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 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 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 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 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 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 } 99 100 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 } 105 106 static int pdc_console_tty_write_room(struct tty_struct *tty) 107 { 108 return 32768; /* no limit, no buffer used */ 109 } 110 111 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 }; 123 124 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; 144 145 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); 197 198 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; 217 218 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 } 231 232 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 */ 250 251 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