1/* 2 * linux/arch/parisc/kernel/pdc_console.c 3 * 4 * The PDC console is a simple console, which can be used for debugging 5 * boot related problems on HP PA-RISC machines. 6 * 7 * This code uses the ROM (=PDC) based functions to read and write characters 8 * from and to PDC's boot path. 9 * Since all character read from that path must be polled, this code never 10 * can or will be a fully functional linux console. 11 */ 12 13/* Define EARLY_BOOTUP_DEBUG to debug kernel related boot problems. 14 * On production kernels EARLY_BOOTUP_DEBUG should be undefined. */ 15#undef EARLY_BOOTUP_DEBUG 16 17 18#include <linux/config.h> 19#include <linux/kernel.h> 20#include <linux/console.h> 21#include <linux/string.h> 22#include <linux/init.h> 23#include <linux/delay.h> 24#include <linux/sched.h> 25#include <linux/interrupt.h> 26#include <asm/page.h> 27#include <asm/types.h> 28#include <asm/system.h> 29#include <asm/pdc.h> /* for iodc_call() proto and friends */ 30 31 32static void pdc_console_write(struct console *co, const char *s, unsigned count) 33{ 34 while(count--) 35 pdc_iodc_putc(*s++); 36} 37 38void pdc_outc(unsigned char c) 39{ 40 pdc_iodc_outc(c); 41} 42 43 44int pdc_console_poll_key(struct console *co) 45{ 46 return pdc_iodc_getc(); 47} 48 49static int pdc_console_setup(struct console *co, char *options) 50{ 51 return 0; 52} 53 54#ifdef CONFIG_PDC_CONSOLE 55static kdev_t pdc_console_device (struct console *c) 56{ 57 return MKDEV(PDCCONS_MAJOR, 0); 58} 59#endif 60 61#ifdef CONFIG_PDC_CONSOLE 62#define PDC_CONSOLE_DEVICE pdc_console_device 63#else 64#define PDC_CONSOLE_DEVICE NULL 65#endif 66 67static struct console pdc_cons = { 68 name: "ttyB", 69 write: pdc_console_write, 70 device: PDC_CONSOLE_DEVICE, 71 setup: pdc_console_setup, 72 flags: CON_BOOT|CON_PRINTBUFFER|CON_ENABLED, 73 index: -1, 74}; 75 76static int pdc_console_initialized; 77 78extern unsigned long con_start; /* kernel/printk.c */ 79extern unsigned long log_end; /* kernel/printk.c */ 80 81static void pdc_console_init_force(void) 82{ 83 if (pdc_console_initialized) 84 return; 85 ++pdc_console_initialized; 86 87 /* If the console is duplex then copy the COUT parameters to CIN. */ 88 if (PAGE0->mem_cons.cl_class == CL_DUPLEX) 89 memcpy(&PAGE0->mem_kbd, &PAGE0->mem_cons, sizeof(PAGE0->mem_cons)); 90 91 /* register the pdc console */ 92 register_console(&pdc_cons); 93} 94 95void pdc_console_init(void) 96{ 97#if defined(EARLY_BOOTUP_DEBUG) || defined(CONFIG_PDC_CONSOLE) 98 pdc_console_init_force(); 99#endif 100#ifdef EARLY_BOOTUP_DEBUG 101 printk(KERN_INFO "Initialized PDC Console for debugging.\n"); 102#endif 103} 104 105 106/* Unregister the pdc console with the printk console layer */ 107void pdc_console_die(void) 108{ 109 if (!pdc_console_initialized) 110 return; 111 --pdc_console_initialized; 112 113 printk(KERN_INFO "Switching from PDC console\n"); 114 115 /* Don't repeat what we've already printed */ 116 con_start = log_end; 117 118 unregister_console(&pdc_cons); 119} 120 121 122/* 123 * Used for emergencies. Currently only used if an HPMC occurs. If an 124 * HPMC occurs, it is possible that the current console may not be 125 * properly initialed after the PDC IO reset. This routine unregisters all 126 * of the current consoles, reinitializes the pdc console and 127 * registers it. 128 */ 129 130void pdc_console_restart(void) 131{ 132 struct console *console; 133 134 if (pdc_console_initialized) 135 return; 136 137 while ((console = console_drivers) != NULL) 138 unregister_console(console_drivers); 139 140 /* Don't repeat what we've already printed */ 141 con_start = log_end; 142 143 /* force registering the pdc console */ 144 pdc_console_init_force(); 145} 146 147