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 #define GRUB_SERIAL_PORT_NUM 4
  32 #else
  33 #include <grub/machine/serial.h>
  34 static const grub_port_t serial_hw_io_addr[] = GRUB_MACHINE_SERIAL_PORTS;
  35 #define GRUB_SERIAL_PORT_NUM (ARRAY_SIZE(serial_hw_io_addr))
  36 #endif
  37
  38 static int dead_ports = 0;
  39
  40 static grub_uint8_t
  41 ns8250_reg_read (struct grub_serial_port *port, grub_addr_t reg)
  42 {
  43   asm volatile("" : : : "memory");
  44   if (port->use_mmio == true)
  45     {
  46       /*
  47        * Note: we assume MMIO UARTs are little endian. This is not true of all
  48        * embedded platforms but will do for now.
  49        */
  50       switch(port->mmio.access_size)
  51         {
  52         default:
  53           /* ACPI tables occasionally uses "0" (legacy) as equivalent to "1" (byte). */
  54         case 1:
  55           return *((volatile grub_uint8_t *) (port->mmio.base + reg));
  56         case 2:
  57           return grub_le_to_cpu16 (*((volatile grub_uint16_t *) (port->mmio.base + (reg << 1))));
  58         case 3:
  59           return grub_le_to_cpu32 (*((volatile grub_uint32_t *) (port->mmio.base + (reg << 2))));
  60         case 4:
  61           /*
  62            * This will only work properly on 64-bit systems since 64-bit
  63            * accessors aren't atomic on 32-bit hardware. Thankfully the
  64            * case of a UART with a 64-bit register spacing on 32-bit
  65            * also probably doesn't exist.
  66            */
  67           return grub_le_to_cpu64 (*((volatile grub_uint64_t *) (port->mmio.base + (reg << 3))));
  68         }
  69     }
  70   return grub_inb (port->port + reg);
  71 }
  72
  73 static void
  74 ns8250_reg_write (struct grub_serial_port *port, grub_uint8_t value, grub_addr_t reg)
  75 {
  76   asm volatile("" : : : "memory");
  77   if (port->use_mmio == true)
  78     {
  79       switch(port->mmio.access_size)
  80         {
  81         default:
  82           /* ACPI tables occasionally uses "0" (legacy) as equivalent to "1" (byte). */
  83         case 1:
  84           *((volatile grub_uint8_t *) (port->mmio.base + reg)) = value;
  85           break;
  86         case 2:
  87           *((volatile grub_uint16_t *) (port->mmio.base + (reg << 1))) = grub_cpu_to_le16 (value);
  88           break;
  89         case 3:
  90           *((volatile grub_uint32_t *) (port->mmio.base + (reg << 2))) = grub_cpu_to_le32 (value);
  91           break;
  92         case 4:
  93           /* See commment in ns8250_reg_read(). */
  94           *((volatile grub_uint64_t *) (port->mmio.base + (reg << 3))) = grub_cpu_to_le64 (value);
  95           break;
  96         }
  97     }
  98   else
  99     grub_outb (value, port->port + reg);
 100 }
 101
 102 /* Convert speed to divisor.  */
 103 static unsigned short
 104 serial_get_divisor (const struct grub_serial_port *port __attribute__ ((unused)),
 105                     const struct grub_serial_config *config)
 106 {
 107   grub_uint32_t base_clock;
 108   grub_uint32_t divisor;
 109   grub_uint32_t actual_speed, error;
 110
 111   /* Get the UART input clock frequency. */
 112   base_clock = config->base_clock ? config->base_clock : UART_DEFAULT_BASE_CLOCK;
 113
 114   /*
 115    * The UART uses 16 times oversampling for the BRG, so adjust the value
 116    * accordingly to calculate the divisor.
 117    */
 118   base_clock >>= 4;
 119
 120   divisor = (base_clock + (config->speed / 2)) / config->speed;
 121   if (config->speed == 0)
 122     return 0;
 123   if (divisor > 0xffff || divisor == 0)
 124     return 0;
 125   actual_speed = base_clock / divisor;
 126   error = actual_speed > config->speed ? (actual_speed - config->speed)
 127     : (config->speed - actual_speed);
 128   if (error > (config->speed / 30 + 1))
 129     return 0;
 130   return divisor;
 131 }
 132
 133 static void
 134 do_real_config (struct grub_serial_port *port)
 135 {
 136   int divisor;
 137   unsigned char status = 0;
 138   grub_uint64_t endtime;
 139
 140   const unsigned char parities[] = {
 141     [GRUB_SERIAL_PARITY_NONE] = UART_NO_PARITY,
 142     [GRUB_SERIAL_PARITY_ODD] = UART_ODD_PARITY,
 143     [GRUB_SERIAL_PARITY_EVEN] = UART_EVEN_PARITY
 144   };
 145   const unsigned char stop_bits[] = {
 146     [GRUB_SERIAL_STOP_BITS_1] = UART_1_STOP_BIT,
 147     [GRUB_SERIAL_STOP_BITS_2] = UART_2_STOP_BITS,
 148   };
 149
 150   if (port->configured)
 151     return;
 152
 153   port->broken = 0;
 154
 155   divisor = serial_get_divisor (port, &port->config);
 156
 157   /* Turn off the interrupt.  */
 158   ns8250_reg_write (port, 0, UART_IER);
 159
 160   /* Set DLAB.  */
 161   ns8250_reg_write (port, UART_DLAB, UART_LCR);
 162
 163   ns8250_reg_write (port, divisor & 0xFF, UART_DLL);
 164   ns8250_reg_write (port, divisor >> 8, UART_DLH);
 165
 166   /* Set the line status.  */
 167   status |= (parities[port->config.parity]
 168              | (port->config.word_len - 5)
 169              | stop_bits[port->config.stop_bits]);
 170   ns8250_reg_write (port, status, UART_LCR);
 171
 172   if (port->config.rtscts)
 173     {
 174       /* Enable the FIFO.  */
 175       ns8250_reg_write (port, UART_ENABLE_FIFO_TRIGGER1, UART_FCR);
 176
 177       /* Turn on DTR and RTS.  */
 178       ns8250_reg_write (port, UART_ENABLE_DTRRTS, UART_MCR);
 179     }
 180   else
 181     {
 182       /* Enable the FIFO.  */
 183       ns8250_reg_write (port, UART_ENABLE_FIFO_TRIGGER14, UART_FCR);
 184
 185       /* Turn on DTR, RTS, and OUT2.  */
 186       ns8250_reg_write (port, UART_ENABLE_DTRRTS | UART_ENABLE_OUT2, UART_MCR);
 187     }
 188
 189   /* Drain the input buffer.  */
 190   endtime = grub_get_time_ms () + 1000;
 191   while (ns8250_reg_read (port, UART_LSR) & UART_DATA_READY)
 192     {
 193       ns8250_reg_read (port, UART_RX);
 194       if (grub_get_time_ms () > endtime)
 195         {
 196           port->broken = 1;
 197           break;
 198         }
 199     }
 200
 201   port->configured = 1;
 202 }
 203
 204 /* Fetch a key.  */
 205 static int
 206 serial_hw_fetch (struct grub_serial_port *port)
 207 {
 208   do_real_config (port);
 209   if (ns8250_reg_read (port, UART_LSR) & UART_DATA_READY)
 210     return ns8250_reg_read (port, UART_RX);
 211
 212   return -1;
 213 }
 214
 215 /* Put a character.  */
 216 static void
 217 serial_hw_put (struct grub_serial_port *port, const int c)
 218 {
 219   grub_uint64_t endtime;
 220
 221   do_real_config (port);
 222
 223   if (port->broken > 5)
 224     endtime = grub_get_time_ms ();
 225   else if (port->broken > 1)
 226     endtime = grub_get_time_ms () + 50;
 227   else
 228     endtime = grub_get_time_ms () + 200;
 229   /* Wait until the transmitter holding register is empty.  */
 230   while ((ns8250_reg_read (port, UART_LSR) & UART_EMPTY_TRANSMITTER) == 0)
 231     {
 232       if (grub_get_time_ms () > endtime)
 233         {
 234           port->broken++;
 235           /* There is something wrong. But what can I do?  */
 236           return;
 237         }
 238     }
 239
 240   if (port->broken)
 241     port->broken--;
 242
 243   ns8250_reg_write (port, c, UART_TX);
 244 }
 245
 246 /* Initialize a serial device. PORT is the port number for a serial device.
 247    SPEED is a DTE-DTE speed which must be one of these: 2400, 4800, 9600,
 248    19200, 38400, 57600 and 115200. WORD_LEN is the word length to be used
 249    for the device. Likewise, PARITY is the type of the parity and
 250    STOP_BIT_LEN is the length of the stop bit. The possible values for
 251    WORD_LEN, PARITY and STOP_BIT_LEN are defined in the header file as
 252    macros.  */
 253 static grub_err_t
 254 serial_hw_configure (struct grub_serial_port *port,
 255                      struct grub_serial_config *config)
 256 {
 257   unsigned short divisor;
 258
 259   divisor = serial_get_divisor (port, config);
 260   if (divisor == 0)
 261     return grub_error (GRUB_ERR_BAD_ARGUMENT,
 262                        N_("unsupported serial port speed"));
 263
 264   if (config->parity != GRUB_SERIAL_PARITY_NONE
 265       && config->parity != GRUB_SERIAL_PARITY_ODD
 266       && config->parity != GRUB_SERIAL_PARITY_EVEN)
 267     return grub_error (GRUB_ERR_BAD_ARGUMENT,
 268                        N_("unsupported serial port parity"));
 269
 270   if (config->stop_bits != GRUB_SERIAL_STOP_BITS_1
 271       && config->stop_bits != GRUB_SERIAL_STOP_BITS_2)
 272     return grub_error (GRUB_ERR_BAD_ARGUMENT,
 273                        N_("unsupported serial port stop bits number"));
 274
 275   if (config->word_len < 5 || config->word_len > 8)
 276     return grub_error (GRUB_ERR_BAD_ARGUMENT,
 277                        N_("unsupported serial port word length"));
 278
 279   port->config = *config;
 280   port->configured = 0;
 281
 282   /*  FIXME: should check if the serial terminal was found.  */
 283
 284   return GRUB_ERR_NONE;
 285 }
 286
 287 struct grub_serial_driver grub_ns8250_driver =
 288   {
 289     .configure = serial_hw_configure,
 290     .fetch = serial_hw_fetch,
 291     .put = serial_hw_put
 292   };
 293
 294 static char com_names[GRUB_SERIAL_PORT_NUM][20];
 295 static struct grub_serial_port com_ports[GRUB_SERIAL_PORT_NUM];
 296
 297 void
 298 grub_ns8250_init (void)
 299 {
 300 #ifdef GRUB_MACHINE_PCBIOS
 301   const unsigned short *serial_hw_io_addr = (const unsigned short *) grub_absolute_pointer (GRUB_MEMORY_MACHINE_BIOS_DATA_AREA_ADDR);
 302 #endif
 303   unsigned i;
 304   for (i = 0; i < GRUB_SERIAL_PORT_NUM; i++)
 305     if (serial_hw_io_addr[i])
 306       {
 307         grub_err_t err;
 308
 309         grub_outb (0x5a, serial_hw_io_addr[i] + UART_SR);
 310         if (grub_inb (serial_hw_io_addr[i] + UART_SR) != 0x5a)
 311           {
 312             dead_ports |= (1 << i);
 313             continue;
 314           }
 315         grub_outb (0xa5, serial_hw_io_addr[i] + UART_SR);
 316         if (grub_inb (serial_hw_io_addr[i] + UART_SR) != 0xa5)
 317           {
 318             dead_ports |= (1 << i);
 319             continue;
 320           }
 321
 322         grub_snprintf (com_names[i], sizeof (com_names[i]), "com%d", i);
 323         com_ports[i].name = com_names[i];
 324         com_ports[i].driver = &grub_ns8250_driver;
 325         com_ports[i].port = serial_hw_io_addr[i];
 326         com_ports[i].use_mmio = false;
 327         err = grub_serial_config_defaults (&com_ports[i]);
 328         if (err)
 329           grub_print_error ();
 330
 331         grub_serial_register (&com_ports[i]);
 332       }
 333 }
 334
 335 /* Return the port number for the UNITth serial device.  */
 336 grub_port_t
 337 grub_ns8250_hw_get_port (const unsigned int unit)
 338 {
 339 #ifdef GRUB_MACHINE_PCBIOS
 340   const unsigned short *serial_hw_io_addr = (const unsigned short *) grub_absolute_pointer (GRUB_MEMORY_MACHINE_BIOS_DATA_AREA_ADDR);
 341 #endif
 342   if (unit < GRUB_SERIAL_PORT_NUM
 343       && !(dead_ports & (1 << unit)))
 344     return serial_hw_io_addr[unit];
 345   else
 346     return 0;
 347 }
 348
 349 struct grub_serial_port *
 350 grub_serial_ns8250_add_port (grub_port_t port, struct grub_serial_config *config)
 351 {
 352   struct grub_serial_port *p;
 353   unsigned i;
 354
 355   for (i = 0; i < GRUB_SERIAL_PORT_NUM; i++)
 356     if (com_ports[i].port == port)
 357       {
 358         if (dead_ports & (1 << i))
 359           return NULL;
 360         /* Give the opportunity for SPCR to configure a default com port. */
 361         if (config != NULL)
 362           grub_serial_port_configure (&com_ports[i], config);
 363         return &com_ports[i];
 364       }
 365
 366   FOR_SERIAL_PORTS (p)
 367     if (p->use_mmio == false && p->port == port)
 368       {
 369         if (config != NULL)
 370           grub_serial_port_configure (p, config);
 371         return p;
 372       }
 373
 374   grub_outb (0x5a, port + UART_SR);
 375   if (grub_inb (port + UART_SR) != 0x5a)
 376     return NULL;
 377
 378   grub_outb (0xa5, port + UART_SR);
 379   if (grub_inb (port + UART_SR) != 0xa5)
 380     return NULL;
 381
 382   p = grub_malloc (sizeof (*p));
 383   if (p == NULL)
 384     return NULL;
 385   p->name = grub_xasprintf ("port%lx", (unsigned long) port);
 386   if (p->name == NULL)
 387     {
 388       grub_free (p);
 389       return NULL;
 390     }
 391   p->driver = &grub_ns8250_driver;
 392   p->use_mmio = false;
 393   p->port = port;
 394   if (config != NULL)
 395     grub_serial_port_configure (p, config);
 396   else
 397     grub_serial_config_defaults (p);
 398   grub_serial_register (p);
 399
 400   return p;
 401 }
 402
 403 struct grub_serial_port *
 404 grub_serial_ns8250_add_mmio (grub_addr_t addr, unsigned int acc_size,
 405                              struct grub_serial_config *config)
 406 {
 407   struct grub_serial_port *p;
 408   unsigned i;
 409
 410   for (i = 0; i < GRUB_SERIAL_PORT_NUM; i++)
 411     if (com_ports[i].use_mmio == true && com_ports[i].mmio.base == addr)
 412       {
 413         if (config != NULL)
 414           grub_serial_port_configure (&com_ports[i], config);
 415         return &com_ports[i];
 416       }
 417
 418   FOR_SERIAL_PORTS (p)
 419     if (p->use_mmio == true && p->mmio.base == addr)
 420       {
 421         if (config != NULL)
 422           grub_serial_port_configure (p, config);
 423         return p;
 424       }
 425
 426   p = grub_malloc (sizeof (*p));
 427   if (p == NULL)
 428     return NULL;
 429   p->name = grub_xasprintf ("mmio,%llx", (unsigned long long) addr);
 430   if (p->name == NULL)
 431     {
 432       grub_free (p);
 433       return NULL;
 434     }
 435   p->driver = &grub_ns8250_driver;
 436   p->use_mmio = true;
 437   p->mmio.base = addr;
 438   p->mmio.access_size = acc_size;
 439   if (config != NULL)
 440     grub_serial_port_configure (p, config);
 441   else
 442     grub_serial_config_defaults (p);
 443   grub_serial_register (p);
 444
 445   return p;
 446 }