grub-core/term/ns8250.c

   1 /*
   2  *  GRUB  --  GRand Unified Bootloader
   3  *  Copyright (C) 2000,2001,2002,2003,2004,2005,2007,2008,2009,2010  Free Software Foundation, Inc.
   4  *
   5  *  GRUB is free software: you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation, either version 3 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  GRUB is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <grub/serial.h>
  20 #include <grub/ns8250.h>
  21 #include <grub/types.h>
  22 #include <grub/dl.h>
  23 #include <grub/misc.h>
  24 #include <grub/cpu/io.h>
  25 #include <grub/mm.h>
  26 #include <grub/time.h>
  27 #include <grub/i18n.h>
  28
  29 #ifdef GRUB_MACHINE_PCBIOS
  30 #include <grub/machine/memory.h>
  31 static const unsigned short *serial_hw_io_addr = (const unsigned short *) GRUB_MEMORY_MACHINE_BIOS_DATA_AREA_ADDR;
  32 #define GRUB_SERIAL_PORT_NUM 4
  33 #else
  34 #include <grub/machine/serial.h>
  35 static const grub_port_t serial_hw_io_addr[] = GRUB_MACHINE_SERIAL_PORTS;
  36 #define GRUB_SERIAL_PORT_NUM (ARRAY_SIZE(serial_hw_io_addr))
  37 #endif
  38
  39 static int dead_ports = 0;
  40
  41 #ifdef GRUB_MACHINE_MIPS_LOONGSON
  42 #define DEFAULT_BASE_CLOCK (2 * 115200)
  43 #else
  44 #define DEFAULT_BASE_CLOCK 115200
  45 #endif
  46
  47
  48 /* Convert speed to divisor.  */
  49 static unsigned short
  50 serial_get_divisor (const struct grub_serial_port *port __attribute__ ((unused)),
  51                     const struct grub_serial_config *config)
  52 {
  53   grub_uint32_t base_clock;
  54   grub_uint32_t divisor;
  55   grub_uint32_t actual_speed, error;
  56
  57   base_clock = config->base_clock ? (config->base_clock >> 4) : DEFAULT_BASE_CLOCK;
  58
  59   divisor = (base_clock + (config->speed / 2)) / config->speed;
  60   if (config->speed == 0)
  61     return 0;
  62   if (divisor > 0xffff || divisor == 0)
  63     return 0;
  64   actual_speed = base_clock / divisor;
  65   error = actual_speed > config->speed ? (actual_speed - config->speed)
  66     : (config->speed - actual_speed);
  67   if (error > (config->speed / 30 + 1))
  68     return 0;
  69   return divisor;
  70 }
  71
  72 static void
  73 do_real_config (struct grub_serial_port *port)
  74 {
  75   int divisor;
  76   unsigned char status = 0;
  77   grub_uint64_t endtime;
  78
  79   const unsigned char parities[] = {
  80     [GRUB_SERIAL_PARITY_NONE] = UART_NO_PARITY,
  81     [GRUB_SERIAL_PARITY_ODD] = UART_ODD_PARITY,
  82     [GRUB_SERIAL_PARITY_EVEN] = UART_EVEN_PARITY
  83   };
  84   const unsigned char stop_bits[] = {
  85     [GRUB_SERIAL_STOP_BITS_1] = UART_1_STOP_BIT,
  86     [GRUB_SERIAL_STOP_BITS_2] = UART_2_STOP_BITS,
  87   };
  88
  89   if (port->configured)
  90     return;
  91
  92   port->broken = 0;
  93
  94   divisor = serial_get_divisor (port, &port->config);
  95
  96   /* Turn off the interrupt.  */
  97   grub_outb (0, port->port + UART_IER);
  98
  99   /* Set DLAB.  */
 100   grub_outb (UART_DLAB, port->port + UART_LCR);
 101
 102   /* Set the baud rate.  */
 103   grub_outb (divisor & 0xFF, port->port + UART_DLL);
 104   grub_outb (divisor >> 8, port->port + UART_DLH);
 105
 106   /* Set the line status.  */
 107   status |= (parities[port->config.parity]
 108              | (port->config.word_len - 5)
 109              | stop_bits[port->config.stop_bits]);
 110   grub_outb (status, port->port + UART_LCR);
 111
 112   if (port->config.rtscts)
 113     {
 114       /* Enable the FIFO.  */
 115       grub_outb (UART_ENABLE_FIFO_TRIGGER1, port->port + UART_FCR);
 116
 117       /* Turn on DTR and RTS.  */
 118       grub_outb (UART_ENABLE_DTRRTS, port->port + UART_MCR);
 119     }
 120   else
 121     {
 122       /* Enable the FIFO.  */
 123       grub_outb (UART_ENABLE_FIFO_TRIGGER14, port->port + UART_FCR);
 124
 125       /* Turn on DTR, RTS, and OUT2.  */
 126       grub_outb (UART_ENABLE_DTRRTS | UART_ENABLE_OUT2, port->port + UART_MCR);
 127     }
 128
 129   /* Drain the input buffer.  */
 130   endtime = grub_get_time_ms () + 1000;
 131   while (grub_inb (port->port + UART_LSR) & UART_DATA_READY)
 132     {
 133       grub_inb (port->port + UART_RX);
 134       if (grub_get_time_ms () > endtime)
 135         {
 136           port->broken = 1;
 137           break;
 138         }
 139     }
 140
 141   port->configured = 1;
 142 }
 143
 144 /* Fetch a key.  */
 145 static int
 146 serial_hw_fetch (struct grub_serial_port *port)
 147 {
 148   do_real_config (port);
 149   if (grub_inb (port->port + UART_LSR) & UART_DATA_READY)
 150     return grub_inb (port->port + UART_RX);
 151
 152   return -1;
 153 }
 154
 155 /* Put a character.  */
 156 static void
 157 serial_hw_put (struct grub_serial_port *port, const int c)
 158 {
 159   grub_uint64_t endtime;
 160
 161   do_real_config (port);
 162
 163   if (port->broken > 5)
 164     endtime = grub_get_time_ms ();
 165   else if (port->broken > 1)
 166     endtime = grub_get_time_ms () + 50;
 167   else
 168     endtime = grub_get_time_ms () + 200;
 169   /* Wait until the transmitter holding register is empty.  */
 170   while ((grub_inb (port->port + UART_LSR) & UART_EMPTY_TRANSMITTER) == 0)
 171     {
 172       if (grub_get_time_ms () > endtime)
 173         {
 174           port->broken++;
 175           /* There is something wrong. But what can I do?  */
 176           return;
 177         }
 178     }
 179
 180   if (port->broken)
 181     port->broken--;
 182
 183   grub_outb (c, port->port + UART_TX);
 184 }
 185
 186 /* Initialize a serial device. PORT is the port number for a serial device.
 187    SPEED is a DTE-DTE speed which must be one of these: 2400, 4800, 9600,
 188    19200, 38400, 57600 and 115200. WORD_LEN is the word length to be used
 189    for the device. Likewise, PARITY is the type of the parity and
 190    STOP_BIT_LEN is the length of the stop bit. The possible values for
 191    WORD_LEN, PARITY and STOP_BIT_LEN are defined in the header file as
 192    macros.  */
 193 static grub_err_t
 194 serial_hw_configure (struct grub_serial_port *port,
 195                      struct grub_serial_config *config)
 196 {
 197   unsigned short divisor;
 198
 199   divisor = serial_get_divisor (port, config);
 200   if (divisor == 0)
 201     return grub_error (GRUB_ERR_BAD_ARGUMENT,
 202                        N_("unsupported serial port speed"));
 203
 204   if (config->parity != GRUB_SERIAL_PARITY_NONE
 205       && config->parity != GRUB_SERIAL_PARITY_ODD
 206       && config->parity != GRUB_SERIAL_PARITY_EVEN)
 207     return grub_error (GRUB_ERR_BAD_ARGUMENT,
 208                        N_("unsupported serial port parity"));
 209
 210   if (config->stop_bits != GRUB_SERIAL_STOP_BITS_1
 211       && config->stop_bits != GRUB_SERIAL_STOP_BITS_2)
 212     return grub_error (GRUB_ERR_BAD_ARGUMENT,
 213                        N_("unsupported serial port stop bits number"));
 214
 215   if (config->word_len < 5 || config->word_len > 8)
 216     return grub_error (GRUB_ERR_BAD_ARGUMENT,
 217                        N_("unsupported serial port word length"));
 218
 219   port->config = *config;
 220   port->configured = 0;
 221
 222   /*  FIXME: should check if the serial terminal was found.  */
 223
 224   return GRUB_ERR_NONE;
 225 }
 226
 227 struct grub_serial_driver grub_ns8250_driver =
 228   {
 229     .configure = serial_hw_configure,
 230     .fetch = serial_hw_fetch,
 231     .put = serial_hw_put
 232   };
 233
 234 static char com_names[GRUB_SERIAL_PORT_NUM][20];
 235 static struct grub_serial_port com_ports[GRUB_SERIAL_PORT_NUM];
 236
 237 void
 238 grub_ns8250_init (void)
 239 {
 240   unsigned i;
 241   for (i = 0; i < GRUB_SERIAL_PORT_NUM; i++)
 242     if (serial_hw_io_addr[i])
 243       {
 244         grub_err_t err;
 245
 246         grub_outb (0x5a, serial_hw_io_addr[i] + UART_SR);
 247         if (grub_inb (serial_hw_io_addr[i] + UART_SR) != 0x5a)
 248           {
 249             dead_ports |= (1 << i);
 250             continue;
 251           }
 252         grub_outb (0xa5, serial_hw_io_addr[i] + UART_SR);
 253         if (grub_inb (serial_hw_io_addr[i] + UART_SR) != 0xa5)
 254           {
 255             dead_ports |= (1 << i);
 256             continue;
 257           }
 258
 259         grub_snprintf (com_names[i], sizeof (com_names[i]), "com%d", i);
 260         com_ports[i].name = com_names[i];
 261         com_ports[i].driver = &grub_ns8250_driver;
 262         com_ports[i].port = serial_hw_io_addr[i];
 263         err = grub_serial_config_defaults (&com_ports[i]);
 264         if (err)
 265           grub_print_error ();
 266
 267         grub_serial_register (&com_ports[i]);
 268       }
 269 }
 270
 271 /* Return the port number for the UNITth serial device.  */
 272 grub_port_t
 273 grub_ns8250_hw_get_port (const unsigned int unit)
 274 {
 275   if (unit < GRUB_SERIAL_PORT_NUM
 276       && !(dead_ports & (1 << unit)))
 277     return serial_hw_io_addr[unit];
 278   else
 279     return 0;
 280 }
 281
 282 char *
 283 grub_serial_ns8250_add_port (grub_port_t port)
 284 {
 285   struct grub_serial_port *p;
 286   unsigned i;
 287   for (i = 0; i < GRUB_SERIAL_PORT_NUM; i++)
 288     if (com_ports[i].port == port)
 289       {
 290         if (dead_ports & (1 << i))
 291           return NULL;
 292         return com_names[i];
 293       }
 294
 295   grub_outb (0x5a, port + UART_SR);
 296   if (grub_inb (port + UART_SR) != 0x5a)
 297     return NULL;
 298
 299   grub_outb (0xa5, port + UART_SR);
 300   if (grub_inb (port + UART_SR) != 0xa5)
 301     return NULL;
 302
 303   p = grub_malloc (sizeof (*p));
 304   if (!p)
 305     return NULL;
 306   p->name = grub_xasprintf ("port%lx", (unsigned long) port);
 307   if (!p->name)
 308     {
 309       grub_free (p);
 310       return NULL;
 311     }
 312   p->driver = &grub_ns8250_driver;
 313   grub_serial_config_defaults (p);
 314   p->port = port;
 315   grub_serial_register (p);
 316
 317   return p->name;
 318 }