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