sim/bfin/dv-bfin_uart.c

   1 /* Blackfin Universal Asynchronous Receiver/Transmitter (UART) model.
   2    For "old style" UARTs on BF53x/etc... parts.
   3
   4    Copyright (C) 2010-2021 Free Software Foundation, Inc.
   5    Contributed by Analog Devices, Inc.
   6
   7    This file is part of simulators.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22 /* This must come before any other includes.  */
  23 #include "defs.h"
  24
  25 #include "sim-main.h"
  26 #include "dv-sockser.h"
  27 #include "devices.h"
  28 #include "dv-bfin_uart.h"
  29
  30 /* XXX: Should we bother emulating the TX/RX FIFOs ?  */
  31
  32 /* Internal state needs to be the same as bfin_uart2.  */
  33 struct bfin_uart
  34 {
  35   /* This top portion matches common dv_bfin struct.  */
  36   bu32 base;
  37   struct hw *dma_master;
  38   bool acked;
  39
  40   struct hw_event *handler;
  41   char saved_byte;
  42   int saved_count;
  43
  44   /* This is aliased to DLH.  */
  45   bu16 ier;
  46   /* These are aliased to DLL.  */
  47   bu16 thr, rbr;
  48
  49   /* Order after here is important -- matches hardware MMR layout.  */
  50   bu16 BFIN_MMR_16(dll);
  51   bu16 BFIN_MMR_16(dlh);
  52   bu16 BFIN_MMR_16(iir);
  53   bu16 BFIN_MMR_16(lcr);
  54   bu16 BFIN_MMR_16(mcr);
  55   bu16 BFIN_MMR_16(lsr);
  56   bu16 BFIN_MMR_16(msr);
  57   bu16 BFIN_MMR_16(scr);
  58   bu16 _pad0[2];
  59   bu16 BFIN_MMR_16(gctl);
  60 };
  61 #define mmr_base()      offsetof(struct bfin_uart, dll)
  62 #define mmr_offset(mmr) (offsetof(struct bfin_uart, mmr) - mmr_base())
  63
  64 static const char * const mmr_names[] =
  65 {
  66   "UART_RBR/UART_THR", "UART_IER", "UART_IIR", "UART_LCR", "UART_MCR",
  67   "UART_LSR", "UART_MSR", "UART_SCR", "<INV>", "UART_GCTL",
  68 };
  69 static const char *mmr_name (struct bfin_uart *uart, bu32 idx)
  70 {
  71   if (uart->lcr & DLAB)
  72     if (idx < 2)
  73       return idx == 0 ? "UART_DLL" : "UART_DLH";
  74   return mmr_names[idx];
  75 }
  76 #define mmr_name(off) mmr_name (uart, (off) / 4)
  77
  78 static void
  79 bfin_uart_poll (struct hw *me, void *data)
  80 {
  81   struct bfin_uart *uart = data;
  82   bu16 lsr;
  83
  84   uart->handler = NULL;
  85
  86   lsr = bfin_uart_get_status (me);
  87   if (lsr & DR)
  88     hw_port_event (me, DV_PORT_RX, 1);
  89
  90   bfin_uart_reschedule (me);
  91 }
  92
  93 void
  94 bfin_uart_reschedule (struct hw *me)
  95 {
  96   struct bfin_uart *uart = hw_data (me);
  97
  98   if (uart->ier & ERBFI)
  99     {
 100       if (!uart->handler)
 101         uart->handler = hw_event_queue_schedule (me, 10000,
 102                                                  bfin_uart_poll, uart);
 103     }
 104   else
 105     {
 106       if (uart->handler)
 107         {
 108           hw_event_queue_deschedule (me, uart->handler);
 109           uart->handler = NULL;
 110         }
 111     }
 112 }
 113
 114 bu16
 115 bfin_uart_write_byte (struct hw *me, bu16 thr, bu16 mcr)
 116 {
 117   struct bfin_uart *uart = hw_data (me);
 118   unsigned char ch = thr;
 119
 120   if (mcr & LOOP_ENA)
 121     {
 122       /* XXX: This probably doesn't work exactly right with
 123               external FIFOs ...  */
 124       uart->saved_byte = thr;
 125       uart->saved_count = 1;
 126     }
 127
 128   bfin_uart_write_buffer (me, &ch, 1);
 129
 130   return thr;
 131 }
 132
 133 static unsigned
 134 bfin_uart_io_write_buffer (struct hw *me, const void *source,
 135                            int space, address_word addr, unsigned nr_bytes)
 136 {
 137   struct bfin_uart *uart = hw_data (me);
 138   bu32 mmr_off;
 139   bu32 value;
 140   bu16 *valuep;
 141
 142   /* Invalid access mode is higher priority than missing register.  */
 143   if (!dv_bfin_mmr_require_16 (me, addr, nr_bytes, true))
 144     return 0;
 145
 146   value = dv_load_2 (source);
 147   mmr_off = addr - uart->base;
 148   valuep = (void *)((unsigned long)uart + mmr_base() + mmr_off);
 149
 150   HW_TRACE_WRITE ();
 151
 152   /* XXX: All MMRs are "8bit" ... what happens to high 8bits ?  */
 153   switch (mmr_off)
 154     {
 155     case mmr_offset(dll):
 156       if (uart->lcr & DLAB)
 157         uart->dll = value;
 158       else
 159         {
 160           uart->thr = bfin_uart_write_byte (me, value, uart->mcr);
 161
 162           if (uart->ier & ETBEI)
 163             hw_port_event (me, DV_PORT_TX, 1);
 164         }
 165       break;
 166     case mmr_offset(dlh):
 167       if (uart->lcr & DLAB)
 168         uart->dlh = value;
 169       else
 170         {
 171           uart->ier = value;
 172           bfin_uart_reschedule (me);
 173         }
 174       break;
 175     case mmr_offset(iir):
 176     case mmr_offset(lsr):
 177       /* XXX: Writes are ignored ?  */
 178       break;
 179     case mmr_offset(lcr):
 180     case mmr_offset(mcr):
 181     case mmr_offset(scr):
 182     case mmr_offset(gctl):
 183       *valuep = value;
 184       break;
 185     default:
 186       dv_bfin_mmr_invalid (me, addr, nr_bytes, true);
 187       return 0;
 188     }
 189
 190   return nr_bytes;
 191 }
 192
 193 /* Switch between socket and stdin on the fly.  */
 194 bu16
 195 bfin_uart_get_next_byte (struct hw *me, bu16 rbr, bu16 mcr, bool *fresh)
 196 {
 197   SIM_DESC sd = hw_system (me);
 198   struct bfin_uart *uart = hw_data (me);
 199   int status = dv_sockser_status (sd);
 200   bool _fresh;
 201
 202   /* NB: The "uart" here may only use interal state.  */
 203
 204   if (!fresh)
 205     fresh = &_fresh;
 206
 207   *fresh = false;
 208
 209   if (uart->saved_count > 0)
 210     {
 211       *fresh = true;
 212       rbr = uart->saved_byte;
 213       --uart->saved_count;
 214     }
 215   else if (mcr & LOOP_ENA)
 216     {
 217       /* RX is disconnected, so only return local data.  */
 218     }
 219   else if (status & DV_SOCKSER_DISCONNECTED)
 220     {
 221       char byte;
 222       int ret = sim_io_poll_read (sd, 0/*STDIN*/, &byte, 1);
 223
 224       if (ret > 0)
 225         {
 226           *fresh = true;
 227           rbr = byte;
 228         }
 229     }
 230   else
 231     rbr = dv_sockser_read (sd);
 232
 233   return rbr;
 234 }
 235
 236 bu16
 237 bfin_uart_get_status (struct hw *me)
 238 {
 239   SIM_DESC sd = hw_system (me);
 240   struct bfin_uart *uart = hw_data (me);
 241   int status = dv_sockser_status (sd);
 242   bu16 lsr = 0;
 243
 244   if (status & DV_SOCKSER_DISCONNECTED)
 245     {
 246       if (uart->saved_count <= 0)
 247         uart->saved_count = sim_io_poll_read (sd, 0/*STDIN*/,
 248                                               &uart->saved_byte, 1);
 249       lsr |= TEMT | THRE | (uart->saved_count > 0 ? DR : 0);
 250     }
 251   else
 252     lsr |= (status & DV_SOCKSER_INPUT_EMPTY ? 0 : DR) |
 253            (status & DV_SOCKSER_OUTPUT_EMPTY ? TEMT | THRE : 0);
 254
 255   return lsr;
 256 }
 257
 258 static unsigned
 259 bfin_uart_io_read_buffer (struct hw *me, void *dest,
 260                           int space, address_word addr, unsigned nr_bytes)
 261 {
 262   struct bfin_uart *uart = hw_data (me);
 263   bu32 mmr_off;
 264   bu16 *valuep;
 265
 266   /* Invalid access mode is higher priority than missing register.  */
 267   if (!dv_bfin_mmr_require_16 (me, addr, nr_bytes, false))
 268     return 0;
 269
 270   mmr_off = addr - uart->base;
 271   valuep = (void *)((unsigned long)uart + mmr_base() + mmr_off);
 272
 273   HW_TRACE_READ ();
 274
 275   switch (mmr_off)
 276     {
 277     case mmr_offset(dll):
 278       if (uart->lcr & DLAB)
 279         dv_store_2 (dest, uart->dll);
 280       else
 281         {
 282           uart->rbr = bfin_uart_get_next_byte (me, uart->rbr, uart->mcr, NULL);
 283           dv_store_2 (dest, uart->rbr);
 284         }
 285       break;
 286     case mmr_offset(dlh):
 287       if (uart->lcr & DLAB)
 288         dv_store_2 (dest, uart->dlh);
 289       else
 290         dv_store_2 (dest, uart->ier);
 291       break;
 292     case mmr_offset(lsr):
 293       /* XXX: Reads are destructive on most parts, but not all ...  */
 294       uart->lsr |= bfin_uart_get_status (me);
 295       dv_store_2 (dest, *valuep);
 296       uart->lsr = 0;
 297       break;
 298     case mmr_offset(iir):
 299       /* XXX: Reads are destructive ...  */
 300     case mmr_offset(lcr):
 301     case mmr_offset(mcr):
 302     case mmr_offset(scr):
 303     case mmr_offset(gctl):
 304       dv_store_2 (dest, *valuep);
 305       break;
 306     default:
 307       dv_bfin_mmr_invalid (me, addr, nr_bytes, false);
 308       return 0;
 309     }
 310
 311   return nr_bytes;
 312 }
 313
 314 unsigned
 315 bfin_uart_read_buffer (struct hw *me, unsigned char *buffer, unsigned nr_bytes)
 316 {
 317   SIM_DESC sd = hw_system (me);
 318   struct bfin_uart *uart = hw_data (me);
 319   int status = dv_sockser_status (sd);
 320   unsigned i = 0;
 321
 322   if (status & DV_SOCKSER_DISCONNECTED)
 323     {
 324       int ret;
 325
 326       while (uart->saved_count > 0 && i < nr_bytes)
 327         {
 328           buffer[i++] = uart->saved_byte;
 329           --uart->saved_count;
 330         }
 331
 332       ret = sim_io_poll_read (sd, 0/*STDIN*/, (char *) buffer, nr_bytes - i);
 333       if (ret > 0)
 334         i += ret;
 335     }
 336   else
 337     buffer[i++] = dv_sockser_read (sd);
 338
 339   return i;
 340 }
 341
 342 static unsigned
 343 bfin_uart_dma_read_buffer (struct hw *me, void *dest, int space,
 344                            unsigned_word addr, unsigned nr_bytes)
 345 {
 346   HW_TRACE_DMA_READ ();
 347   return bfin_uart_read_buffer (me, dest, nr_bytes);
 348 }
 349
 350 unsigned
 351 bfin_uart_write_buffer (struct hw *me, const unsigned char *buffer,
 352                         unsigned nr_bytes)
 353 {
 354   SIM_DESC sd = hw_system (me);
 355   int status = dv_sockser_status (sd);
 356
 357   if (status & DV_SOCKSER_DISCONNECTED)
 358     {
 359       sim_io_write_stdout (sd, (const char *) buffer, nr_bytes);
 360       sim_io_flush_stdout (sd);
 361     }
 362   else
 363     {
 364       /* Normalize errors to a value of 0.  */
 365       int ret = dv_sockser_write_buffer (sd, buffer, nr_bytes);
 366       nr_bytes = CLAMP (ret, 0, nr_bytes);
 367     }
 368
 369   return nr_bytes;
 370 }
 371
 372 static unsigned
 373 bfin_uart_dma_write_buffer (struct hw *me, const void *source,
 374                             int space, unsigned_word addr,
 375                             unsigned nr_bytes,
 376                             int violate_read_only_section)
 377 {
 378   struct bfin_uart *uart = hw_data (me);
 379   unsigned ret;
 380
 381   HW_TRACE_DMA_WRITE ();
 382
 383   ret = bfin_uart_write_buffer (me, source, nr_bytes);
 384
 385   if (ret == nr_bytes && (uart->ier & ETBEI))
 386     hw_port_event (me, DV_PORT_TX, 1);
 387
 388   return ret;
 389 }
 390
 391 static const struct hw_port_descriptor bfin_uart_ports[] =
 392 {
 393   { "tx",   DV_PORT_TX,   0, output_port, },
 394   { "rx",   DV_PORT_RX,   0, output_port, },
 395   { "stat", DV_PORT_STAT, 0, output_port, },
 396   { NULL, 0, 0, 0, },
 397 };
 398
 399 static void
 400 attach_bfin_uart_regs (struct hw *me, struct bfin_uart *uart)
 401 {
 402   address_word attach_address;
 403   int attach_space;
 404   unsigned attach_size;
 405   reg_property_spec reg;
 406
 407   if (hw_find_property (me, "reg") == NULL)
 408     hw_abort (me, "Missing \"reg\" property");
 409
 410   if (!hw_find_reg_array_property (me, "reg", 0, &reg))
 411     hw_abort (me, "\"reg\" property must contain three addr/size entries");
 412
 413   hw_unit_address_to_attach_address (hw_parent (me),
 414                                      &reg.address,
 415                                      &attach_space, &attach_address, me);
 416   hw_unit_size_to_attach_size (hw_parent (me), &reg.size, &attach_size, me);
 417
 418   if (attach_size != BFIN_MMR_UART_SIZE)
 419     hw_abort (me, "\"reg\" size must be %#x", BFIN_MMR_UART_SIZE);
 420
 421   hw_attach_address (hw_parent (me),
 422                      0, attach_space, attach_address, attach_size, me);
 423
 424   uart->base = attach_address;
 425 }
 426
 427 static void
 428 bfin_uart_finish (struct hw *me)
 429 {
 430   struct bfin_uart *uart;
 431
 432   uart = HW_ZALLOC (me, struct bfin_uart);
 433
 434   set_hw_data (me, uart);
 435   set_hw_io_read_buffer (me, bfin_uart_io_read_buffer);
 436   set_hw_io_write_buffer (me, bfin_uart_io_write_buffer);
 437   set_hw_dma_read_buffer (me, bfin_uart_dma_read_buffer);
 438   set_hw_dma_write_buffer (me, bfin_uart_dma_write_buffer);
 439   set_hw_ports (me, bfin_uart_ports);
 440
 441   attach_bfin_uart_regs (me, uart);
 442
 443   /* Initialize the UART.  */
 444   uart->dll = 0x0001;
 445   uart->iir = 0x0001;
 446   uart->lsr = 0x0060;
 447 }
 448
 449 const struct hw_descriptor dv_bfin_uart_descriptor[] =
 450 {
 451   {"bfin_uart", bfin_uart_finish,},
 452   {NULL, NULL},
 453 };