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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 if (xfer->delay_usecs) {
174 delay = xfer->delay_usecs;
175 } else {
176 delay = spi_delay_to_ns(&xfer->delay, xfer);
177 if (delay < 0)
178 return;
179 delay /= 1000;
180 }
181
182 if (delay == 0)
183 return;
184
185 t = DIV_ROUND_UP(delay * spi_clk, (clk_div + 1) * 2);
186 while (t) {
187 unsigned int n = min(t, 256U);
188
189 spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_SLEEP(n - 1));
190 t -= n;
191 }
192}
193
194static void spi_engine_gen_cs(struct spi_engine_program *p, bool dry,
195 struct spi_device *spi, bool assert)
196{
197 unsigned int mask = 0xff;
198
199 if (assert)
200 mask ^= BIT(spi->chip_select);
201
202 spi_engine_program_add_cmd(p, dry, SPI_ENGINE_CMD_ASSERT(1, mask));
203}
204
205static int spi_engine_compile_message(struct spi_engine *spi_engine,
206 struct spi_message *msg, bool dry, struct spi_engine_program *p)
207{
208 struct spi_device *spi = msg->spi;
209 struct spi_transfer *xfer;
210 int clk_div, new_clk_div;
211 bool cs_change = true;
212
213 clk_div = -1;
214
215 spi_engine_program_add_cmd(p, dry,
216 SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CONFIG,
217 spi_engine_get_config(spi)));
218
219 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
220 new_clk_div = spi_engine_get_clk_div(spi_engine, spi, xfer);
221 if (new_clk_div != clk_div) {
222 clk_div = new_clk_div;
223 spi_engine_program_add_cmd(p, dry,
224 SPI_ENGINE_CMD_WRITE(SPI_ENGINE_CMD_REG_CLK_DIV,
225 clk_div));
226 }
227
228 if (cs_change)
229 spi_engine_gen_cs(p, dry, spi, true);
230
231 spi_engine_gen_xfer(p, dry, xfer);
232 spi_engine_gen_sleep(p, dry, spi_engine, clk_div, xfer);
233
234 cs_change = xfer->cs_change;
235 if (list_is_last(&xfer->transfer_list, &msg->transfers))
236 cs_change = !cs_change;
237
238 if (cs_change)
239 spi_engine_gen_cs(p, dry, spi, false);
240 }
241
242 return 0;
243}
244
245static void spi_engine_xfer_next(struct spi_engine *spi_engine,
246 struct spi_transfer **_xfer)
247{
248 struct spi_message *msg = spi_engine->msg;
249 struct spi_transfer *xfer = *_xfer;
250
251 if (!xfer) {
252 xfer = list_first_entry(&msg->transfers,
253 struct spi_transfer, transfer_list);
254 } else if (list_is_last(&xfer->transfer_list, &msg->transfers)) {
255 xfer = NULL;
256 } else {
257 xfer = list_next_entry(xfer, transfer_list);
258 }
259
260 *_xfer = xfer;
261}
262
263static void spi_engine_tx_next(struct spi_engine *spi_engine)
264{
265 struct spi_transfer *xfer = spi_engine->tx_xfer;
266
267 do {
268 spi_engine_xfer_next(spi_engine, &xfer);
269 } while (xfer && !xfer->tx_buf);
270
271 spi_engine->tx_xfer = xfer;
272 if (xfer) {
273 spi_engine->tx_length = xfer->len;
274 spi_engine->tx_buf = xfer->tx_buf;
275 } else {
276 spi_engine->tx_buf = NULL;
277 }
278}
279
280static void spi_engine_rx_next(struct spi_engine *spi_engine)
281{
282 struct spi_transfer *xfer = spi_engine->rx_xfer;
283
284 do {
285 spi_engine_xfer_next(spi_engine, &xfer);
286 } while (xfer && !xfer->rx_buf);
287
288 spi_engine->rx_xfer = xfer;
289 if (xfer) {
290 spi_engine->rx_length = xfer->len;
291 spi_engine->rx_buf = xfer->rx_buf;
292 } else {
293 spi_engine->rx_buf = NULL;
294 }
295}
296
297static bool spi_engine_write_cmd_fifo(struct spi_engine *spi_engine)
298{
299 void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_CMD_FIFO;
300 unsigned int n, m, i;
301 const uint16_t *buf;
302
303 n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_CMD_FIFO_ROOM);
304 while (n && spi_engine->cmd_length) {
305 m = min(n, spi_engine->cmd_length);
306 buf = spi_engine->cmd_buf;
307 for (i = 0; i < m; i++)
308 writel_relaxed(buf[i], addr);
309 spi_engine->cmd_buf += m;
310 spi_engine->cmd_length -= m;
311 n -= m;
312 }
313
314 return spi_engine->cmd_length != 0;
315}
316
317static bool spi_engine_write_tx_fifo(struct spi_engine *spi_engine)
318{
319 void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDO_DATA_FIFO;
320 unsigned int n, m, i;
321 const uint8_t *buf;
322
323 n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDO_FIFO_ROOM);
324 while (n && spi_engine->tx_length) {
325 m = min(n, spi_engine->tx_length);
326 buf = spi_engine->tx_buf;
327 for (i = 0; i < m; i++)
328 writel_relaxed(buf[i], addr);
329 spi_engine->tx_buf += m;
330 spi_engine->tx_length -= m;
331 n -= m;
332 if (spi_engine->tx_length == 0)
333 spi_engine_tx_next(spi_engine);
334 }
335
336 return spi_engine->tx_length != 0;
337}
338
339static bool spi_engine_read_rx_fifo(struct spi_engine *spi_engine)
340{
341 void __iomem *addr = spi_engine->base + SPI_ENGINE_REG_SDI_DATA_FIFO;
342 unsigned int n, m, i;
343 uint8_t *buf;
344
345 n = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_SDI_FIFO_LEVEL);
346 while (n && spi_engine->rx_length) {
347 m = min(n, spi_engine->rx_length);
348 buf = spi_engine->rx_buf;
349 for (i = 0; i < m; i++)
350 buf[i] = readl_relaxed(addr);
351 spi_engine->rx_buf += m;
352 spi_engine->rx_length -= m;
353 n -= m;
354 if (spi_engine->rx_length == 0)
355 spi_engine_rx_next(spi_engine);
356 }
357
358 return spi_engine->rx_length != 0;
359}
360
361static irqreturn_t spi_engine_irq(int irq, void *devid)
362{
363 struct spi_master *master = devid;
364 struct spi_engine *spi_engine = spi_master_get_devdata(master);
365 unsigned int disable_int = 0;
366 unsigned int pending;
367
368 pending = readl_relaxed(spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
369
370 if (pending & SPI_ENGINE_INT_SYNC) {
371 writel_relaxed(SPI_ENGINE_INT_SYNC,
372 spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
373 spi_engine->completed_id = readl_relaxed(
374 spi_engine->base + SPI_ENGINE_REG_SYNC_ID);
375 }
376
377 spin_lock(&spi_engine->lock);
378
379 if (pending & SPI_ENGINE_INT_CMD_ALMOST_EMPTY) {
380 if (!spi_engine_write_cmd_fifo(spi_engine))
381 disable_int |= SPI_ENGINE_INT_CMD_ALMOST_EMPTY;
382 }
383
384 if (pending & SPI_ENGINE_INT_SDO_ALMOST_EMPTY) {
385 if (!spi_engine_write_tx_fifo(spi_engine))
386 disable_int |= SPI_ENGINE_INT_SDO_ALMOST_EMPTY;
387 }
388
389 if (pending & (SPI_ENGINE_INT_SDI_ALMOST_FULL | SPI_ENGINE_INT_SYNC)) {
390 if (!spi_engine_read_rx_fifo(spi_engine))
391 disable_int |= SPI_ENGINE_INT_SDI_ALMOST_FULL;
392 }
393
394 if (pending & SPI_ENGINE_INT_SYNC) {
395 if (spi_engine->msg &&
396 spi_engine->completed_id == spi_engine->sync_id) {
397 struct spi_message *msg = spi_engine->msg;
398
399 kfree(spi_engine->p);
400 msg->status = 0;
401 msg->actual_length = msg->frame_length;
402 spi_engine->msg = NULL;
403 spi_finalize_current_message(master);
404 disable_int |= SPI_ENGINE_INT_SYNC;
405 }
406 }
407
408 if (disable_int) {
409 spi_engine->int_enable &= ~disable_int;
410 writel_relaxed(spi_engine->int_enable,
411 spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
412 }
413
414 spin_unlock(&spi_engine->lock);
415
416 return IRQ_HANDLED;
417}
418
419static int spi_engine_transfer_one_message(struct spi_master *master,
420 struct spi_message *msg)
421{
422 struct spi_engine_program p_dry, *p;
423 struct spi_engine *spi_engine = spi_master_get_devdata(master);
424 unsigned int int_enable = 0;
425 unsigned long flags;
426 size_t size;
427
428 p_dry.length = 0;
429 spi_engine_compile_message(spi_engine, msg, true, &p_dry);
430
431 size = sizeof(*p->instructions) * (p_dry.length + 1);
432 p = kzalloc(sizeof(*p) + size, GFP_KERNEL);
433 if (!p)
434 return -ENOMEM;
435 spi_engine_compile_message(spi_engine, msg, false, p);
436
437 spin_lock_irqsave(&spi_engine->lock, flags);
438 spi_engine->sync_id = (spi_engine->sync_id + 1) & 0xff;
439 spi_engine_program_add_cmd(p, false,
440 SPI_ENGINE_CMD_SYNC(spi_engine->sync_id));
441
442 spi_engine->msg = msg;
443 spi_engine->p = p;
444
445 spi_engine->cmd_buf = p->instructions;
446 spi_engine->cmd_length = p->length;
447 if (spi_engine_write_cmd_fifo(spi_engine))
448 int_enable |= SPI_ENGINE_INT_CMD_ALMOST_EMPTY;
449
450 spi_engine_tx_next(spi_engine);
451 if (spi_engine_write_tx_fifo(spi_engine))
452 int_enable |= SPI_ENGINE_INT_SDO_ALMOST_EMPTY;
453
454 spi_engine_rx_next(spi_engine);
455 if (spi_engine->rx_length != 0)
456 int_enable |= SPI_ENGINE_INT_SDI_ALMOST_FULL;
457
458 int_enable |= SPI_ENGINE_INT_SYNC;
459
460 writel_relaxed(int_enable,
461 spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
462 spi_engine->int_enable = int_enable;
463 spin_unlock_irqrestore(&spi_engine->lock, flags);
464
465 return 0;
466}
467
468static int spi_engine_probe(struct platform_device *pdev)
469{
470 struct spi_engine *spi_engine;
471 struct spi_master *master;
472 unsigned int version;
473 int irq;
474 int ret;
475
476 irq = platform_get_irq(pdev, 0);
477 if (irq <= 0)
478 return -ENXIO;
479
480 spi_engine = devm_kzalloc(&pdev->dev, sizeof(*spi_engine), GFP_KERNEL);
481 if (!spi_engine)
482 return -ENOMEM;
483
484 master = spi_alloc_master(&pdev->dev, 0);
485 if (!master)
486 return -ENOMEM;
487
488 spi_master_set_devdata(master, spi_engine);
489
490 spin_lock_init(&spi_engine->lock);
491
492 spi_engine->base = devm_platform_ioremap_resource(pdev, 0);
493 if (IS_ERR(spi_engine->base)) {
494 ret = PTR_ERR(spi_engine->base);
495 goto err_put_master;
496 }
497
498 version = readl(spi_engine->base + SPI_ENGINE_REG_VERSION);
499 if (SPI_ENGINE_VERSION_MAJOR(version) != 1) {
500 dev_err(&pdev->dev, "Unsupported peripheral version %u.%u.%c\n",
501 SPI_ENGINE_VERSION_MAJOR(version),
502 SPI_ENGINE_VERSION_MINOR(version),
503 SPI_ENGINE_VERSION_PATCH(version));
504 ret = -ENODEV;
505 goto err_put_master;
506 }
507
508 spi_engine->clk = devm_clk_get(&pdev->dev, "s_axi_aclk");
509 if (IS_ERR(spi_engine->clk)) {
510 ret = PTR_ERR(spi_engine->clk);
511 goto err_put_master;
512 }
513
514 spi_engine->ref_clk = devm_clk_get(&pdev->dev, "spi_clk");
515 if (IS_ERR(spi_engine->ref_clk)) {
516 ret = PTR_ERR(spi_engine->ref_clk);
517 goto err_put_master;
518 }
519
520 ret = clk_prepare_enable(spi_engine->clk);
521 if (ret)
522 goto err_put_master;
523
524 ret = clk_prepare_enable(spi_engine->ref_clk);
525 if (ret)
526 goto err_clk_disable;
527
528 writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_RESET);
529 writel_relaxed(0xff, spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
530 writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
531
532 ret = request_irq(irq, spi_engine_irq, 0, pdev->name, master);
533 if (ret)
534 goto err_ref_clk_disable;
535
536 master->dev.of_node = pdev->dev.of_node;
537 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_3WIRE;
538 master->bits_per_word_mask = SPI_BPW_MASK(8);
539 master->max_speed_hz = clk_get_rate(spi_engine->ref_clk) / 2;
540 master->transfer_one_message = spi_engine_transfer_one_message;
541 master->num_chipselect = 8;
542
543 ret = spi_register_master(master);
544 if (ret)
545 goto err_free_irq;
546
547 platform_set_drvdata(pdev, master);
548
549 return 0;
550err_free_irq:
551 free_irq(irq, master);
552err_ref_clk_disable:
553 clk_disable_unprepare(spi_engine->ref_clk);
554err_clk_disable:
555 clk_disable_unprepare(spi_engine->clk);
556err_put_master:
557 spi_master_put(master);
558 return ret;
559}
560
561static int spi_engine_remove(struct platform_device *pdev)
562{
563 struct spi_master *master = spi_master_get(platform_get_drvdata(pdev));
564 struct spi_engine *spi_engine = spi_master_get_devdata(master);
565 int irq = platform_get_irq(pdev, 0);
566
567 spi_unregister_master(master);
568
569 free_irq(irq, master);
570
571 spi_master_put(master);
572
573 writel_relaxed(0xff, spi_engine->base + SPI_ENGINE_REG_INT_PENDING);
574 writel_relaxed(0x00, spi_engine->base + SPI_ENGINE_REG_INT_ENABLE);
575 writel_relaxed(0x01, spi_engine->base + SPI_ENGINE_REG_RESET);
576
577 clk_disable_unprepare(spi_engine->ref_clk);
578 clk_disable_unprepare(spi_engine->clk);
579
580 return 0;
581}
582
583static const struct of_device_id spi_engine_match_table[] = {
584 { .compatible = "adi,axi-spi-engine-1.00.a" },
585 { },
586};
587MODULE_DEVICE_TABLE(of, spi_engine_match_table);
588
589static struct platform_driver spi_engine_driver = {
590 .probe = spi_engine_probe,
591 .remove = spi_engine_remove,
592 .driver = {
593 .name = "spi-engine",
594 .of_match_table = spi_engine_match_table,
595 },
596};
597module_platform_driver(spi_engine_driver);
598
599MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
600MODULE_DESCRIPTION("Analog Devices SPI engine peripheral driver");
601MODULE_LICENSE("GPL");
602
