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 "hw/irq.h" 24 #include "hw/qdev-properties.h" 25 #include "migration/vmstate.h" 26 #include "qemu/log.h" 27 #include "qemu/module.h" 28 29 #ifndef DEBUG_IMX_UART 30 #define DEBUG_IMX_UART 0 31 #endif 32 33 #define DPRINTF(fmt, args...) \ 34 do { \ 35 if (DEBUG_IMX_UART) { \ 36 fprintf(stderr, "[%s]%s: " fmt , TYPE_IMX_SERIAL, \ 37 __func__, ##args); \ 38 } \ 39 } while (0) 40 41 static const VMStateDescription vmstate_imx_serial = { 42 .name = TYPE_IMX_SERIAL, 43 .version_id = 2, 44 .minimum_version_id = 2, 45 .fields = (VMStateField[]) { 46 VMSTATE_INT32(readbuff, IMXSerialState), 47 VMSTATE_UINT32(usr1, IMXSerialState), 48 VMSTATE_UINT32(usr2, IMXSerialState), 49 VMSTATE_UINT32(ucr1, IMXSerialState), 50 VMSTATE_UINT32(uts1, IMXSerialState), 51 VMSTATE_UINT32(onems, IMXSerialState), 52 VMSTATE_UINT32(ufcr, IMXSerialState), 53 VMSTATE_UINT32(ubmr, IMXSerialState), 54 VMSTATE_UINT32(ubrc, IMXSerialState), 55 VMSTATE_UINT32(ucr3, IMXSerialState), 56 VMSTATE_UINT32(ucr4, IMXSerialState), 57 VMSTATE_END_OF_LIST() 58 }, 59 }; 60 61 static void imx_update(IMXSerialState *s) 62 { 63 uint32_t usr1; 64 uint32_t usr2; 65 uint32_t mask; 66 67 /* 68 * Lucky for us TRDY and RRDY has the same offset in both USR1 and 69 * UCR1, so we can get away with something as simple as the 70 * following: 71 */ 72 usr1 = s->usr1 & s->ucr1 & (USR1_TRDY | USR1_RRDY); 73 /* 74 * Bits that we want in USR2 are not as conveniently laid out, 75 * unfortunately. 76 */ 77 mask = (s->ucr1 & UCR1_TXMPTYEN) ? USR2_TXFE : 0; 78 /* 79 * TCEN and TXDC are both bit 3 80 * RDR and DREN are both bit 0 81 */ 82 mask |= s->ucr4 & (UCR4_TCEN | UCR4_DREN); 83 84 usr2 = s->usr2 & mask; 85 86 qemu_set_irq(s->irq, usr1 || usr2); 87 } 88 89 static void imx_serial_reset(IMXSerialState *s) 90 { 91 92 s->usr1 = USR1_TRDY | USR1_RXDS; 93 /* 94 * Fake attachment of a terminal: assert RTS. 95 */ 96 s->usr1 |= USR1_RTSS; 97 s->usr2 = USR2_TXFE | USR2_TXDC | USR2_DCDIN; 98 s->uts1 = UTS1_RXEMPTY | UTS1_TXEMPTY; 99 s->ucr1 = 0; 100 s->ucr2 = UCR2_SRST; 101 s->ucr3 = 0x700; 102 s->ubmr = 0; 103 s->ubrc = 4; 104 s->readbuff = URXD_ERR; 105 } 106 107 static void imx_serial_reset_at_boot(DeviceState *dev) 108 { 109 IMXSerialState *s = IMX_SERIAL(dev); 110 111 imx_serial_reset(s); 112 113 /* 114 * enable the uart on boot, so messages from the linux decompresser 115 * are visible. On real hardware this is done by the boot rom 116 * before anything else is loaded. 117 */ 118 s->ucr1 = UCR1_UARTEN; 119 s->ucr2 = UCR2_TXEN; 120 121 } 122 123 static uint64_t imx_serial_read(void *opaque, hwaddr offset, 124 unsigned size) 125 { 126 IMXSerialState *s = (IMXSerialState *)opaque; 127 uint32_t c; 128 129 DPRINTF("read(offset=0x%" HWADDR_PRIx ")\n", offset); 130 131 switch (offset >> 2) { 132 case 0x0: /* URXD */ 133 c = s->readbuff; 134 if (!(s->uts1 & UTS1_RXEMPTY)) { 135 /* Character is valid */ 136 c |= URXD_CHARRDY; 137 s->usr1 &= ~USR1_RRDY; 138 s->usr2 &= ~USR2_RDR; 139 s->uts1 |= UTS1_RXEMPTY; 140 imx_update(s); 141 qemu_chr_fe_accept_input(&s->chr); 142 } 143 return c; 144 145 case 0x20: /* UCR1 */ 146 return s->ucr1; 147 148 case 0x21: /* UCR2 */ 149 return s->ucr2; 150 151 case 0x25: /* USR1 */ 152 return s->usr1; 153 154 case 0x26: /* USR2 */ 155 return s->usr2; 156 157 case 0x2A: /* BRM Modulator */ 158 return s->ubmr; 159 160 case 0x2B: /* Baud Rate Count */ 161 return s->ubrc; 162 163 case 0x2d: /* Test register */ 164 return s->uts1; 165 166 case 0x24: /* UFCR */ 167 return s->ufcr; 168 169 case 0x2c: 170 return s->onems; 171 172 case 0x22: /* UCR3 */ 173 return s->ucr3; 174 175 case 0x23: /* UCR4 */ 176 return s->ucr4; 177 178 case 0x29: /* BRM Incremental */ 179 return 0x0; /* TODO */ 180 181 default: 182 qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad register at offset 0x%" 183 HWADDR_PRIx "\n", TYPE_IMX_SERIAL, __func__, offset); 184 return 0; 185 } 186 } 187 188 static void imx_serial_write(void *opaque, hwaddr offset, 189 uint64_t value, unsigned size) 190 { 191 IMXSerialState *s = (IMXSerialState *)opaque; 192 Chardev *chr = qemu_chr_fe_get_driver(&s->chr); 193 unsigned char ch; 194 195 DPRINTF("write(offset=0x%" HWADDR_PRIx ", value = 0x%x) to %s\n", 196 offset, (unsigned int)value, chr ? chr->label : "NODEV"); 197 198 switch (offset >> 2) { 199 case 0x10: /* UTXD */ 200 ch = value; 201 if (s->ucr2 & UCR2_TXEN) { 202 /* XXX this blocks entire thread. Rewrite to use 203 * qemu_chr_fe_write and background I/O callbacks */ 204 qemu_chr_fe_write_all(&s->chr, &ch, 1); 205 s->usr1 &= ~USR1_TRDY; 206 s->usr2 &= ~USR2_TXDC; 207 imx_update(s); 208 s->usr1 |= USR1_TRDY; 209 s->usr2 |= USR2_TXDC; 210 imx_update(s); 211 } 212 break; 213 214 case 0x20: /* UCR1 */ 215 s->ucr1 = value & 0xffff; 216 217 DPRINTF("write(ucr1=%x)\n", (unsigned int)value); 218 219 imx_update(s); 220 break; 221 222 case 0x21: /* UCR2 */ 223 /* 224 * Only a few bits in control register 2 are implemented as yet. 225 * If it's intended to use a real serial device as a back-end, this 226 * register will have to be implemented more fully. 227 */ 228 if (!(value & UCR2_SRST)) { 229 imx_serial_reset(s); 230 imx_update(s); 231 value |= UCR2_SRST; 232 } 233 if (value & UCR2_RXEN) { 234 if (!(s->ucr2 & UCR2_RXEN)) { 235 qemu_chr_fe_accept_input(&s->chr); 236 } 237 } 238 s->ucr2 = value & 0xffff; 239 break; 240 241 case 0x25: /* USR1 */ 242 value &= USR1_AWAKE | USR1_AIRINT | USR1_DTRD | USR1_AGTIM | 243 USR1_FRAMERR | USR1_ESCF | USR1_RTSD | USR1_PARTYER; 244 s->usr1 &= ~value; 245 break; 246 247 case 0x26: /* USR2 */ 248 /* 249 * Writing 1 to some bits clears them; all other 250 * values are ignored 251 */ 252 value &= USR2_ADET | USR2_DTRF | USR2_IDLE | USR2_ACST | 253 USR2_RIDELT | USR2_IRINT | USR2_WAKE | 254 USR2_DCDDELT | USR2_RTSF | USR2_BRCD | USR2_ORE; 255 s->usr2 &= ~value; 256 break; 257 258 /* 259 * Linux expects to see what it writes to these registers 260 * We don't currently alter the baud rate 261 */ 262 case 0x29: /* UBIR */ 263 s->ubrc = value & 0xffff; 264 break; 265 266 case 0x2a: /* UBMR */ 267 s->ubmr = value & 0xffff; 268 break; 269 270 case 0x2c: /* One ms reg */ 271 s->onems = value & 0xffff; 272 break; 273 274 case 0x24: /* FIFO control register */ 275 s->ufcr = value & 0xffff; 276 break; 277 278 case 0x22: /* UCR3 */ 279 s->ucr3 = value & 0xffff; 280 break; 281 282 case 0x23: /* UCR4 */ 283 s->ucr4 = value & 0xffff; 284 imx_update(s); 285 break; 286 287 case 0x2d: /* UTS1 */ 288 qemu_log_mask(LOG_UNIMP, "[%s]%s: Unimplemented reg 0x%" 289 HWADDR_PRIx "\n", TYPE_IMX_SERIAL, __func__, offset); 290 /* TODO */ 291 break; 292 293 default: 294 qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad register at offset 0x%" 295 HWADDR_PRIx "\n", TYPE_IMX_SERIAL, __func__, offset); 296 } 297 } 298 299 static int imx_can_receive(void *opaque) 300 { 301 IMXSerialState *s = (IMXSerialState *)opaque; 302 return !(s->usr1 & USR1_RRDY); 303 } 304 305 static void imx_put_data(void *opaque, uint32_t value) 306 { 307 IMXSerialState *s = (IMXSerialState *)opaque; 308 309 DPRINTF("received char\n"); 310 311 s->usr1 |= USR1_RRDY; 312 s->usr2 |= USR2_RDR; 313 s->uts1 &= ~UTS1_RXEMPTY; 314 s->readbuff = value; 315 if (value & URXD_BRK) { 316 s->usr2 |= USR2_BRCD; 317 } 318 imx_update(s); 319 } 320 321 static void imx_receive(void *opaque, const uint8_t *buf, int size) 322 { 323 imx_put_data(opaque, *buf); 324 } 325 326 static void imx_event(void *opaque, QEMUChrEvent event) 327 { 328 if (event == CHR_EVENT_BREAK) { 329 imx_put_data(opaque, URXD_BRK | URXD_FRMERR | URXD_ERR); 330 } 331 } 332 333 334 static const struct MemoryRegionOps imx_serial_ops = { 335 .read = imx_serial_read, 336 .write = imx_serial_write, 337 .endianness = DEVICE_NATIVE_ENDIAN, 338 }; 339 340 static void imx_serial_realize(DeviceState *dev, Error **errp) 341 { 342 IMXSerialState *s = IMX_SERIAL(dev); 343 344 DPRINTF("char dev for uart: %p\n", qemu_chr_fe_get_driver(&s->chr)); 345 346 qemu_chr_fe_set_handlers(&s->chr, imx_can_receive, imx_receive, 347 imx_event, NULL, s, NULL, true); 348 } 349 350 static void imx_serial_init(Object *obj) 351 { 352 SysBusDevice *sbd = SYS_BUS_DEVICE(obj); 353 IMXSerialState *s = IMX_SERIAL(obj); 354 355 memory_region_init_io(&s->iomem, obj, &imx_serial_ops, s, 356 TYPE_IMX_SERIAL, 0x1000); 357 sysbus_init_mmio(sbd, &s->iomem); 358 sysbus_init_irq(sbd, &s->irq); 359 } 360 361 static Property imx_serial_properties[] = { 362 DEFINE_PROP_CHR("chardev", IMXSerialState, chr), 363 DEFINE_PROP_END_OF_LIST(), 364 }; 365 366 static void imx_serial_class_init(ObjectClass *klass, void *data) 367 { 368 DeviceClass *dc = DEVICE_CLASS(klass); 369 370 dc->realize = imx_serial_realize; 371 dc->vmsd = &vmstate_imx_serial; 372 dc->reset = imx_serial_reset_at_boot; 373 set_bit(DEVICE_CATEGORY_INPUT, dc->categories); 374 dc->desc = "i.MX series UART"; 375 device_class_set_props(dc, imx_serial_properties); 376 } 377 378 static const TypeInfo imx_serial_info = { 379 .name = TYPE_IMX_SERIAL, 380 .parent = TYPE_SYS_BUS_DEVICE, 381 .instance_size = sizeof(IMXSerialState), 382 .instance_init = imx_serial_init, 383 .class_init = imx_serial_class_init, 384 }; 385 386 static void imx_serial_register_types(void) 387 { 388 type_register_static(&imx_serial_info); 389 } 390 391 type_init(imx_serial_register_types) 392