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