1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * SPI-Engine SPI controller driver 4 * Copyright 2015 Analog Devices Inc. 5 * Author: Lars-Peter Clausen <lars@metafoo.de> 6 */ 7 8 #include <linux/clk.h> 9 #include <linux/interrupt.h> 10 #include <linux/io.h> 11 #include <linux/of.h> 12 #include <linux/module.h> 13 #include <linux/platform_device.h> 14 #include <linux/spi/spi.h> 15 16 #define SPI_ENGINE_VERSION_MAJOR(x) ((x >> 16) & 0xff) 17 #define SPI_ENGINE_VERSION_MINOR(x) ((x >> 8) & 0xff) 18 #define SPI_ENGINE_VERSION_PATCH(x) (x & 0xff) 19 20 #define SPI_ENGINE_REG_VERSION 0x00 21 22 #define SPI_ENGINE_REG_RESET 0x40 23 24 #define SPI_ENGINE_REG_INT_ENABLE 0x80 25 #define SPI_ENGINE_REG_INT_PENDING 0x84 26 #define SPI_ENGINE_REG_INT_SOURCE 0x88 27 28 #define SPI_ENGINE_REG_SYNC_ID 0xc0 29 30 #define SPI_ENGINE_REG_CMD_FIFO_ROOM 0xd0 31 #define SPI_ENGINE_REG_SDO_FIFO_ROOM 0xd4 32 #define SPI_ENGINE_REG_SDI_FIFO_LEVEL 0xd8 33 34 #define SPI_ENGINE_REG_CMD_FIFO 0xe0 35 #define SPI_ENGINE_REG_SDO_DATA_FIFO 0xe4 36 #define SPI_ENGINE_REG_SDI_DATA_FIFO 0xe8 37 #define SPI_ENGINE_REG_SDI_DATA_FIFO_PEEK 0xec 38 39 #define SPI_ENGINE_INT_CMD_ALMOST_EMPTY BIT(0) 40 #define SPI_ENGINE_INT_SDO_ALMOST_EMPTY BIT(1) 41 #define SPI_ENGINE_INT_SDI_ALMOST_FULL BIT(2) 42 #define SPI_ENGINE_INT_SYNC BIT(3) 43 44 #define SPI_ENGINE_CONFIG_CPHA BIT(0) 45 #define SPI_ENGINE_CONFIG_CPOL BIT(1) 46 #define SPI_ENGINE_CONFIG_3WIRE BIT(2) 47 48 #define SPI_ENGINE_INST_TRANSFER 0x0 49 #define SPI_ENGINE_INST_ASSERT 0x1 50 #define SPI_ENGINE_INST_WRITE 0x2 51 #define SPI_ENGINE_INST_MISC 0x3 52 53 #define SPI_ENGINE_CMD_REG_CLK_DIV 0x0 54 #define SPI_ENGINE_CMD_REG_CONFIG 0x1 55 56 #define SPI_ENGINE_MISC_SYNC 0x0 57 #define SPI_ENGINE_MISC_SLEEP 0x1 58 59 #define SPI_ENGINE_TRANSFER_WRITE 0x1 60 #define SPI_ENGINE_TRANSFER_READ 0x2 61 62 #define SPI_ENGINE_CMD(inst, arg1, arg2) \ 63 (((inst) << 12) | ((arg1) << 8) | (arg2)) 64 65 #define SPI_ENGINE_CMD_TRANSFER(flags, n) \ 66 SPI_ENGINE_CMD(SPI_ENGINE_INST_TRANSFER, (flags), (n)) 67 #define SPI_ENGINE_CMD_ASSERT(delay, cs) \ 68 SPI_ENGINE_CMD(SPI_ENGINE_INST_ASSERT, (delay), (cs)) 69 #define SPI_ENGINE_CMD_WRITE(reg, val) \ 70 SPI_ENGINE_CMD(SPI_ENGINE_INST_WRITE, (reg), (val)) 71 #define SPI_ENGINE_CMD_SLEEP(delay) \ 72 SPI_ENGINE_CMD(SPI_ENGINE_INST_MISC, SPI_ENGINE_MISC_SLEEP, (delay)) 73 #define SPI_ENGINE_CMD_SYNC(id) \ 74 SPI_ENGINE_CMD(SPI_ENGINE_INST_MISC, SPI_ENGINE_MISC_SYNC, (id)) 75 76 struct spi_engine_program { 77 unsigned int length; 78 uint16_t instructions[]; 79 }; 80 81 struct spi_engine { 82 struct clk *clk; 83 struct clk *ref_clk; 84 85 spinlock_t lock; 86 87 void __iomem *base; 88 89 struct spi_message *msg; 90 struct spi_engine_program *p; 91 unsigned cmd_length; 92 const uint16_t *cmd_buf; 93 94 struct spi_transfer *tx_xfer; 95 unsigned int tx_length; 96 const uint8_t *tx_buf; 97 98 struct spi_transfer *rx_xfer; 99 unsigned int rx_length; 100 uint8_t *rx_buf; 101 102 unsigned int sync_id; 103 unsigned int completed_id; 104 105 unsigned int int_enable; 106 }; 107 108 static void spi_engine_program_add_cmd(struct spi_engine_program *p, 109 bool dry, uint16_t cmd) 110 { 111 if (!dry) 112 p->instructions[p->length] = cmd; 113 p->length++; 114 } 115 116 static unsigned int spi_engine_get_config(struct spi_device *spi) 117 { 118 unsigned int config = 0; 119 120 if (spi->mode & SPI_CPOL) 121 config |= SPI_ENGINE_CONFIG_CPOL; 122 if (spi->mode & SPI_CPHA) 123 config |= SPI_ENGINE_CONFIG_CPHA; 124 if (spi->mode & SPI_3WIRE) 125 config |= SPI_ENGINE_CONFIG_3WIRE; 126 127 return config; 128 } 129 130 static unsigned int spi_engine_get_clk_div(struct spi_engine *spi_engine, 131 struct spi_device *spi, struct spi_transfer *xfer) 132 { 133 unsigned int clk_div; 134 135 clk_div = DIV_ROUND_UP(clk_get_rate(spi_engine->ref_clk), 136 xfer->speed_hz * 2); 137 if (clk_div > 255) 138 clk_div = 255; 139 else if (clk_div > 0) 140 clk_div -= 1; 141 142 return clk_div; 143 } 144 145 static void spi_engine_gen_xfer(struct spi_engine_program *p, bool dry, 146 struct spi_transfer *xfer) 147 { 148 unsigned int len = xfer->len; 149 150 while (len) { 151 unsigned int n = min(len, 256U); 152 unsigned int flags = 0; 153 154 if (xfer->tx_buf) 155 flags |= SPI_ENGINE_TRANSFER_WRITE; 156 if (xfer->rx_buf) 157 flags |= SPI_ENGINE_TRANSFER_READ; 158 159 spi_engine_program_add_cmd(p, dry, 160 SPI_ENGINE_CMD_TRANSFER(flags, n - 1)); 161 len -= n; 162 } 163 } 164 165 static void spi_engine_gen_sleep(struct spi_engine_program *p, bool dry, 166 struct spi_engine *spi_engine, unsigned int clk_div, unsigned int delay) 167 { 168 unsigned int spi_clk = clk_get_rate(spi_engine->ref_clk); 169 unsigned int t; 170 171 if (delay == 0) 172 return; 173 174 t = DIV_ROUND_UP(delay * spi_clk, (clk_div + 1) * 2); 175 while (t) { 176 unsigned int n = min(t, 256U); 177 178 spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_SLEEP(n - 1)); 179 t -= n; 180 } 181 } 182 183 static void spi_engine_gen_cs(struct spi_engine_program *p, bool dry, 184 struct spi_device *spi, bool assert) 185 { 186 unsigned int mask = 0xff; 187 188 if (assert) 189 mask ^= BIT(spi->chip_select); 190 191 spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_ASSERT(1, mask)); 192 } 193 194 static int spi_engine_compile_message(struct spi_engine *spi_engine, 195 struct spi_message *msg, bool dry, struct spi_engine_program *p) 196 { 197 struct spi_device *spi = msg->spi; 198 struct spi_transfer *xfer; 199 int clk_div, new_clk_div; 200 bool cs_change = true; 201 202 clk_div = -1; 203 204 spi_engine_program_add_cmd(p, dry, 205 SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CONFIG, 206 spi_engine_get_config(spi))); 207 208 list_for_each_entry(xfer, &msg->transfers, transfer_list) { 209 new_clk_div = spi_engine_get_clk_div(spi_engine, spi, xfer); 210 if (new_clk_div != clk_div) { 211 clk_div = new_clk_div; 212 spi_engine_program_add_cmd(p, dry, 213 SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CLK_DIV, 214 clk_div)); 215 } 216 217 if (cs_change) 218 spi_engine_gen_cs(p, dry, spi, true); 219 220 spi_engine_gen_xfer(p, dry, xfer); 221 spi_engine_gen_sleep(p, dry, spi_engine, clk_div, 222 xfer->delay_usecs); 223 224 cs_change = xfer->cs_change; 225 if (list_is_last(&xfer->transfer_list, &msg->transfers)) 226 cs_change = !cs_change; 227 228 if (cs_change) 229 spi_engine_gen_cs(p, dry, spi, false); 230 } 231 232 return 0; 233 } 234 235 static void spi_engine_xfer_next(struct spi_engine *spi_engine, 236 struct spi_transfer **_xfer) 237 { 238 struct spi_message *msg = spi_engine->msg; 239 struct spi_transfer *xfer = *_xfer; 240 241 if (!xfer) { 242 xfer = list_first_entry(&msg->transfers, 243 struct spi_transfer, transfer_list); 244 } else if (list_is_last(&xfer->transfer_list, &msg->transfers)) { 245 xfer = NULL; 246 } else { 247 xfer = list_next_entry(xfer, transfer_list); 248 } 249 250 *_xfer = xfer; 251 } 252 253 static void spi_engine_tx_next(struct spi_engine *spi_engine) 254 { 255 struct spi_transfer *xfer = spi_engine->tx_xfer; 256 257 do { 258 spi_engine_xfer_next(spi_engine, &xfer); 259 } while (xfer && !xfer->tx_buf); 260 261 spi_engine->tx_xfer = xfer; 262 if (xfer) { 263 spi_engine->tx_length = xfer->len; 264 spi_engine->tx_buf = xfer->tx_buf; 265 } else { 266 spi_engine->tx_buf = NULL; 267 } 268 } 269 270 static void spi_engine_rx_next(struct spi_engine *spi_engine) 271 { 272 struct spi_transfer *xfer = spi_engine->rx_xfer; 273 274 do { 275 spi_engine_xfer_next(spi_engine, &xfer); 276 } while (xfer && !xfer->rx_buf); 277 278 spi_engine->rx_xfer = xfer; 279 if (xfer) { 280 spi_engine->rx_length = xfer->len; 281 spi_engine->rx_buf = xfer->rx_buf; 282 } else { 283 spi_engine->rx_buf = NULL; 284 } 285 } 286 287 static bool spi_engine_write_cmd_fifo(struct spi_engine *spi_engine) 288 { 289 void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_CMD_FIFO; 290 unsigned int n, m, i; 291 const uint16_t *buf; 292 293 n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_CMD_FIFO_ROOM); 294 while (n && spi_engine->cmd_length) { 295 m = min(n, spi_engine->cmd_length); 296 buf = spi_engine->cmd_buf; 297 for (i = 0; i < m; i++) 298 writel_relaxed(buf[i], addr); 299 spi_engine->cmd_buf += m; 300 spi_engine->cmd_length -= m; 301 n -= m; 302 } 303 304 return spi_engine->cmd_length != 0; 305 } 306 307 static bool spi_engine_write_tx_fifo(struct spi_engine *spi_engine) 308 { 309 void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDO_DATA_FIFO; 310 unsigned int n, m, i; 311 const uint8_t *buf; 312 313 n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDO_FIFO_ROOM); 314 while (n && spi_engine->tx_length) { 315 m = min(n, spi_engine->tx_length); 316 buf = spi_engine->tx_buf; 317 for (i = 0; i < m; i++) 318 writel_relaxed(buf[i], addr); 319 spi_engine->tx_buf += m; 320 spi_engine->tx_length -= m; 321 n -= m; 322 if (spi_engine->tx_length == 0) 323 spi_engine_tx_next(spi_engine); 324 } 325 326 return spi_engine->tx_length != 0; 327 } 328 329 static bool spi_engine_read_rx_fifo(struct spi_engine *spi_engine) 330 { 331 void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDI_DATA_FIFO; 332 unsigned int n, m, i; 333 uint8_t *buf; 334 335 n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDI_FIFO_LEVEL); 336 while (n && spi_engine->rx_length) { 337 m = min(n, spi_engine->rx_length); 338 buf = spi_engine->rx_buf; 339 for (i = 0; i < m; i++) 340 buf[i] = readl_relaxed(addr); 341 spi_engine->rx_buf += m; 342 spi_engine->rx_length -= m; 343 n -= m; 344 if (spi_engine->rx_length == 0) 345 spi_engine_rx_next(spi_engine); 346 } 347 348 return spi_engine->rx_length != 0; 349 } 350 351 static irqreturn_t spi_engine_irq(int irq, void *devid) 352 { 353 struct spi_master *master = devid; 354 struct spi_engine *spi_engine = spi_master_get_devdata(master); 355 unsigned int disable_int = 0; 356 unsigned int pending; 357 358 pending = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_INT_PENDING); 359 360 if (pending & SPI_ENGINE_INT_SYNC) { 361 writel_relaxed(SPI_ENGINE_INT_SYNC, 362 spi_engine->base + SPI_ENGINE_REG_INT_PENDING); 363 spi_engine->completed_id = readl_relaxed( 364 spi_engine->base + SPI_ENGINE_REG_SYNC_ID); 365 } 366 367 spin_lock(&spi_engine->lock); 368 369 if (pending & SPI_ENGINE_INT_CMD_ALMOST_EMPTY) { 370 if (!spi_engine_write_cmd_fifo(spi_engine)) 371 disable_int |= SPI_ENGINE_INT_CMD_ALMOST_EMPTY; 372 } 373 374 if (pending & SPI_ENGINE_INT_SDO_ALMOST_EMPTY) { 375 if (!spi_engine_write_tx_fifo(spi_engine)) 376 disable_int |= SPI_ENGINE_INT_SDO_ALMOST_EMPTY; 377 } 378 379 if (pending & (SPI_ENGINE_INT_SDI_ALMOST_FULL | SPI_ENGINE_INT_SYNC)) { 380 if (!spi_engine_read_rx_fifo(spi_engine)) 381 disable_int |= SPI_ENGINE_INT_SDI_ALMOST_FULL; 382 } 383 384 if (pending & SPI_ENGINE_INT_SYNC) { 385 if (spi_engine->msg && 386 spi_engine->completed_id == spi_engine->sync_id) { 387 struct spi_message *msg = spi_engine->msg; 388 389 kfree(spi_engine->p); 390 msg->status = 0; 391 msg->actual_length = msg->frame_length; 392 spi_engine->msg = NULL; 393 spi_finalize_current_message(master); 394 disable_int |= SPI_ENGINE_INT_SYNC; 395 } 396 } 397 398 if (disable_int) { 399 spi_engine->int_enable &= ~disable_int; 400 writel_relaxed(spi_engine->int_enable, 401 spi_engine->base + SPI_ENGINE_REG_INT_ENABLE); 402 } 403 404 spin_unlock(&spi_engine->lock); 405 406 return IRQ_HANDLED; 407 } 408 409 static int spi_engine_transfer_one_message(struct spi_master *master, 410 struct spi_message *msg) 411 { 412 struct spi_engine_program p_dry, *p; 413 struct spi_engine *spi_engine = spi_master_get_devdata(master); 414 unsigned int int_enable = 0; 415 unsigned long flags; 416 size_t size; 417 418 p_dry.length = 0; 419 spi_engine_compile_message(spi_engine, msg, true, &p_dry); 420 421 size = sizeof(*p->instructions) * (p_dry.length + 1); 422 p = kzalloc(sizeof(*p) + size, GFP_KERNEL); 423 if (!p) 424 return -ENOMEM; 425 spi_engine_compile_message(spi_engine, msg, false, p); 426 427 spin_lock_irqsave(&spi_engine->lock, flags); 428 spi_engine->sync_id = (spi_engine->sync_id + 1) & 0xff; 429 spi_engine_program_add_cmd(p, false, 430 SPI_ENGINE_CMD_SYNC(spi_engine->sync_id)); 431 432 spi_engine->msg = msg; 433 spi_engine->p = p; 434 435 spi_engine->cmd_buf = p->instructions; 436 spi_engine->cmd_length = p->length; 437 if (spi_engine_write_cmd_fifo(spi_engine)) 438 int_enable |= SPI_ENGINE_INT_CMD_ALMOST_EMPTY; 439 440 spi_engine_tx_next(spi_engine); 441 if (spi_engine_write_tx_fifo(spi_engine)) 442 int_enable |= SPI_ENGINE_INT_SDO_ALMOST_EMPTY; 443 444 spi_engine_rx_next(spi_engine); 445 if (spi_engine->rx_length != 0) 446 int_enable |= SPI_ENGINE_INT_SDI_ALMOST_FULL; 447 448 int_enable |= SPI_ENGINE_INT_SYNC; 449 450 writel_relaxed(int_enable, 451 spi_engine->base + SPI_ENGINE_REG_INT_ENABLE); 452 spi_engine->int_enable = int_enable; 453 spin_unlock_irqrestore(&spi_engine->lock, flags); 454 455 return 0; 456 } 457 458 static int spi_engine_probe(struct platform_device *pdev) 459 { 460 struct spi_engine *spi_engine; 461 struct spi_master *master; 462 unsigned int version; 463 int irq; 464 int ret; 465 466 irq = platform_get_irq(pdev, 0); 467 if (irq <= 0) 468 return -ENXIO; 469 470 spi_engine = devm_kzalloc(&pdev->dev, sizeof(*spi_engine), GFP_KERNEL); 471 if (!spi_engine) 472 return -ENOMEM; 473 474 master = spi_alloc_master(&pdev->dev, 0); 475 if (!master) 476 return -ENOMEM; 477 478 spi_master_set_devdata(master, spi_engine); 479 480 spin_lock_init(&spi_engine->lock); 481 482 spi_engine->base = devm_platform_ioremap_resource(pdev, 0); 483 if (IS_ERR(spi_engine->base)) { 484 ret = PTR_ERR(spi_engine->base); 485 goto err_put_master; 486 } 487 488 version = readl(spi_engine->base + SPI_ENGINE_REG_VERSION); 489 if (SPI_ENGINE_VERSION_MAJOR(version) != 1) { 490 dev_err(&pdev->dev, "Unsupported peripheral version %u.%u.%c\n", 491 SPI_ENGINE_VERSION_MAJOR(version), 492 SPI_ENGINE_VERSION_MINOR(version), 493 SPI_ENGINE_VERSION_PATCH(version)); 494 ret = -ENODEV; 495 goto err_put_master; 496 } 497 498 spi_engine->clk = devm_clk_get(&pdev->dev, "s_axi_aclk"); 499 if (IS_ERR(spi_engine->clk)) { 500 ret = PTR_ERR(spi_engine->clk); 501 goto err_put_master; 502 } 503 504 spi_engine->ref_clk = devm_clk_get(&pdev->dev, "spi_clk"); 505 if (IS_ERR(spi_engine->ref_clk)) { 506 ret = PTR_ERR(spi_engine->ref_clk); 507 goto err_put_master; 508 } 509 510 ret = clk_prepare_enable(spi_engine->clk); 511 if (ret) 512 goto err_put_master; 513 514 ret = clk_prepare_enable(spi_engine->ref_clk); 515 if (ret) 516 goto err_clk_disable; 517 518 writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_RESET); 519 writel_relaxed(0xff, spi_engine->base + SPI_ENGINE_REG_INT_PENDING); 520 writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE); 521 522 ret = request_irq(irq, spi_engine_irq, 0, pdev->name, master); 523 if (ret) 524 goto err_ref_clk_disable; 525 526 master->dev.of_node = pdev->dev.of_node; 527 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_3WIRE; 528 master->bits_per_word_mask = SPI_BPW_MASK(8); 529 master->max_speed_hz = clk_get_rate(spi_engine->ref_clk) / 2; 530 master->transfer_one_message = spi_engine_transfer_one_message; 531 master->num_chipselect = 8; 532 533 ret = spi_register_master(master); 534 if (ret) 535 goto err_free_irq; 536 537 platform_set_drvdata(pdev, master); 538 539 return 0; 540 err_free_irq: 541 free_irq(irq, master); 542 err_ref_clk_disable: 543 clk_disable_unprepare(spi_engine->ref_clk); 544 err_clk_disable: 545 clk_disable_unprepare(spi_engine->clk); 546 err_put_master: 547 spi_master_put(master); 548 return ret; 549 } 550 551 static int spi_engine_remove(struct platform_device *pdev) 552 { 553 struct spi_master *master = spi_master_get(platform_get_drvdata(pdev)); 554 struct spi_engine *spi_engine = spi_master_get_devdata(master); 555 int irq = platform_get_irq(pdev, 0); 556 557 spi_unregister_master(master); 558 559 free_irq(irq, master); 560 561 spi_master_put(master); 562 563 writel_relaxed(0xff, spi_engine->base + SPI_ENGINE_REG_INT_PENDING); 564 writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE); 565 writel_relaxed(0x01, spi_engine->base + SPI_ENGINE_REG_RESET); 566 567 clk_disable_unprepare(spi_engine->ref_clk); 568 clk_disable_unprepare(spi_engine->clk); 569 570 return 0; 571 } 572 573 static const struct of_device_id spi_engine_match_table[] = { 574 { .compatible = "adi,axi-spi-engine-1.00.a" }, 575 { }, 576 }; 577 MODULE_DEVICE_TABLE(of, spi_engine_match_table); 578 579 static struct platform_driver spi_engine_driver = { 580 .probe = spi_engine_probe, 581 .remove = spi_engine_remove, 582 .driver = { 583 .name = "spi-engine", 584 .of_match_table = spi_engine_match_table, 585 }, 586 }; 587 module_platform_driver(spi_engine_driver); 588 589 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 590 MODULE_DESCRIPTION("Analog Devices SPI engine peripheral driver"); 591 MODULE_LICENSE("GPL"); 592