1 // SPDX-License-Identifier: GPL-2.0-or-later
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>
16 * Copyright (C) 2010 Guy Martin <gmsoft at tuxicoman.be>
17 */
18
19 /*
20 * The PDC console is a simple console, which can be used for debugging
21 * boot related problems on HP PA-RISC machines. It is also useful when no
22 * other console works.
23 *
24 * This code uses the ROM (=PDC) based functions to read and write characters
25 * from and to PDC's boot path.
26 */
27
28 /* Define EARLY_BOOTUP_DEBUG to debug kernel related boot problems.
29 * On production kernels EARLY_BOOTUP_DEBUG should be undefined. */
30 #define EARLY_BOOTUP_DEBUG
31
32
33 #include <linux/kernel.h>
34 #include <linux/console.h>
35 #include <linux/string.h>
36 #include <linux/init.h>
37 #include <linux/major.h>
38 #include <linux/tty.h>
39 #include <asm/page.h> /* for PAGE0 */
40 #include <asm/pdc.h> /* for iodc_call() proto and friends */
41
42 static DEFINE_SPINLOCK(pdc_console_lock);
43 static struct console pdc_cons;
44
pdc_console_write(struct console * co,const char * s,unsigned count)45 static void pdc_console_write(struct console *co, const char *s, unsigned count)
46 {
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);
55 }
56
pdc_console_poll_key(struct console * co)57 int pdc_console_poll_key(struct console *co)
58 {
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;
67 }
68
pdc_console_setup(struct console * co,char * options)69 static int pdc_console_setup(struct console *co, char *options)
70 {
71 return 0;
72 }
73
74 #if defined(CONFIG_PDC_CONSOLE)
75 #include <linux/vt_kern.h>
76 #include <linux/tty_flip.h>
77
78 #define PDC_CONS_POLL_DELAY (30 * HZ / 1000)
79
80 static void pdc_console_poll(struct timer_list *unused);
81 static DEFINE_TIMER(pdc_console_timer, pdc_console_poll);
82 static struct tty_port tty_port;
83
pdc_console_tty_open(struct tty_struct * tty,struct file * filp)84 static int pdc_console_tty_open(struct tty_struct *tty, struct file *filp)
85 {
86 tty_port_tty_set(&tty_port, tty);
87 mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
88
89 return 0;
90 }
91
pdc_console_tty_close(struct tty_struct * tty,struct file * filp)92 static void pdc_console_tty_close(struct tty_struct *tty, struct file *filp)
93 {
94 if (tty->count == 1) {
95 del_timer_sync(&pdc_console_timer);
96 tty_port_tty_set(&tty_port, NULL);
97 }
98 }
99
pdc_console_tty_write(struct tty_struct * tty,const unsigned char * buf,int count)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
pdc_console_tty_write_room(struct tty_struct * tty)106 static int pdc_console_tty_write_room(struct tty_struct *tty)
107 {
108 return 32768; /* no limit, no buffer used */
109 }
110
pdc_console_tty_chars_in_buffer(struct tty_struct * tty)111 static int pdc_console_tty_chars_in_buffer(struct tty_struct *tty)
112 {
113 return 0; /* no buffer */
114 }
115
116 static const struct tty_operations pdc_console_tty_ops = {
117 .open = pdc_console_tty_open,
118 .close = pdc_console_tty_close,
119 .write = pdc_console_tty_write,
120 .write_room = pdc_console_tty_write_room,
121 .chars_in_buffer = pdc_console_tty_chars_in_buffer,
122 };
123
pdc_console_poll(struct timer_list * unused)124 static void pdc_console_poll(struct timer_list *unused)
125 {
126 int data, count = 0;
127
128 while (1) {
129 data = pdc_console_poll_key(NULL);
130 if (data == -1)
131 break;
132 tty_insert_flip_char(&tty_port, data & 0xFF, TTY_NORMAL);
133 count ++;
134 }
135
136 if (count)
137 tty_flip_buffer_push(&tty_port);
138
139 if (pdc_cons.flags & CON_ENABLED)
140 mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
141 }
142
143 static struct tty_driver *pdc_console_tty_driver;
144
pdc_console_tty_driver_init(void)145 static int __init pdc_console_tty_driver_init(void)
146 {
147 int err;
148
149 /* Check if the console driver is still registered.
150 * It is unregistered if the pdc console was not selected as the
151 * primary console. */
152
153 struct console *tmp;
154
155 console_lock();
156 for_each_console(tmp)
157 if (tmp == &pdc_cons)
158 break;
159 console_unlock();
160
161 if (!tmp) {
162 printk(KERN_INFO "PDC console driver not registered anymore, not creating %s\n", pdc_cons.name);
163 return -ENODEV;
164 }
165
166 printk(KERN_INFO "The PDC console driver is still registered, removing CON_BOOT flag\n");
167 pdc_cons.flags &= ~CON_BOOT;
168
169 pdc_console_tty_driver = alloc_tty_driver(1);
170
171 if (!pdc_console_tty_driver)
172 return -ENOMEM;
173
174 tty_port_init(&tty_port);
175
176 pdc_console_tty_driver->driver_name = "pdc_cons";
177 pdc_console_tty_driver->name = "ttyB";
178 pdc_console_tty_driver->major = MUX_MAJOR;
179 pdc_console_tty_driver->minor_start = 0;
180 pdc_console_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
181 pdc_console_tty_driver->init_termios = tty_std_termios;
182 pdc_console_tty_driver->flags = TTY_DRIVER_REAL_RAW |
183 TTY_DRIVER_RESET_TERMIOS;
184 tty_set_operations(pdc_console_tty_driver, &pdc_console_tty_ops);
185 tty_port_link_device(&tty_port, pdc_console_tty_driver, 0);
186
187 err = tty_register_driver(pdc_console_tty_driver);
188 if (err) {
189 printk(KERN_ERR "Unable to register the PDC console TTY driver\n");
190 tty_port_destroy(&tty_port);
191 return err;
192 }
193
194 return 0;
195 }
196 device_initcall(pdc_console_tty_driver_init);
197
pdc_console_device(struct console * c,int * index)198 static struct tty_driver * pdc_console_device (struct console *c, int *index)
199 {
200 *index = c->index;
201 return pdc_console_tty_driver;
202 }
203 #else
204 #define pdc_console_device NULL
205 #endif
206
207 static struct console pdc_cons = {
208 .name = "ttyB",
209 .write = pdc_console_write,
210 .device = pdc_console_device,
211 .setup = pdc_console_setup,
212 .flags = CON_BOOT | CON_PRINTBUFFER,
213 .index = -1,
214 };
215
216 static int pdc_console_initialized;
217
pdc_console_init_force(void)218 static void pdc_console_init_force(void)
219 {
220 if (pdc_console_initialized)
221 return;
222 ++pdc_console_initialized;
223
224 /* If the console is duplex then copy the COUT parameters to CIN. */
225 if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
226 memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));
227
228 /* register the pdc console */
229 register_console(&pdc_cons);
230 }
231
pdc_console_init(void)232 void __init pdc_console_init(void)
233 {
234 #if defined(EARLY_BOOTUP_DEBUG) || defined(CONFIG_PDC_CONSOLE)
235 pdc_console_init_force();
236 #endif
237 #ifdef EARLY_BOOTUP_DEBUG
238 printk(KERN_INFO "Initialized PDC Console for debugging.\n");
239 #endif
240 }
241
242
243 /*
244 * Used for emergencies. Currently only used if an HPMC occurs. If an
245 * HPMC occurs, it is possible that the current console may not be
246 * properly initialised after the PDC IO reset. This routine unregisters
247 * all of the current consoles, reinitializes the pdc console and
248 * registers it.
249 */
250
pdc_console_restart(void)251 void pdc_console_restart(void)
252 {
253 struct console *console;
254
255 if (pdc_console_initialized)
256 return;
257
258 /* If we've already seen the output, don't bother to print it again */
259 if (console_drivers != NULL)
260 pdc_cons.flags &= ~CON_PRINTBUFFER;
261
262 while ((console = console_drivers) != NULL)
263 unregister_console(console_drivers);
264
265 /* force registering the pdc console */
266 pdc_console_init_force();
267 }
268