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 *
16 *
17 *    This program is free software; you can redistribute it and/or modify
18 *    it under the terms of the GNU General Public License as published by
19 *    the Free Software Foundation; either version 2 of the License, or
20 *    (at your option) any later version.
21 *
22 *    This program is distributed in the hope that it will be useful,
23 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
24 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
25 *    GNU General Public License for more details.
26 *
27 *    You should have received a copy of the GNU General Public License
28 *    along with this program; if not, write to the Free Software
29 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
30 */
31
32/*
33 *  The PDC console is a simple console, which can be used for debugging
34 *  boot related problems on HP PA-RISC machines.
35 *
36 *  This code uses the ROM (=PDC) based functions to read and write characters
37 *  from and to PDC's boot path.
38 *  Since all character read from that path must be polled, this code never
39 *  can or will be a fully functional linux console.
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/pdc.h>		/* for iodc_call() proto and friends */
54
55
56static void pdc_console_write(struct console *co, const char *s, unsigned count)
57{
58	while(count--)
59		pdc_iodc_putc(*s++);
60}
61
62void pdc_outc(unsigned char c)
63{
64	pdc_iodc_outc(c);
65}
66
67void pdc_printf(const char *fmt, ...)
68{
69	va_list args;
70	char buf[1024];
71	int i, len;
72
73	va_start(args, fmt);
74	len = vscnprintf(buf, sizeof(buf), fmt, args);
75	va_end(args);
76
77	for (i = 0; i < len; i++)
78		pdc_iodc_outc(buf[i]);
79}
80
81int pdc_console_poll_key(struct console *co)
82{
83	return pdc_iodc_getc();
84}
85
86static int pdc_console_setup(struct console *co, char *options)
87{
88	return 0;
89}
90
91#if defined(CONFIG_PDC_CONSOLE)
92#include <linux/vt_kern.h>
93
94static struct tty_driver * pdc_console_device (struct console *c, int *index)
95{
96	extern struct tty_driver console_driver;
97	*index = c->index ? c->index-1 : fg_console;
98	return &console_driver;
99}
100#else
101#define pdc_console_device NULL
102#endif
103
104static struct console pdc_cons = {
105	.name =		"ttyB",
106	.write =	pdc_console_write,
107	.device =	pdc_console_device,
108	.setup =	pdc_console_setup,
109	.flags =	CON_BOOT | CON_PRINTBUFFER | CON_ENABLED,
110	.index =	-1,
111};
112
113static int pdc_console_initialized;
114
115static void pdc_console_init_force(void)
116{
117	if (pdc_console_initialized)
118		return;
119	++pdc_console_initialized;
120
121	/* If the console is duplex then copy the COUT parameters to CIN. */
122	if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
123		memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));
124
125	/* register the pdc console */
126	register_console(&pdc_cons);
127}
128
129void __init pdc_console_init(void)
130{
131#if defined(EARLY_BOOTUP_DEBUG) || defined(CONFIG_PDC_CONSOLE)
132	pdc_console_init_force();
133#endif
134#ifdef EARLY_BOOTUP_DEBUG
135	printk(KERN_INFO "Initialized PDC Console for debugging.\n");
136#endif
137}
138
139
140/*
141 * Used for emergencies. Currently only used if an HPMC occurs. If an
142 * HPMC occurs, it is possible that the current console may not be
143 * properly initialised after the PDC IO reset. This routine unregisters
144 * all of the current consoles, reinitializes the pdc console and
145 * registers it.
146 */
147
148void pdc_console_restart(void)
149{
150	struct console *console;
151
152	if (pdc_console_initialized)
153		return;
154
155	/* If we've already seen the output, don't bother to print it again */
156	if (console_drivers != NULL)
157		pdc_cons.flags &= ~CON_PRINTBUFFER;
158
159	while ((console = console_drivers) != NULL)
160		unregister_console(console_drivers);
161
162	/* force registering the pdc console */
163	pdc_console_init_force();
164}
165