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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * SPI driver for Nvidia's Tegra20 Serial Flash Controller.
4 *
5 * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
6 *
7 * Author: Laxman Dewangan <[email protected]>
8 */
9
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_controller *host;
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 /* Write 1 to clear status register */
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_controller_get_devdata(spi->controller);
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_get_chipselect(spi, 0);
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_controller *host,
307 struct spi_message *msg)
308{
309 bool is_first_msg = true;
310 int single_xfer;
311 struct tegra_sflash_data *tsd = spi_controller_get_devdata(host);
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(host);
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_controller *host;
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 host = devm_spi_alloc_host(&pdev->dev, sizeof(*tsd));
431 if (!host)
432 return -ENOMEM;
433
434 /* the spi->mode bits understood by this driver: */
435 host->mode_bits = SPI_CPOL | SPI_CPHA;
436 host->transfer_one_message = tegra_sflash_transfer_one_message;
437 host->auto_runtime_pm = true;
438 host->num_chipselect = MAX_CHIP_SELECT;
439
440 platform_set_drvdata(pdev, host);
441 tsd = spi_controller_get_devdata(host);
442 tsd->host = host;
443 tsd->dev = &pdev->dev;
444 spin_lock_init(&tsd->lock);
445
446 if (of_property_read_u32(tsd->dev->of_node, "spi-max-frequency",
447 &host->max_speed_hz))
448 host->max_speed_hz = 25000000; /* 25MHz */
449
450 tsd->base = devm_platform_ioremap_resource(pdev, 0);
451 if (IS_ERR(tsd->base))
452 return PTR_ERR(tsd->base);
453
454 ret = platform_get_irq(pdev, 0);
455 if (ret < 0)
456 return ret;
457
458 tsd->irq = ret;
459
460 ret = request_irq(tsd->irq, tegra_sflash_isr, 0,
461 dev_name(&pdev->dev), tsd);
462 if (ret < 0) {
463 dev_err(&pdev->dev, "Failed to register ISR for IRQ %d\n",
464 tsd->irq);
465 return ret;
466 }
467
468 tsd->clk = devm_clk_get(&pdev->dev, NULL);
469 if (IS_ERR(tsd->clk)) {
470 dev_err(&pdev->dev, "can not get clock\n");
471 ret = PTR_ERR(tsd->clk);
472 goto exit_free_irq;
473 }
474
475 tsd->rst = devm_reset_control_get_exclusive(&pdev->dev, "spi");
476 if (IS_ERR(tsd->rst)) {
477 dev_err(&pdev->dev, "can not get reset\n");
478 ret = PTR_ERR(tsd->rst);
479 goto exit_free_irq;
480 }
481
482 init_completion(&tsd->xfer_completion);
483 pm_runtime_enable(&pdev->dev);
484 if (!pm_runtime_enabled(&pdev->dev)) {
485 ret = tegra_sflash_runtime_resume(&pdev->dev);
486 if (ret)
487 goto exit_pm_disable;
488 }
489
490 ret = pm_runtime_resume_and_get(&pdev->dev);
491 if (ret < 0) {
492 dev_err(&pdev->dev, "pm runtime get failed, e = %d\n", ret);
493 goto exit_pm_disable;
494 }
495
496 /* Reset controller */
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 ret = spi_register_controller(host);
506 if (ret < 0) {
507 dev_err(&pdev->dev, "can not register to host err %d\n", ret);
508 goto exit_pm_disable;
509 }
510 return ret;
511
512exit_pm_disable:
513 pm_runtime_disable(&pdev->dev);
514 if (!pm_runtime_status_suspended(&pdev->dev))
515 tegra_sflash_runtime_suspend(&pdev->dev);
516exit_free_irq:
517 free_irq(tsd->irq, tsd);
518
519 return ret;
520}
521
522static void tegra_sflash_remove(struct platform_device *pdev)
523{
524 struct spi_controller *host = platform_get_drvdata(pdev);
525 struct tegra_sflash_data *tsd = spi_controller_get_devdata(host);
526
527 spi_unregister_controller(host);
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
536static int tegra_sflash_suspend(struct device *dev)
537{
538 struct spi_controller *host = dev_get_drvdata(dev);
539
540 return spi_controller_suspend(host);
541}
542
543static int tegra_sflash_resume(struct device *dev)
544{
545 struct spi_controller *host = dev_get_drvdata(dev);
546 struct tegra_sflash_data *tsd = spi_controller_get_devdata(host);
547 int ret;
548
549 ret = pm_runtime_resume_and_get(dev);
550 if (ret < 0) {
551 dev_err(dev, "pm runtime failed, e = %d\n", ret);
552 return ret;
553 }
554 tegra_sflash_writel(tsd, tsd->command_reg, SPI_COMMAND);
555 pm_runtime_put(dev);
556
557 return spi_controller_resume(host);
558}
559
560static int tegra_sflash_runtime_suspend(struct device *dev)
561{
562 struct spi_controller *host = dev_get_drvdata(dev);
563 struct tegra_sflash_data *tsd = spi_controller_get_devdata(host);
564
565 /* Flush all write which are in PPSB queue by reading back */
566 tegra_sflash_readl(tsd, SPI_COMMAND);
567
568 clk_disable_unprepare(tsd->clk);
569 return 0;
570}
571
572static int tegra_sflash_runtime_resume(struct device *dev)
573{
574 struct spi_controller *host = dev_get_drvdata(dev);
575 struct tegra_sflash_data *tsd = spi_controller_get_devdata(host);
576 int ret;
577
578 ret = clk_prepare_enable(tsd->clk);
579 if (ret < 0) {
580 dev_err(tsd->dev, "clk_prepare failed: %d\n", ret);
581 return ret;
582 }
583 return 0;
584}
585
586static const struct dev_pm_ops slink_pm_ops = {
587 RUNTIME_PM_OPS(tegra_sflash_runtime_suspend,
588 tegra_sflash_runtime_resume, NULL)
589 SYSTEM_SLEEP_PM_OPS(tegra_sflash_suspend, tegra_sflash_resume)
590};
591static struct platform_driver tegra_sflash_driver = {
592 .driver = {
593 .name = "spi-tegra-sflash",
594 .pm = pm_ptr(&slink_pm_ops),
595 .of_match_table = tegra_sflash_of_match,
596 },
597 .probe = tegra_sflash_probe,
598 .remove = tegra_sflash_remove,
599};
600module_platform_driver(tegra_sflash_driver);
601
602MODULE_ALIAS("platform:spi-tegra-sflash");
603MODULE_DESCRIPTION("NVIDIA Tegra20 Serial Flash Controller Driver");
604MODULE_AUTHOR("Laxman Dewangan <[email protected]>");
605MODULE_LICENSE("GPL v2");