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 unsigned int pdc_console_tty_write_room(struct tty_struct *tty) 107 { 108 return 32768; /* no limit, no buffer used */ 109 } 110 111 static const struct tty_operations pdc_console_tty_ops = { 112 .open = pdc_console_tty_open, 113 .close = pdc_console_tty_close, 114 .write = pdc_console_tty_write, 115 .write_room = pdc_console_tty_write_room, 116 }; 117 118 static void pdc_console_poll(struct timer_list *unused) 119 { 120 int data, count = 0; 121 122 while (1) { 123 data = pdc_console_poll_key(NULL); 124 if (data == -1) 125 break; 126 tty_insert_flip_char(&tty_port, data & 0xFF, TTY_NORMAL); 127 count ++; 128 } 129 130 if (count) 131 tty_flip_buffer_push(&tty_port); 132 133 if (pdc_cons.flags & CON_ENABLED) 134 mod_timer(&pdc_console_timer, jiffies + PDC_CONS_POLL_DELAY); 135 } 136 137 static struct tty_driver *pdc_console_tty_driver; 138 139 static int __init pdc_console_tty_driver_init(void) 140 { 141 struct tty_driver *driver; 142 int err; 143 144 /* Check if the console driver is still registered. 145 * It is unregistered if the pdc console was not selected as the 146 * primary console. */ 147 148 struct console *tmp; 149 150 console_lock(); 151 for_each_console(tmp) 152 if (tmp == &pdc_cons) 153 break; 154 console_unlock(); 155 156 if (!tmp) { 157 printk(KERN_INFO "PDC console driver not registered anymore, not creating %s\n", pdc_cons.name); 158 return -ENODEV; 159 } 160 161 printk(KERN_INFO "The PDC console driver is still registered, removing CON_BOOT flag\n"); 162 pdc_cons.flags &= ~CON_BOOT; 163 164 driver = tty_alloc_driver(1, TTY_DRIVER_REAL_RAW | 165 TTY_DRIVER_RESET_TERMIOS); 166 if (IS_ERR(driver)) 167 return PTR_ERR(driver); 168 169 tty_port_init(&tty_port); 170 171 driver->driver_name = "pdc_cons"; 172 driver->name = "ttyB"; 173 driver->major = MUX_MAJOR; 174 driver->minor_start = 0; 175 driver->type = TTY_DRIVER_TYPE_SYSTEM; 176 driver->init_termios = tty_std_termios; 177 tty_set_operations(driver, &pdc_console_tty_ops); 178 tty_port_link_device(&tty_port, driver, 0); 179 180 err = tty_register_driver(driver); 181 if (err) { 182 printk(KERN_ERR "Unable to register the PDC console TTY driver\n"); 183 tty_port_destroy(&tty_port); 184 tty_driver_kref_put(driver); 185 return err; 186 } 187 188 pdc_console_tty_driver = driver; 189 190 return 0; 191 } 192 device_initcall(pdc_console_tty_driver_init); 193 194 static struct tty_driver * pdc_console_device (struct console *c, int *index) 195 { 196 *index = c->index; 197 return pdc_console_tty_driver; 198 } 199 #else 200 #define pdc_console_device NULL 201 #endif 202 203 static struct console pdc_cons = { 204 .name = "ttyB", 205 .write = pdc_console_write, 206 .device = pdc_console_device, 207 .setup = pdc_console_setup, 208 .flags = CON_BOOT | CON_PRINTBUFFER, 209 .index = -1, 210 }; 211 212 static int pdc_console_initialized; 213 214 static void pdc_console_init_force(void) 215 { 216 if (pdc_console_initialized) 217 return; 218 ++pdc_console_initialized; 219 220 /* If the console is duplex then copy the COUT parameters to CIN. */ 221 if (PAGE0->mem_cons.cl_class == CL_DUPLEX) 222 memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons)); 223 224 /* register the pdc console */ 225 register_console(&pdc_cons); 226 } 227 228 void __init pdc_console_init(void) 229 { 230 #if defined(EARLY_BOOTUP_DEBUG) || defined(CONFIG_PDC_CONSOLE) 231 pdc_console_init_force(); 232 #endif 233 #ifdef EARLY_BOOTUP_DEBUG 234 printk(KERN_INFO "Initialized PDC Console for debugging.\n"); 235 #endif 236 } 237 238 239 /* 240 * Used for emergencies. Currently only used if an HPMC occurs. If an 241 * HPMC occurs, it is possible that the current console may not be 242 * properly initialised after the PDC IO reset. This routine unregisters 243 * all of the current consoles, reinitializes the pdc console and 244 * registers it. 245 */ 246 247 void pdc_console_restart(void) 248 { 249 struct console *console; 250 251 if (pdc_console_initialized) 252 return; 253 254 /* If we've already seen the output, don't bother to print it again */ 255 if (console_drivers != NULL) 256 pdc_cons.flags &= ~CON_PRINTBUFFER; 257 258 while ((console = console_drivers) != NULL) 259 unregister_console(console_drivers); 260 261 /* force registering the pdc console */ 262 pdc_console_init_force(); 263 } 264