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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 int dw_spi_debugfs_init(struct dw_spi *dws)
61{
62 char name[32];
63
64 snprintf(name, 32, "dw_spi%d", dws->master->bus_num);
65 dws->debugfs = debugfs_create_dir(name, NULL);
66 if (!dws->debugfs)
67 return -ENOMEM;
68
69 dws->regset.regs = dw_spi_dbgfs_regs;
70 dws->regset.nregs = ARRAY_SIZE(dw_spi_dbgfs_regs);
71 dws->regset.base = dws->regs;
72 debugfs_create_regset32("registers", 0400, dws->debugfs, &dws->regset);
73
74 return 0;
75}
76
77static void dw_spi_debugfs_remove(struct dw_spi *dws)
78{
79 debugfs_remove_recursive(dws->debugfs);
80}
81
82#else
83static inline int dw_spi_debugfs_init(struct dw_spi *dws)
84{
85 return 0;
86}
87
88static inline void dw_spi_debugfs_remove(struct dw_spi *dws)
89{
90}
91#endif /* CONFIG_DEBUG_FS */
92
93void dw_spi_set_cs(struct spi_device *spi, bool enable)
94{
95 struct dw_spi *dws = spi_controller_get_devdata(spi->controller);
96 bool cs_high = !!(spi->mode & SPI_CS_HIGH);
97
98 /*
99 * DW SPI controller demands any native CS being set in order to
100 * proceed with data transfer. So in order to activate the SPI
101 * communications we must set a corresponding bit in the Slave
102 * Enable register no matter whether the SPI core is configured to
103 * support active-high or active-low CS level.
104 */
105 if (cs_high == enable)
106 dw_writel(dws, DW_SPI_SER, BIT(spi->chip_select));
107 else
108 dw_writel(dws, DW_SPI_SER, 0);
109}
110EXPORT_SYMBOL_NS_GPL(dw_spi_set_cs, SPI_DW_CORE);
111
112/* Return the max entries we can fill into tx fifo */
113static inline u32 dw_spi_tx_max(struct dw_spi *dws)
114{
115 u32 tx_room, rxtx_gap;
116
117 tx_room = dws->fifo_len - dw_readl(dws, DW_SPI_TXFLR);
118
119 /*
120 * Another concern is about the tx/rx mismatch, we
121 * though to use (dws->fifo_len - rxflr - txflr) as
122 * one maximum value for tx, but it doesn't cover the
123 * data which is out of tx/rx fifo and inside the
124 * shift registers. So a control from sw point of
125 * view is taken.
126 */
127 rxtx_gap = dws->fifo_len - (dws->rx_len - dws->tx_len);
128
129 return min3((u32)dws->tx_len, tx_room, rxtx_gap);
130}
131
132/* Return the max entries we should read out of rx fifo */
133static inline u32 dw_spi_rx_max(struct dw_spi *dws)
134{
135 return min_t(u32, dws->rx_len, dw_readl(dws, DW_SPI_RXFLR));
136}
137
138static void dw_writer(struct dw_spi *dws)
139{
140 u32 max = dw_spi_tx_max(dws);
141 u32 txw = 0;
142
143 while (max--) {
144 if (dws->tx) {
145 if (dws->n_bytes == 1)
146 txw = *(u8 *)(dws->tx);
147 else if (dws->n_bytes == 2)
148 txw = *(u16 *)(dws->tx);
149 else
150 txw = *(u32 *)(dws->tx);
151
152 dws->tx += dws->n_bytes;
153 }
154 dw_write_io_reg(dws, DW_SPI_DR, txw);
155 --dws->tx_len;
156 }
157}
158
159static void dw_reader(struct dw_spi *dws)
160{
161 u32 max = dw_spi_rx_max(dws);
162 u32 rxw;
163
164 while (max--) {
165 rxw = dw_read_io_reg(dws, DW_SPI_DR);
166 if (dws->rx) {
167 if (dws->n_bytes == 1)
168 *(u8 *)(dws->rx) = rxw;
169 else if (dws->n_bytes == 2)
170 *(u16 *)(dws->rx) = rxw;
171 else
172 *(u32 *)(dws->rx) = rxw;
173
174 dws->rx += dws->n_bytes;
175 }
176 --dws->rx_len;
177 }
178}
179
180int dw_spi_check_status(struct dw_spi *dws, bool raw)
181{
182 u32 irq_status;
183 int ret = 0;
184
185 if (raw)
186 irq_status = dw_readl(dws, DW_SPI_RISR);
187 else
188 irq_status = dw_readl(dws, DW_SPI_ISR);
189
190 if (irq_status & DW_SPI_INT_RXOI) {
191 dev_err(&dws->master->dev, "RX FIFO overflow detected\n");
192 ret = -EIO;
193 }
194
195 if (irq_status & DW_SPI_INT_RXUI) {
196 dev_err(&dws->master->dev, "RX FIFO underflow detected\n");
197 ret = -EIO;
198 }
199
200 if (irq_status & DW_SPI_INT_TXOI) {
201 dev_err(&dws->master->dev, "TX FIFO overflow detected\n");
202 ret = -EIO;
203 }
204
205 /* Generically handle the erroneous situation */
206 if (ret) {
207 dw_spi_reset_chip(dws);
208 if (dws->master->cur_msg)
209 dws->master->cur_msg->status = ret;
210 }
211
212 return ret;
213}
214EXPORT_SYMBOL_NS_GPL(dw_spi_check_status, SPI_DW_CORE);
215
216static irqreturn_t dw_spi_transfer_handler(struct dw_spi *dws)
217{
218 u16 irq_status = dw_readl(dws, DW_SPI_ISR);
219
220 if (dw_spi_check_status(dws, false)) {
221 spi_finalize_current_transfer(dws->master);
222 return IRQ_HANDLED;
223 }
224
225 /*
226 * Read data from the Rx FIFO every time we've got a chance executing
227 * this method. If there is nothing left to receive, terminate the
228 * procedure. Otherwise adjust the Rx FIFO Threshold level if it's a
229 * final stage of the transfer. By doing so we'll get the next IRQ
230 * right when the leftover incoming data is received.
231 */
232 dw_reader(dws);
233 if (!dws->rx_len) {
234 dw_spi_mask_intr(dws, 0xff);
235 spi_finalize_current_transfer(dws->master);
236 } else if (dws->rx_len <= dw_readl(dws, DW_SPI_RXFTLR)) {
237 dw_writel(dws, DW_SPI_RXFTLR, dws->rx_len - 1);
238 }
239
240 /*
241 * Send data out if Tx FIFO Empty IRQ is received. The IRQ will be
242 * disabled after the data transmission is finished so not to
243 * have the TXE IRQ flood at the final stage of the transfer.
244 */
245 if (irq_status & DW_SPI_INT_TXEI) {
246 dw_writer(dws);
247 if (!dws->tx_len)
248 dw_spi_mask_intr(dws, DW_SPI_INT_TXEI);
249 }
250
251 return IRQ_HANDLED;
252}
253
254static irqreturn_t dw_spi_irq(int irq, void *dev_id)
255{
256 struct spi_controller *master = dev_id;
257 struct dw_spi *dws = spi_controller_get_devdata(master);
258 u16 irq_status = dw_readl(dws, DW_SPI_ISR) & DW_SPI_INT_MASK;
259
260 if (!irq_status)
261 return IRQ_NONE;
262
263 if (!master->cur_msg) {
264 dw_spi_mask_intr(dws, 0xff);
265 return IRQ_HANDLED;
266 }
267
268 return dws->transfer_handler(dws);
269}
270
271static u32 dw_spi_prepare_cr0(struct dw_spi *dws, struct spi_device *spi)
272{
273 u32 cr0 = 0;
274
275 if (dw_spi_ip_is(dws, PSSI)) {
276 /* CTRLR0[ 5: 4] Frame Format */
277 cr0 |= FIELD_PREP(DW_PSSI_CTRLR0_FRF_MASK, DW_SPI_CTRLR0_FRF_MOTO_SPI);
278
279 /*
280 * SPI mode (SCPOL|SCPH)
281 * CTRLR0[ 6] Serial Clock Phase
282 * CTRLR0[ 7] Serial Clock Polarity
283 */
284 if (spi->mode & SPI_CPOL)
285 cr0 |= DW_PSSI_CTRLR0_SCPOL;
286 if (spi->mode & SPI_CPHA)
287 cr0 |= DW_PSSI_CTRLR0_SCPHA;
288
289 /* CTRLR0[11] Shift Register Loop */
290 if (spi->mode & SPI_LOOP)
291 cr0 |= DW_PSSI_CTRLR0_SRL;
292 } else {
293 /* CTRLR0[ 7: 6] Frame Format */
294 cr0 |= FIELD_PREP(DW_HSSI_CTRLR0_FRF_MASK, DW_SPI_CTRLR0_FRF_MOTO_SPI);
295
296 /*
297 * SPI mode (SCPOL|SCPH)
298 * CTRLR0[ 8] Serial Clock Phase
299 * CTRLR0[ 9] Serial Clock Polarity
300 */
301 if (spi->mode & SPI_CPOL)
302 cr0 |= DW_HSSI_CTRLR0_SCPOL;
303 if (spi->mode & SPI_CPHA)
304 cr0 |= DW_HSSI_CTRLR0_SCPHA;
305
306 /* CTRLR0[13] Shift Register Loop */
307 if (spi->mode & SPI_LOOP)
308 cr0 |= DW_HSSI_CTRLR0_SRL;
309
310 /* CTRLR0[31] MST */
311 if (dw_spi_ver_is_ge(dws, HSSI, 102A))
312 cr0 |= DW_HSSI_CTRLR0_MST;
313 }
314
315 return cr0;
316}
317
318void dw_spi_update_config(struct dw_spi *dws, struct spi_device *spi,
319 struct dw_spi_cfg *cfg)
320{
321 struct dw_spi_chip_data *chip = spi_get_ctldata(spi);
322 u32 cr0 = chip->cr0;
323 u32 speed_hz;
324 u16 clk_div;
325
326 /* CTRLR0[ 4/3: 0] or CTRLR0[ 20: 16] Data Frame Size */
327 cr0 |= (cfg->dfs - 1) << dws->dfs_offset;
328
329 if (dw_spi_ip_is(dws, PSSI))
330 /* CTRLR0[ 9:8] Transfer Mode */
331 cr0 |= FIELD_PREP(DW_PSSI_CTRLR0_TMOD_MASK, cfg->tmode);
332 else
333 /* CTRLR0[11:10] Transfer Mode */
334 cr0 |= FIELD_PREP(DW_HSSI_CTRLR0_TMOD_MASK, cfg->tmode);
335
336 dw_writel(dws, DW_SPI_CTRLR0, cr0);
337
338 if (cfg->tmode == DW_SPI_CTRLR0_TMOD_EPROMREAD ||
339 cfg->tmode == DW_SPI_CTRLR0_TMOD_RO)
340 dw_writel(dws, DW_SPI_CTRLR1, cfg->ndf ? cfg->ndf - 1 : 0);
341
342 /* Note DW APB SSI clock divider doesn't support odd numbers */
343 clk_div = (DIV_ROUND_UP(dws->max_freq, cfg->freq) + 1) & 0xfffe;
344 speed_hz = dws->max_freq / clk_div;
345
346 if (dws->current_freq != speed_hz) {
347 dw_spi_set_clk(dws, clk_div);
348 dws->current_freq = speed_hz;
349 }
350
351 /* Update RX sample delay if required */
352 if (dws->cur_rx_sample_dly != chip->rx_sample_dly) {
353 dw_writel(dws, DW_SPI_RX_SAMPLE_DLY, chip->rx_sample_dly);
354 dws->cur_rx_sample_dly = chip->rx_sample_dly;
355 }
356}
357EXPORT_SYMBOL_NS_GPL(dw_spi_update_config, SPI_DW_CORE);
358
359static void dw_spi_irq_setup(struct dw_spi *dws)
360{
361 u16 level;
362 u8 imask;
363
364 /*
365 * Originally Tx and Rx data lengths match. Rx FIFO Threshold level
366 * will be adjusted at the final stage of the IRQ-based SPI transfer
367 * execution so not to lose the leftover of the incoming data.
368 */
369 level = min_t(unsigned int, dws->fifo_len / 2, dws->tx_len);
370 dw_writel(dws, DW_SPI_TXFTLR, level);
371 dw_writel(dws, DW_SPI_RXFTLR, level - 1);
372
373 dws->transfer_handler = dw_spi_transfer_handler;
374
375 imask = DW_SPI_INT_TXEI | DW_SPI_INT_TXOI |
376 DW_SPI_INT_RXUI | DW_SPI_INT_RXOI | DW_SPI_INT_RXFI;
377 dw_spi_umask_intr(dws, imask);
378}
379
380/*
381 * The iterative procedure of the poll-based transfer is simple: write as much
382 * as possible to the Tx FIFO, wait until the pending to receive data is ready
383 * to be read, read it from the Rx FIFO and check whether the performed
384 * procedure has been successful.
385 *
386 * Note this method the same way as the IRQ-based transfer won't work well for
387 * the SPI devices connected to the controller with native CS due to the
388 * automatic CS assertion/de-assertion.
389 */
390static int dw_spi_poll_transfer(struct dw_spi *dws,
391 struct spi_transfer *transfer)
392{
393 struct spi_delay delay;
394 u16 nbits;
395 int ret;
396
397 delay.unit = SPI_DELAY_UNIT_SCK;
398 nbits = dws->n_bytes * BITS_PER_BYTE;
399
400 do {
401 dw_writer(dws);
402
403 delay.value = nbits * (dws->rx_len - dws->tx_len);
404 spi_delay_exec(&delay, transfer);
405
406 dw_reader(dws);
407
408 ret = dw_spi_check_status(dws, true);
409 if (ret)
410 return ret;
411 } while (dws->rx_len);
412
413 return 0;
414}
415
416static int dw_spi_transfer_one(struct spi_controller *master,
417 struct spi_device *spi,
418 struct spi_transfer *transfer)
419{
420 struct dw_spi *dws = spi_controller_get_devdata(master);
421 struct dw_spi_cfg cfg = {
422 .tmode = DW_SPI_CTRLR0_TMOD_TR,
423 .dfs = transfer->bits_per_word,
424 .freq = transfer->speed_hz,
425 };
426 int ret;
427
428 dws->dma_mapped = 0;
429 dws->n_bytes = DIV_ROUND_UP(transfer->bits_per_word, BITS_PER_BYTE);
430 dws->tx = (void *)transfer->tx_buf;
431 dws->tx_len = transfer->len / dws->n_bytes;
432 dws->rx = transfer->rx_buf;
433 dws->rx_len = dws->tx_len;
434
435 /* Ensure the data above is visible for all CPUs */
436 smp_mb();
437
438 dw_spi_enable_chip(dws, 0);
439
440 dw_spi_update_config(dws, spi, &cfg);
441
442 transfer->effective_speed_hz = dws->current_freq;
443
444 /* Check if current transfer is a DMA transaction */
445 if (master->can_dma && master->can_dma(master, spi, transfer))
446 dws->dma_mapped = master->cur_msg_mapped;
447
448 /* For poll mode just disable all interrupts */
449 dw_spi_mask_intr(dws, 0xff);
450
451 if (dws->dma_mapped) {
452 ret = dws->dma_ops->dma_setup(dws, transfer);
453 if (ret)
454 return ret;
455 }
456
457 dw_spi_enable_chip(dws, 1);
458
459 if (dws->dma_mapped)
460 return dws->dma_ops->dma_transfer(dws, transfer);
461 else if (dws->irq == IRQ_NOTCONNECTED)
462 return dw_spi_poll_transfer(dws, transfer);
463
464 dw_spi_irq_setup(dws);
465
466 return 1;
467}
468
469static void dw_spi_handle_err(struct spi_controller *master,
470 struct spi_message *msg)
471{
472 struct dw_spi *dws = spi_controller_get_devdata(master);
473
474 if (dws->dma_mapped)
475 dws->dma_ops->dma_stop(dws);
476
477 dw_spi_reset_chip(dws);
478}
479
480static int dw_spi_adjust_mem_op_size(struct spi_mem *mem, struct spi_mem_op *op)
481{
482 if (op->data.dir == SPI_MEM_DATA_IN)
483 op->data.nbytes = clamp_val(op->data.nbytes, 0, DW_SPI_NDF_MASK + 1);
484
485 return 0;
486}
487
488static bool dw_spi_supports_mem_op(struct spi_mem *mem,
489 const struct spi_mem_op *op)
490{
491 if (op->data.buswidth > 1 || op->addr.buswidth > 1 ||
492 op->dummy.buswidth > 1 || op->cmd.buswidth > 1)
493 return false;
494
495 return spi_mem_default_supports_op(mem, op);
496}
497
498static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op)
499{
500 unsigned int i, j, len;
501 u8 *out;
502
503 /*
504 * Calculate the total length of the EEPROM command transfer and
505 * either use the pre-allocated buffer or create a temporary one.
506 */
507 len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
508 if (op->data.dir == SPI_MEM_DATA_OUT)
509 len += op->data.nbytes;
510
511 if (len <= DW_SPI_BUF_SIZE) {
512 out = dws->buf;
513 } else {
514 out = kzalloc(len, GFP_KERNEL);
515 if (!out)
516 return -ENOMEM;
517 }
518
519 /*
520 * Collect the operation code, address and dummy bytes into the single
521 * buffer. If it's a transfer with data to be sent, also copy it into the
522 * single buffer in order to speed the data transmission up.
523 */
524 for (i = 0; i < op->cmd.nbytes; ++i)
525 out[i] = DW_SPI_GET_BYTE(op->cmd.opcode, op->cmd.nbytes - i - 1);
526 for (j = 0; j < op->addr.nbytes; ++i, ++j)
527 out[i] = DW_SPI_GET_BYTE(op->addr.val, op->addr.nbytes - j - 1);
528 for (j = 0; j < op->dummy.nbytes; ++i, ++j)
529 out[i] = 0x0;
530
531 if (op->data.dir == SPI_MEM_DATA_OUT)
532 memcpy(&out[i], op->data.buf.out, op->data.nbytes);
533
534 dws->n_bytes = 1;
535 dws->tx = out;
536 dws->tx_len = len;
537 if (op->data.dir == SPI_MEM_DATA_IN) {
538 dws->rx = op->data.buf.in;
539 dws->rx_len = op->data.nbytes;
540 } else {
541 dws->rx = NULL;
542 dws->rx_len = 0;
543 }
544
545 return 0;
546}
547
548static void dw_spi_free_mem_buf(struct dw_spi *dws)
549{
550 if (dws->tx != dws->buf)
551 kfree(dws->tx);
552}
553
554static int dw_spi_write_then_read(struct dw_spi *dws, struct spi_device *spi)
555{
556 u32 room, entries, sts;
557 unsigned int len;
558 u8 *buf;
559
560 /*
561 * At initial stage we just pre-fill the Tx FIFO in with no rush,
562 * since native CS hasn't been enabled yet and the automatic data
563 * transmission won't start til we do that.
564 */
565 len = min(dws->fifo_len, dws->tx_len);
566 buf = dws->tx;
567 while (len--)
568 dw_write_io_reg(dws, DW_SPI_DR, *buf++);
569
570 /*
571 * After setting any bit in the SER register the transmission will
572 * start automatically. We have to keep up with that procedure
573 * otherwise the CS de-assertion will happen whereupon the memory
574 * operation will be pre-terminated.
575 */
576 len = dws->tx_len - ((void *)buf - dws->tx);
577 dw_spi_set_cs(spi, false);
578 while (len) {
579 entries = readl_relaxed(dws->regs + DW_SPI_TXFLR);
580 if (!entries) {
581 dev_err(&dws->master->dev, "CS de-assertion on Tx\n");
582 return -EIO;
583 }
584 room = min(dws->fifo_len - entries, len);
585 for (; room; --room, --len)
586 dw_write_io_reg(dws, DW_SPI_DR, *buf++);
587 }
588
589 /*
590 * Data fetching will start automatically if the EEPROM-read mode is
591 * activated. We have to keep up with the incoming data pace to
592 * prevent the Rx FIFO overflow causing the inbound data loss.
593 */
594 len = dws->rx_len;
595 buf = dws->rx;
596 while (len) {
597 entries = readl_relaxed(dws->regs + DW_SPI_RXFLR);
598 if (!entries) {
599 sts = readl_relaxed(dws->regs + DW_SPI_RISR);
600 if (sts & DW_SPI_INT_RXOI) {
601 dev_err(&dws->master->dev, "FIFO overflow on Rx\n");
602 return -EIO;
603 }
604 continue;
605 }
606 entries = min(entries, len);
607 for (; entries; --entries, --len)
608 *buf++ = dw_read_io_reg(dws, DW_SPI_DR);
609 }
610
611 return 0;
612}
613
614static inline bool dw_spi_ctlr_busy(struct dw_spi *dws)
615{
616 return dw_readl(dws, DW_SPI_SR) & DW_SPI_SR_BUSY;
617}
618
619static int dw_spi_wait_mem_op_done(struct dw_spi *dws)
620{
621 int retry = DW_SPI_WAIT_RETRIES;
622 struct spi_delay delay;
623 unsigned long ns, us;
624 u32 nents;
625
626 nents = dw_readl(dws, DW_SPI_TXFLR);
627 ns = NSEC_PER_SEC / dws->current_freq * nents;
628 ns *= dws->n_bytes * BITS_PER_BYTE;
629 if (ns <= NSEC_PER_USEC) {
630 delay.unit = SPI_DELAY_UNIT_NSECS;
631 delay.value = ns;
632 } else {
633 us = DIV_ROUND_UP(ns, NSEC_PER_USEC);
634 delay.unit = SPI_DELAY_UNIT_USECS;
635 delay.value = clamp_val(us, 0, USHRT_MAX);
636 }
637
638 while (dw_spi_ctlr_busy(dws) && retry--)
639 spi_delay_exec(&delay, NULL);
640
641 if (retry < 0) {
642 dev_err(&dws->master->dev, "Mem op hanged up\n");
643 return -EIO;
644 }
645
646 return 0;
647}
648
649static void dw_spi_stop_mem_op(struct dw_spi *dws, struct spi_device *spi)
650{
651 dw_spi_enable_chip(dws, 0);
652 dw_spi_set_cs(spi, true);
653 dw_spi_enable_chip(dws, 1);
654}
655
656/*
657 * The SPI memory operation implementation below is the best choice for the
658 * devices, which are selected by the native chip-select lane. It's
659 * specifically developed to workaround the problem with automatic chip-select
660 * lane toggle when there is no data in the Tx FIFO buffer. Luckily the current
661 * SPI-mem core calls exec_op() callback only if the GPIO-based CS is
662 * unavailable.
663 */
664static int dw_spi_exec_mem_op(struct spi_mem *mem, const struct spi_mem_op *op)
665{
666 struct dw_spi *dws = spi_controller_get_devdata(mem->spi->controller);
667 struct dw_spi_cfg cfg;
668 unsigned long flags;
669 int ret;
670
671 /*
672 * Collect the outbound data into a single buffer to speed the
673 * transmission up at least on the initial stage.
674 */
675 ret = dw_spi_init_mem_buf(dws, op);
676 if (ret)
677 return ret;
678
679 /*
680 * DW SPI EEPROM-read mode is required only for the SPI memory Data-IN
681 * operation. Transmit-only mode is suitable for the rest of them.
682 */
683 cfg.dfs = 8;
684 cfg.freq = clamp(mem->spi->max_speed_hz, 0U, dws->max_mem_freq);
685 if (op->data.dir == SPI_MEM_DATA_IN) {
686 cfg.tmode = DW_SPI_CTRLR0_TMOD_EPROMREAD;
687 cfg.ndf = op->data.nbytes;
688 } else {
689 cfg.tmode = DW_SPI_CTRLR0_TMOD_TO;
690 }
691
692 dw_spi_enable_chip(dws, 0);
693
694 dw_spi_update_config(dws, mem->spi, &cfg);
695
696 dw_spi_mask_intr(dws, 0xff);
697
698 dw_spi_enable_chip(dws, 1);
699
700 /*
701 * DW APB SSI controller has very nasty peculiarities. First originally
702 * (without any vendor-specific modifications) it doesn't provide a
703 * direct way to set and clear the native chip-select signal. Instead
704 * the controller asserts the CS lane if Tx FIFO isn't empty and a
705 * transmission is going on, and automatically de-asserts it back to
706 * the high level if the Tx FIFO doesn't have anything to be pushed
707 * out. Due to that a multi-tasking or heavy IRQs activity might be
708 * fatal, since the transfer procedure preemption may cause the Tx FIFO
709 * getting empty and sudden CS de-assertion, which in the middle of the
710 * transfer will most likely cause the data loss. Secondly the
711 * EEPROM-read or Read-only DW SPI transfer modes imply the incoming
712 * data being automatically pulled in into the Rx FIFO. So if the
713 * driver software is late in fetching the data from the FIFO before
714 * it's overflown, new incoming data will be lost. In order to make
715 * sure the executed memory operations are CS-atomic and to prevent the
716 * Rx FIFO overflow we have to disable the local interrupts so to block
717 * any preemption during the subsequent IO operations.
718 *
719 * Note. At some circumstances disabling IRQs may not help to prevent
720 * the problems described above. The CS de-assertion and Rx FIFO
721 * overflow may still happen due to the relatively slow system bus or
722 * CPU not working fast enough, so the write-then-read algo implemented
723 * here just won't keep up with the SPI bus data transfer. Such
724 * situation is highly platform specific and is supposed to be fixed by
725 * manually restricting the SPI bus frequency using the
726 * dws->max_mem_freq parameter.
727 */
728 local_irq_save(flags);
729 preempt_disable();
730
731 ret = dw_spi_write_then_read(dws, mem->spi);
732
733 local_irq_restore(flags);
734 preempt_enable();
735
736 /*
737 * Wait for the operation being finished and check the controller
738 * status only if there hasn't been any run-time error detected. In the
739 * former case it's just pointless. In the later one to prevent an
740 * additional error message printing since any hw error flag being set
741 * would be due to an error detected on the data transfer.
742 */
743 if (!ret) {
744 ret = dw_spi_wait_mem_op_done(dws);
745 if (!ret)
746 ret = dw_spi_check_status(dws, true);
747 }
748
749 dw_spi_stop_mem_op(dws, mem->spi);
750
751 dw_spi_free_mem_buf(dws);
752
753 return ret;
754}
755
756/*
757 * Initialize the default memory operations if a glue layer hasn't specified
758 * custom ones. Direct mapping operations will be preserved anyway since DW SPI
759 * controller doesn't have an embedded dirmap interface. Note the memory
760 * operations implemented in this driver is the best choice only for the DW APB
761 * SSI controller with standard native CS functionality. If a hardware vendor
762 * has fixed the automatic CS assertion/de-assertion peculiarity, then it will
763 * be safer to use the normal SPI-messages-based transfers implementation.
764 */
765static void dw_spi_init_mem_ops(struct dw_spi *dws)
766{
767 if (!dws->mem_ops.exec_op && !(dws->caps & DW_SPI_CAP_CS_OVERRIDE) &&
768 !dws->set_cs) {
769 dws->mem_ops.adjust_op_size = dw_spi_adjust_mem_op_size;
770 dws->mem_ops.supports_op = dw_spi_supports_mem_op;
771 dws->mem_ops.exec_op = dw_spi_exec_mem_op;
772 if (!dws->max_mem_freq)
773 dws->max_mem_freq = dws->max_freq;
774 }
775}
776
777/* This may be called twice for each spi dev */
778static int dw_spi_setup(struct spi_device *spi)
779{
780 struct dw_spi *dws = spi_controller_get_devdata(spi->controller);
781 struct dw_spi_chip_data *chip;
782
783 /* Only alloc on first setup */
784 chip = spi_get_ctldata(spi);
785 if (!chip) {
786 struct dw_spi *dws = spi_controller_get_devdata(spi->controller);
787 u32 rx_sample_dly_ns;
788
789 chip = kzalloc(sizeof(*chip), GFP_KERNEL);
790 if (!chip)
791 return -ENOMEM;
792 spi_set_ctldata(spi, chip);
793 /* Get specific / default rx-sample-delay */
794 if (device_property_read_u32(&spi->dev,
795 "rx-sample-delay-ns",
796 &rx_sample_dly_ns) != 0)
797 /* Use default controller value */
798 rx_sample_dly_ns = dws->def_rx_sample_dly_ns;
799 chip->rx_sample_dly = DIV_ROUND_CLOSEST(rx_sample_dly_ns,
800 NSEC_PER_SEC /
801 dws->max_freq);
802 }
803
804 /*
805 * Update CR0 data each time the setup callback is invoked since
806 * the device parameters could have been changed, for instance, by
807 * the MMC SPI driver or something else.
808 */
809 chip->cr0 = dw_spi_prepare_cr0(dws, spi);
810
811 return 0;
812}
813
814static void dw_spi_cleanup(struct spi_device *spi)
815{
816 struct dw_spi_chip_data *chip = spi_get_ctldata(spi);
817
818 kfree(chip);
819 spi_set_ctldata(spi, NULL);
820}
821
822/* Restart the controller, disable all interrupts, clean rx fifo */
823static void dw_spi_hw_init(struct device *dev, struct dw_spi *dws)
824{
825 dw_spi_reset_chip(dws);
826
827 /*
828 * Retrieve the Synopsys component version if it hasn't been specified
829 * by the platform. CoreKit version ID is encoded as a 3-chars ASCII
830 * code enclosed with '*' (typical for the most of Synopsys IP-cores).
831 */
832 if (!dws->ver) {
833 dws->ver = dw_readl(dws, DW_SPI_VERSION);
834
835 dev_dbg(dev, "Synopsys DWC%sSSI v%c.%c%c\n",
836 dw_spi_ip_is(dws, PSSI) ? " APB " : " ",
837 DW_SPI_GET_BYTE(dws->ver, 3), DW_SPI_GET_BYTE(dws->ver, 2),
838 DW_SPI_GET_BYTE(dws->ver, 1));
839 }
840
841 /*
842 * Try to detect the FIFO depth if not set by interface driver,
843 * the depth could be from 2 to 256 from HW spec
844 */
845 if (!dws->fifo_len) {
846 u32 fifo;
847
848 for (fifo = 1; fifo < 256; fifo++) {
849 dw_writel(dws, DW_SPI_TXFTLR, fifo);
850 if (fifo != dw_readl(dws, DW_SPI_TXFTLR))
851 break;
852 }
853 dw_writel(dws, DW_SPI_TXFTLR, 0);
854
855 dws->fifo_len = (fifo == 1) ? 0 : fifo;
856 dev_dbg(dev, "Detected FIFO size: %u bytes\n", dws->fifo_len);
857 }
858
859 /*
860 * Detect CTRLR0.DFS field size and offset by testing the lowest bits
861 * writability. Note DWC SSI controller also has the extended DFS, but
862 * with zero offset.
863 */
864 if (dw_spi_ip_is(dws, PSSI)) {
865 u32 cr0, tmp = dw_readl(dws, DW_SPI_CTRLR0);
866
867 dw_spi_enable_chip(dws, 0);
868 dw_writel(dws, DW_SPI_CTRLR0, 0xffffffff);
869 cr0 = dw_readl(dws, DW_SPI_CTRLR0);
870 dw_writel(dws, DW_SPI_CTRLR0, tmp);
871 dw_spi_enable_chip(dws, 1);
872
873 if (!(cr0 & DW_PSSI_CTRLR0_DFS_MASK)) {
874 dws->caps |= DW_SPI_CAP_DFS32;
875 dws->dfs_offset = __bf_shf(DW_PSSI_CTRLR0_DFS32_MASK);
876 dev_dbg(dev, "Detected 32-bits max data frame size\n");
877 }
878 } else {
879 dws->caps |= DW_SPI_CAP_DFS32;
880 }
881
882 /* enable HW fixup for explicit CS deselect for Amazon's alpine chip */
883 if (dws->caps & DW_SPI_CAP_CS_OVERRIDE)
884 dw_writel(dws, DW_SPI_CS_OVERRIDE, 0xF);
885}
886
887int dw_spi_add_host(struct device *dev, struct dw_spi *dws)
888{
889 struct spi_controller *master;
890 int ret;
891
892 if (!dws)
893 return -EINVAL;
894
895 master = spi_alloc_master(dev, 0);
896 if (!master)
897 return -ENOMEM;
898
899 device_set_node(&master->dev, dev_fwnode(dev));
900
901 dws->master = master;
902 dws->dma_addr = (dma_addr_t)(dws->paddr + DW_SPI_DR);
903
904 spi_controller_set_devdata(master, dws);
905
906 /* Basic HW init */
907 dw_spi_hw_init(dev, dws);
908
909 ret = request_irq(dws->irq, dw_spi_irq, IRQF_SHARED, dev_name(dev),
910 master);
911 if (ret < 0 && ret != -ENOTCONN) {
912 dev_err(dev, "can not get IRQ\n");
913 goto err_free_master;
914 }
915
916 dw_spi_init_mem_ops(dws);
917
918 master->use_gpio_descriptors = true;
919 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP;
920 if (dws->caps & DW_SPI_CAP_DFS32)
921 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32);
922 else
923 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
924 master->bus_num = dws->bus_num;
925 master->num_chipselect = dws->num_cs;
926 master->setup = dw_spi_setup;
927 master->cleanup = dw_spi_cleanup;
928 if (dws->set_cs)
929 master->set_cs = dws->set_cs;
930 else
931 master->set_cs = dw_spi_set_cs;
932 master->transfer_one = dw_spi_transfer_one;
933 master->handle_err = dw_spi_handle_err;
934 if (dws->mem_ops.exec_op)
935 master->mem_ops = &dws->mem_ops;
936 master->max_speed_hz = dws->max_freq;
937 master->flags = SPI_MASTER_GPIO_SS;
938 master->auto_runtime_pm = true;
939
940 /* Get default rx sample delay */
941 device_property_read_u32(dev, "rx-sample-delay-ns",
942 &dws->def_rx_sample_dly_ns);
943
944 if (dws->dma_ops && dws->dma_ops->dma_init) {
945 ret = dws->dma_ops->dma_init(dev, dws);
946 if (ret == -EPROBE_DEFER) {
947 goto err_free_irq;
948 } else if (ret) {
949 dev_warn(dev, "DMA init failed\n");
950 } else {
951 master->can_dma = dws->dma_ops->can_dma;
952 master->flags |= SPI_CONTROLLER_MUST_TX;
953 }
954 }
955
956 ret = spi_register_controller(master);
957 if (ret) {
958 dev_err_probe(dev, ret, "problem registering spi master\n");
959 goto err_dma_exit;
960 }
961
962 dw_spi_debugfs_init(dws);
963 return 0;
964
965err_dma_exit:
966 if (dws->dma_ops && dws->dma_ops->dma_exit)
967 dws->dma_ops->dma_exit(dws);
968 dw_spi_enable_chip(dws, 0);
969err_free_irq:
970 free_irq(dws->irq, master);
971err_free_master:
972 spi_controller_put(master);
973 return ret;
974}
975EXPORT_SYMBOL_NS_GPL(dw_spi_add_host, SPI_DW_CORE);
976
977void dw_spi_remove_host(struct dw_spi *dws)
978{
979 dw_spi_debugfs_remove(dws);
980
981 spi_unregister_controller(dws->master);
982
983 if (dws->dma_ops && dws->dma_ops->dma_exit)
984 dws->dma_ops->dma_exit(dws);
985
986 dw_spi_shutdown_chip(dws);
987
988 free_irq(dws->irq, dws->master);
989}
990EXPORT_SYMBOL_NS_GPL(dw_spi_remove_host, SPI_DW_CORE);
991
992int dw_spi_suspend_host(struct dw_spi *dws)
993{
994 int ret;
995
996 ret = spi_controller_suspend(dws->master);
997 if (ret)
998 return ret;
999
1000 dw_spi_shutdown_chip(dws);
1001 return 0;
1002}
1003EXPORT_SYMBOL_NS_GPL(dw_spi_suspend_host, SPI_DW_CORE);
1004
1005int dw_spi_resume_host(struct dw_spi *dws)
1006{
1007 dw_spi_hw_init(&dws->master->dev, dws);
1008 return spi_controller_resume(dws->master);
1009}
1010EXPORT_SYMBOL_NS_GPL(dw_spi_resume_host, SPI_DW_CORE);
1011
1012MODULE_AUTHOR("Feng Tang <feng.tang@intel.com>");
1013MODULE_DESCRIPTION("Driver for DesignWare SPI controller core");
1014MODULE_LICENSE("GPL v2");