hw/sh_serial.c

   1 /*
   2  * QEMU SCI/SCIF serial port emulation
   3  *
   4  * Copyright (c) 2007 Magnus Damm
   5  *
   6  * Based on serial.c - QEMU 16450 UART emulation
   7  * Copyright (c) 2003-2004 Fabrice Bellard
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a copy
  10  * of this software and associated documentation files (the "Software"), to deal
  11  * in the Software without restriction, including without limitation the rights
  12  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  13  * copies of the Software, and to permit persons to whom the Software is
  14  * furnished to do so, subject to the following conditions:
  15  *
  16  * The above copyright notice and this permission notice shall be included in
  17  * all copies or substantial portions of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  22  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  23  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  24  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  25  * THE SOFTWARE.
  26  */
  27 #include "hw.h"
  28 #include "sh.h"
  29 #include "qemu-char.h"
  30
  31 //#define DEBUG_SERIAL
  32
  33 #define SH_SERIAL_FLAG_TEND (1 << 0)
  34 #define SH_SERIAL_FLAG_TDE  (1 << 1)
  35 #define SH_SERIAL_FLAG_RDF  (1 << 2)
  36 #define SH_SERIAL_FLAG_BRK  (1 << 3)
  37 #define SH_SERIAL_FLAG_DR   (1 << 4)
  38
  39 #define SH_RX_FIFO_LENGTH (16)
  40
  41 typedef struct {
  42     uint8_t smr;
  43     uint8_t brr;
  44     uint8_t scr;
  45     uint8_t dr; /* ftdr / tdr */
  46     uint8_t sr; /* fsr / ssr */
  47     uint16_t fcr;
  48     uint8_t sptr;
  49
  50     uint8_t rx_fifo[SH_RX_FIFO_LENGTH]; /* frdr / rdr */
  51     uint8_t rx_cnt;
  52     uint8_t rx_tail;
  53     uint8_t rx_head;
  54
  55     int freq;
  56     int feat;
  57     int flags;
  58     int rtrg;
  59
  60     CharDriverState *chr;
  61
  62     qemu_irq eri;
  63     qemu_irq rxi;
  64     qemu_irq txi;
  65     qemu_irq tei;
  66     qemu_irq bri;
  67 } sh_serial_state;
  68
  69 static void sh_serial_clear_fifo(sh_serial_state * s)
  70 {
  71     memset(s->rx_fifo, 0, SH_RX_FIFO_LENGTH);
  72     s->rx_cnt = 0;
  73     s->rx_head = 0;
  74     s->rx_tail = 0;
  75 }
  76
  77 static void sh_serial_write(void *opaque, uint32_t offs, uint32_t val)
  78 {
  79     sh_serial_state *s = opaque;
  80     unsigned char ch;
  81
  82 #ifdef DEBUG_SERIAL
  83     printf("sh_serial: write offs=0x%02x val=0x%02x\n",
  84            offs, val);
  85 #endif
  86     switch(offs) {
  87     case 0x00: /* SMR */
  88         s->smr = val & ((s->feat & SH_SERIAL_FEAT_SCIF) ? 0x7b : 0xff);
  89         return;
  90     case 0x04: /* BRR */
  91         s->brr = val;
  92         return;
  93     case 0x08: /* SCR */
  94         /* TODO : For SH7751, SCIF mask should be 0xfb. */
  95         s->scr = val & ((s->feat & SH_SERIAL_FEAT_SCIF) ? 0xfa : 0xff);
  96         if (!(val & (1 << 5)))
  97             s->flags |= SH_SERIAL_FLAG_TEND;
  98         if ((s->feat & SH_SERIAL_FEAT_SCIF) && s->txi) {
  99             qemu_set_irq(s->txi, val & (1 << 7));
 100         }
 101         if (!(val & (1 << 6))) {
 102             qemu_set_irq(s->rxi, 0);
 103         }
 104         return;
 105     case 0x0c: /* FTDR / TDR */
 106         if (s->chr) {
 107             ch = val;
 108             qemu_chr_write(s->chr, &ch, 1);
 109         }
 110         s->dr = val;
 111         s->flags &= ~SH_SERIAL_FLAG_TDE;
 112         return;
 113 #if 0
 114     case 0x14: /* FRDR / RDR */
 115         ret = 0;
 116         break;
 117 #endif
 118     }
 119     if (s->feat & SH_SERIAL_FEAT_SCIF) {
 120         switch(offs) {
 121         case 0x10: /* FSR */
 122             if (!(val & (1 << 6)))
 123                 s->flags &= ~SH_SERIAL_FLAG_TEND;
 124             if (!(val & (1 << 5)))
 125                 s->flags &= ~SH_SERIAL_FLAG_TDE;
 126             if (!(val & (1 << 4)))
 127                 s->flags &= ~SH_SERIAL_FLAG_BRK;
 128             if (!(val & (1 << 1)))
 129                 s->flags &= ~SH_SERIAL_FLAG_RDF;
 130             if (!(val & (1 << 0)))
 131                 s->flags &= ~SH_SERIAL_FLAG_DR;
 132
 133             if (!(val & (1 << 1)) || !(val & (1 << 0))) {
 134                 if (s->rxi) {
 135                     qemu_set_irq(s->rxi, 0);
 136                 }
 137             }
 138             return;
 139         case 0x18: /* FCR */
 140             s->fcr = val;
 141             switch ((val >> 6) & 3) {
 142             case 0:
 143                 s->rtrg = 1;
 144                 break;
 145             case 1:
 146                 s->rtrg = 4;
 147                 break;
 148             case 2:
 149                 s->rtrg = 8;
 150                 break;
 151             case 3:
 152                 s->rtrg = 14;
 153                 break;
 154             }
 155             if (val & (1 << 1)) {
 156                 sh_serial_clear_fifo(s);
 157                 s->sr &= ~(1 << 1);
 158             }
 159
 160             return;
 161         case 0x20: /* SPTR */
 162             s->sptr = val & 0xf3;
 163             return;
 164         case 0x24: /* LSR */
 165             return;
 166         }
 167     }
 168     else {
 169         switch(offs) {
 170 #if 0
 171         case 0x0c:
 172             ret = s->dr;
 173             break;
 174         case 0x10:
 175             ret = 0;
 176             break;
 177 #endif
 178         case 0x1c:
 179             s->sptr = val & 0x8f;
 180             return;
 181         }
 182     }
 183
 184     fprintf(stderr, "sh_serial: unsupported write to 0x%02x\n", offs);
 185     abort();
 186 }
 187
 188 static uint32_t sh_serial_read(void *opaque, uint32_t offs)
 189 {
 190     sh_serial_state *s = opaque;
 191     uint32_t ret = ~0;
 192
 193 #if 0
 194     switch(offs) {
 195     case 0x00:
 196         ret = s->smr;
 197         break;
 198     case 0x04:
 199         ret = s->brr;
 200         break;
 201     case 0x08:
 202         ret = s->scr;
 203         break;
 204     case 0x14:
 205         ret = 0;
 206         break;
 207     }
 208 #endif
 209     if (s->feat & SH_SERIAL_FEAT_SCIF) {
 210         switch(offs) {
 211         case 0x00: /* SMR */
 212             ret = s->smr;
 213             break;
 214         case 0x08: /* SCR */
 215             ret = s->scr;
 216             break;
 217         case 0x10: /* FSR */
 218             ret = 0;
 219             if (s->flags & SH_SERIAL_FLAG_TEND)
 220                 ret |= (1 << 6);
 221             if (s->flags & SH_SERIAL_FLAG_TDE)
 222                 ret |= (1 << 5);
 223             if (s->flags & SH_SERIAL_FLAG_BRK)
 224                 ret |= (1 << 4);
 225             if (s->flags & SH_SERIAL_FLAG_RDF)
 226                 ret |= (1 << 1);
 227             if (s->flags & SH_SERIAL_FLAG_DR)
 228                 ret |= (1 << 0);
 229
 230             if (s->scr & (1 << 5))
 231                 s->flags |= SH_SERIAL_FLAG_TDE | SH_SERIAL_FLAG_TEND;
 232
 233             break;
 234         case 0x14:
 235             if (s->rx_cnt > 0) {
 236                 ret = s->rx_fifo[s->rx_tail++];
 237                 s->rx_cnt--;
 238                 if (s->rx_tail == SH_RX_FIFO_LENGTH)
 239                     s->rx_tail = 0;
 240                 if (s->rx_cnt < s->rtrg)
 241                     s->flags &= ~SH_SERIAL_FLAG_RDF;
 242             }
 243             break;
 244 #if 0
 245         case 0x18:
 246             ret = s->fcr;
 247             break;
 248 #endif
 249         case 0x1c:
 250             ret = s->rx_cnt;
 251             break;
 252         case 0x20:
 253             ret = s->sptr;
 254             break;
 255         case 0x24:
 256             ret = 0;
 257             break;
 258         }
 259     }
 260     else {
 261         switch(offs) {
 262 #if 0
 263         case 0x0c:
 264             ret = s->dr;
 265             break;
 266         case 0x10:
 267             ret = 0;
 268             break;
 269         case 0x14:
 270             ret = s->rx_fifo[0];
 271             break;
 272 #endif
 273         case 0x1c:
 274             ret = s->sptr;
 275             break;
 276         }
 277     }
 278 #ifdef DEBUG_SERIAL
 279     printf("sh_serial: read offs=0x%02x val=0x%x\n",
 280            offs, ret);
 281 #endif
 282
 283     if (ret & ~((1 << 16) - 1)) {
 284         fprintf(stderr, "sh_serial: unsupported read from 0x%02x\n", offs);
 285         abort();
 286     }
 287
 288     return ret;
 289 }
 290
 291 static int sh_serial_can_receive(sh_serial_state *s)
 292 {
 293     return s->scr & (1 << 4);
 294 }
 295
 296 static void sh_serial_receive_break(sh_serial_state *s)
 297 {
 298     if (s->feat & SH_SERIAL_FEAT_SCIF)
 299         s->sr |= (1 << 4);
 300 }
 301
 302 static int sh_serial_can_receive1(void *opaque)
 303 {
 304     sh_serial_state *s = opaque;
 305     return sh_serial_can_receive(s);
 306 }
 307
 308 static void sh_serial_receive1(void *opaque, const uint8_t *buf, int size)
 309 {
 310     sh_serial_state *s = opaque;
 311
 312     if (s->feat & SH_SERIAL_FEAT_SCIF) {
 313         int i;
 314         for (i = 0; i < size; i++) {
 315             if (s->rx_cnt < SH_RX_FIFO_LENGTH) {
 316                 s->rx_fifo[s->rx_head++] = buf[i];
 317                 if (s->rx_head == SH_RX_FIFO_LENGTH) {
 318                     s->rx_head = 0;
 319                 }
 320                 s->rx_cnt++;
 321                 if (s->rx_cnt >= s->rtrg) {
 322                     s->flags |= SH_SERIAL_FLAG_RDF;
 323                     if (s->scr & (1 << 6) && s->rxi) {
 324                         qemu_set_irq(s->rxi, 1);
 325                     }
 326                 }
 327             }
 328         }
 329     } else {
 330         s->rx_fifo[0] = buf[0];
 331     }
 332 }
 333
 334 static void sh_serial_event(void *opaque, int event)
 335 {
 336     sh_serial_state *s = opaque;
 337     if (event == CHR_EVENT_BREAK)
 338         sh_serial_receive_break(s);
 339 }
 340
 341 static CPUReadMemoryFunc * const sh_serial_readfn[] = {
 342     &sh_serial_read,
 343     &sh_serial_read,
 344     &sh_serial_read,
 345 };
 346
 347 static CPUWriteMemoryFunc * const sh_serial_writefn[] = {
 348     &sh_serial_write,
 349     &sh_serial_write,
 350     &sh_serial_write,
 351 };
 352
 353 void sh_serial_init (target_phys_addr_t base, int feat,
 354                      uint32_t freq, CharDriverState *chr,
 355                      qemu_irq eri_source,
 356                      qemu_irq rxi_source,
 357                      qemu_irq txi_source,
 358                      qemu_irq tei_source,
 359                      qemu_irq bri_source)
 360 {
 361     sh_serial_state *s;
 362     int s_io_memory;
 363
 364     s = qemu_mallocz(sizeof(sh_serial_state));
 365
 366     s->feat = feat;
 367     s->flags = SH_SERIAL_FLAG_TEND | SH_SERIAL_FLAG_TDE;
 368     s->rtrg = 1;
 369
 370     s->smr = 0;
 371     s->brr = 0xff;
 372     s->scr = 1 << 5; /* pretend that TX is enabled so early printk works */
 373     s->sptr = 0;
 374
 375     if (feat & SH_SERIAL_FEAT_SCIF) {
 376         s->fcr = 0;
 377     }
 378     else {
 379         s->dr = 0xff;
 380     }
 381
 382     sh_serial_clear_fifo(s);
 383
 384     s_io_memory = cpu_register_io_memory(sh_serial_readfn,
 385                                          sh_serial_writefn, s,
 386                                          DEVICE_NATIVE_ENDIAN);
 387     cpu_register_physical_memory(P4ADDR(base), 0x28, s_io_memory);
 388     cpu_register_physical_memory(A7ADDR(base), 0x28, s_io_memory);
 389
 390     s->chr = chr;
 391
 392     if (chr)
 393         qemu_chr_add_handlers(chr, sh_serial_can_receive1, sh_serial_receive1,
 394                               sh_serial_event, s);
 395
 396     s->eri = eri_source;
 397     s->rxi = rxi_source;
 398     s->txi = txi_source;
 399     s->tei = tei_source;
 400     s->bri = bri_source;
 401 }