PageRenderTime 48ms CodeModel.GetById 17ms app.highlight 25ms RepoModel.GetById 1ms app.codeStats 0ms

/arch/parisc/kernel/pdc_cons.c

https://github.com/aicjofs/android_kernel_lge_v500_20d
C | 286 lines | 176 code | 55 blank | 55 comment | 23 complexity | 269b0fa6c1fb9abd28a24a8f1c70777b MD5 | raw file
  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	struct tty_struct *tty = tty_port_tty_get(&tty_port);
142
143	if (!tty)
144		return;
145
146	while (1) {
147		data = pdc_console_poll_key(NULL);
148		if (data == -1)
149			break;
150		tty_insert_flip_char(tty, data & 0xFF, TTY_NORMAL);
151		count ++;
152	}
153
154	if (count)
155		tty_flip_buffer_push(tty);
156
157	tty_kref_put(tty);
158
159	if (pdc_cons.flags & CON_ENABLED)
160		mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY);
161}
162
163static struct tty_driver *pdc_console_tty_driver;
164
165static int __init pdc_console_tty_driver_init(void)
166{
167	int err;
168
169	/* Check if the console driver is still registered.
170	 * It is unregistered if the pdc console was not selected as the
171	 * primary console. */
172
173	struct console *tmp;
174
175	console_lock();
176	for_each_console(tmp)
177		if (tmp == &pdc_cons)
178			break;
179	console_unlock();
180
181	if (!tmp) {
182		printk(KERN_INFO "PDC console driver not registered anymore, not creating %s\n", pdc_cons.name);
183		return -ENODEV;
184	}
185
186	printk(KERN_INFO "The PDC console driver is still registered, removing CON_BOOT flag\n");
187	pdc_cons.flags &= ~CON_BOOT;
188
189	tty_port_init(&tty_port);
190
191	pdc_console_tty_driver = alloc_tty_driver(1);
192
193	if (!pdc_console_tty_driver)
194		return -ENOMEM;
195
196	pdc_console_tty_driver->driver_name = "pdc_cons";
197	pdc_console_tty_driver->name = "ttyB";
198	pdc_console_tty_driver->major = MUX_MAJOR;
199	pdc_console_tty_driver->minor_start = 0;
200	pdc_console_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
201	pdc_console_tty_driver->init_termios = tty_std_termios;
202	pdc_console_tty_driver->flags = TTY_DRIVER_REAL_RAW |
203		TTY_DRIVER_RESET_TERMIOS;
204	tty_set_operations(pdc_console_tty_driver, &pdc_console_tty_ops);
205
206	err = tty_register_driver(pdc_console_tty_driver);
207	if (err) {
208		printk(KERN_ERR "Unable to register the PDC console TTY driver\n");
209		return err;
210	}
211
212	return 0;
213}
214
215module_init(pdc_console_tty_driver_init);
216
217static struct tty_driver * pdc_console_device (struct console *c, int *index)
218{
219	*index = c->index;
220	return pdc_console_tty_driver;
221}
222#else
223#define pdc_console_device NULL
224#endif
225
226static struct console pdc_cons = {
227	.name =		"ttyB",
228	.write =	pdc_console_write,
229	.device =	pdc_console_device,
230	.setup =	pdc_console_setup,
231	.flags =	CON_BOOT | CON_PRINTBUFFER,
232	.index =	-1,
233};
234
235static int pdc_console_initialized;
236
237static void pdc_console_init_force(void)
238{
239	if (pdc_console_initialized)
240		return;
241	++pdc_console_initialized;
242	
243	/* If the console is duplex then copy the COUT parameters to CIN. */
244	if (PAGE0->mem_cons.cl_class == CL_DUPLEX)
245		memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons));
246
247	/* register the pdc console */
248	register_console(&pdc_cons);
249}
250
251void __init pdc_console_init(void)
252{
253#if defined(EARLY_BOOTUP_DEBUG) || defined(CONFIG_PDC_CONSOLE)
254	pdc_console_init_force();
255#endif
256#ifdef EARLY_BOOTUP_DEBUG
257	printk(KERN_INFO "Initialized PDC Console for debugging.\n");
258#endif
259}
260
261
262/*
263 * Used for emergencies. Currently only used if an HPMC occurs. If an
264 * HPMC occurs, it is possible that the current console may not be
265 * properly initialised after the PDC IO reset. This routine unregisters
266 * all of the current consoles, reinitializes the pdc console and
267 * registers it.
268 */
269
270void pdc_console_restart(void)
271{
272	struct console *console;
273
274	if (pdc_console_initialized)
275		return;
276
277	/* If we've already seen the output, don't bother to print it again */
278	if (console_drivers != NULL)
279		pdc_cons.flags &= ~CON_PRINTBUFFER;
280
281	while ((console = console_drivers) != NULL)
282		unregister_console(console_drivers);
283
284	/* force registering the pdc console */
285	pdc_console_init_force();
286}