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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
76struct spi_engine_program {
77 unsigned int length;
78 uint16_t instructions[];
79};
80
81struct 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
108static 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
116static 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
130static 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
145static 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
165static void spi_engine_gen_sleep(struct spi_engine_program *p, bool dry,
166 struct spi_engine *spi_engine, unsigned int clk_div,
167 struct spi_transfer *xfer)
168{
169 unsigned int spi_clk = clk_get_rate(spi_engine->ref_clk);
170 unsigned int t;
171 int delay;
172
173 delay = spi_delay_to_ns(&xfer->delay, xfer);
174 if (delay < 0)
175 return;
176 delay /= 1000;
177
178 if (delay == 0)
179 return;
180
181 t = DIV_ROUND_UP(delay * spi_clk, (clk_div + 1) * 2);
182 while (t) {
183 unsigned int n = min(t, 256U);
184
185 spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_SLEEP(n - 1));
186 t -= n;
187 }
188}
189
190static void spi_engine_gen_cs(struct spi_engine_program *p, bool dry,
191 struct spi_device *spi, bool assert)
192{
193 unsigned int mask = 0xff;
194
195 if (assert)
196 mask ^= BIT(spi->chip_select);
197
198 spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_ASSERT(1, mask));
199}
200
201static int spi_engine_compile_message(struct spi_engine *spi_engine,
202 struct spi_message *msg, bool dry, struct spi_engine_program *p)
203{
204 struct spi_device *spi = msg->spi;
205 struct spi_transfer *xfer;
206 int clk_div, new_clk_div;
207 bool cs_change = true;
208
209 clk_div = -1;
210
211 spi_engine_program_add_cmd(p, dry,
212 SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CONFIG,
213 spi_engine_get_config(spi)));
214
215 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
216 new_clk_div = spi_engine_get_clk_div(spi_engine, spi, xfer);
217 if (new_clk_div != clk_div) {
218 clk_div = new_clk_div;
219 spi_engine_program_add_cmd(p, dry,
220 SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CLK_DIV,
221 clk_div));
222 }
223
224 if (cs_change)
225 spi_engine_gen_cs(p, dry, spi, true);
226
227 spi_engine_gen_xfer(p, dry, xfer);
228 spi_engine_gen_sleep(p, dry, spi_engine, clk_div, xfer);
229
230 cs_change = xfer->cs_change;
231 if (list_is_last(&xfer->transfer_list, &msg->transfers))
232 cs_change = !cs_change;
233
234 if (cs_change)
235 spi_engine_gen_cs(p, dry, spi, false);
236 }
237
238 return 0;
239}
240
241static void spi_engine_xfer_next(struct spi_engine *spi_engine,
242 struct spi_transfer **_xfer)
243{
244 struct spi_message *msg = spi_engine->msg;
245 struct spi_transfer *xfer = *_xfer;
246
247 if (!xfer) {
248 xfer = list_first_entry(&msg->transfers,
249 struct spi_transfer, transfer_list);
250 } else if (list_is_last(&xfer->transfer_list, &msg->transfers)) {
251 xfer = NULL;
252 } else {
253 xfer = list_next_entry(xfer, transfer_list);
254 }
255
256 *_xfer = xfer;
257}
258
259static void spi_engine_tx_next(struct spi_engine *spi_engine)
260{
261 struct spi_transfer *xfer = spi_engine->tx_xfer;
262
263 do {
264 spi_engine_xfer_next(spi_engine, &xfer);
265 } while (xfer && !xfer->tx_buf);
266
267 spi_engine->tx_xfer = xfer;
268 if (xfer) {
269 spi_engine->tx_length = xfer->len;
270 spi_engine->tx_buf = xfer->tx_buf;
271 } else {
272 spi_engine->tx_buf = NULL;
273 }
274}
275
276static void spi_engine_rx_next(struct spi_engine *spi_engine)
277{
278 struct spi_transfer *xfer = spi_engine->rx_xfer;
279
280 do {
281 spi_engine_xfer_next(spi_engine, &xfer);
282 } while (xfer && !xfer->rx_buf);
283
284 spi_engine->rx_xfer = xfer;
285 if (xfer) {
286 spi_engine->rx_length = xfer->len;
287 spi_engine->rx_buf = xfer->rx_buf;
288 } else {
289 spi_engine->rx_buf = NULL;
290 }
291}
292
293static bool spi_engine_write_cmd_fifo(struct spi_engine *spi_engine)
294{
295 void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_CMD_FIFO;
296 unsigned int n, m, i;
297 const uint16_t *buf;
298
299 n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_CMD_FIFO_ROOM);
300 while (n && spi_engine->cmd_length) {
301 m = min(n, spi_engine->cmd_length);
302 buf = spi_engine->cmd_buf;
303 for (i = 0; i < m; i++)
304 writel_relaxed(buf[i], addr);
305 spi_engine->cmd_buf += m;
306 spi_engine->cmd_length -= m;
307 n -= m;
308 }
309
310 return spi_engine->cmd_length != 0;
311}
312
313static bool spi_engine_write_tx_fifo(struct spi_engine *spi_engine)
314{
315 void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDO_DATA_FIFO;
316 unsigned int n, m, i;
317 const uint8_t *buf;
318
319 n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDO_FIFO_ROOM);
320 while (n && spi_engine->tx_length) {
321 m = min(n, spi_engine->tx_length);
322 buf = spi_engine->tx_buf;
323 for (i = 0; i < m; i++)
324 writel_relaxed(buf[i], addr);
325 spi_engine->tx_buf += m;
326 spi_engine->tx_length -= m;
327 n -= m;
328 if (spi_engine->tx_length == 0)
329 spi_engine_tx_next(spi_engine);
330 }
331
332 return spi_engine->tx_length != 0;
333}
334
335static bool spi_engine_read_rx_fifo(struct spi_engine *spi_engine)
336{
337 void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDI_DATA_FIFO;
338 unsigned int n, m, i;
339 uint8_t *buf;
340
341 n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDI_FIFO_LEVEL);
342 while (n && spi_engine->rx_length) {
343 m = min(n, spi_engine->rx_length);
344 buf = spi_engine->rx_buf;
345 for (i = 0; i < m; i++)
346 buf[i] = readl_relaxed(addr);
347 spi_engine->rx_buf += m;
348 spi_engine->rx_length -= m;
349 n -= m;
350 if (spi_engine->rx_length == 0)
351 spi_engine_rx_next(spi_engine);
352 }
353
354 return spi_engine->rx_length != 0;
355}
356
357static irqreturn_t spi_engine_irq(int irq, void *devid)
358{
359 struct spi_master *master = devid;
360 struct spi_engine *spi_engine = spi_master_get_devdata(master);
361 unsigned int disable_int = 0;
362 unsigned int pending;
363
364 pending = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
365
366 if (pending & SPI_ENGINE_INT_SYNC) {
367 writel_relaxed(SPI_ENGINE_INT_SYNC,
368 spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
369 spi_engine->completed_id = readl_relaxed(
370 spi_engine->base + SPI_ENGINE_REG_SYNC_ID);
371 }
372
373 spin_lock(&spi_engine->lock);
374
375 if (pending & SPI_ENGINE_INT_CMD_ALMOST_EMPTY) {
376 if (!spi_engine_write_cmd_fifo(spi_engine))
377 disable_int |= SPI_ENGINE_INT_CMD_ALMOST_EMPTY;
378 }
379
380 if (pending & SPI_ENGINE_INT_SDO_ALMOST_EMPTY) {
381 if (!spi_engine_write_tx_fifo(spi_engine))
382 disable_int |= SPI_ENGINE_INT_SDO_ALMOST_EMPTY;
383 }
384
385 if (pending & (SPI_ENGINE_INT_SDI_ALMOST_FULL | SPI_ENGINE_INT_SYNC)) {
386 if (!spi_engine_read_rx_fifo(spi_engine))
387 disable_int |= SPI_ENGINE_INT_SDI_ALMOST_FULL;
388 }
389
390 if (pending & SPI_ENGINE_INT_SYNC) {
391 if (spi_engine->msg &&
392 spi_engine->completed_id == spi_engine->sync_id) {
393 struct spi_message *msg = spi_engine->msg;
394
395 kfree(spi_engine->p);
396 msg->status = 0;
397 msg->actual_length = msg->frame_length;
398 spi_engine->msg = NULL;
399 spi_finalize_current_message(master);
400 disable_int |= SPI_ENGINE_INT_SYNC;
401 }
402 }
403
404 if (disable_int) {
405 spi_engine->int_enable &= ~disable_int;
406 writel_relaxed(spi_engine->int_enable,
407 spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
408 }
409
410 spin_unlock(&spi_engine->lock);
411
412 return IRQ_HANDLED;
413}
414
415static int spi_engine_transfer_one_message(struct spi_master *master,
416 struct spi_message *msg)
417{
418 struct spi_engine_program p_dry, *p;
419 struct spi_engine *spi_engine = spi_master_get_devdata(master);
420 unsigned int int_enable = 0;
421 unsigned long flags;
422 size_t size;
423
424 p_dry.length = 0;
425 spi_engine_compile_message(spi_engine, msg, true, &p_dry);
426
427 size = sizeof(*p->instructions) * (p_dry.length + 1);
428 p = kzalloc(sizeof(*p) + size, GFP_KERNEL);
429 if (!p)
430 return -ENOMEM;
431 spi_engine_compile_message(spi_engine, msg, false, p);
432
433 spin_lock_irqsave(&spi_engine->lock, flags);
434 spi_engine->sync_id = (spi_engine->sync_id + 1) & 0xff;
435 spi_engine_program_add_cmd(p, false,
436 SPI_ENGINE_CMD_SYNC(spi_engine->sync_id));
437
438 spi_engine->msg = msg;
439 spi_engine->p = p;
440
441 spi_engine->cmd_buf = p->instructions;
442 spi_engine->cmd_length = p->length;
443 if (spi_engine_write_cmd_fifo(spi_engine))
444 int_enable |= SPI_ENGINE_INT_CMD_ALMOST_EMPTY;
445
446 spi_engine_tx_next(spi_engine);
447 if (spi_engine_write_tx_fifo(spi_engine))
448 int_enable |= SPI_ENGINE_INT_SDO_ALMOST_EMPTY;
449
450 spi_engine_rx_next(spi_engine);
451 if (spi_engine->rx_length != 0)
452 int_enable |= SPI_ENGINE_INT_SDI_ALMOST_FULL;
453
454 int_enable |= SPI_ENGINE_INT_SYNC;
455
456 writel_relaxed(int_enable,
457 spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
458 spi_engine->int_enable = int_enable;
459 spin_unlock_irqrestore(&spi_engine->lock, flags);
460
461 return 0;
462}
463
464static int spi_engine_probe(struct platform_device *pdev)
465{
466 struct spi_engine *spi_engine;
467 struct spi_master *master;
468 unsigned int version;
469 int irq;
470 int ret;
471
472 irq = platform_get_irq(pdev, 0);
473 if (irq <= 0)
474 return -ENXIO;
475
476 spi_engine = devm_kzalloc(&pdev->dev, sizeof(*spi_engine), GFP_KERNEL);
477 if (!spi_engine)
478 return -ENOMEM;
479
480 master = spi_alloc_master(&pdev->dev, 0);
481 if (!master)
482 return -ENOMEM;
483
484 spi_master_set_devdata(master, spi_engine);
485
486 spin_lock_init(&spi_engine->lock);
487
488 spi_engine->clk = devm_clk_get(&pdev->dev, "s_axi_aclk");
489 if (IS_ERR(spi_engine->clk)) {
490 ret = PTR_ERR(spi_engine->clk);
491 goto err_put_master;
492 }
493
494 spi_engine->ref_clk = devm_clk_get(&pdev->dev, "spi_clk");
495 if (IS_ERR(spi_engine->ref_clk)) {
496 ret = PTR_ERR(spi_engine->ref_clk);
497 goto err_put_master;
498 }
499
500 ret = clk_prepare_enable(spi_engine->clk);
501 if (ret)
502 goto err_put_master;
503
504 ret = clk_prepare_enable(spi_engine->ref_clk);
505 if (ret)
506 goto err_clk_disable;
507
508 spi_engine->base = devm_platform_ioremap_resource(pdev, 0);
509 if (IS_ERR(spi_engine->base)) {
510 ret = PTR_ERR(spi_engine->base);
511 goto err_ref_clk_disable;
512 }
513
514 version = readl(spi_engine->base + SPI_ENGINE_REG_VERSION);
515 if (SPI_ENGINE_VERSION_MAJOR(version) != 1) {
516 dev_err(&pdev->dev, "Unsupported peripheral version %u.%u.%c\n",
517 SPI_ENGINE_VERSION_MAJOR(version),
518 SPI_ENGINE_VERSION_MINOR(version),
519 SPI_ENGINE_VERSION_PATCH(version));
520 ret = -ENODEV;
521 goto err_ref_clk_disable;
522 }
523
524 writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_RESET);
525 writel_relaxed(0xff, spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
526 writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
527
528 ret = request_irq(irq, spi_engine_irq, 0, pdev->name, master);
529 if (ret)
530 goto err_ref_clk_disable;
531
532 master->dev.of_node = pdev->dev.of_node;
533 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_3WIRE;
534 master->bits_per_word_mask = SPI_BPW_MASK(8);
535 master->max_speed_hz = clk_get_rate(spi_engine->ref_clk) / 2;
536 master->transfer_one_message = spi_engine_transfer_one_message;
537 master->num_chipselect = 8;
538
539 ret = spi_register_master(master);
540 if (ret)
541 goto err_free_irq;
542
543 platform_set_drvdata(pdev, master);
544
545 return 0;
546err_free_irq:
547 free_irq(irq, master);
548err_ref_clk_disable:
549 clk_disable_unprepare(spi_engine->ref_clk);
550err_clk_disable:
551 clk_disable_unprepare(spi_engine->clk);
552err_put_master:
553 spi_master_put(master);
554 return ret;
555}
556
557static int spi_engine_remove(struct platform_device *pdev)
558{
559 struct spi_master *master = spi_master_get(platform_get_drvdata(pdev));
560 struct spi_engine *spi_engine = spi_master_get_devdata(master);
561 int irq = platform_get_irq(pdev, 0);
562
563 spi_unregister_master(master);
564
565 free_irq(irq, master);
566
567 spi_master_put(master);
568
569 writel_relaxed(0xff, spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
570 writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
571 writel_relaxed(0x01, spi_engine->base + SPI_ENGINE_REG_RESET);
572
573 clk_disable_unprepare(spi_engine->ref_clk);
574 clk_disable_unprepare(spi_engine->clk);
575
576 return 0;
577}
578
579static const struct of_device_id spi_engine_match_table[] = {
580 { .compatible = "adi,axi-spi-engine-1.00.a" },
581 { },
582};
583MODULE_DEVICE_TABLE(of, spi_engine_match_table);
584
585static struct platform_driver spi_engine_driver = {
586 .probe = spi_engine_probe,
587 .remove = spi_engine_remove,
588 .driver = {
589 .name = "spi-engine",
590 .of_match_table = spi_engine_match_table,
591 },
592};
593module_platform_driver(spi_engine_driver);
594
595MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
596MODULE_DESCRIPTION("Analog Devices SPI engine peripheral driver");
597MODULE_LICENSE("GPL");
598
