* Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
	12	* Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
	13	* Copyright (C) 2001 Helge Deller <deller at parisc-linux.org>
	14	* Copyright (C) 2001 Thomas Bogendoerfer <tsbogend at parisc-linux.org>
	15	* Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
650a35f8	16	* Copyright (C) 2010 Guy Martin <gmsoft at tuxicoman.be>
1da177e4 LT	17	*/
	18
	19	/*
	20	* The PDC console is a simple console, which can be used for debugging
650a35f8 GM	21	* boot related problems on HP PA-RISC machines. It is also useful when no
650a35f8 GM	22	* other console works.
1da177e4 LT	23	*
	24	* This code uses the ROM (=PDC) based functions to read and write characters
	25	* from and to PDC's boot path.
1da177e4 LT	26	*/
	27
	28	/* Define EARLY_BOOTUP_DEBUG to debug kernel related boot problems.
	29	* On production kernels EARLY_BOOTUP_DEBUG should be undefined. */
7c92e972	30	#define EARLY_BOOTUP_DEBUG
1da177e4 LT	31
1da177e4 LT	32
1da177e4 LT	33	#include <linux/kernel.h>
	34	#include <linux/console.h>
	35	#include <linux/string.h>
	36	#include <linux/init.h>
1da177e4 LT	37	#include <linux/major.h>
1da177e4 LT	38	#include <linux/tty.h>
4a8a0788	39	#include <asm/page.h> /* for PAGE0 */
1da177e4 LT	40	#include <asm/pdc.h> /* for iodc_call() proto and friends */
1da177e4 LT	41
aefa8b6b	42	static DEFINE_SPINLOCK(pdc_console_lock);
650a35f8	43	static struct console pdc_cons;
1da177e4 LT	44
	45	static void pdc_console_write(struct console co, const char s, unsigned count)
	46	{
ef1afd4d KM	47	int i = 0;
	48	unsigned long flags;
	49
	50	spin_lock_irqsave(&pdc_console_lock, flags);
	51	do {
	52	i += pdc_iodc_print(s + i, count - i);
	53	} while (i < count);
	54	spin_unlock_irqrestore(&pdc_console_lock, flags);
1da177e4 LT	55	}
1da177e4 LT	56
1da177e4 LT	57	int pdc_console_poll_key(struct console *co)
1da177e4 LT	58	{
ef1afd4d KM	59	int c;
	60	unsigned long flags;
	61
	62	spin_lock_irqsave(&pdc_console_lock, flags);
	63	c = pdc_iodc_getc();
	64	spin_unlock_irqrestore(&pdc_console_lock, flags);
	65
	66	return c;
1da177e4 LT	67	}
	68
	69	static int pdc_console_setup(struct console co, char options)
	70	{
	71	return 0;
	72	}
	73
	74	#if defined(CONFIG_PDC_CONSOLE)
a8f340e3	75	#include <linux/vt_kern.h>
650a35f8 GM	76	#include <linux/tty_flip.h>
	77
	78	#define PDC_CONS_POLL_DELAY (30 * HZ / 1000)
	79
24ed960a	80	static void pdc_console_poll(struct timer_list *unused);
1d27e3e2	81	static DEFINE_TIMER(pdc_console_timer, pdc_console_poll);
5dd5bc40	82	static struct tty_port tty_port;
650a35f8	83
650a35f8 GM	84	static int pdc_console_tty_open(struct tty_struct tty, struct file filp)
650a35f8 GM	85	{
5dd5bc40	86	tty_port_tty_set(&tty_port, tty);
650a35f8 GM	87	mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
	88
	89	return 0;
	90	}
	91
	92	static void pdc_console_tty_close(struct tty_struct tty, struct file filp)
	93	{
49a5f3cf	94	if (tty->count == 1) {
e380a81e	95	del_timer_sync(&pdc_console_timer);
5dd5bc40 JS	96	tty_port_tty_set(&tty_port, NULL);
5dd5bc40 JS	97	}
650a35f8 GM	98	}
	99
	100	static int pdc_console_tty_write(struct tty_struct tty, const unsigned char buf, int count)
	101	{
	102	pdc_console_write(NULL, buf, count);
	103	return count;
	104	}
	105
03b3b1a2	106	static unsigned int pdc_console_tty_write_room(struct tty_struct *tty)
650a35f8 GM	107	{
	108	return 32768; /* no limit, no buffer used */
	109	}
	110
650a35f8 GM	111	static const struct tty_operations pdc_console_tty_ops = {
	112	.open = pdc_console_tty_open,
	113	.close = pdc_console_tty_close,
	114	.write = pdc_console_tty_write,
	115	.write_room = pdc_console_tty_write_room,
650a35f8 GM	116	};
650a35f8 GM	117
24ed960a	118	static void pdc_console_poll(struct timer_list *unused)
650a35f8	119	{
650a35f8	120	int data, count = 0;
650a35f8 GM	121
	122	while (1) {
	123	data = pdc_console_poll_key(NULL);
	124	if (data == -1)
	125	break;
92a19f9c	126	tty_insert_flip_char(&tty_port, data & 0xFF, TTY_NORMAL);
650a35f8 GM	127	count ++;
	128	}
	129
	130	if (count)
2e124b4a	131	tty_flip_buffer_push(&tty_port);
5dd5bc40	132
e380a81e	133	if (pdc_cons.flags & CON_ENABLED)
650a35f8 GM	134	mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
	135	}
	136
5dd5bc40 JS	137	static struct tty_driver *pdc_console_tty_driver;
5dd5bc40 JS	138
650a35f8 GM	139	static int __init pdc_console_tty_driver_init(void)
650a35f8 GM	140	{
0524513a	141	struct tty_driver *driver;
650a35f8	142	int err;
650a35f8 GM	143
	144	/* Check if the console driver is still registered.
	145	* It is unregistered if the pdc console was not selected as the
	146	* primary console. */
	147
597c606f	148	struct console *tmp;
650a35f8	149
ac751efa	150	console_lock();
597c606f	151	for_each_console(tmp)
650a35f8 GM	152	if (tmp == &pdc_cons)
650a35f8 GM	153	break;
ac751efa	154	console_unlock();
650a35f8 GM	155
	156	if (!tmp) {
	157	printk(KERN_INFO "PDC console driver not registered anymore, not creating %s\n", pdc_cons.name);
	158	return -ENODEV;
	159	}
	160
	161	printk(KERN_INFO "The PDC console driver is still registered, removing CON_BOOT flag\n");
	162	pdc_cons.flags &= ~CON_BOOT;
	163
39b7b42b JS	164	driver = tty_alloc_driver(1, TTY_DRIVER_REAL_RAW \|
	165	TTY_DRIVER_RESET_TERMIOS);
	166	if (IS_ERR(driver))
	167	return PTR_ERR(driver);
650a35f8	168
191c5f10 JS	169	tty_port_init(&tty_port);
191c5f10 JS	170
0524513a JS	171	driver->driver_name = "pdc_cons";
	172	driver->name = "ttyB";
	173	driver->major = MUX_MAJOR;
	174	driver->minor_start = 0;
	175	driver->type = TTY_DRIVER_TYPE_SYSTEM;
	176	driver->init_termios = tty_std_termios;
0524513a JS	177	tty_set_operations(driver, &pdc_console_tty_ops);
0524513a JS	178	tty_port_link_device(&tty_port, driver, 0);
0b479d54	179
0524513a	180	err = tty_register_driver(driver);
650a35f8 GM	181	if (err) {
650a35f8 GM	182	printk(KERN_ERR "Unable to register the PDC console TTY driver\n");
191c5f10	183	tty_port_destroy(&tty_port);
72fdb403	184	tty_driver_kref_put(driver);
650a35f8 GM	185	return err;
	186	}
	187
0524513a JS	188	pdc_console_tty_driver = driver;
0524513a JS	189
650a35f8 GM	190	return 0;
650a35f8 GM	191	}
aed6850a	192	device_initcall(pdc_console_tty_driver_init);
a8f340e3	193
1da177e4 LT	194	static struct tty_driver * pdc_console_device (struct console c, int index)
1da177e4 LT	195	{
650a35f8 GM	196	*index = c->index;
650a35f8 GM	197	return pdc_console_tty_driver;
1da177e4 LT	198	}
1da177e4 LT	199	#else
7c92e972	200	#define pdc_console_device NULL
1da177e4 LT	201	#endif
	202
	203	static struct console pdc_cons = {
	204	.name = "ttyB",
	205	.write = pdc_console_write,
7c92e972	206	.device = pdc_console_device,
1da177e4	207	.setup = pdc_console_setup,
650a35f8	208	.flags = CON_BOOT \| CON_PRINTBUFFER,
1da177e4 LT	209	.index = -1,
	210	};
	211
	212	static int pdc_console_initialized;
1da177e4 LT	213
	214	static void pdc_console_init_force(void)
	215	{
	216	if (pdc_console_initialized)
	217	return;
	218	++pdc_console_initialized;
	219
	220	/* If the console is duplex then copy the COUT parameters to CIN. */
	221	if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
	222	memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));
	223
	224	/* register the pdc console */
	225	register_console(&pdc_cons);
	226	}
	227
	228	void __init pdc_console_init(void)
	229	{
	230	#if defined(EARLY_BOOTUP_DEBUG) \|\| defined(CONFIG_PDC_CONSOLE)
	231	pdc_console_init_force();
	232	#endif
	233	#ifdef EARLY_BOOTUP_DEBUG
	234	printk(KERN_INFO "Initialized PDC Console for debugging.\n");
	235	#endif
	236	}
	237
	238
1da177e4 LT	239	/*
	240	* Used for emergencies. Currently only used if an HPMC occurs. If an
	241	* HPMC occurs, it is possible that the current console may not be
7c92e972 MW	242	* properly initialised after the PDC IO reset. This routine unregisters
7c92e972 MW	243	* all of the current consoles, reinitializes the pdc console and
1da177e4 LT	244	* registers it.
	245	*/
	246
	247	void pdc_console_restart(void)
	248	{
	249	struct console *console;
	250
	251	if (pdc_console_initialized)
	252	return;
	253
7c92e972 MW	254	/* If we've already seen the output, don't bother to print it again */
	255	if (console_drivers != NULL)
	256	pdc_cons.flags &= ~CON_PRINTBUFFER;
	257
1da177e4 LT	258	while ((console = console_drivers) != NULL)
	259	unregister_console(console_drivers);
	260
1da177e4 LT	261	/* force registering the pdc console */
	262	pdc_console_init_force();
	263	}