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10#include <linux/clk.h>
11#include <linux/completion.h>
12#include <linux/delay.h>
13#include <linux/err.h>
14#include <linux/interrupt.h>
15#include <linux/io.h>
16#include <linux/kernel.h>
17#include <linux/kthread.h>
18#include <linux/module.h>
19#include <linux/platform_device.h>
20#include <linux/pm_runtime.h>
21#include <linux/of.h>
22#include <linux/of_device.h>
23#include <linux/reset.h>
24#include <linux/spi/spi.h>
25
26#define SPI_COMMAND 0x000
27#define SPI_GO BIT(30)
28#define SPI_M_S BIT(28)
29#define SPI_ACTIVE_SCLK_MASK (0x3 << 26)
30#define SPI_ACTIVE_SCLK_DRIVE_LOW (0 << 26)
31#define SPI_ACTIVE_SCLK_DRIVE_HIGH (1 << 26)
32#define SPI_ACTIVE_SCLK_PULL_LOW (2 << 26)
33#define SPI_ACTIVE_SCLK_PULL_HIGH (3 << 26)
34
35#define SPI_CK_SDA_FALLING (1 << 21)
36#define SPI_CK_SDA_RISING (0 << 21)
37#define SPI_CK_SDA_MASK (1 << 21)
38#define SPI_ACTIVE_SDA (0x3 << 18)
39#define SPI_ACTIVE_SDA_DRIVE_LOW (0 << 18)
40#define SPI_ACTIVE_SDA_DRIVE_HIGH (1 << 18)
41#define SPI_ACTIVE_SDA_PULL_LOW (2 << 18)
42#define SPI_ACTIVE_SDA_PULL_HIGH (3 << 18)
43
44#define SPI_CS_POL_INVERT BIT(16)
45#define SPI_TX_EN BIT(15)
46#define SPI_RX_EN BIT(14)
47#define SPI_CS_VAL_HIGH BIT(13)
48#define SPI_CS_VAL_LOW 0x0
49#define SPI_CS_SW BIT(12)
50#define SPI_CS_HW 0x0
51#define SPI_CS_DELAY_MASK (7 << 9)
52#define SPI_CS3_EN BIT(8)
53#define SPI_CS2_EN BIT(7)
54#define SPI_CS1_EN BIT(6)
55#define SPI_CS0_EN BIT(5)
56
57#define SPI_CS_MASK (SPI_CS3_EN | SPI_CS2_EN | \
58 SPI_CS1_EN | SPI_CS0_EN)
59#define SPI_BIT_LENGTH(x) (((x) & 0x1f) << 0)
60
61#define SPI_MODES (SPI_ACTIVE_SCLK_MASK | SPI_CK_SDA_MASK)
62
63#define SPI_STATUS 0x004
64#define SPI_BSY BIT(31)
65#define SPI_RDY BIT(30)
66#define SPI_TXF_FLUSH BIT(29)
67#define SPI_RXF_FLUSH BIT(28)
68#define SPI_RX_UNF BIT(27)
69#define SPI_TX_OVF BIT(26)
70#define SPI_RXF_EMPTY BIT(25)
71#define SPI_RXF_FULL BIT(24)
72#define SPI_TXF_EMPTY BIT(23)
73#define SPI_TXF_FULL BIT(22)
74#define SPI_BLK_CNT(count) (((count) & 0xffff) + 1)
75
76#define SPI_FIFO_ERROR (SPI_RX_UNF | SPI_TX_OVF)
77#define SPI_FIFO_EMPTY (SPI_TX_EMPTY | SPI_RX_EMPTY)
78
79#define SPI_RX_CMP 0x8
80#define SPI_DMA_CTL 0x0C
81#define SPI_DMA_EN BIT(31)
82#define SPI_IE_RXC BIT(27)
83#define SPI_IE_TXC BIT(26)
84#define SPI_PACKED BIT(20)
85#define SPI_RX_TRIG_MASK (0x3 << 18)
86#define SPI_RX_TRIG_1W (0x0 << 18)
87#define SPI_RX_TRIG_4W (0x1 << 18)
88#define SPI_TX_TRIG_MASK (0x3 << 16)
89#define SPI_TX_TRIG_1W (0x0 << 16)
90#define SPI_TX_TRIG_4W (0x1 << 16)
91#define SPI_DMA_BLK_COUNT(count) (((count) - 1) & 0xFFFF)
92
93#define SPI_TX_FIFO 0x10
94#define SPI_RX_FIFO 0x20
95
96#define DATA_DIR_TX (1 << 0)
97#define DATA_DIR_RX (1 << 1)
98
99#define MAX_CHIP_SELECT 4
100#define SPI_FIFO_DEPTH 4
101#define SPI_DMA_TIMEOUT (msecs_to_jiffies(1000))
102
103struct tegra_sflash_data {
104 struct device *dev;
105 struct spi_master *master;
106 spinlock_t lock;
107
108 struct clk *clk;
109 struct reset_control *rst;
110 void __iomem *base;
111 unsigned irq;
112 u32 cur_speed;
113
114 struct spi_device *cur_spi;
115 unsigned cur_pos;
116 unsigned cur_len;
117 unsigned bytes_per_word;
118 unsigned cur_direction;
119 unsigned curr_xfer_words;
120
121 unsigned cur_rx_pos;
122 unsigned cur_tx_pos;
123
124 u32 tx_status;
125 u32 rx_status;
126 u32 status_reg;
127
128 u32 def_command_reg;
129 u32 command_reg;
130 u32 dma_control_reg;
131
132 struct completion xfer_completion;
133 struct spi_transfer *curr_xfer;
134};
135
136static int tegra_sflash_runtime_suspend(struct device *dev);
137static int tegra_sflash_runtime_resume(struct device *dev);
138
139static inline u32 tegra_sflash_readl(struct tegra_sflash_data *tsd,
140 unsigned long reg)
141{
142 return readl(tsd->base + reg);
143}
144
145static inline void tegra_sflash_writel(struct tegra_sflash_data *tsd,
146 u32 val, unsigned long reg)
147{
148 writel(val, tsd->base + reg);
149}
150
151static void tegra_sflash_clear_status(struct tegra_sflash_data *tsd)
152{
153
154 tegra_sflash_writel(tsd, SPI_RDY | SPI_FIFO_ERROR, SPI_STATUS);
155}
156
157static unsigned tegra_sflash_calculate_curr_xfer_param(
158 struct spi_device *spi, struct tegra_sflash_data *tsd,
159 struct spi_transfer *t)
160{
161 unsigned remain_len = t->len - tsd->cur_pos;
162 unsigned max_word;
163
164 tsd->bytes_per_word = DIV_ROUND_UP(t->bits_per_word, 8);
165 max_word = remain_len / tsd->bytes_per_word;
166 if (max_word > SPI_FIFO_DEPTH)
167 max_word = SPI_FIFO_DEPTH;
168 tsd->curr_xfer_words = max_word;
169 return max_word;
170}
171
172static unsigned tegra_sflash_fill_tx_fifo_from_client_txbuf(
173 struct tegra_sflash_data *tsd, struct spi_transfer *t)
174{
175 unsigned nbytes;
176 u32 status;
177 unsigned max_n_32bit = tsd->curr_xfer_words;
178 u8 *tx_buf = (u8 *)t->tx_buf + tsd->cur_tx_pos;
179
180 if (max_n_32bit > SPI_FIFO_DEPTH)
181 max_n_32bit = SPI_FIFO_DEPTH;
182 nbytes = max_n_32bit * tsd->bytes_per_word;
183
184 status = tegra_sflash_readl(tsd, SPI_STATUS);
185 while (!(status & SPI_TXF_FULL)) {
186 int i;
187 u32 x = 0;
188
189 for (i = 0; nbytes && (i < tsd->bytes_per_word);
190 i++, nbytes--)
191 x |= (u32)(*tx_buf++) << (i * 8);
192 tegra_sflash_writel(tsd, x, SPI_TX_FIFO);
193 if (!nbytes)
194 break;
195
196 status = tegra_sflash_readl(tsd, SPI_STATUS);
197 }
198 tsd->cur_tx_pos += max_n_32bit * tsd->bytes_per_word;
199 return max_n_32bit;
200}
201
202static int tegra_sflash_read_rx_fifo_to_client_rxbuf(
203 struct tegra_sflash_data *tsd, struct spi_transfer *t)
204{
205 u32 status;
206 unsigned int read_words = 0;
207 u8 *rx_buf = (u8 *)t->rx_buf + tsd->cur_rx_pos;
208
209 status = tegra_sflash_readl(tsd, SPI_STATUS);
210 while (!(status & SPI_RXF_EMPTY)) {
211 int i;
212 u32 x = tegra_sflash_readl(tsd, SPI_RX_FIFO);
213
214 for (i = 0; (i < tsd->bytes_per_word); i++)
215 *rx_buf++ = (x >> (i*8)) & 0xFF;
216 read_words++;
217 status = tegra_sflash_readl(tsd, SPI_STATUS);
218 }
219 tsd->cur_rx_pos += read_words * tsd->bytes_per_word;
220 return 0;
221}
222
223static int tegra_sflash_start_cpu_based_transfer(
224 struct tegra_sflash_data *tsd, struct spi_transfer *t)
225{
226 u32 val = 0;
227 unsigned cur_words;
228
229 if (tsd->cur_direction & DATA_DIR_TX)
230 val |= SPI_IE_TXC;
231
232 if (tsd->cur_direction & DATA_DIR_RX)
233 val |= SPI_IE_RXC;
234
235 tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
236 tsd->dma_control_reg = val;
237
238 if (tsd->cur_direction & DATA_DIR_TX)
239 cur_words = tegra_sflash_fill_tx_fifo_from_client_txbuf(tsd, t);
240 else
241 cur_words = tsd->curr_xfer_words;
242 val |= SPI_DMA_BLK_COUNT(cur_words);
243 tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
244 tsd->dma_control_reg = val;
245 val |= SPI_DMA_EN;
246 tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
247 return 0;
248}
249
250static int tegra_sflash_start_transfer_one(struct spi_device *spi,
251 struct spi_transfer *t, bool is_first_of_msg,
252 bool is_single_xfer)
253{
254 struct tegra_sflash_data *tsd = spi_master_get_devdata(spi->master);
255 u32 speed;
256 u32 command;
257
258 speed = t->speed_hz;
259 if (speed != tsd->cur_speed) {
260 clk_set_rate(tsd->clk, speed);
261 tsd->cur_speed = speed;
262 }
263
264 tsd->cur_spi = spi;
265 tsd->cur_pos = 0;
266 tsd->cur_rx_pos = 0;
267 tsd->cur_tx_pos = 0;
268 tsd->curr_xfer = t;
269 tegra_sflash_calculate_curr_xfer_param(spi, tsd, t);
270 if (is_first_of_msg) {
271 command = tsd->def_command_reg;
272 command |= SPI_BIT_LENGTH(t->bits_per_word - 1);
273 command |= SPI_CS_VAL_HIGH;
274
275 command &= ~SPI_MODES;
276 if (spi->mode & SPI_CPHA)
277 command |= SPI_CK_SDA_FALLING;
278
279 if (spi->mode & SPI_CPOL)
280 command |= SPI_ACTIVE_SCLK_DRIVE_HIGH;
281 else
282 command |= SPI_ACTIVE_SCLK_DRIVE_LOW;
283 command |= SPI_CS0_EN << spi->chip_select;
284 } else {
285 command = tsd->command_reg;
286 command &= ~SPI_BIT_LENGTH(~0);
287 command |= SPI_BIT_LENGTH(t->bits_per_word - 1);
288 command &= ~(SPI_RX_EN | SPI_TX_EN);
289 }
290
291 tsd->cur_direction = 0;
292 if (t->rx_buf) {
293 command |= SPI_RX_EN;
294 tsd->cur_direction |= DATA_DIR_RX;
295 }
296 if (t->tx_buf) {
297 command |= SPI_TX_EN;
298 tsd->cur_direction |= DATA_DIR_TX;
299 }
300 tegra_sflash_writel(tsd, command, SPI_COMMAND);
301 tsd->command_reg = command;
302
303 return tegra_sflash_start_cpu_based_transfer(tsd, t);
304}
305
306static int tegra_sflash_transfer_one_message(struct spi_master *master,
307 struct spi_message *msg)
308{
309 bool is_first_msg = true;
310 int single_xfer;
311 struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
312 struct spi_transfer *xfer;
313 struct spi_device *spi = msg->spi;
314 int ret;
315
316 msg->status = 0;
317 msg->actual_length = 0;
318 single_xfer = list_is_singular(&msg->transfers);
319 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
320 reinit_completion(&tsd->xfer_completion);
321 ret = tegra_sflash_start_transfer_one(spi, xfer,
322 is_first_msg, single_xfer);
323 if (ret < 0) {
324 dev_err(tsd->dev,
325 "spi can not start transfer, err %d\n", ret);
326 goto exit;
327 }
328 is_first_msg = false;
329 ret = wait_for_completion_timeout(&tsd->xfer_completion,
330 SPI_DMA_TIMEOUT);
331 if (WARN_ON(ret == 0)) {
332 dev_err(tsd->dev,
333 "spi transfer timeout, err %d\n", ret);
334 ret = -EIO;
335 goto exit;
336 }
337
338 if (tsd->tx_status || tsd->rx_status) {
339 dev_err(tsd->dev, "Error in Transfer\n");
340 ret = -EIO;
341 goto exit;
342 }
343 msg->actual_length += xfer->len;
344 if (xfer->cs_change && xfer->delay.value) {
345 tegra_sflash_writel(tsd, tsd->def_command_reg,
346 SPI_COMMAND);
347 spi_transfer_delay_exec(xfer);
348 }
349 }
350 ret = 0;
351exit:
352 tegra_sflash_writel(tsd, tsd->def_command_reg, SPI_COMMAND);
353 msg->status = ret;
354 spi_finalize_current_message(master);
355 return ret;
356}
357
358static irqreturn_t handle_cpu_based_xfer(struct tegra_sflash_data *tsd)
359{
360 struct spi_transfer *t = tsd->curr_xfer;
361
362 spin_lock(&tsd->lock);
363 if (tsd->tx_status || tsd->rx_status || (tsd->status_reg & SPI_BSY)) {
364 dev_err(tsd->dev,
365 "CpuXfer ERROR bit set 0x%x\n", tsd->status_reg);
366 dev_err(tsd->dev,
367 "CpuXfer 0x%08x:0x%08x\n", tsd->command_reg,
368 tsd->dma_control_reg);
369 reset_control_assert(tsd->rst);
370 udelay(2);
371 reset_control_deassert(tsd->rst);
372 complete(&tsd->xfer_completion);
373 goto exit;
374 }
375
376 if (tsd->cur_direction & DATA_DIR_RX)
377 tegra_sflash_read_rx_fifo_to_client_rxbuf(tsd, t);
378
379 if (tsd->cur_direction & DATA_DIR_TX)
380 tsd->cur_pos = tsd->cur_tx_pos;
381 else
382 tsd->cur_pos = tsd->cur_rx_pos;
383
384 if (tsd->cur_pos == t->len) {
385 complete(&tsd->xfer_completion);
386 goto exit;
387 }
388
389 tegra_sflash_calculate_curr_xfer_param(tsd->cur_spi, tsd, t);
390 tegra_sflash_start_cpu_based_transfer(tsd, t);
391exit:
392 spin_unlock(&tsd->lock);
393 return IRQ_HANDLED;
394}
395
396static irqreturn_t tegra_sflash_isr(int irq, void *context_data)
397{
398 struct tegra_sflash_data *tsd = context_data;
399
400 tsd->status_reg = tegra_sflash_readl(tsd, SPI_STATUS);
401 if (tsd->cur_direction & DATA_DIR_TX)
402 tsd->tx_status = tsd->status_reg & SPI_TX_OVF;
403
404 if (tsd->cur_direction & DATA_DIR_RX)
405 tsd->rx_status = tsd->status_reg & SPI_RX_UNF;
406 tegra_sflash_clear_status(tsd);
407
408 return handle_cpu_based_xfer(tsd);
409}
410
411static const struct of_device_id tegra_sflash_of_match[] = {
412 { .compatible = "nvidia,tegra20-sflash", },
413 {}
414};
415MODULE_DEVICE_TABLE(of, tegra_sflash_of_match);
416
417static int tegra_sflash_probe(struct platform_device *pdev)
418{
419 struct spi_master *master;
420 struct tegra_sflash_data *tsd;
421 int ret;
422 const struct of_device_id *match;
423
424 match = of_match_device(tegra_sflash_of_match, &pdev->dev);
425 if (!match) {
426 dev_err(&pdev->dev, "Error: No device match found\n");
427 return -ENODEV;
428 }
429
430 master = spi_alloc_master(&pdev->dev, sizeof(*tsd));
431 if (!master) {
432 dev_err(&pdev->dev, "master allocation failed\n");
433 return -ENOMEM;
434 }
435
436
437 master->mode_bits = SPI_CPOL | SPI_CPHA;
438 master->transfer_one_message = tegra_sflash_transfer_one_message;
439 master->auto_runtime_pm = true;
440 master->num_chipselect = MAX_CHIP_SELECT;
441
442 platform_set_drvdata(pdev, master);
443 tsd = spi_master_get_devdata(master);
444 tsd->master = master;
445 tsd->dev = &pdev->dev;
446 spin_lock_init(&tsd->lock);
447
448 if (of_property_read_u32(tsd->dev->of_node, "spi-max-frequency",
449 &master->max_speed_hz))
450 master->max_speed_hz = 25000000;
451
452 tsd->base = devm_platform_ioremap_resource(pdev, 0);
453 if (IS_ERR(tsd->base)) {
454 ret = PTR_ERR(tsd->base);
455 goto exit_free_master;
456 }
457
458 tsd->irq = platform_get_irq(pdev, 0);
459 ret = request_irq(tsd->irq, tegra_sflash_isr, 0,
460 dev_name(&pdev->dev), tsd);
461 if (ret < 0) {
462 dev_err(&pdev->dev, "Failed to register ISR for IRQ %d\n",
463 tsd->irq);
464 goto exit_free_master;
465 }
466
467 tsd->clk = devm_clk_get(&pdev->dev, NULL);
468 if (IS_ERR(tsd->clk)) {
469 dev_err(&pdev->dev, "can not get clock\n");
470 ret = PTR_ERR(tsd->clk);
471 goto exit_free_irq;
472 }
473
474 tsd->rst = devm_reset_control_get_exclusive(&pdev->dev, "spi");
475 if (IS_ERR(tsd->rst)) {
476 dev_err(&pdev->dev, "can not get reset\n");
477 ret = PTR_ERR(tsd->rst);
478 goto exit_free_irq;
479 }
480
481 init_completion(&tsd->xfer_completion);
482 pm_runtime_enable(&pdev->dev);
483 if (!pm_runtime_enabled(&pdev->dev)) {
484 ret = tegra_sflash_runtime_resume(&pdev->dev);
485 if (ret)
486 goto exit_pm_disable;
487 }
488
489 ret = pm_runtime_get_sync(&pdev->dev);
490 if (ret < 0) {
491 dev_err(&pdev->dev, "pm runtime get failed, e = %d\n", ret);
492 pm_runtime_put_noidle(&pdev->dev);
493 goto exit_pm_disable;
494 }
495
496
497 reset_control_assert(tsd->rst);
498 udelay(2);
499 reset_control_deassert(tsd->rst);
500
501 tsd->def_command_reg = SPI_M_S | SPI_CS_SW;
502 tegra_sflash_writel(tsd, tsd->def_command_reg, SPI_COMMAND);
503 pm_runtime_put(&pdev->dev);
504
505 master->dev.of_node = pdev->dev.of_node;
506 ret = devm_spi_register_master(&pdev->dev, master);
507 if (ret < 0) {
508 dev_err(&pdev->dev, "can not register to master err %d\n", ret);
509 goto exit_pm_disable;
510 }
511 return ret;
512
513exit_pm_disable:
514 pm_runtime_disable(&pdev->dev);
515 if (!pm_runtime_status_suspended(&pdev->dev))
516 tegra_sflash_runtime_suspend(&pdev->dev);
517exit_free_irq:
518 free_irq(tsd->irq, tsd);
519exit_free_master:
520 spi_master_put(master);
521 return ret;
522}
523
524static int tegra_sflash_remove(struct platform_device *pdev)
525{
526 struct spi_master *master = platform_get_drvdata(pdev);
527 struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
528
529 free_irq(tsd->irq, tsd);
530
531 pm_runtime_disable(&pdev->dev);
532 if (!pm_runtime_status_suspended(&pdev->dev))
533 tegra_sflash_runtime_suspend(&pdev->dev);
534
535 return 0;
536}
537
538#ifdef CONFIG_PM_SLEEP
539static int tegra_sflash_suspend(struct device *dev)
540{
541 struct spi_master *master = dev_get_drvdata(dev);
542
543 return spi_master_suspend(master);
544}
545
546static int tegra_sflash_resume(struct device *dev)
547{
548 struct spi_master *master = dev_get_drvdata(dev);
549 struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
550 int ret;
551
552 ret = pm_runtime_get_sync(dev);
553 if (ret < 0) {
554 pm_runtime_put_noidle(dev);
555 dev_err(dev, "pm runtime failed, e = %d\n", ret);
556 return ret;
557 }
558 tegra_sflash_writel(tsd, tsd->command_reg, SPI_COMMAND);
559 pm_runtime_put(dev);
560
561 return spi_master_resume(master);
562}
563#endif
564
565static int tegra_sflash_runtime_suspend(struct device *dev)
566{
567 struct spi_master *master = dev_get_drvdata(dev);
568 struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
569
570
571 tegra_sflash_readl(tsd, SPI_COMMAND);
572
573 clk_disable_unprepare(tsd->clk);
574 return 0;
575}
576
577static int tegra_sflash_runtime_resume(struct device *dev)
578{
579 struct spi_master *master = dev_get_drvdata(dev);
580 struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
581 int ret;
582
583 ret = clk_prepare_enable(tsd->clk);
584 if (ret < 0) {
585 dev_err(tsd->dev, "clk_prepare failed: %d\n", ret);
586 return ret;
587 }
588 return 0;
589}
590
591static const struct dev_pm_ops slink_pm_ops = {
592 SET_RUNTIME_PM_OPS(tegra_sflash_runtime_suspend,
593 tegra_sflash_runtime_resume, NULL)
594 SET_SYSTEM_SLEEP_PM_OPS(tegra_sflash_suspend, tegra_sflash_resume)
595};
596static struct platform_driver tegra_sflash_driver = {
597 .driver = {
598 .name = "spi-tegra-sflash",
599 .pm = &slink_pm_ops,
600 .of_match_table = tegra_sflash_of_match,
601 },
602 .probe = tegra_sflash_probe,
603 .remove = tegra_sflash_remove,
604};
605module_platform_driver(tegra_sflash_driver);
606
607MODULE_ALIAS("platform:spi-tegra-sflash");
608MODULE_DESCRIPTION("NVIDIA Tegra20 Serial Flash Controller Driver");
609MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
610MODULE_LICENSE("GPL v2");
611
