1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * Designware SPI core controller driver (refer pxa2xx_spi.c) 4 * 5 * Copyright (c) 2009, Intel Corporation. 6 */ 7 8#include <linux/bitfield.h> 9#include <linux/dma-mapping.h> 10#include <linux/interrupt.h> 11#include <linux/module.h> 12#include <linux/preempt.h> 13#include <linux/highmem.h> 14#include <linux/delay.h> 15#include <linux/slab.h> 16#include <linux/spi/spi.h> 17#include <linux/spi/spi-mem.h> 18#include <linux/string.h> 19#include <linux/of.h> 20 21#include "spi-dw.h" 22 23#ifdef CONFIG_DEBUG_FS 24#include <linux/debugfs.h> 25#endif 26 27/* Slave spi_device related */ 28struct dw_spi_chip_data { 29 u32 cr0; 30 u32 rx_sample_dly; /* RX sample delay */ 31}; 32 33#ifdef CONFIG_DEBUG_FS 34 35#define DW_SPI_DBGFS_REG(_name, _off) \ 36{ \ 37 .name = _name, \ 38 .offset = _off, \ 39} 40 41static const struct debugfs_reg32 dw_spi_dbgfs_regs[] = { 42 DW_SPI_DBGFS_REG("CTRLR0", DW_SPI_CTRLR0), 43 DW_SPI_DBGFS_REG("CTRLR1", DW_SPI_CTRLR1), 44 DW_SPI_DBGFS_REG("SSIENR", DW_SPI_SSIENR), 45 DW_SPI_DBGFS_REG("SER", DW_SPI_SER), 46 DW_SPI_DBGFS_REG("BAUDR", DW_SPI_BAUDR), 47 DW_SPI_DBGFS_REG("TXFTLR", DW_SPI_TXFTLR), 48 DW_SPI_DBGFS_REG("RXFTLR", DW_SPI_RXFTLR), 49 DW_SPI_DBGFS_REG("TXFLR", DW_SPI_TXFLR), 50 DW_SPI_DBGFS_REG("RXFLR", DW_SPI_RXFLR), 51 DW_SPI_DBGFS_REG("SR", DW_SPI_SR), 52 DW_SPI_DBGFS_REG("IMR", DW_SPI_IMR), 53 DW_SPI_DBGFS_REG("ISR", DW_SPI_ISR), 54 DW_SPI_DBGFS_REG("DMACR", DW_SPI_DMACR), 55 DW_SPI_DBGFS_REG("DMATDLR", DW_SPI_DMATDLR), 56 DW_SPI_DBGFS_REG("DMARDLR", DW_SPI_DMARDLR), 57 DW_SPI_DBGFS_REG("RX_SAMPLE_DLY", DW_SPI_RX_SAMPLE_DLY), 58}; 59 60static void dw_spi_debugfs_init(struct dw_spi *dws) 61{ 62 char name[32]; 63 64 snprintf(name, 32, "dw_spi%d", dws->host->bus_num); 65 dws->debugfs = debugfs_create_dir(name, NULL); 66 67 dws->regset.regs = dw_spi_dbgfs_regs; 68 dws->regset.nregs = ARRAY_SIZE(dw_spi_dbgfs_regs); 69 dws->regset.base = dws->regs; 70 debugfs_create_regset32("registers", 0400, dws->debugfs, &dws->regset); 71} 72 73static void dw_spi_debugfs_remove(struct dw_spi *dws) 74{ 75 debugfs_remove_recursive(dws->debugfs); 76} 77 78#else 79static inline void dw_spi_debugfs_init(struct dw_spi *dws) 80{ 81} 82 83static inline void dw_spi_debugfs_remove(struct dw_spi *dws) 84{ 85} 86#endif /* CONFIG_DEBUG_FS */ 87 88void dw_spi_set_cs(struct spi_device *spi, bool enable) 89{ 90 struct dw_spi *dws = spi_controller_get_devdata(spi->controller); 91 bool cs_high = !!(spi->mode & SPI_CS_HIGH); 92 93 /* 94 * DW SPI controller demands any native CS being set in order to 95 * proceed with data transfer. So in order to activate the SPI 96 * communications we must set a corresponding bit in the Slave 97 * Enable register no matter whether the SPI core is configured to 98 * support active-high or active-low CS level. 99 */ 100 if (cs_high == enable) 101 dw_writel(dws, DW_SPI_SER, BIT(spi_get_chipselect(spi, 0))); 102 else 103 dw_writel(dws, DW_SPI_SER, 0); 104} 105EXPORT_SYMBOL_NS_GPL(dw_spi_set_cs, SPI_DW_CORE); 106 107/* Return the max entries we can fill into tx fifo */ 108static inline u32 dw_spi_tx_max(struct dw_spi *dws) 109{ 110 u32 tx_room, rxtx_gap; 111 112 tx_room = dws->fifo_len - dw_readl(dws, DW_SPI_TXFLR); 113 114 /* 115 * Another concern is about the tx/rx mismatch, we 116 * though to use (dws->fifo_len - rxflr - txflr) as 117 * one maximum value for tx, but it doesn't cover the 118 * data which is out of tx/rx fifo and inside the 119 * shift registers. So a control from sw point of 120 * view is taken. 121 */ 122 rxtx_gap = dws->fifo_len - (dws->rx_len - dws->tx_len); 123 124 return min3((u32)dws->tx_len, tx_room, rxtx_gap); 125} 126 127/* Return the max entries we should read out of rx fifo */ 128static inline u32 dw_spi_rx_max(struct dw_spi *dws) 129{ 130 return min_t(u32, dws->rx_len, dw_readl(dws, DW_SPI_RXFLR)); 131} 132 133static void dw_writer(struct dw_spi *dws) 134{ 135 u32 max = dw_spi_tx_max(dws); 136 u32 txw = 0; 137 138 while (max--) { 139 if (dws->tx) { 140 if (dws->n_bytes == 1) 141 txw = *(u8 *)(dws->tx); 142 else if (dws->n_bytes == 2) 143 txw = *(u16 *)(dws->tx); 144 else 145 txw = *(u32 *)(dws->tx); 146 147 dws->tx += dws->n_bytes; 148 } 149 dw_write_io_reg(dws, DW_SPI_DR, txw); 150 --dws->tx_len; 151 } 152} 153 154static void dw_reader(struct dw_spi *dws) 155{ 156 u32 max = dw_spi_rx_max(dws); 157 u32 rxw; 158 159 while (max--) { 160 rxw = dw_read_io_reg(dws, DW_SPI_DR); 161 if (dws->rx) { 162 if (dws->n_bytes == 1) 163 *(u8 *)(dws->rx) = rxw; 164 else if (dws->n_bytes == 2) 165 *(u16 *)(dws->rx) = rxw; 166 else 167 *(u32 *)(dws->rx) = rxw; 168 169 dws->rx += dws->n_bytes; 170 } 171 --dws->rx_len; 172 } 173} 174 175int dw_spi_check_status(struct dw_spi *dws, bool raw) 176{ 177 u32 irq_status; 178 int ret = 0; 179 180 if (raw) 181 irq_status = dw_readl(dws, DW_SPI_RISR); 182 else 183 irq_status = dw_readl(dws, DW_SPI_ISR); 184 185 if (irq_status & DW_SPI_INT_RXOI) { 186 dev_err(&dws->host->dev, "RX FIFO overflow detected\n"); 187 ret = -EIO; 188 } 189 190 if (irq_status & DW_SPI_INT_RXUI) { 191 dev_err(&dws->host->dev, "RX FIFO underflow detected\n"); 192 ret = -EIO; 193 } 194 195 if (irq_status & DW_SPI_INT_TXOI) { 196 dev_err(&dws->host->dev, "TX FIFO overflow detected\n"); 197 ret = -EIO; 198 } 199 200 /* Generically handle the erroneous situation */ 201 if (ret) { 202 dw_spi_reset_chip(dws); 203 if (dws->host->cur_msg) 204 dws->host->cur_msg->status = ret; 205 } 206 207 return ret; 208} 209EXPORT_SYMBOL_NS_GPL(dw_spi_check_status, SPI_DW_CORE); 210 211static irqreturn_t dw_spi_transfer_handler(struct dw_spi *dws) 212{ 213 u16 irq_status = dw_readl(dws, DW_SPI_ISR); 214 215 if (dw_spi_check_status(dws, false)) { 216 spi_finalize_current_transfer(dws->host); 217 return IRQ_HANDLED; 218 } 219 220 /* 221 * Read data from the Rx FIFO every time we've got a chance executing 222 * this method. If there is nothing left to receive, terminate the 223 * procedure. Otherwise adjust the Rx FIFO Threshold level if it's a 224 * final stage of the transfer. By doing so we'll get the next IRQ 225 * right when the leftover incoming data is received. 226 */ 227 dw_reader(dws); 228 if (!dws->rx_len) { 229 dw_spi_mask_intr(dws, 0xff); 230 spi_finalize_current_transfer(dws->host); 231 } else if (dws->rx_len <= dw_readl(dws, DW_SPI_RXFTLR)) { 232 dw_writel(dws, DW_SPI_RXFTLR, dws->rx_len - 1); 233 } 234 235 /* 236 * Send data out if Tx FIFO Empty IRQ is received. The IRQ will be 237 * disabled after the data transmission is finished so not to 238 * have the TXE IRQ flood at the final stage of the transfer. 239 */ 240 if (irq_status & DW_SPI_INT_TXEI) { 241 dw_writer(dws); 242 if (!dws->tx_len) 243 dw_spi_mask_intr(dws, DW_SPI_INT_TXEI); 244 } 245 246 return IRQ_HANDLED; 247} 248 249static irqreturn_t dw_spi_irq(int irq, void *dev_id) 250{ 251 struct spi_controller *host = dev_id; 252 struct dw_spi *dws = spi_controller_get_devdata(host); 253 u16 irq_status = dw_readl(dws, DW_SPI_ISR) & DW_SPI_INT_MASK; 254 255 if (!irq_status) 256 return IRQ_NONE; 257 258 if (!host->cur_msg) { 259 dw_spi_mask_intr(dws, 0xff); 260 return IRQ_HANDLED; 261 } 262 263 return dws->transfer_handler(dws); 264} 265 266static u32 dw_spi_prepare_cr0(struct dw_spi *dws, struct spi_device *spi) 267{ 268 u32 cr0 = 0; 269 270 if (dw_spi_ip_is(dws, PSSI)) { 271 /* CTRLR0[ 5: 4] Frame Format */ 272 cr0 |= FIELD_PREP(DW_PSSI_CTRLR0_FRF_MASK, DW_SPI_CTRLR0_FRF_MOTO_SPI); 273 274 /* 275 * SPI mode (SCPOL|SCPH) 276 * CTRLR0[ 6] Serial Clock Phase 277 * CTRLR0[ 7] Serial Clock Polarity 278 */ 279 if (spi->mode & SPI_CPOL) 280 cr0 |= DW_PSSI_CTRLR0_SCPOL; 281 if (spi->mode & SPI_CPHA) 282 cr0 |= DW_PSSI_CTRLR0_SCPHA; 283 284 /* CTRLR0[11] Shift Register Loop */ 285 if (spi->mode & SPI_LOOP) 286 cr0 |= DW_PSSI_CTRLR0_SRL; 287 } else { 288 /* CTRLR0[ 7: 6] Frame Format */ 289 cr0 |= FIELD_PREP(DW_HSSI_CTRLR0_FRF_MASK, DW_SPI_CTRLR0_FRF_MOTO_SPI); 290 291 /* 292 * SPI mode (SCPOL|SCPH) 293 * CTRLR0[ 8] Serial Clock Phase 294 * CTRLR0[ 9] Serial Clock Polarity 295 */ 296 if (spi->mode & SPI_CPOL) 297 cr0 |= DW_HSSI_CTRLR0_SCPOL; 298 if (spi->mode & SPI_CPHA) 299 cr0 |= DW_HSSI_CTRLR0_SCPHA; 300 301 /* CTRLR0[13] Shift Register Loop */ 302 if (spi->mode & SPI_LOOP) 303 cr0 |= DW_HSSI_CTRLR0_SRL; 304 305 /* CTRLR0[31] MST */ 306 if (dw_spi_ver_is_ge(dws, HSSI, 102A)) 307 cr0 |= DW_HSSI_CTRLR0_MST; 308 } 309 310 return cr0; 311} 312 313void dw_spi_update_config(struct dw_spi *dws, struct spi_device *spi, 314 struct dw_spi_cfg *cfg) 315{ 316 struct dw_spi_chip_data *chip = spi_get_ctldata(spi); 317 u32 cr0 = chip->cr0; 318 u32 speed_hz; 319 u16 clk_div; 320 321 /* CTRLR0[ 4/3: 0] or CTRLR0[ 20: 16] Data Frame Size */ 322 cr0 |= (cfg->dfs - 1) << dws->dfs_offset; 323 324 if (dw_spi_ip_is(dws, PSSI)) 325 /* CTRLR0[ 9:8] Transfer Mode */ 326 cr0 |= FIELD_PREP(DW_PSSI_CTRLR0_TMOD_MASK, cfg->tmode); 327 else 328 /* CTRLR0[11:10] Transfer Mode */ 329 cr0 |= FIELD_PREP(DW_HSSI_CTRLR0_TMOD_MASK, cfg->tmode); 330 331 dw_writel(dws, DW_SPI_CTRLR0, cr0); 332 333 if (cfg->tmode == DW_SPI_CTRLR0_TMOD_EPROMREAD || 334 cfg->tmode == DW_SPI_CTRLR0_TMOD_RO) 335 dw_writel(dws, DW_SPI_CTRLR1, cfg->ndf ? cfg->ndf - 1 : 0); 336 337 /* Note DW APB SSI clock divider doesn't support odd numbers */ 338 clk_div = (DIV_ROUND_UP(dws->max_freq, cfg->freq) + 1) & 0xfffe; 339 speed_hz = dws->max_freq / clk_div; 340 341 if (dws->current_freq != speed_hz) { 342 dw_spi_set_clk(dws, clk_div); 343 dws->current_freq = speed_hz; 344 } 345 346 /* Update RX sample delay if required */ 347 if (dws->cur_rx_sample_dly != chip->rx_sample_dly) { 348 dw_writel(dws, DW_SPI_RX_SAMPLE_DLY, chip->rx_sample_dly); 349 dws->cur_rx_sample_dly = chip->rx_sample_dly; 350 } 351} 352EXPORT_SYMBOL_NS_GPL(dw_spi_update_config, SPI_DW_CORE); 353 354static void dw_spi_irq_setup(struct dw_spi *dws) 355{ 356 u16 level; 357 u8 imask; 358 359 /* 360 * Originally Tx and Rx data lengths match. Rx FIFO Threshold level 361 * will be adjusted at the final stage of the IRQ-based SPI transfer 362 * execution so not to lose the leftover of the incoming data. 363 */ 364 level = min_t(unsigned int, dws->fifo_len / 2, dws->tx_len); 365 dw_writel(dws, DW_SPI_TXFTLR, level); 366 dw_writel(dws, DW_SPI_RXFTLR, level - 1); 367 368 dws->transfer_handler = dw_spi_transfer_handler; 369 370 imask = DW_SPI_INT_TXEI | DW_SPI_INT_TXOI | 371 DW_SPI_INT_RXUI | DW_SPI_INT_RXOI | DW_SPI_INT_RXFI; 372 dw_spi_umask_intr(dws, imask); 373} 374 375/* 376 * The iterative procedure of the poll-based transfer is simple: write as much 377 * as possible to the Tx FIFO, wait until the pending to receive data is ready 378 * to be read, read it from the Rx FIFO and check whether the performed 379 * procedure has been successful. 380 * 381 * Note this method the same way as the IRQ-based transfer won't work well for 382 * the SPI devices connected to the controller with native CS due to the 383 * automatic CS assertion/de-assertion. 384 */ 385static int dw_spi_poll_transfer(struct dw_spi *dws, 386 struct spi_transfer *transfer) 387{ 388 struct spi_delay delay; 389 u16 nbits; 390 int ret; 391 392 delay.unit = SPI_DELAY_UNIT_SCK; 393 nbits = dws->n_bytes * BITS_PER_BYTE; 394 395 do { 396 dw_writer(dws); 397 398 delay.value = nbits * (dws->rx_len - dws->tx_len); 399 spi_delay_exec(&delay, transfer); 400 401 dw_reader(dws); 402 403 ret = dw_spi_check_status(dws, true); 404 if (ret) 405 return ret; 406 } while (dws->rx_len); 407 408 return 0; 409} 410 411static int dw_spi_transfer_one(struct spi_controller *host, 412 struct spi_device *spi, 413 struct spi_transfer *transfer) 414{ 415 struct dw_spi *dws = spi_controller_get_devdata(host); 416 struct dw_spi_cfg cfg = { 417 .tmode = DW_SPI_CTRLR0_TMOD_TR, 418 .dfs = transfer->bits_per_word, 419 .freq = transfer->speed_hz, 420 }; 421 int ret; 422 423 dws->dma_mapped = 0; 424 dws->n_bytes = 425 roundup_pow_of_two(DIV_ROUND_UP(transfer->bits_per_word, 426 BITS_PER_BYTE)); 427 428 dws->tx = (void *)transfer->tx_buf; 429 dws->tx_len = transfer->len / dws->n_bytes; 430 dws->rx = transfer->rx_buf; 431 dws->rx_len = dws->tx_len; 432 433 /* Ensure the data above is visible for all CPUs */ 434 smp_mb(); 435 436 dw_spi_enable_chip(dws, 0); 437 438 dw_spi_update_config(dws, spi, &cfg); 439 440 transfer->effective_speed_hz = dws->current_freq; 441 442 /* Check if current transfer is a DMA transaction */ 443 if (host->can_dma && host->can_dma(host, spi, transfer)) 444 dws->dma_mapped = host->cur_msg_mapped; 445 446 /* For poll mode just disable all interrupts */ 447 dw_spi_mask_intr(dws, 0xff); 448 449 if (dws->dma_mapped) { 450 ret = dws->dma_ops->dma_setup(dws, transfer); 451 if (ret) 452 return ret; 453 } 454 455 dw_spi_enable_chip(dws, 1); 456 457 if (dws->dma_mapped) 458 return dws->dma_ops->dma_transfer(dws, transfer); 459 else if (dws->irq == IRQ_NOTCONNECTED) 460 return dw_spi_poll_transfer(dws, transfer); 461 462 dw_spi_irq_setup(dws); 463 464 return 1; 465} 466 467static void dw_spi_handle_err(struct spi_controller *host, 468 struct spi_message *msg) 469{ 470 struct dw_spi *dws = spi_controller_get_devdata(host); 471 472 if (dws->dma_mapped) 473 dws->dma_ops->dma_stop(dws); 474 475 dw_spi_reset_chip(dws); 476} 477 478static int dw_spi_adjust_mem_op_size(struct spi_mem *mem, struct spi_mem_op *op) 479{ 480 if (op->data.dir == SPI_MEM_DATA_IN) 481 op->data.nbytes = clamp_val(op->data.nbytes, 0, DW_SPI_NDF_MASK + 1); 482 483 return 0; 484} 485 486static bool dw_spi_supports_mem_op(struct spi_mem *mem, 487 const struct spi_mem_op *op) 488{ 489 if (op->data.buswidth > 1 || op->addr.buswidth > 1 || 490 op->dummy.buswidth > 1 || op->cmd.buswidth > 1) 491 return false; 492 493 return spi_mem_default_supports_op(mem, op); 494} 495 496static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op) 497{ 498 unsigned int i, j, len; 499 u8 *out; 500 501 /* 502 * Calculate the total length of the EEPROM command transfer and 503 * either use the pre-allocated buffer or create a temporary one. 504 */ 505 len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes; 506 if (op->data.dir == SPI_MEM_DATA_OUT) 507 len += op->data.nbytes; 508 509 if (len <= DW_SPI_BUF_SIZE) { 510 out = dws->buf; 511 } else { 512 out = kzalloc(len, GFP_KERNEL); 513 if (!out) 514 return -ENOMEM; 515 } 516 517 /* 518 * Collect the operation code, address and dummy bytes into the single 519 * buffer. If it's a transfer with data to be sent, also copy it into the 520 * single buffer in order to speed the data transmission up. 521 */ 522 for (i = 0; i < op->cmd.nbytes; ++i) 523 out[i] = DW_SPI_GET_BYTE(op->cmd.opcode, op->cmd.nbytes - i - 1); 524 for (j = 0; j < op->addr.nbytes; ++i, ++j) 525 out[i] = DW_SPI_GET_BYTE(op->addr.val, op->addr.nbytes - j - 1); 526 for (j = 0; j < op->dummy.nbytes; ++i, ++j) 527 out[i] = 0x0; 528 529 if (op->data.dir == SPI_MEM_DATA_OUT) 530 memcpy(&out[i], op->data.buf.out, op->data.nbytes); 531 532 dws->n_bytes = 1; 533 dws->tx = out; 534 dws->tx_len = len; 535 if (op->data.dir == SPI_MEM_DATA_IN) { 536 dws->rx = op->data.buf.in; 537 dws->rx_len = op->data.nbytes; 538 } else { 539 dws->rx = NULL; 540 dws->rx_len = 0; 541 } 542 543 return 0; 544} 545 546static void dw_spi_free_mem_buf(struct dw_spi *dws) 547{ 548 if (dws->tx != dws->buf) 549 kfree(dws->tx); 550} 551 552static int dw_spi_write_then_read(struct dw_spi *dws, struct spi_device *spi) 553{ 554 u32 room, entries, sts; 555 unsigned int len; 556 u8 *buf; 557 558 /* 559 * At initial stage we just pre-fill the Tx FIFO in with no rush, 560 * since native CS hasn't been enabled yet and the automatic data 561 * transmission won't start til we do that. 562 */ 563 len = min(dws->fifo_len, dws->tx_len); 564 buf = dws->tx; 565 while (len--) 566 dw_write_io_reg(dws, DW_SPI_DR, *buf++); 567 568 /* 569 * After setting any bit in the SER register the transmission will 570 * start automatically. We have to keep up with that procedure 571 * otherwise the CS de-assertion will happen whereupon the memory 572 * operation will be pre-terminated. 573 */ 574 len = dws->tx_len - ((void *)buf - dws->tx); 575 dw_spi_set_cs(spi, false); 576 while (len) { 577 entries = readl_relaxed(dws->regs + DW_SPI_TXFLR); 578 if (!entries) { 579 dev_err(&dws->host->dev, "CS de-assertion on Tx\n"); 580 return -EIO; 581 } 582 room = min(dws->fifo_len - entries, len); 583 for (; room; --room, --len) 584 dw_write_io_reg(dws, DW_SPI_DR, *buf++); 585 } 586 587 /* 588 * Data fetching will start automatically if the EEPROM-read mode is 589 * activated. We have to keep up with the incoming data pace to 590 * prevent the Rx FIFO overflow causing the inbound data loss. 591 */ 592 len = dws->rx_len; 593 buf = dws->rx; 594 while (len) { 595 entries = readl_relaxed(dws->regs + DW_SPI_RXFLR); 596 if (!entries) { 597 sts = readl_relaxed(dws->regs + DW_SPI_RISR); 598 if (sts & DW_SPI_INT_RXOI) { 599 dev_err(&dws->host->dev, "FIFO overflow on Rx\n"); 600 return -EIO; 601 } 602 continue; 603 } 604 entries = min(entries, len); 605 for (; entries; --entries, --len) 606 *buf++ = dw_read_io_reg(dws, DW_SPI_DR); 607 } 608 609 return 0; 610} 611 612static inline bool dw_spi_ctlr_busy(struct dw_spi *dws) 613{ 614 return dw_readl(dws, DW_SPI_SR) & DW_SPI_SR_BUSY; 615} 616 617static int dw_spi_wait_mem_op_done(struct dw_spi *dws) 618{ 619 int retry = DW_SPI_WAIT_RETRIES; 620 struct spi_delay delay; 621 unsigned long ns, us; 622 u32 nents; 623 624 nents = dw_readl(dws, DW_SPI_TXFLR); 625 ns = NSEC_PER_SEC / dws->current_freq * nents; 626 ns *= dws->n_bytes * BITS_PER_BYTE; 627 if (ns <= NSEC_PER_USEC) { 628 delay.unit = SPI_DELAY_UNIT_NSECS; 629 delay.value = ns; 630 } else { 631 us = DIV_ROUND_UP(ns, NSEC_PER_USEC); 632 delay.unit = SPI_DELAY_UNIT_USECS; 633 delay.value = clamp_val(us, 0, USHRT_MAX); 634 } 635 636 while (dw_spi_ctlr_busy(dws) && retry--) 637 spi_delay_exec(&delay, NULL); 638 639 if (retry < 0) { 640 dev_err(&dws->host->dev, "Mem op hanged up\n"); 641 return -EIO; 642 } 643 644 return 0; 645} 646 647static void dw_spi_stop_mem_op(struct dw_spi *dws, struct spi_device *spi) 648{ 649 dw_spi_enable_chip(dws, 0); 650 dw_spi_set_cs(spi, true); 651 dw_spi_enable_chip(dws, 1); 652} 653 654/* 655 * The SPI memory operation implementation below is the best choice for the 656 * devices, which are selected by the native chip-select lane. It's 657 * specifically developed to workaround the problem with automatic chip-select 658 * lane toggle when there is no data in the Tx FIFO buffer. Luckily the current 659 * SPI-mem core calls exec_op() callback only if the GPIO-based CS is 660 * unavailable. 661 */ 662static int dw_spi_exec_mem_op(struct spi_mem *mem, const struct spi_mem_op *op) 663{ 664 struct dw_spi *dws = spi_controller_get_devdata(mem->spi->controller); 665 struct dw_spi_cfg cfg; 666 unsigned long flags; 667 int ret; 668 669 /* 670 * Collect the outbound data into a single buffer to speed the 671 * transmission up at least on the initial stage. 672 */ 673 ret = dw_spi_init_mem_buf(dws, op); 674 if (ret) 675 return ret; 676 677 /* 678 * DW SPI EEPROM-read mode is required only for the SPI memory Data-IN 679 * operation. Transmit-only mode is suitable for the rest of them. 680 */ 681 cfg.dfs = 8; 682 cfg.freq = clamp(mem->spi->max_speed_hz, 0U, dws->max_mem_freq); 683 if (op->data.dir == SPI_MEM_DATA_IN) { 684 cfg.tmode = DW_SPI_CTRLR0_TMOD_EPROMREAD; 685 cfg.ndf = op->data.nbytes; 686 } else { 687 cfg.tmode = DW_SPI_CTRLR0_TMOD_TO; 688 } 689 690 dw_spi_enable_chip(dws, 0); 691 692 dw_spi_update_config(dws, mem->spi, &cfg); 693 694 dw_spi_mask_intr(dws, 0xff); 695 696 dw_spi_enable_chip(dws, 1); 697 698 /* 699 * DW APB SSI controller has very nasty peculiarities. First originally 700 * (without any vendor-specific modifications) it doesn't provide a 701 * direct way to set and clear the native chip-select signal. Instead 702 * the controller asserts the CS lane if Tx FIFO isn't empty and a 703 * transmission is going on, and automatically de-asserts it back to 704 * the high level if the Tx FIFO doesn't have anything to be pushed 705 * out. Due to that a multi-tasking or heavy IRQs activity might be 706 * fatal, since the transfer procedure preemption may cause the Tx FIFO 707 * getting empty and sudden CS de-assertion, which in the middle of the 708 * transfer will most likely cause the data loss. Secondly the 709 * EEPROM-read or Read-only DW SPI transfer modes imply the incoming 710 * data being automatically pulled in into the Rx FIFO. So if the 711 * driver software is late in fetching the data from the FIFO before 712 * it's overflown, new incoming data will be lost. In order to make 713 * sure the executed memory operations are CS-atomic and to prevent the 714 * Rx FIFO overflow we have to disable the local interrupts so to block 715 * any preemption during the subsequent IO operations. 716 * 717 * Note. At some circumstances disabling IRQs may not help to prevent 718 * the problems described above. The CS de-assertion and Rx FIFO 719 * overflow may still happen due to the relatively slow system bus or 720 * CPU not working fast enough, so the write-then-read algo implemented 721 * here just won't keep up with the SPI bus data transfer. Such 722 * situation is highly platform specific and is supposed to be fixed by 723 * manually restricting the SPI bus frequency using the 724 * dws->max_mem_freq parameter. 725 */ 726 local_irq_save(flags); 727 preempt_disable(); 728 729 ret = dw_spi_write_then_read(dws, mem->spi); 730 731 local_irq_restore(flags); 732 preempt_enable(); 733 734 /* 735 * Wait for the operation being finished and check the controller 736 * status only if there hasn't been any run-time error detected. In the 737 * former case it's just pointless. In the later one to prevent an 738 * additional error message printing since any hw error flag being set 739 * would be due to an error detected on the data transfer. 740 */ 741 if (!ret) { 742 ret = dw_spi_wait_mem_op_done(dws); 743 if (!ret) 744 ret = dw_spi_check_status(dws, true); 745 } 746 747 dw_spi_stop_mem_op(dws, mem->spi); 748 749 dw_spi_free_mem_buf(dws); 750 751 return ret; 752} 753 754/* 755 * Initialize the default memory operations if a glue layer hasn't specified 756 * custom ones. Direct mapping operations will be preserved anyway since DW SPI 757 * controller doesn't have an embedded dirmap interface. Note the memory 758 * operations implemented in this driver is the best choice only for the DW APB 759 * SSI controller with standard native CS functionality. If a hardware vendor 760 * has fixed the automatic CS assertion/de-assertion peculiarity, then it will 761 * be safer to use the normal SPI-messages-based transfers implementation. 762 */ 763static void dw_spi_init_mem_ops(struct dw_spi *dws) 764{ 765 if (!dws->mem_ops.exec_op && !(dws->caps & DW_SPI_CAP_CS_OVERRIDE) && 766 !dws->set_cs) { 767 dws->mem_ops.adjust_op_size = dw_spi_adjust_mem_op_size; 768 dws->mem_ops.supports_op = dw_spi_supports_mem_op; 769 dws->mem_ops.exec_op = dw_spi_exec_mem_op; 770 if (!dws->max_mem_freq) 771 dws->max_mem_freq = dws->max_freq; 772 } 773} 774 775/* This may be called twice for each spi dev */ 776static int dw_spi_setup(struct spi_device *spi) 777{ 778 struct dw_spi *dws = spi_controller_get_devdata(spi->controller); 779 struct dw_spi_chip_data *chip; 780 781 /* Only alloc on first setup */ 782 chip = spi_get_ctldata(spi); 783 if (!chip) { 784 struct dw_spi *dws = spi_controller_get_devdata(spi->controller); 785 u32 rx_sample_dly_ns; 786 787 chip = kzalloc(sizeof(*chip), GFP_KERNEL); 788 if (!chip) 789 return -ENOMEM; 790 spi_set_ctldata(spi, chip); 791 /* Get specific / default rx-sample-delay */ 792 if (device_property_read_u32(&spi->dev, 793 "rx-sample-delay-ns", 794 &rx_sample_dly_ns) != 0) 795 /* Use default controller value */ 796 rx_sample_dly_ns = dws->def_rx_sample_dly_ns; 797 chip->rx_sample_dly = DIV_ROUND_CLOSEST(rx_sample_dly_ns, 798 NSEC_PER_SEC / 799 dws->max_freq); 800 } 801 802 /* 803 * Update CR0 data each time the setup callback is invoked since 804 * the device parameters could have been changed, for instance, by 805 * the MMC SPI driver or something else. 806 */ 807 chip->cr0 = dw_spi_prepare_cr0(dws, spi); 808 809 return 0; 810} 811 812static void dw_spi_cleanup(struct spi_device *spi) 813{ 814 struct dw_spi_chip_data *chip = spi_get_ctldata(spi); 815 816 kfree(chip); 817 spi_set_ctldata(spi, NULL); 818} 819 820/* Restart the controller, disable all interrupts, clean rx fifo */ 821static void dw_spi_hw_init(struct device *dev, struct dw_spi *dws) 822{ 823 dw_spi_reset_chip(dws); 824 825 /* 826 * Retrieve the Synopsys component version if it hasn't been specified 827 * by the platform. CoreKit version ID is encoded as a 3-chars ASCII 828 * code enclosed with '*' (typical for the most of Synopsys IP-cores). 829 */ 830 if (!dws->ver) { 831 dws->ver = dw_readl(dws, DW_SPI_VERSION); 832 833 dev_dbg(dev, "Synopsys DWC%sSSI v%c.%c%c\n", 834 dw_spi_ip_is(dws, PSSI) ? " APB " : " ", 835 DW_SPI_GET_BYTE(dws->ver, 3), DW_SPI_GET_BYTE(dws->ver, 2), 836 DW_SPI_GET_BYTE(dws->ver, 1)); 837 } 838 839 /* 840 * Try to detect the FIFO depth if not set by interface driver, 841 * the depth could be from 2 to 256 from HW spec 842 */ 843 if (!dws->fifo_len) { 844 u32 fifo; 845 846 for (fifo = 1; fifo < 256; fifo++) { 847 dw_writel(dws, DW_SPI_TXFTLR, fifo); 848 if (fifo != dw_readl(dws, DW_SPI_TXFTLR)) 849 break; 850 } 851 dw_writel(dws, DW_SPI_TXFTLR, 0); 852 853 dws->fifo_len = (fifo == 1) ? 0 : fifo; 854 dev_dbg(dev, "Detected FIFO size: %u bytes\n", dws->fifo_len); 855 } 856 857 /* 858 * Detect CTRLR0.DFS field size and offset by testing the lowest bits 859 * writability. Note DWC SSI controller also has the extended DFS, but 860 * with zero offset. 861 */ 862 if (dw_spi_ip_is(dws, PSSI)) { 863 u32 cr0, tmp = dw_readl(dws, DW_SPI_CTRLR0); 864 865 dw_spi_enable_chip(dws, 0); 866 dw_writel(dws, DW_SPI_CTRLR0, 0xffffffff); 867 cr0 = dw_readl(dws, DW_SPI_CTRLR0); 868 dw_writel(dws, DW_SPI_CTRLR0, tmp); 869 dw_spi_enable_chip(dws, 1); 870 871 if (!(cr0 & DW_PSSI_CTRLR0_DFS_MASK)) { 872 dws->caps |= DW_SPI_CAP_DFS32; 873 dws->dfs_offset = __bf_shf(DW_PSSI_CTRLR0_DFS32_MASK); 874 dev_dbg(dev, "Detected 32-bits max data frame size\n"); 875 } 876 } else { 877 dws->caps |= DW_SPI_CAP_DFS32; 878 } 879 880 /* enable HW fixup for explicit CS deselect for Amazon's alpine chip */ 881 if (dws->caps & DW_SPI_CAP_CS_OVERRIDE) 882 dw_writel(dws, DW_SPI_CS_OVERRIDE, 0xF); 883} 884 885int dw_spi_add_host(struct device *dev, struct dw_spi *dws) 886{ 887 struct spi_controller *host; 888 int ret; 889 890 if (!dws) 891 return -EINVAL; 892 893 host = spi_alloc_host(dev, 0); 894 if (!host) 895 return -ENOMEM; 896 897 device_set_node(&host->dev, dev_fwnode(dev)); 898 899 dws->host = host; 900 dws->dma_addr = (dma_addr_t)(dws->paddr + DW_SPI_DR); 901 902 spi_controller_set_devdata(host, dws); 903 904 /* Basic HW init */ 905 dw_spi_hw_init(dev, dws); 906 907 ret = request_irq(dws->irq, dw_spi_irq, IRQF_SHARED, dev_name(dev), 908 host); 909 if (ret < 0 && ret != -ENOTCONN) { 910 dev_err(dev, "can not get IRQ\n"); 911 goto err_free_host; 912 } 913 914 dw_spi_init_mem_ops(dws); 915 916 host->use_gpio_descriptors = true; 917 host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP; 918 if (dws->caps & DW_SPI_CAP_DFS32) 919 host->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32); 920 else 921 host->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16); 922 host->bus_num = dws->bus_num; 923 host->num_chipselect = dws->num_cs; 924 host->setup = dw_spi_setup; 925 host->cleanup = dw_spi_cleanup; 926 if (dws->set_cs) 927 host->set_cs = dws->set_cs; 928 else 929 host->set_cs = dw_spi_set_cs; 930 host->transfer_one = dw_spi_transfer_one; 931 host->handle_err = dw_spi_handle_err; 932 if (dws->mem_ops.exec_op) 933 host->mem_ops = &dws->mem_ops; 934 host->max_speed_hz = dws->max_freq; 935 host->flags = SPI_CONTROLLER_GPIO_SS; 936 host->auto_runtime_pm = true; 937 938 /* Get default rx sample delay */ 939 device_property_read_u32(dev, "rx-sample-delay-ns", 940 &dws->def_rx_sample_dly_ns); 941 942 if (dws->dma_ops && dws->dma_ops->dma_init) { 943 ret = dws->dma_ops->dma_init(dev, dws); 944 if (ret == -EPROBE_DEFER) { 945 goto err_free_irq; 946 } else if (ret) { 947 dev_warn(dev, "DMA init failed\n"); 948 } else { 949 host->can_dma = dws->dma_ops->can_dma; 950 host->flags |= SPI_CONTROLLER_MUST_TX; 951 } 952 } 953 954 ret = spi_register_controller(host); 955 if (ret) { 956 dev_err_probe(dev, ret, "problem registering spi host\n"); 957 goto err_dma_exit; 958 } 959 960 dw_spi_debugfs_init(dws); 961 return 0; 962 963err_dma_exit: 964 if (dws->dma_ops && dws->dma_ops->dma_exit) 965 dws->dma_ops->dma_exit(dws); 966 dw_spi_enable_chip(dws, 0); 967err_free_irq: 968 free_irq(dws->irq, host); 969err_free_host: 970 spi_controller_put(host); 971 return ret; 972} 973EXPORT_SYMBOL_NS_GPL(dw_spi_add_host, SPI_DW_CORE); 974 975void dw_spi_remove_host(struct dw_spi *dws) 976{ 977 dw_spi_debugfs_remove(dws); 978 979 spi_unregister_controller(dws->host); 980 981 if (dws->dma_ops && dws->dma_ops->dma_exit) 982 dws->dma_ops->dma_exit(dws); 983 984 dw_spi_shutdown_chip(dws); 985 986 free_irq(dws->irq, dws->host); 987} 988EXPORT_SYMBOL_NS_GPL(dw_spi_remove_host, SPI_DW_CORE); 989 990int dw_spi_suspend_host(struct dw_spi *dws) 991{ 992 int ret; 993 994 ret = spi_controller_suspend(dws->host); 995 if (ret) 996 return ret; 997 998 dw_spi_shutdown_chip(dws); 999 return 0; 1000} 1001EXPORT_SYMBOL_NS_GPL(dw_spi_suspend_host, SPI_DW_CORE); 1002 1003int dw_spi_resume_host(struct dw_spi *dws) 1004{ 1005 dw_spi_hw_init(&dws->host->dev, dws); 1006 return spi_controller_resume(dws->host); 1007} 1008EXPORT_SYMBOL_NS_GPL(dw_spi_resume_host, SPI_DW_CORE); 1009 1010MODULE_AUTHOR("Feng Tang <feng.tang@intel.com>"); 1011MODULE_DESCRIPTION("Driver for DesignWare SPI controller core"); 1012MODULE_LICENSE("GPL v2"); 1013