hw/char/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
  28 #include "qemu/osdep.h"
  29 #include "hw/irq.h"
  30 #include "hw/sh4/sh.h"
  31 #include "chardev/char-fe.h"
  32 #include "qapi/error.h"
  33 #include "qemu/timer.h"
  34
  35 //#define DEBUG_SERIAL
  36
  37 #define SH_SERIAL_FLAG_TEND (1 << 0)
  38 #define SH_SERIAL_FLAG_TDE  (1 << 1)
  39 #define SH_SERIAL_FLAG_RDF  (1 << 2)
  40 #define SH_SERIAL_FLAG_BRK  (1 << 3)
  41 #define SH_SERIAL_FLAG_DR   (1 << 4)
  42
  43 #define SH_RX_FIFO_LENGTH (16)
  44
  45 typedef struct {
  46     MemoryRegion iomem;
  47     MemoryRegion iomem_p4;
  48     MemoryRegion iomem_a7;
  49     uint8_t smr;
  50     uint8_t brr;
  51     uint8_t scr;
  52     uint8_t dr; /* ftdr / tdr */
  53     uint8_t sr; /* fsr / ssr */
  54     uint16_t fcr;
  55     uint8_t sptr;
  56
  57     uint8_t rx_fifo[SH_RX_FIFO_LENGTH]; /* frdr / rdr */
  58     uint8_t rx_cnt;
  59     uint8_t rx_tail;
  60     uint8_t rx_head;
  61
  62     int freq;
  63     int feat;
  64     int flags;
  65     int rtrg;
  66
  67     CharBackend chr;
  68     QEMUTimer *fifo_timeout_timer;
  69     uint64_t etu; /* Elementary Time Unit (ns) */
  70
  71     qemu_irq eri;
  72     qemu_irq rxi;
  73     qemu_irq txi;
  74     qemu_irq tei;
  75     qemu_irq bri;
  76 } sh_serial_state;
  77
  78 static void sh_serial_clear_fifo(sh_serial_state * s)
  79 {
  80     memset(s->rx_fifo, 0, SH_RX_FIFO_LENGTH);
  81     s->rx_cnt = 0;
  82     s->rx_head = 0;
  83     s->rx_tail = 0;
  84 }
  85
  86 static void sh_serial_write(void *opaque, hwaddr offs,
  87                             uint64_t val, unsigned size)
  88 {
  89     sh_serial_state *s = opaque;
  90     unsigned char ch;
  91
  92 #ifdef DEBUG_SERIAL
  93     printf("sh_serial: write offs=0x%02x val=0x%02x\n",
  94            offs, val);
  95 #endif
  96     switch(offs) {
  97     case 0x00: /* SMR */
  98         s->smr = val & ((s->feat & SH_SERIAL_FEAT_SCIF) ? 0x7b : 0xff);
  99         return;
 100     case 0x04: /* BRR */
 101         s->brr = val;
 102         return;
 103     case 0x08: /* SCR */
 104         /* TODO : For SH7751, SCIF mask should be 0xfb. */
 105         s->scr = val & ((s->feat & SH_SERIAL_FEAT_SCIF) ? 0xfa : 0xff);
 106         if (!(val & (1 << 5)))
 107             s->flags |= SH_SERIAL_FLAG_TEND;
 108         if ((s->feat & SH_SERIAL_FEAT_SCIF) && s->txi) {
 109             qemu_set_irq(s->txi, val & (1 << 7));
 110         }
 111         if (!(val & (1 << 6))) {
 112             qemu_set_irq(s->rxi, 0);
 113         }
 114         return;
 115     case 0x0c: /* FTDR / TDR */
 116         if (qemu_chr_fe_backend_connected(&s->chr)) {
 117             ch = val;
 118             /* XXX this blocks entire thread. Rewrite to use
 119              * qemu_chr_fe_write and background I/O callbacks */
 120             qemu_chr_fe_write_all(&s->chr, &ch, 1);
 121         }
 122         s->dr = val;
 123         s->flags &= ~SH_SERIAL_FLAG_TDE;
 124         return;
 125 #if 0
 126     case 0x14: /* FRDR / RDR */
 127         ret = 0;
 128         break;
 129 #endif
 130     }
 131     if (s->feat & SH_SERIAL_FEAT_SCIF) {
 132         switch(offs) {
 133         case 0x10: /* FSR */
 134             if (!(val & (1 << 6)))
 135                 s->flags &= ~SH_SERIAL_FLAG_TEND;
 136             if (!(val & (1 << 5)))
 137                 s->flags &= ~SH_SERIAL_FLAG_TDE;
 138             if (!(val & (1 << 4)))
 139                 s->flags &= ~SH_SERIAL_FLAG_BRK;
 140             if (!(val & (1 << 1)))
 141                 s->flags &= ~SH_SERIAL_FLAG_RDF;
 142             if (!(val & (1 << 0)))
 143                 s->flags &= ~SH_SERIAL_FLAG_DR;
 144
 145             if (!(val & (1 << 1)) || !(val & (1 << 0))) {
 146                 if (s->rxi) {
 147                     qemu_set_irq(s->rxi, 0);
 148                 }
 149             }
 150             return;
 151         case 0x18: /* FCR */
 152             s->fcr = val;
 153             switch ((val >> 6) & 3) {
 154             case 0:
 155                 s->rtrg = 1;
 156                 break;
 157             case 1:
 158                 s->rtrg = 4;
 159                 break;
 160             case 2:
 161                 s->rtrg = 8;
 162                 break;
 163             case 3:
 164                 s->rtrg = 14;
 165                 break;
 166             }
 167             if (val & (1 << 1)) {
 168                 sh_serial_clear_fifo(s);
 169                 s->sr &= ~(1 << 1);
 170             }
 171
 172             return;
 173         case 0x20: /* SPTR */
 174             s->sptr = val & 0xf3;
 175             return;
 176         case 0x24: /* LSR */
 177             return;
 178         }
 179     }
 180     else {
 181         switch(offs) {
 182 #if 0
 183         case 0x0c:
 184             ret = s->dr;
 185             break;
 186         case 0x10:
 187             ret = 0;
 188             break;
 189 #endif
 190         case 0x1c:
 191             s->sptr = val & 0x8f;
 192             return;
 193         }
 194     }
 195
 196     fprintf(stderr, "sh_serial: unsupported write to 0x%02"
 197             HWADDR_PRIx "\n", offs);
 198     abort();
 199 }
 200
 201 static uint64_t sh_serial_read(void *opaque, hwaddr offs,
 202                                unsigned size)
 203 {
 204     sh_serial_state *s = opaque;
 205     uint32_t ret = ~0;
 206
 207 #if 0
 208     switch(offs) {
 209     case 0x00:
 210         ret = s->smr;
 211         break;
 212     case 0x04:
 213         ret = s->brr;
 214         break;
 215     case 0x08:
 216         ret = s->scr;
 217         break;
 218     case 0x14:
 219         ret = 0;
 220         break;
 221     }
 222 #endif
 223     if (s->feat & SH_SERIAL_FEAT_SCIF) {
 224         switch(offs) {
 225         case 0x00: /* SMR */
 226             ret = s->smr;
 227             break;
 228         case 0x08: /* SCR */
 229             ret = s->scr;
 230             break;
 231         case 0x10: /* FSR */
 232             ret = 0;
 233             if (s->flags & SH_SERIAL_FLAG_TEND)
 234                 ret |= (1 << 6);
 235             if (s->flags & SH_SERIAL_FLAG_TDE)
 236                 ret |= (1 << 5);
 237             if (s->flags & SH_SERIAL_FLAG_BRK)
 238                 ret |= (1 << 4);
 239             if (s->flags & SH_SERIAL_FLAG_RDF)
 240                 ret |= (1 << 1);
 241             if (s->flags & SH_SERIAL_FLAG_DR)
 242                 ret |= (1 << 0);
 243
 244             if (s->scr & (1 << 5))
 245                 s->flags |= SH_SERIAL_FLAG_TDE | SH_SERIAL_FLAG_TEND;
 246
 247             break;
 248         case 0x14:
 249             if (s->rx_cnt > 0) {
 250                 ret = s->rx_fifo[s->rx_tail++];
 251                 s->rx_cnt--;
 252                 if (s->rx_tail == SH_RX_FIFO_LENGTH)
 253                     s->rx_tail = 0;
 254                 if (s->rx_cnt < s->rtrg)
 255                     s->flags &= ~SH_SERIAL_FLAG_RDF;
 256             }
 257             break;
 258         case 0x18:
 259             ret = s->fcr;
 260             break;
 261         case 0x1c:
 262             ret = s->rx_cnt;
 263             break;
 264         case 0x20:
 265             ret = s->sptr;
 266             break;
 267         case 0x24:
 268             ret = 0;
 269             break;
 270         }
 271     }
 272     else {
 273         switch(offs) {
 274 #if 0
 275         case 0x0c:
 276             ret = s->dr;
 277             break;
 278         case 0x10:
 279             ret = 0;
 280             break;
 281         case 0x14:
 282             ret = s->rx_fifo[0];
 283             break;
 284 #endif
 285         case 0x1c:
 286             ret = s->sptr;
 287             break;
 288         }
 289     }
 290 #ifdef DEBUG_SERIAL
 291     printf("sh_serial: read offs=0x%02x val=0x%x\n",
 292            offs, ret);
 293 #endif
 294
 295     if (ret & ~((1 << 16) - 1)) {
 296         fprintf(stderr, "sh_serial: unsupported read from 0x%02"
 297                 HWADDR_PRIx "\n", offs);
 298         abort();
 299     }
 300
 301     return ret;
 302 }
 303
 304 static int sh_serial_can_receive(sh_serial_state *s)
 305 {
 306     return s->scr & (1 << 4);
 307 }
 308
 309 static void sh_serial_receive_break(sh_serial_state *s)
 310 {
 311     if (s->feat & SH_SERIAL_FEAT_SCIF)
 312         s->sr |= (1 << 4);
 313 }
 314
 315 static int sh_serial_can_receive1(void *opaque)
 316 {
 317     sh_serial_state *s = opaque;
 318     return sh_serial_can_receive(s);
 319 }
 320
 321 static void sh_serial_timeout_int(void *opaque)
 322 {
 323     sh_serial_state *s = opaque;
 324
 325     s->flags |= SH_SERIAL_FLAG_RDF;
 326     if (s->scr & (1 << 6) && s->rxi) {
 327         qemu_set_irq(s->rxi, 1);
 328     }
 329 }
 330
 331 static void sh_serial_receive1(void *opaque, const uint8_t *buf, int size)
 332 {
 333     sh_serial_state *s = opaque;
 334
 335     if (s->feat & SH_SERIAL_FEAT_SCIF) {
 336         int i;
 337         for (i = 0; i < size; i++) {
 338             if (s->rx_cnt < SH_RX_FIFO_LENGTH) {
 339                 s->rx_fifo[s->rx_head++] = buf[i];
 340                 if (s->rx_head == SH_RX_FIFO_LENGTH) {
 341                     s->rx_head = 0;
 342                 }
 343                 s->rx_cnt++;
 344                 if (s->rx_cnt >= s->rtrg) {
 345                     s->flags |= SH_SERIAL_FLAG_RDF;
 346                     if (s->scr & (1 << 6) && s->rxi) {
 347                         timer_del(s->fifo_timeout_timer);
 348                         qemu_set_irq(s->rxi, 1);
 349                     }
 350                 } else {
 351                     timer_mod(s->fifo_timeout_timer,
 352                         qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 15 * s->etu);
 353                 }
 354             }
 355         }
 356     } else {
 357         s->rx_fifo[0] = buf[0];
 358     }
 359 }
 360
 361 static void sh_serial_event(void *opaque, int event)
 362 {
 363     sh_serial_state *s = opaque;
 364     if (event == CHR_EVENT_BREAK)
 365         sh_serial_receive_break(s);
 366 }
 367
 368 static const MemoryRegionOps sh_serial_ops = {
 369     .read = sh_serial_read,
 370     .write = sh_serial_write,
 371     .endianness = DEVICE_NATIVE_ENDIAN,
 372 };
 373
 374 void sh_serial_init(MemoryRegion *sysmem,
 375                     hwaddr base, int feat,
 376                     uint32_t freq, Chardev *chr,
 377                     qemu_irq eri_source,
 378                     qemu_irq rxi_source,
 379                     qemu_irq txi_source,
 380                     qemu_irq tei_source,
 381                     qemu_irq bri_source)
 382 {
 383     sh_serial_state *s;
 384
 385     s = g_malloc0(sizeof(sh_serial_state));
 386
 387     s->feat = feat;
 388     s->flags = SH_SERIAL_FLAG_TEND | SH_SERIAL_FLAG_TDE;
 389     s->rtrg = 1;
 390
 391     s->smr = 0;
 392     s->brr = 0xff;
 393     s->scr = 1 << 5; /* pretend that TX is enabled so early printk works */
 394     s->sptr = 0;
 395
 396     if (feat & SH_SERIAL_FEAT_SCIF) {
 397         s->fcr = 0;
 398     }
 399     else {
 400         s->dr = 0xff;
 401     }
 402
 403     sh_serial_clear_fifo(s);
 404
 405     memory_region_init_io(&s->iomem, NULL, &sh_serial_ops, s,
 406                           "serial", 0x100000000ULL);
 407
 408     memory_region_init_alias(&s->iomem_p4, NULL, "serial-p4", &s->iomem,
 409                              0, 0x28);
 410     memory_region_add_subregion(sysmem, P4ADDR(base), &s->iomem_p4);
 411
 412     memory_region_init_alias(&s->iomem_a7, NULL, "serial-a7", &s->iomem,
 413                              0, 0x28);
 414     memory_region_add_subregion(sysmem, A7ADDR(base), &s->iomem_a7);
 415
 416     if (chr) {
 417         qemu_chr_fe_init(&s->chr, chr, &error_abort);
 418         qemu_chr_fe_set_handlers(&s->chr, sh_serial_can_receive1,
 419                                  sh_serial_receive1,
 420                                  sh_serial_event, NULL, s, NULL, true);
 421     }
 422
 423     s->fifo_timeout_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
 424                                          sh_serial_timeout_int, s);
 425     s->etu = NANOSECONDS_PER_SECOND / 9600;
 426     s->eri = eri_source;
 427     s->rxi = rxi_source;
 428     s->txi = txi_source;
 429     s->tei = tei_source;
 430     s->bri = bri_source;
 431 }