summaryrefslogtreecommitdiff
path: root/arch/parisc/kernel/pdc_cons.c
blob: 11bdd68e576239bffe235dc8b4b3d3a38709beed (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
/* 
 *    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>
 *
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/*
 *  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/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 struct timer_list pdc_console_timer;

static int pdc_console_tty_open(struct tty_struct *tty, struct file *filp)
{

	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)
		del_timer(&pdc_console_timer);
}

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

static int pdc_console_tty_chars_in_buffer(struct tty_struct *tty)
{
	return 0; /* no buffer */
}

static struct tty_driver *pdc_console_tty_driver;

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,
	.chars_in_buffer = pdc_console_tty_chars_in_buffer,
};

static void pdc_console_poll(unsigned long unused)
{

	int data, count = 0;

	struct tty_struct *tty = pdc_console_tty_driver->ttys[0];

	if (!tty)
		return;

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

	if (count)
		tty_flip_buffer_push(tty);

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

static int __init pdc_console_tty_driver_init(void)
{

	int err;
	struct tty_driver *drv;

	/* 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;

	acquire_console_sem();
	for_each_console(tmp)
		if (tmp == &pdc_cons)
			break;
	release_console_sem();

	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;

	drv = alloc_tty_driver(1);

	if (!drv)
		return -ENOMEM;

	drv->driver_name = "pdc_cons";
	drv->name = "ttyB";
	drv->major = MUX_MAJOR;
	drv->minor_start = 0;
	drv->type = TTY_DRIVER_TYPE_SYSTEM;
	drv->init_termios = tty_std_termios;
	drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_RESET_TERMIOS;
	tty_set_operations(drv, &pdc_console_tty_ops);

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

	pdc_console_tty_driver = drv;

	/* No need to initialize the pdc_console_timer if tty isn't allocated */
	init_timer(&pdc_console_timer);
	pdc_console_timer.function = pdc_console_poll;

	return 0;
}

module_init(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();
}