src/core/serial.c

   1 /*
   2  * Copyright (C) 2014 Michael Brown <mbrown@fensystems.co.uk>.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation; either version 2 of the
   7  * License, or any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301, USA.
  18  *
  19  * You can also choose to distribute this program under the terms of
  20  * the Unmodified Binary Distribution Licence (as given in the file
  21  * COPYING.UBDL), provided that you have satisfied its requirements.
  22  */
  23
  24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  25
  26 /** @file
  27  *
  28  * Serial console
  29  *
  30  */
  31
  32 #include <stddef.h>
  33 #include <string.h>
  34 #include <ipxe/init.h>
  35 #include <ipxe/uart.h>
  36 #include <ipxe/console.h>
  37 #include <ipxe/serial.h>
  38 #include <config/console.h>
  39 #include <config/serial.h>
  40
  41 /* Set default console usage if applicable */
  42 #if ! ( defined ( CONSOLE_SERIAL ) && CONSOLE_EXPLICIT ( CONSOLE_SERIAL ) )
  43 #undef CONSOLE_SERIAL
  44 #define CONSOLE_SERIAL ( CONSOLE_USAGE_ALL & ~CONSOLE_USAGE_LOG )
  45 #endif
  46
  47 /* UART port number */
  48 #ifdef COMCONSOLE
  49 #define CONSOLE_PORT COMCONSOLE
  50 #else
  51 #define CONSOLE_PORT 0
  52 #endif
  53
  54 /* UART baud rate */
  55 #ifdef COMPRESERVE
  56 #define CONSOLE_BAUD 0
  57 #else
  58 #define CONSOLE_BAUD COMSPEED
  59 #endif
  60
  61 /* UART line control register value */
  62 #ifdef COMPRESERVE
  63 #define CONSOLE_LCR 0
  64 #else
  65 #define CONSOLE_LCR UART_LCR_WPS ( COMDATA, COMPARITY, COMSTOP )
  66 #endif
  67
  68 /** Serial console UART */
  69 struct uart serial_console;
  70
  71 /**
  72  * Print a character to serial console
  73  *
  74  * @v character         Character to be printed
  75  */
  76 static void serial_putchar ( int character ) {
  77
  78         /* Do nothing if we have no UART */
  79         if ( ! serial_console.base )
  80                 return;
  81
  82         /* Transmit character */
  83         uart_transmit ( &serial_console, character );
  84 }
  85
  86 /**
  87  * Get character from serial console
  88  *
  89  * @ret character       Character read from console
  90  */
  91 static int serial_getchar ( void ) {
  92         uint8_t data;
  93
  94         /* Do nothing if we have no UART */
  95         if ( ! serial_console.base )
  96                 return 0;
  97
  98         /* Wait for data to be ready */
  99         while ( ! uart_data_ready ( &serial_console ) ) {}
 100
 101         /* Receive data */
 102         data = uart_receive ( &serial_console );
 103
 104         /* Strip any high bit and convert DEL to backspace */
 105         data &= 0x7f;
 106         if ( data == 0x7f )
 107                 data = 0x08;
 108
 109         return data;
 110 }
 111
 112 /**
 113  * Check for character ready to read from serial console
 114  *
 115  * @ret True            Character available to read
 116  * @ret False           No character available to read
 117  */
 118 static int serial_iskey ( void ) {
 119
 120         /* Do nothing if we have no UART */
 121         if ( ! serial_console.base )
 122                 return 0;
 123
 124         /* Check UART */
 125         return uart_data_ready ( &serial_console );
 126 }
 127
 128 /** Serial console */
 129 struct console_driver serial_console_driver __console_driver = {
 130         .putchar = serial_putchar,
 131         .getchar = serial_getchar,
 132         .iskey = serial_iskey,
 133         .usage = CONSOLE_SERIAL,
 134 };
 135
 136 /** Initialise serial console */
 137 static void serial_init ( void ) {
 138         int rc;
 139
 140         /* Do nothing if we have no default port */
 141         if ( ! CONSOLE_PORT )
 142                 return;
 143
 144         /* Select UART */
 145         if ( ( rc = uart_select ( &serial_console, CONSOLE_PORT ) ) != 0 ) {
 146                 DBG ( "Could not select UART %d: %s\n",
 147                       CONSOLE_PORT, strerror ( rc ) );
 148                 return;
 149         }
 150
 151         /* Initialise UART */
 152         if ( ( rc = uart_init ( &serial_console, CONSOLE_BAUD,
 153                                 CONSOLE_LCR ) ) != 0 ) {
 154                 DBG ( "Could not initialise UART %d baud %d LCR %#02x: %s\n",
 155                       CONSOLE_PORT, CONSOLE_BAUD, CONSOLE_LCR, strerror ( rc ));
 156                 return;
 157         }
 158 }
 159
 160 /**
 161  * Shut down serial console
 162  *
 163  * @v flags             Shutdown flags
 164  */
 165 static void serial_shutdown ( int flags __unused ) {
 166
 167         /* Do nothing if we have no UART */
 168         if ( ! serial_console.base )
 169                 return;
 170
 171         /* Flush any pending output */
 172         uart_flush ( &serial_console );
 173
 174         /* Leave console enabled; it's still usable */
 175 }
 176
 177 /** Serial console initialisation function */
 178 struct init_fn serial_console_init_fn __init_fn ( INIT_CONSOLE ) = {
 179         .initialise = serial_init,
 180 };
 181
 182 /** Serial console startup function */
 183 struct startup_fn serial_startup_fn __startup_fn ( STARTUP_EARLY ) = {
 184         .name = "serial",
 185         .shutdown = serial_shutdown,
 186 };