hw/char/imx_serial.c

   1 /*
   2  * IMX31 UARTS
   3  *
   4  * Copyright (c) 2008 OKL
   5  * Originally Written by Hans Jiang
   6  * Copyright (c) 2011 NICTA Pty Ltd.
   7  * Updated by Jean-Christophe Dubois <jcd@tribudubois.net>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  *
  12  * This is a `bare-bones' implementation of the IMX series serial ports.
  13  * TODO:
  14  *  -- implement FIFOs.  The real hardware has 32 word transmit
  15  *                       and receive FIFOs; we currently use a 1-char buffer
  16  *  -- implement DMA
  17  *  -- implement BAUD-rate and modem lines, for when the backend
  18  *     is a real serial device.
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include "hw/char/imx_serial.h"
  23 #include "sysemu/sysemu.h"
  24 #include "sysemu/char.h"
  25 #include "qemu/log.h"
  26
  27 #ifndef DEBUG_IMX_UART
  28 #define DEBUG_IMX_UART 0
  29 #endif
  30
  31 #define DPRINTF(fmt, args...) \
  32     do { \
  33         if (DEBUG_IMX_UART) { \
  34             fprintf(stderr, "[%s]%s: " fmt , TYPE_IMX_SERIAL, \
  35                                              __func__, ##args); \
  36         } \
  37     } while (0)
  38
  39 static const VMStateDescription vmstate_imx_serial = {
  40     .name = TYPE_IMX_SERIAL,
  41     .version_id = 1,
  42     .minimum_version_id = 1,
  43     .fields = (VMStateField[]) {
  44         VMSTATE_INT32(readbuff, IMXSerialState),
  45         VMSTATE_UINT32(usr1, IMXSerialState),
  46         VMSTATE_UINT32(usr2, IMXSerialState),
  47         VMSTATE_UINT32(ucr1, IMXSerialState),
  48         VMSTATE_UINT32(uts1, IMXSerialState),
  49         VMSTATE_UINT32(onems, IMXSerialState),
  50         VMSTATE_UINT32(ufcr, IMXSerialState),
  51         VMSTATE_UINT32(ubmr, IMXSerialState),
  52         VMSTATE_UINT32(ubrc, IMXSerialState),
  53         VMSTATE_UINT32(ucr3, IMXSerialState),
  54         VMSTATE_END_OF_LIST()
  55     },
  56 };
  57
  58 static void imx_update(IMXSerialState *s)
  59 {
  60     uint32_t flags;
  61
  62     flags = (s->usr1 & s->ucr1) & (USR1_TRDY|USR1_RRDY);
  63     if (s->ucr1 & UCR1_TXMPTYEN) {
  64         flags |= (s->uts1 & UTS1_TXEMPTY);
  65     } else {
  66         flags &= ~USR1_TRDY;
  67     }
  68
  69     qemu_set_irq(s->irq, !!flags);
  70 }
  71
  72 static void imx_serial_reset(IMXSerialState *s)
  73 {
  74
  75     s->usr1 = USR1_TRDY | USR1_RXDS;
  76     /*
  77      * Fake attachment of a terminal: assert RTS.
  78      */
  79     s->usr1 |= USR1_RTSS;
  80     s->usr2 = USR2_TXFE | USR2_TXDC | USR2_DCDIN;
  81     s->uts1 = UTS1_RXEMPTY | UTS1_TXEMPTY;
  82     s->ucr1 = 0;
  83     s->ucr2 = UCR2_SRST;
  84     s->ucr3 = 0x700;
  85     s->ubmr = 0;
  86     s->ubrc = 4;
  87     s->readbuff = URXD_ERR;
  88 }
  89
  90 static void imx_serial_reset_at_boot(DeviceState *dev)
  91 {
  92     IMXSerialState *s = IMX_SERIAL(dev);
  93
  94     imx_serial_reset(s);
  95
  96     /*
  97      * enable the uart on boot, so messages from the linux decompresser
  98      * are visible.  On real hardware this is done by the boot rom
  99      * before anything else is loaded.
 100      */
 101     s->ucr1 = UCR1_UARTEN;
 102     s->ucr2 = UCR2_TXEN;
 103
 104 }
 105
 106 static uint64_t imx_serial_read(void *opaque, hwaddr offset,
 107                                 unsigned size)
 108 {
 109     IMXSerialState *s = (IMXSerialState *)opaque;
 110     uint32_t c;
 111
 112     DPRINTF("read(offset=0x%" HWADDR_PRIx ")\n", offset);
 113
 114     switch (offset >> 2) {
 115     case 0x0: /* URXD */
 116         c = s->readbuff;
 117         if (!(s->uts1 & UTS1_RXEMPTY)) {
 118             /* Character is valid */
 119             c |= URXD_CHARRDY;
 120             s->usr1 &= ~USR1_RRDY;
 121             s->usr2 &= ~USR2_RDR;
 122             s->uts1 |= UTS1_RXEMPTY;
 123             imx_update(s);
 124             qemu_chr_fe_accept_input(&s->chr);
 125         }
 126         return c;
 127
 128     case 0x20: /* UCR1 */
 129         return s->ucr1;
 130
 131     case 0x21: /* UCR2 */
 132         return s->ucr2;
 133
 134     case 0x25: /* USR1 */
 135         return s->usr1;
 136
 137     case 0x26: /* USR2 */
 138         return s->usr2;
 139
 140     case 0x2A: /* BRM Modulator */
 141         return s->ubmr;
 142
 143     case 0x2B: /* Baud Rate Count */
 144         return s->ubrc;
 145
 146     case 0x2d: /* Test register */
 147         return s->uts1;
 148
 149     case 0x24: /* UFCR */
 150         return s->ufcr;
 151
 152     case 0x2c:
 153         return s->onems;
 154
 155     case 0x22: /* UCR3 */
 156         return s->ucr3;
 157
 158     case 0x23: /* UCR4 */
 159     case 0x29: /* BRM Incremental */
 160         return 0x0; /* TODO */
 161
 162     default:
 163         qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad register at offset 0x%"
 164                       HWADDR_PRIx "\n", TYPE_IMX_SERIAL, __func__, offset);
 165         return 0;
 166     }
 167 }
 168
 169 static void imx_serial_write(void *opaque, hwaddr offset,
 170                              uint64_t value, unsigned size)
 171 {
 172     IMXSerialState *s = (IMXSerialState *)opaque;
 173     Chardev *chr = qemu_chr_fe_get_driver(&s->chr);
 174     unsigned char ch;
 175
 176     DPRINTF("write(offset=0x%" HWADDR_PRIx ", value = 0x%x) to %s\n",
 177             offset, (unsigned int)value, chr ? chr->label : "NODEV");
 178
 179     switch (offset >> 2) {
 180     case 0x10: /* UTXD */
 181         ch = value;
 182         if (s->ucr2 & UCR2_TXEN) {
 183             /* XXX this blocks entire thread. Rewrite to use
 184              * qemu_chr_fe_write and background I/O callbacks */
 185             qemu_chr_fe_write_all(&s->chr, &ch, 1);
 186             s->usr1 &= ~USR1_TRDY;
 187             imx_update(s);
 188             s->usr1 |= USR1_TRDY;
 189             imx_update(s);
 190         }
 191         break;
 192
 193     case 0x20: /* UCR1 */
 194         s->ucr1 = value & 0xffff;
 195
 196         DPRINTF("write(ucr1=%x)\n", (unsigned int)value);
 197
 198         imx_update(s);
 199         break;
 200
 201     case 0x21: /* UCR2 */
 202         /*
 203          * Only a few bits in control register 2 are implemented as yet.
 204          * If it's intended to use a real serial device as a back-end, this
 205          * register will have to be implemented more fully.
 206          */
 207         if (!(value & UCR2_SRST)) {
 208             imx_serial_reset(s);
 209             imx_update(s);
 210             value |= UCR2_SRST;
 211         }
 212         if (value & UCR2_RXEN) {
 213             if (!(s->ucr2 & UCR2_RXEN)) {
 214                 qemu_chr_fe_accept_input(&s->chr);
 215             }
 216         }
 217         s->ucr2 = value & 0xffff;
 218         break;
 219
 220     case 0x25: /* USR1 */
 221         value &= USR1_AWAKE | USR1_AIRINT | USR1_DTRD | USR1_AGTIM |
 222                  USR1_FRAMERR | USR1_ESCF | USR1_RTSD | USR1_PARTYER;
 223         s->usr1 &= ~value;
 224         break;
 225
 226     case 0x26: /* USR2 */
 227         /*
 228          * Writing 1 to some bits clears them; all other
 229          * values are ignored
 230          */
 231         value &= USR2_ADET | USR2_DTRF | USR2_IDLE | USR2_ACST |
 232                  USR2_RIDELT | USR2_IRINT | USR2_WAKE |
 233                  USR2_DCDDELT | USR2_RTSF | USR2_BRCD | USR2_ORE;
 234         s->usr2 &= ~value;
 235         break;
 236
 237     /*
 238      * Linux expects to see what it writes to these registers
 239      * We don't currently alter the baud rate
 240      */
 241     case 0x29: /* UBIR */
 242         s->ubrc = value & 0xffff;
 243         break;
 244
 245     case 0x2a: /* UBMR */
 246         s->ubmr = value & 0xffff;
 247         break;
 248
 249     case 0x2c: /* One ms reg */
 250         s->onems = value & 0xffff;
 251         break;
 252
 253     case 0x24: /* FIFO control register */
 254         s->ufcr = value & 0xffff;
 255         break;
 256
 257     case 0x22: /* UCR3 */
 258         s->ucr3 = value & 0xffff;
 259         break;
 260
 261     case 0x2d: /* UTS1 */
 262     case 0x23: /* UCR4 */
 263         qemu_log_mask(LOG_UNIMP, "[%s]%s: Unimplemented reg 0x%"
 264                       HWADDR_PRIx "\n", TYPE_IMX_SERIAL, __func__, offset);
 265         /* TODO */
 266         break;
 267
 268     default:
 269         qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad register at offset 0x%"
 270                       HWADDR_PRIx "\n", TYPE_IMX_SERIAL, __func__, offset);
 271     }
 272 }
 273
 274 static int imx_can_receive(void *opaque)
 275 {
 276     IMXSerialState *s = (IMXSerialState *)opaque;
 277     return !(s->usr1 & USR1_RRDY);
 278 }
 279
 280 static void imx_put_data(void *opaque, uint32_t value)
 281 {
 282     IMXSerialState *s = (IMXSerialState *)opaque;
 283
 284     DPRINTF("received char\n");
 285
 286     s->usr1 |= USR1_RRDY;
 287     s->usr2 |= USR2_RDR;
 288     s->uts1 &= ~UTS1_RXEMPTY;
 289     s->readbuff = value;
 290     imx_update(s);
 291 }
 292
 293 static void imx_receive(void *opaque, const uint8_t *buf, int size)
 294 {
 295     imx_put_data(opaque, *buf);
 296 }
 297
 298 static void imx_event(void *opaque, int event)
 299 {
 300     if (event == CHR_EVENT_BREAK) {
 301         imx_put_data(opaque, URXD_BRK);
 302     }
 303 }
 304
 305
 306 static const struct MemoryRegionOps imx_serial_ops = {
 307     .read = imx_serial_read,
 308     .write = imx_serial_write,
 309     .endianness = DEVICE_NATIVE_ENDIAN,
 310 };
 311
 312 static void imx_serial_realize(DeviceState *dev, Error **errp)
 313 {
 314     IMXSerialState *s = IMX_SERIAL(dev);
 315
 316     DPRINTF("char dev for uart: %p\n", qemu_chr_fe_get_driver(&s->chr));
 317
 318     qemu_chr_fe_set_handlers(&s->chr, imx_can_receive, imx_receive,
 319                              imx_event, s, NULL, true);
 320 }
 321
 322 static void imx_serial_init(Object *obj)
 323 {
 324     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
 325     IMXSerialState *s = IMX_SERIAL(obj);
 326
 327     memory_region_init_io(&s->iomem, obj, &imx_serial_ops, s,
 328                           TYPE_IMX_SERIAL, 0x1000);
 329     sysbus_init_mmio(sbd, &s->iomem);
 330     sysbus_init_irq(sbd, &s->irq);
 331 }
 332
 333 static Property imx_serial_properties[] = {
 334     DEFINE_PROP_CHR("chardev", IMXSerialState, chr),
 335     DEFINE_PROP_END_OF_LIST(),
 336 };
 337
 338 static void imx_serial_class_init(ObjectClass *klass, void *data)
 339 {
 340     DeviceClass *dc = DEVICE_CLASS(klass);
 341
 342     dc->realize = imx_serial_realize;
 343     dc->vmsd = &vmstate_imx_serial;
 344     dc->reset = imx_serial_reset_at_boot;
 345     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
 346     dc->desc = "i.MX series UART";
 347     dc->props = imx_serial_properties;
 348 }
 349
 350 static const TypeInfo imx_serial_info = {
 351     .name           = TYPE_IMX_SERIAL,
 352     .parent         = TYPE_SYS_BUS_DEVICE,
 353     .instance_size  = sizeof(IMXSerialState),
 354     .instance_init  = imx_serial_init,
 355     .class_init     = imx_serial_class_init,
 356 };
 357
 358 static void imx_serial_register_types(void)
 359 {
 360     type_register_static(&imx_serial_info);
 361 }
 362
 363 type_init(imx_serial_register_types)