1/*
2 *    PDC Console support - ie use firmware to dump text via boot console
3 *
4 *    Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
5 *    Copyright (C) 2000 Martin K Petersen <mkp at mkp.net>
6 *    Copyright (C) 2000 John Marvin <jsm at parisc-linux.org>
7 *    Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
8 *    Copyright (C) 2000 Philipp Rumpf <prumpf with tux.org>
9 *    Copyright (C) 2000 Michael Ang <mang with subcarrier.org>
10 *    Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
11 *    Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
12 *    Copyright (C) 2001 Helge Deller <deller at parisc-linux.org>
13 *    Copyright (C) 2001 Thomas Bogendoerfer <tsbogend at parisc-linux.org>
14 *    Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
15 *    Copyright (C) 2010 Guy Martin <gmsoft at tuxicoman.be>
16 *
17 *
18 *    This program is free software; you can redistribute it and/or modify
19 *    it under the terms of the GNU General Public License as published by
20 *    the Free Software Foundation; either version 2 of the License, or
21 *    (at your option) any later version.
22 *
23 *    This program is distributed in the hope that it will be useful,
24 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
25 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
26 *    GNU General Public License for more details.
27 *
28 *    You should have received a copy of the GNU General Public License
29 *    along with this program; if not, write to the Free Software
30 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
31 */
32
33/*
34 *  The PDC console is a simple console, which can be used for debugging
35 *  boot related problems on HP PA-RISC machines. It is also useful when no
36 *  other console works.
37 *
38 *  This code uses the ROM (=PDC) based functions to read and write characters
39 *  from and to PDC's boot path.
40 */
41
42/* Define EARLY_BOOTUP_DEBUG to debug kernel related boot problems.
43 * On production kernels EARLY_BOOTUP_DEBUG should be undefined. */
44#define EARLY_BOOTUP_DEBUG
45
46
47#include <linux/kernel.h>
48#include <linux/console.h>
49#include <linux/string.h>
50#include <linux/init.h>
51#include <linux/major.h>
52#include <linux/tty.h>
53#include <asm/page.h>		/* for PAGE0 */
54#include <asm/pdc.h>		/* for iodc_call() proto and friends */
55
56static DEFINE_SPINLOCK(pdc_console_lock);
57static struct console pdc_cons;
58
59static void pdc_console_write(struct console *co, const char *s, unsigned count)
60{
61	int i = 0;
62	unsigned long flags;
63
64	spin_lock_irqsave(&pdc_console_lock, flags);
65	do {
66		i += pdc_iodc_print(s + i, count - i);
67	} while (i < count);
68	spin_unlock_irqrestore(&pdc_console_lock, flags);
69}
70
71int pdc_console_poll_key(struct console *co)
72{
73	int c;
74	unsigned long flags;
75
76	spin_lock_irqsave(&pdc_console_lock, flags);
77	c = pdc_iodc_getc();
78	spin_unlock_irqrestore(&pdc_console_lock, flags);
79
80	return c;
81}
82
83static int pdc_console_setup(struct console *co, char *options)
84{
85	return 0;
86}
87
88#if defined(CONFIG_PDC_CONSOLE)
89#include <linux/vt_kern.h>
90#include <linux/tty_flip.h>
91
92#define PDC_CONS_POLL_DELAY (30 * HZ / 1000)
93
94static void pdc_console_poll(unsigned long unused);
95static DEFINE_TIMER(pdc_console_timer, pdc_console_poll, 0, 0);
96static struct tty_port tty_port;
97
98static int pdc_console_tty_open(struct tty_struct *tty, struct file *filp)
99{
100	tty_port_tty_set(&tty_port, tty);
101	mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
102
103	return 0;
104}
105
106static void pdc_console_tty_close(struct tty_struct *tty, struct file *filp)
107{
108	if (tty->count == 1) {
109		del_timer_sync(&pdc_console_timer);
110		tty_port_tty_set(&tty_port, NULL);
111	}
112}
113
114static int pdc_console_tty_write(struct tty_struct *tty, const unsigned char *buf, int count)
115{
116	pdc_console_write(NULL, buf, count);
117	return count;
118}
119
120static int pdc_console_tty_write_room(struct tty_struct *tty)
121{
122	return 32768; /* no limit, no buffer used */
123}
124
125static int pdc_console_tty_chars_in_buffer(struct tty_struct *tty)
126{
127	return 0; /* no buffer */
128}
129
130static const struct tty_operations pdc_console_tty_ops = {
131	.open = pdc_console_tty_open,
132	.close = pdc_console_tty_close,
133	.write = pdc_console_tty_write,
134	.write_room = pdc_console_tty_write_room,
135	.chars_in_buffer = pdc_console_tty_chars_in_buffer,
136};
137
138static void pdc_console_poll(unsigned long unused)
139{
140	int data, count = 0;
141
142	while (1) {
143		data = pdc_console_poll_key(NULL);
144		if (data == -1)
145			break;
146		tty_insert_flip_char(&tty_port, data & 0xFF, TTY_NORMAL);
147		count ++;
148	}
149
150	if (count)
151		tty_flip_buffer_push(&tty_port);
152
153	if (pdc_cons.flags & CON_ENABLED)
154		mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
155}
156
157static struct tty_driver *pdc_console_tty_driver;
158
159static int __init pdc_console_tty_driver_init(void)
160{
161	int err;
162
163	/* Check if the console driver is still registered.
164	 * It is unregistered if the pdc console was not selected as the
165	 * primary console. */
166
167	struct console *tmp;
168
169	console_lock();
170	for_each_console(tmp)
171		if (tmp == &pdc_cons)
172			break;
173	console_unlock();
174
175	if (!tmp) {
176		printk(KERN_INFO "PDC console driver not registered anymore, not creating %s\n", pdc_cons.name);
177		return -ENODEV;
178	}
179
180	printk(KERN_INFO "The PDC console driver is still registered, removing CON_BOOT flag\n");
181	pdc_cons.flags &= ~CON_BOOT;
182
183	pdc_console_tty_driver = alloc_tty_driver(1);
184
185	if (!pdc_console_tty_driver)
186		return -ENOMEM;
187
188	tty_port_init(&tty_port);
189
190	pdc_console_tty_driver->driver_name = "pdc_cons";
191	pdc_console_tty_driver->name = "ttyB";
192	pdc_console_tty_driver->major = MUX_MAJOR;
193	pdc_console_tty_driver->minor_start = 0;
194	pdc_console_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
195	pdc_console_tty_driver->init_termios = tty_std_termios;
196	pdc_console_tty_driver->flags = TTY_DRIVER_REAL_RAW |
197		TTY_DRIVER_RESET_TERMIOS;
198	tty_set_operations(pdc_console_tty_driver, &pdc_console_tty_ops);
199	tty_port_link_device(&tty_port, pdc_console_tty_driver, 0);
200
201	err = tty_register_driver(pdc_console_tty_driver);
202	if (err) {
203		printk(KERN_ERR "Unable to register the PDC console TTY driver\n");
204		tty_port_destroy(&tty_port);
205		return err;
206	}
207
208	return 0;
209}
210
211module_init(pdc_console_tty_driver_init);
212
213static struct tty_driver * pdc_console_device (struct console *c, int *index)
214{
215	*index = c->index;
216	return pdc_console_tty_driver;
217}
218#else
219#define pdc_console_device NULL
220#endif
221
222static struct console pdc_cons = {
223	.name =		"ttyB",
224	.write =	pdc_console_write,
225	.device =	pdc_console_device,
226	.setup =	pdc_console_setup,
227	.flags =	CON_BOOT | CON_PRINTBUFFER,
228	.index =	-1,
229};
230
231static int pdc_console_initialized;
232
233static void pdc_console_init_force(void)
234{
235	if (pdc_console_initialized)
236		return;
237	++pdc_console_initialized;
238
239	/* If the console is duplex then copy the COUT parameters to CIN. */
240	if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
241		memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));
242
243	/* register the pdc console */
244	register_console(&pdc_cons);
245}
246
247void __init pdc_console_init(void)
248{
249#if defined(EARLY_BOOTUP_DEBUG) || defined(CONFIG_PDC_CONSOLE)
250	pdc_console_init_force();
251#endif
252#ifdef EARLY_BOOTUP_DEBUG
253	printk(KERN_INFO "Initialized PDC Console for debugging.\n");
254#endif
255}
256
257
258/*
259 * Used for emergencies. Currently only used if an HPMC occurs. If an
260 * HPMC occurs, it is possible that the current console may not be
261 * properly initialised after the PDC IO reset. This routine unregisters
262 * all of the current consoles, reinitializes the pdc console and
263 * registers it.
264 */
265
266void pdc_console_restart(void)
267{
268	struct console *console;
269
270	if (pdc_console_initialized)
271		return;
272
273	/* If we've already seen the output, don't bother to print it again */
274	if (console_drivers != NULL)
275		pdc_cons.flags &= ~CON_PRINTBUFFER;
276
277	while ((console = console_drivers) != NULL)
278		unregister_console(console_drivers);
279
280	/* force registering the pdc console */
281	pdc_console_init_force();
282}
283