1#include "boot.h" 2 3#define DEFAULT_SERIAL_PORT 0x3f8 /* ttyS0 */ 4 5#define XMTRDY 0x20 6 7#define DLAB 0x80 8 9#define TXR 0 /* Transmit register (WRITE) */ 10#define RXR 0 /* Receive register (READ) */ 11#define IER 1 /* Interrupt Enable */ 12#define IIR 2 /* Interrupt ID */ 13#define FCR 2 /* FIFO control */ 14#define LCR 3 /* Line control */ 15#define MCR 4 /* Modem control */ 16#define LSR 5 /* Line Status */ 17#define MSR 6 /* Modem Status */ 18#define DLL 0 /* Divisor Latch Low */ 19#define DLH 1 /* Divisor latch High */ 20 21#define DEFAULT_BAUD 9600 22 23static void early_serial_init(int port, int baud) 24{ 25 unsigned char c; 26 unsigned divisor; 27 28 outb(0x3, port + LCR); /* 8n1 */ 29 outb(0, port + IER); /* no interrupt */ 30 outb(0, port + FCR); /* no fifo */ 31 outb(0x3, port + MCR); /* DTR + RTS */ 32 33 divisor = 115200 / baud; 34 c = inb(port + LCR); 35 outb(c | DLAB, port + LCR); 36 outb(divisor & 0xff, port + DLL); 37 outb((divisor >> 8) & 0xff, port + DLH); 38 outb(c & ~DLAB, port + LCR); 39 40 early_serial_base = port; 41} 42 43static void parse_earlyprintk(void) 44{ 45 int baud = DEFAULT_BAUD; 46 char arg[32]; 47 int pos = 0; 48 int port = 0; 49 50 if (cmdline_find_option("earlyprintk", arg, sizeof arg) > 0) { 51 char *e; 52 53 if (!strncmp(arg, "serial", 6)) { 54 port = DEFAULT_SERIAL_PORT; 55 pos += 6; 56 } 57 58 if (arg[pos] == ',') 59 pos++; 60 61 /* 62 * make sure we have 63 * "serial,0x3f8,115200" 64 * "serial,ttyS0,115200" 65 * "ttyS0,115200" 66 */ 67 if (pos == 7 && !strncmp(arg + pos, "0x", 2)) { 68 port = simple_strtoull(arg + pos, &e, 16); 69 if (port == 0 || arg + pos == e) 70 port = DEFAULT_SERIAL_PORT; 71 else 72 pos = e - arg; 73 } else if (!strncmp(arg + pos, "ttyS", 4)) { 74 static const int bases[] = { 0x3f8, 0x2f8 }; 75 int idx = 0; 76 77 if (!strncmp(arg + pos, "ttyS", 4)) 78 pos += 4; 79 80 if (arg[pos++] == '1') 81 idx = 1; 82 83 port = bases[idx]; 84 } 85 86 if (arg[pos] == ',') 87 pos++; 88 89 baud = simple_strtoull(arg + pos, &e, 0); 90 if (baud == 0 || arg + pos == e) 91 baud = DEFAULT_BAUD; 92 } 93 94 if (port) 95 early_serial_init(port, baud); 96} 97 98#define BASE_BAUD (1843200/16) 99static unsigned int probe_baud(int port) 100{ 101 unsigned char lcr, dll, dlh; 102 unsigned int quot; 103 104 lcr = inb(port + LCR); 105 outb(lcr | DLAB, port + LCR); 106 dll = inb(port + DLL); 107 dlh = inb(port + DLH); 108 outb(lcr, port + LCR); 109 quot = (dlh << 8) | dll; 110 111 return BASE_BAUD / quot; 112} 113 114static void parse_console_uart8250(void) 115{ 116 char optstr[64], *options; 117 int baud = DEFAULT_BAUD; 118 int port = 0; 119 120 /* 121 * console=uart8250,io,0x3f8,115200n8 122 * need to make sure it is last one console ! 123 */ 124 if (cmdline_find_option("console", optstr, sizeof optstr) <= 0) 125 return; 126 127 options = optstr; 128 129 if (!strncmp(options, "uart8250,io,", 12)) 130 port = simple_strtoull(options + 12, &options, 0); 131 else if (!strncmp(options, "uart,io,", 8)) 132 port = simple_strtoull(options + 8, &options, 0); 133 else 134 return; 135 136 if (options && (options[0] == ',')) 137 baud = simple_strtoull(options + 1, &options, 0); 138 else 139 baud = probe_baud(port); 140 141 if (port) 142 early_serial_init(port, baud); 143} 144 145void console_init(void) 146{ 147 parse_earlyprintk(); 148 149 if (!early_serial_base) 150 parse_console_uart8250(); 151} 152