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