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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 
56 static DEFINE_SPINLOCK(pdc_console_lock);
57 static struct console pdc_cons;
58 
pdc_console_write(struct console * co,const char * s,unsigned count)59 static 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 
pdc_console_poll_key(struct console * co)71 int 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 
pdc_console_setup(struct console * co,char * options)83 static 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 
94 static void pdc_console_poll(unsigned long unused);
95 static DEFINE_TIMER(pdc_console_timer, pdc_console_poll, 0, 0);
96 static struct tty_port tty_port;
97 
pdc_console_tty_open(struct tty_struct * tty,struct file * filp)98 static 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 
pdc_console_tty_close(struct tty_struct * tty,struct file * filp)106 static 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 
pdc_console_tty_write(struct tty_struct * tty,const unsigned char * buf,int count)114 static 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 
pdc_console_tty_write_room(struct tty_struct * tty)120 static int pdc_console_tty_write_room(struct tty_struct *tty)
121 {
122 	return 32768; /* no limit, no buffer used */
123 }
124 
pdc_console_tty_chars_in_buffer(struct tty_struct * tty)125 static int pdc_console_tty_chars_in_buffer(struct tty_struct *tty)
126 {
127 	return 0; /* no buffer */
128 }
129 
130 static 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 
pdc_console_poll(unsigned long unused)138 static 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 
157 static struct tty_driver *pdc_console_tty_driver;
158 
pdc_console_tty_driver_init(void)159 static 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 device_initcall(pdc_console_tty_driver_init);
211 
pdc_console_device(struct console * c,int * index)212 static struct tty_driver * pdc_console_device (struct console *c, int *index)
213 {
214 	*index = c->index;
215 	return pdc_console_tty_driver;
216 }
217 #else
218 #define pdc_console_device NULL
219 #endif
220 
221 static struct console pdc_cons = {
222 	.name =		"ttyB",
223 	.write =	pdc_console_write,
224 	.device =	pdc_console_device,
225 	.setup =	pdc_console_setup,
226 	.flags =	CON_BOOT | CON_PRINTBUFFER,
227 	.index =	-1,
228 };
229 
230 static int pdc_console_initialized;
231 
pdc_console_init_force(void)232 static void pdc_console_init_force(void)
233 {
234 	if (pdc_console_initialized)
235 		return;
236 	++pdc_console_initialized;
237 
238 	/* If the console is duplex then copy the COUT parameters to CIN. */
239 	if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
240 		memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));
241 
242 	/* register the pdc console */
243 	register_console(&pdc_cons);
244 }
245 
pdc_console_init(void)246 void __init pdc_console_init(void)
247 {
248 #if defined(EARLY_BOOTUP_DEBUG) || defined(CONFIG_PDC_CONSOLE)
249 	pdc_console_init_force();
250 #endif
251 #ifdef EARLY_BOOTUP_DEBUG
252 	printk(KERN_INFO "Initialized PDC Console for debugging.\n");
253 #endif
254 }
255 
256 
257 /*
258  * Used for emergencies. Currently only used if an HPMC occurs. If an
259  * HPMC occurs, it is possible that the current console may not be
260  * properly initialised after the PDC IO reset. This routine unregisters
261  * all of the current consoles, reinitializes the pdc console and
262  * registers it.
263  */
264 
pdc_console_restart(void)265 void pdc_console_restart(void)
266 {
267 	struct console *console;
268 
269 	if (pdc_console_initialized)
270 		return;
271 
272 	/* If we've already seen the output, don't bother to print it again */
273 	if (console_drivers != NULL)
274 		pdc_cons.flags &= ~CON_PRINTBUFFER;
275 
276 	while ((console = console_drivers) != NULL)
277 		unregister_console(console_drivers);
278 
279 	/* force registering the pdc console */
280 	pdc_console_init_force();
281 }
282