1 /* 2 * IMX SPI Controller 3 * 4 * Copyright (c) 2016 Jean-Christophe Dubois <jcd@tribudubois.net> 5 * 6 * This work is licensed under the terms of the GNU GPL, version 2 or later. 7 * See the COPYING file in the top-level directory. 8 * 9 */ 10 11 #include "qemu/osdep.h" 12 #include "hw/irq.h" 13 #include "hw/ssi/imx_spi.h" 14 #include "migration/vmstate.h" 15 #include "qemu/log.h" 16 #include "qemu/module.h" 17 18 #ifndef DEBUG_IMX_SPI 19 #define DEBUG_IMX_SPI 0 20 #endif 21 22 #define DPRINTF(fmt, args...) \ 23 do { \ 24 if (DEBUG_IMX_SPI) { \ 25 fprintf(stderr, "[%s]%s: " fmt , TYPE_IMX_SPI, \ 26 __func__, ##args); \ 27 } \ 28 } while (0) 29 30 static const char *imx_spi_reg_name(uint32_t reg) 31 { 32 static char unknown[20]; 33 34 switch (reg) { 35 case ECSPI_RXDATA: 36 return "ECSPI_RXDATA"; 37 case ECSPI_TXDATA: 38 return "ECSPI_TXDATA"; 39 case ECSPI_CONREG: 40 return "ECSPI_CONREG"; 41 case ECSPI_CONFIGREG: 42 return "ECSPI_CONFIGREG"; 43 case ECSPI_INTREG: 44 return "ECSPI_INTREG"; 45 case ECSPI_DMAREG: 46 return "ECSPI_DMAREG"; 47 case ECSPI_STATREG: 48 return "ECSPI_STATREG"; 49 case ECSPI_PERIODREG: 50 return "ECSPI_PERIODREG"; 51 case ECSPI_TESTREG: 52 return "ECSPI_TESTREG"; 53 case ECSPI_MSGDATA: 54 return "ECSPI_MSGDATA"; 55 default: 56 sprintf(unknown, "%u ?", reg); 57 return unknown; 58 } 59 } 60 61 static const VMStateDescription vmstate_imx_spi = { 62 .name = TYPE_IMX_SPI, 63 .version_id = 1, 64 .minimum_version_id = 1, 65 .fields = (VMStateField[]) { 66 VMSTATE_FIFO32(tx_fifo, IMXSPIState), 67 VMSTATE_FIFO32(rx_fifo, IMXSPIState), 68 VMSTATE_INT16(burst_length, IMXSPIState), 69 VMSTATE_UINT32_ARRAY(regs, IMXSPIState, ECSPI_MAX), 70 VMSTATE_END_OF_LIST() 71 }, 72 }; 73 74 static void imx_spi_txfifo_reset(IMXSPIState *s) 75 { 76 fifo32_reset(&s->tx_fifo); 77 s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TE; 78 s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_TF; 79 } 80 81 static void imx_spi_rxfifo_reset(IMXSPIState *s) 82 { 83 fifo32_reset(&s->rx_fifo); 84 s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RR; 85 s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RF; 86 s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RO; 87 } 88 89 static void imx_spi_update_irq(IMXSPIState *s) 90 { 91 int level; 92 93 if (fifo32_is_empty(&s->rx_fifo)) { 94 s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RR; 95 } else { 96 s->regs[ECSPI_STATREG] |= ECSPI_STATREG_RR; 97 } 98 99 if (fifo32_is_full(&s->rx_fifo)) { 100 s->regs[ECSPI_STATREG] |= ECSPI_STATREG_RF; 101 } else { 102 s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_RF; 103 } 104 105 if (fifo32_is_empty(&s->tx_fifo)) { 106 s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TE; 107 } else { 108 s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_TE; 109 } 110 111 if (fifo32_is_full(&s->tx_fifo)) { 112 s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TF; 113 } else { 114 s->regs[ECSPI_STATREG] &= ~ECSPI_STATREG_TF; 115 } 116 117 level = s->regs[ECSPI_STATREG] & s->regs[ECSPI_INTREG] ? 1 : 0; 118 119 qemu_set_irq(s->irq, level); 120 121 DPRINTF("IRQ level is %d\n", level); 122 } 123 124 static uint8_t imx_spi_selected_channel(IMXSPIState *s) 125 { 126 return EXTRACT(s->regs[ECSPI_CONREG], ECSPI_CONREG_CHANNEL_SELECT); 127 } 128 129 static uint32_t imx_spi_burst_length(IMXSPIState *s) 130 { 131 return EXTRACT(s->regs[ECSPI_CONREG], ECSPI_CONREG_BURST_LENGTH) + 1; 132 } 133 134 static bool imx_spi_is_enabled(IMXSPIState *s) 135 { 136 return s->regs[ECSPI_CONREG] & ECSPI_CONREG_EN; 137 } 138 139 static bool imx_spi_channel_is_master(IMXSPIState *s) 140 { 141 uint8_t mode = EXTRACT(s->regs[ECSPI_CONREG], ECSPI_CONREG_CHANNEL_MODE); 142 143 return (mode & (1 << imx_spi_selected_channel(s))) ? true : false; 144 } 145 146 static bool imx_spi_is_multiple_master_burst(IMXSPIState *s) 147 { 148 uint8_t wave = EXTRACT(s->regs[ECSPI_CONFIGREG], ECSPI_CONFIGREG_SS_CTL); 149 150 return imx_spi_channel_is_master(s) && 151 !(s->regs[ECSPI_CONREG] & ECSPI_CONREG_SMC) && 152 ((wave & (1 << imx_spi_selected_channel(s))) ? true : false); 153 } 154 155 static void imx_spi_flush_txfifo(IMXSPIState *s) 156 { 157 uint32_t tx; 158 uint32_t rx; 159 160 DPRINTF("Begin: TX Fifo Size = %d, RX Fifo Size = %d\n", 161 fifo32_num_used(&s->tx_fifo), fifo32_num_used(&s->rx_fifo)); 162 163 while (!fifo32_is_empty(&s->tx_fifo)) { 164 int tx_burst = 0; 165 int index = 0; 166 167 if (s->burst_length <= 0) { 168 s->burst_length = imx_spi_burst_length(s); 169 170 DPRINTF("Burst length = %d\n", s->burst_length); 171 172 if (imx_spi_is_multiple_master_burst(s)) { 173 s->regs[ECSPI_CONREG] |= ECSPI_CONREG_XCH; 174 } 175 } 176 177 tx = fifo32_pop(&s->tx_fifo); 178 179 DPRINTF("data tx:0x%08x\n", tx); 180 181 tx_burst = MIN(s->burst_length, 32); 182 183 rx = 0; 184 185 while (tx_burst > 0) { 186 uint8_t byte = tx & 0xff; 187 188 DPRINTF("writing 0x%02x\n", (uint32_t)byte); 189 190 /* We need to write one byte at a time */ 191 byte = ssi_transfer(s->bus, byte); 192 193 DPRINTF("0x%02x read\n", (uint32_t)byte); 194 195 tx = tx >> 8; 196 rx |= (byte << (index * 8)); 197 198 /* Remove 8 bits from the actual burst */ 199 tx_burst -= 8; 200 s->burst_length -= 8; 201 index++; 202 } 203 204 DPRINTF("data rx:0x%08x\n", rx); 205 206 if (fifo32_is_full(&s->rx_fifo)) { 207 s->regs[ECSPI_STATREG] |= ECSPI_STATREG_RO; 208 } else { 209 fifo32_push(&s->rx_fifo, rx); 210 } 211 212 if (s->burst_length <= 0) { 213 if (!imx_spi_is_multiple_master_burst(s)) { 214 s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TC; 215 break; 216 } 217 } 218 } 219 220 if (fifo32_is_empty(&s->tx_fifo)) { 221 s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TC; 222 s->regs[ECSPI_CONREG] &= ~ECSPI_CONREG_XCH; 223 } 224 225 /* TODO: We should also use TDR and RDR bits */ 226 227 DPRINTF("End: TX Fifo Size = %d, RX Fifo Size = %d\n", 228 fifo32_num_used(&s->tx_fifo), fifo32_num_used(&s->rx_fifo)); 229 } 230 231 static void imx_spi_reset(DeviceState *dev) 232 { 233 IMXSPIState *s = IMX_SPI(dev); 234 235 DPRINTF("\n"); 236 237 memset(s->regs, 0, sizeof(s->regs)); 238 239 s->regs[ECSPI_STATREG] = 0x00000003; 240 241 imx_spi_rxfifo_reset(s); 242 imx_spi_txfifo_reset(s); 243 244 imx_spi_update_irq(s); 245 246 s->burst_length = 0; 247 } 248 249 static uint64_t imx_spi_read(void *opaque, hwaddr offset, unsigned size) 250 { 251 uint32_t value = 0; 252 IMXSPIState *s = opaque; 253 uint32_t index = offset >> 2; 254 255 if (index >= ECSPI_MAX) { 256 qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad register at offset 0x%" 257 HWADDR_PRIx "\n", TYPE_IMX_SPI, __func__, offset); 258 return 0; 259 } 260 261 switch (index) { 262 case ECSPI_RXDATA: 263 if (!imx_spi_is_enabled(s)) { 264 value = 0; 265 } else if (fifo32_is_empty(&s->rx_fifo)) { 266 /* value is undefined */ 267 value = 0xdeadbeef; 268 } else { 269 /* read from the RX FIFO */ 270 value = fifo32_pop(&s->rx_fifo); 271 } 272 273 break; 274 case ECSPI_TXDATA: 275 qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to read from TX FIFO\n", 276 TYPE_IMX_SPI, __func__); 277 278 /* Reading from TXDATA gives 0 */ 279 280 break; 281 case ECSPI_MSGDATA: 282 qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to read from MSG FIFO\n", 283 TYPE_IMX_SPI, __func__); 284 285 /* Reading from MSGDATA gives 0 */ 286 287 break; 288 default: 289 value = s->regs[index]; 290 break; 291 } 292 293 DPRINTF("reg[%s] => 0x%" PRIx32 "\n", imx_spi_reg_name(index), value); 294 295 imx_spi_update_irq(s); 296 297 return (uint64_t)value; 298 } 299 300 static void imx_spi_write(void *opaque, hwaddr offset, uint64_t value, 301 unsigned size) 302 { 303 IMXSPIState *s = opaque; 304 uint32_t index = offset >> 2; 305 uint32_t change_mask; 306 307 if (index >= ECSPI_MAX) { 308 qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad register at offset 0x%" 309 HWADDR_PRIx "\n", TYPE_IMX_SPI, __func__, offset); 310 return; 311 } 312 313 DPRINTF("reg[%s] <= 0x%" PRIx32 "\n", imx_spi_reg_name(index), 314 (uint32_t)value); 315 316 change_mask = s->regs[index] ^ value; 317 318 switch (index) { 319 case ECSPI_RXDATA: 320 qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to write to RX FIFO\n", 321 TYPE_IMX_SPI, __func__); 322 break; 323 case ECSPI_TXDATA: 324 if (!imx_spi_is_enabled(s)) { 325 /* Ignore writes if device is disabled */ 326 break; 327 } else if (fifo32_is_full(&s->tx_fifo)) { 328 /* Ignore writes if queue is full */ 329 break; 330 } 331 332 fifo32_push(&s->tx_fifo, (uint32_t)value); 333 334 if (imx_spi_channel_is_master(s) && 335 (s->regs[ECSPI_CONREG] & ECSPI_CONREG_SMC)) { 336 /* 337 * Start emitting if current channel is master and SMC bit is 338 * set. 339 */ 340 imx_spi_flush_txfifo(s); 341 } 342 343 break; 344 case ECSPI_STATREG: 345 /* the RO and TC bits are write-one-to-clear */ 346 value &= ECSPI_STATREG_RO | ECSPI_STATREG_TC; 347 s->regs[ECSPI_STATREG] &= ~value; 348 349 break; 350 case ECSPI_CONREG: 351 s->regs[ECSPI_CONREG] = value; 352 353 if (!imx_spi_is_enabled(s)) { 354 /* device is disabled, so this is a reset */ 355 imx_spi_reset(DEVICE(s)); 356 return; 357 } 358 359 if (imx_spi_channel_is_master(s)) { 360 int i; 361 362 /* We are in master mode */ 363 364 for (i = 0; i < 4; i++) { 365 qemu_set_irq(s->cs_lines[i], 366 i == imx_spi_selected_channel(s) ? 0 : 1); 367 } 368 369 if ((value & change_mask & ECSPI_CONREG_SMC) && 370 !fifo32_is_empty(&s->tx_fifo)) { 371 /* SMC bit is set and TX FIFO has some slots filled in */ 372 imx_spi_flush_txfifo(s); 373 } else if ((value & change_mask & ECSPI_CONREG_XCH) && 374 !(value & ECSPI_CONREG_SMC)) { 375 /* This is a request to start emitting */ 376 imx_spi_flush_txfifo(s); 377 } 378 } 379 380 break; 381 case ECSPI_MSGDATA: 382 /* it is not clear from the spec what MSGDATA is for */ 383 /* Anyway it is not used by Linux driver */ 384 /* So for now we just ignore it */ 385 qemu_log_mask(LOG_UNIMP, 386 "[%s]%s: Trying to write to MSGDATA, ignoring\n", 387 TYPE_IMX_SPI, __func__); 388 break; 389 default: 390 s->regs[index] = value; 391 392 break; 393 } 394 395 imx_spi_update_irq(s); 396 } 397 398 static const struct MemoryRegionOps imx_spi_ops = { 399 .read = imx_spi_read, 400 .write = imx_spi_write, 401 .endianness = DEVICE_NATIVE_ENDIAN, 402 .valid = { 403 /* 404 * Our device would not work correctly if the guest was doing 405 * unaligned access. This might not be a limitation on the real 406 * device but in practice there is no reason for a guest to access 407 * this device unaligned. 408 */ 409 .min_access_size = 4, 410 .max_access_size = 4, 411 .unaligned = false, 412 }, 413 }; 414 415 static void imx_spi_realize(DeviceState *dev, Error **errp) 416 { 417 IMXSPIState *s = IMX_SPI(dev); 418 int i; 419 420 s->bus = ssi_create_bus(dev, "spi"); 421 422 memory_region_init_io(&s->iomem, OBJECT(dev), &imx_spi_ops, s, 423 TYPE_IMX_SPI, 0x1000); 424 sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem); 425 sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->irq); 426 427 for (i = 0; i < 4; ++i) { 428 sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->cs_lines[i]); 429 } 430 431 s->burst_length = 0; 432 433 fifo32_create(&s->tx_fifo, ECSPI_FIFO_SIZE); 434 fifo32_create(&s->rx_fifo, ECSPI_FIFO_SIZE); 435 } 436 437 static void imx_spi_class_init(ObjectClass *klass, void *data) 438 { 439 DeviceClass *dc = DEVICE_CLASS(klass); 440 441 dc->realize = imx_spi_realize; 442 dc->vmsd = &vmstate_imx_spi; 443 dc->reset = imx_spi_reset; 444 dc->desc = "i.MX SPI Controller"; 445 } 446 447 static const TypeInfo imx_spi_info = { 448 .name = TYPE_IMX_SPI, 449 .parent = TYPE_SYS_BUS_DEVICE, 450 .instance_size = sizeof(IMXSPIState), 451 .class_init = imx_spi_class_init, 452 }; 453 454 static void imx_spi_register_types(void) 455 { 456 type_register_static(&imx_spi_info); 457 } 458 459 type_init(imx_spi_register_types) 460