1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * SPI driver for Nvidia's Tegra20/Tegra30 SLINK Controller.
4  *
5  * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
6  */
7 
8 #include <linux/clk.h>
9 #include <linux/completion.h>
10 #include <linux/delay.h>
11 #include <linux/dmaengine.h>
12 #include <linux/dma-mapping.h>
13 #include <linux/dmapool.h>
14 #include <linux/err.h>
15 #include <linux/interrupt.h>
16 #include <linux/io.h>
17 #include <linux/kernel.h>
18 #include <linux/kthread.h>
19 #include <linux/module.h>
20 #include <linux/platform_device.h>
21 #include <linux/pm_runtime.h>
22 #include <linux/of.h>
23 #include <linux/of_device.h>
24 #include <linux/reset.h>
25 #include <linux/spi/spi.h>
26 
27 #define SLINK_COMMAND			0x000
28 #define SLINK_BIT_LENGTH(x)		(((x) & 0x1f) << 0)
29 #define SLINK_WORD_SIZE(x)		(((x) & 0x1f) << 5)
30 #define SLINK_BOTH_EN			(1 << 10)
31 #define SLINK_CS_SW			(1 << 11)
32 #define SLINK_CS_VALUE			(1 << 12)
33 #define SLINK_CS_POLARITY		(1 << 13)
34 #define SLINK_IDLE_SDA_DRIVE_LOW	(0 << 16)
35 #define SLINK_IDLE_SDA_DRIVE_HIGH	(1 << 16)
36 #define SLINK_IDLE_SDA_PULL_LOW		(2 << 16)
37 #define SLINK_IDLE_SDA_PULL_HIGH	(3 << 16)
38 #define SLINK_IDLE_SDA_MASK		(3 << 16)
39 #define SLINK_CS_POLARITY1		(1 << 20)
40 #define SLINK_CK_SDA			(1 << 21)
41 #define SLINK_CS_POLARITY2		(1 << 22)
42 #define SLINK_CS_POLARITY3		(1 << 23)
43 #define SLINK_IDLE_SCLK_DRIVE_LOW	(0 << 24)
44 #define SLINK_IDLE_SCLK_DRIVE_HIGH	(1 << 24)
45 #define SLINK_IDLE_SCLK_PULL_LOW	(2 << 24)
46 #define SLINK_IDLE_SCLK_PULL_HIGH	(3 << 24)
47 #define SLINK_IDLE_SCLK_MASK		(3 << 24)
48 #define SLINK_M_S			(1 << 28)
49 #define SLINK_WAIT			(1 << 29)
50 #define SLINK_GO			(1 << 30)
51 #define SLINK_ENB			(1 << 31)
52 
53 #define SLINK_MODES			(SLINK_IDLE_SCLK_MASK | SLINK_CK_SDA)
54 
55 #define SLINK_COMMAND2			0x004
56 #define SLINK_LSBFE			(1 << 0)
57 #define SLINK_SSOE			(1 << 1)
58 #define SLINK_SPIE			(1 << 4)
59 #define SLINK_BIDIROE			(1 << 6)
60 #define SLINK_MODFEN			(1 << 7)
61 #define SLINK_INT_SIZE(x)		(((x) & 0x1f) << 8)
62 #define SLINK_CS_ACTIVE_BETWEEN		(1 << 17)
63 #define SLINK_SS_EN_CS(x)		(((x) & 0x3) << 18)
64 #define SLINK_SS_SETUP(x)		(((x) & 0x3) << 20)
65 #define SLINK_FIFO_REFILLS_0		(0 << 22)
66 #define SLINK_FIFO_REFILLS_1		(1 << 22)
67 #define SLINK_FIFO_REFILLS_2		(2 << 22)
68 #define SLINK_FIFO_REFILLS_3		(3 << 22)
69 #define SLINK_FIFO_REFILLS_MASK		(3 << 22)
70 #define SLINK_WAIT_PACK_INT(x)		(((x) & 0x7) << 26)
71 #define SLINK_SPC0			(1 << 29)
72 #define SLINK_TXEN			(1 << 30)
73 #define SLINK_RXEN			(1 << 31)
74 
75 #define SLINK_STATUS			0x008
76 #define SLINK_COUNT(val)		(((val) >> 0) & 0x1f)
77 #define SLINK_WORD(val)			(((val) >> 5) & 0x1f)
78 #define SLINK_BLK_CNT(val)		(((val) >> 0) & 0xffff)
79 #define SLINK_MODF			(1 << 16)
80 #define SLINK_RX_UNF			(1 << 18)
81 #define SLINK_TX_OVF			(1 << 19)
82 #define SLINK_TX_FULL			(1 << 20)
83 #define SLINK_TX_EMPTY			(1 << 21)
84 #define SLINK_RX_FULL			(1 << 22)
85 #define SLINK_RX_EMPTY			(1 << 23)
86 #define SLINK_TX_UNF			(1 << 24)
87 #define SLINK_RX_OVF			(1 << 25)
88 #define SLINK_TX_FLUSH			(1 << 26)
89 #define SLINK_RX_FLUSH			(1 << 27)
90 #define SLINK_SCLK			(1 << 28)
91 #define SLINK_ERR			(1 << 29)
92 #define SLINK_RDY			(1 << 30)
93 #define SLINK_BSY			(1 << 31)
94 #define SLINK_FIFO_ERROR		(SLINK_TX_OVF | SLINK_RX_UNF |	\
95 					SLINK_TX_UNF | SLINK_RX_OVF)
96 
97 #define SLINK_FIFO_EMPTY		(SLINK_TX_EMPTY | SLINK_RX_EMPTY)
98 
99 #define SLINK_MAS_DATA			0x010
100 #define SLINK_SLAVE_DATA		0x014
101 
102 #define SLINK_DMA_CTL			0x018
103 #define SLINK_DMA_BLOCK_SIZE(x)		(((x) & 0xffff) << 0)
104 #define SLINK_TX_TRIG_1			(0 << 16)
105 #define SLINK_TX_TRIG_4			(1 << 16)
106 #define SLINK_TX_TRIG_8			(2 << 16)
107 #define SLINK_TX_TRIG_16		(3 << 16)
108 #define SLINK_TX_TRIG_MASK		(3 << 16)
109 #define SLINK_RX_TRIG_1			(0 << 18)
110 #define SLINK_RX_TRIG_4			(1 << 18)
111 #define SLINK_RX_TRIG_8			(2 << 18)
112 #define SLINK_RX_TRIG_16		(3 << 18)
113 #define SLINK_RX_TRIG_MASK		(3 << 18)
114 #define SLINK_PACKED			(1 << 20)
115 #define SLINK_PACK_SIZE_4		(0 << 21)
116 #define SLINK_PACK_SIZE_8		(1 << 21)
117 #define SLINK_PACK_SIZE_16		(2 << 21)
118 #define SLINK_PACK_SIZE_32		(3 << 21)
119 #define SLINK_PACK_SIZE_MASK		(3 << 21)
120 #define SLINK_IE_TXC			(1 << 26)
121 #define SLINK_IE_RXC			(1 << 27)
122 #define SLINK_DMA_EN			(1 << 31)
123 
124 #define SLINK_STATUS2			0x01c
125 #define SLINK_TX_FIFO_EMPTY_COUNT(val)	(((val) & 0x3f) >> 0)
126 #define SLINK_RX_FIFO_FULL_COUNT(val)	(((val) & 0x3f0000) >> 16)
127 #define SLINK_SS_HOLD_TIME(val)		(((val) & 0xF) << 6)
128 
129 #define SLINK_TX_FIFO			0x100
130 #define SLINK_RX_FIFO			0x180
131 
132 #define DATA_DIR_TX			(1 << 0)
133 #define DATA_DIR_RX			(1 << 1)
134 
135 #define SLINK_DMA_TIMEOUT		(msecs_to_jiffies(1000))
136 
137 #define DEFAULT_SPI_DMA_BUF_LEN		(16*1024)
138 #define TX_FIFO_EMPTY_COUNT_MAX		SLINK_TX_FIFO_EMPTY_COUNT(0x20)
139 #define RX_FIFO_FULL_COUNT_ZERO		SLINK_RX_FIFO_FULL_COUNT(0)
140 
141 #define SLINK_STATUS2_RESET \
142 	(TX_FIFO_EMPTY_COUNT_MAX | RX_FIFO_FULL_COUNT_ZERO << 16)
143 
144 #define MAX_CHIP_SELECT			4
145 #define SLINK_FIFO_DEPTH		32
146 
147 struct tegra_slink_chip_data {
148 	bool cs_hold_time;
149 };
150 
151 struct tegra_slink_data {
152 	struct device				*dev;
153 	struct spi_master			*master;
154 	const struct tegra_slink_chip_data	*chip_data;
155 	spinlock_t				lock;
156 
157 	struct clk				*clk;
158 	struct reset_control			*rst;
159 	void __iomem				*base;
160 	phys_addr_t				phys;
161 	unsigned				irq;
162 	u32					cur_speed;
163 
164 	struct spi_device			*cur_spi;
165 	unsigned				cur_pos;
166 	unsigned				cur_len;
167 	unsigned				words_per_32bit;
168 	unsigned				bytes_per_word;
169 	unsigned				curr_dma_words;
170 	unsigned				cur_direction;
171 
172 	unsigned				cur_rx_pos;
173 	unsigned				cur_tx_pos;
174 
175 	unsigned				dma_buf_size;
176 	unsigned				max_buf_size;
177 	bool					is_curr_dma_xfer;
178 
179 	struct completion			rx_dma_complete;
180 	struct completion			tx_dma_complete;
181 
182 	u32					tx_status;
183 	u32					rx_status;
184 	u32					status_reg;
185 	bool					is_packed;
186 	u32					packed_size;
187 
188 	u32					command_reg;
189 	u32					command2_reg;
190 	u32					dma_control_reg;
191 	u32					def_command_reg;
192 	u32					def_command2_reg;
193 
194 	struct completion			xfer_completion;
195 	struct spi_transfer			*curr_xfer;
196 	struct dma_chan				*rx_dma_chan;
197 	u32					*rx_dma_buf;
198 	dma_addr_t				rx_dma_phys;
199 	struct dma_async_tx_descriptor		*rx_dma_desc;
200 
201 	struct dma_chan				*tx_dma_chan;
202 	u32					*tx_dma_buf;
203 	dma_addr_t				tx_dma_phys;
204 	struct dma_async_tx_descriptor		*tx_dma_desc;
205 };
206 
207 static int tegra_slink_runtime_suspend(struct device *dev);
208 static int tegra_slink_runtime_resume(struct device *dev);
209 
210 static inline u32 tegra_slink_readl(struct tegra_slink_data *tspi,
211 		unsigned long reg)
212 {
213 	return readl(tspi->base + reg);
214 }
215 
216 static inline void tegra_slink_writel(struct tegra_slink_data *tspi,
217 		u32 val, unsigned long reg)
218 {
219 	writel(val, tspi->base + reg);
220 
221 	/* Read back register to make sure that register writes completed */
222 	if (reg != SLINK_TX_FIFO)
223 		readl(tspi->base + SLINK_MAS_DATA);
224 }
225 
226 static void tegra_slink_clear_status(struct tegra_slink_data *tspi)
227 {
228 	u32 val_write;
229 
230 	tegra_slink_readl(tspi, SLINK_STATUS);
231 
232 	/* Write 1 to clear status register */
233 	val_write = SLINK_RDY | SLINK_FIFO_ERROR;
234 	tegra_slink_writel(tspi, val_write, SLINK_STATUS);
235 }
236 
237 static u32 tegra_slink_get_packed_size(struct tegra_slink_data *tspi,
238 				  struct spi_transfer *t)
239 {
240 	switch (tspi->bytes_per_word) {
241 	case 0:
242 		return SLINK_PACK_SIZE_4;
243 	case 1:
244 		return SLINK_PACK_SIZE_8;
245 	case 2:
246 		return SLINK_PACK_SIZE_16;
247 	case 4:
248 		return SLINK_PACK_SIZE_32;
249 	default:
250 		return 0;
251 	}
252 }
253 
254 static unsigned tegra_slink_calculate_curr_xfer_param(
255 	struct spi_device *spi, struct tegra_slink_data *tspi,
256 	struct spi_transfer *t)
257 {
258 	unsigned remain_len = t->len - tspi->cur_pos;
259 	unsigned max_word;
260 	unsigned bits_per_word;
261 	unsigned max_len;
262 	unsigned total_fifo_words;
263 
264 	bits_per_word = t->bits_per_word;
265 	tspi->bytes_per_word = DIV_ROUND_UP(bits_per_word, 8);
266 
267 	if (bits_per_word == 8 || bits_per_word == 16) {
268 		tspi->is_packed = true;
269 		tspi->words_per_32bit = 32/bits_per_word;
270 	} else {
271 		tspi->is_packed = false;
272 		tspi->words_per_32bit = 1;
273 	}
274 	tspi->packed_size = tegra_slink_get_packed_size(tspi, t);
275 
276 	if (tspi->is_packed) {
277 		max_len = min(remain_len, tspi->max_buf_size);
278 		tspi->curr_dma_words = max_len/tspi->bytes_per_word;
279 		total_fifo_words = max_len/4;
280 	} else {
281 		max_word = (remain_len - 1) / tspi->bytes_per_word + 1;
282 		max_word = min(max_word, tspi->max_buf_size/4);
283 		tspi->curr_dma_words = max_word;
284 		total_fifo_words = max_word;
285 	}
286 	return total_fifo_words;
287 }
288 
289 static unsigned tegra_slink_fill_tx_fifo_from_client_txbuf(
290 	struct tegra_slink_data *tspi, struct spi_transfer *t)
291 {
292 	unsigned nbytes;
293 	unsigned tx_empty_count;
294 	u32 fifo_status;
295 	unsigned max_n_32bit;
296 	unsigned i, count;
297 	unsigned int written_words;
298 	unsigned fifo_words_left;
299 	u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_tx_pos;
300 
301 	fifo_status = tegra_slink_readl(tspi, SLINK_STATUS2);
302 	tx_empty_count = SLINK_TX_FIFO_EMPTY_COUNT(fifo_status);
303 
304 	if (tspi->is_packed) {
305 		fifo_words_left = tx_empty_count * tspi->words_per_32bit;
306 		written_words = min(fifo_words_left, tspi->curr_dma_words);
307 		nbytes = written_words * tspi->bytes_per_word;
308 		max_n_32bit = DIV_ROUND_UP(nbytes, 4);
309 		for (count = 0; count < max_n_32bit; count++) {
310 			u32 x = 0;
311 			for (i = 0; (i < 4) && nbytes; i++, nbytes--)
312 				x |= (u32)(*tx_buf++) << (i * 8);
313 			tegra_slink_writel(tspi, x, SLINK_TX_FIFO);
314 		}
315 	} else {
316 		max_n_32bit = min(tspi->curr_dma_words,  tx_empty_count);
317 		written_words = max_n_32bit;
318 		nbytes = written_words * tspi->bytes_per_word;
319 		for (count = 0; count < max_n_32bit; count++) {
320 			u32 x = 0;
321 			for (i = 0; nbytes && (i < tspi->bytes_per_word);
322 							i++, nbytes--)
323 				x |= (u32)(*tx_buf++) << (i * 8);
324 			tegra_slink_writel(tspi, x, SLINK_TX_FIFO);
325 		}
326 	}
327 	tspi->cur_tx_pos += written_words * tspi->bytes_per_word;
328 	return written_words;
329 }
330 
331 static unsigned int tegra_slink_read_rx_fifo_to_client_rxbuf(
332 		struct tegra_slink_data *tspi, struct spi_transfer *t)
333 {
334 	unsigned rx_full_count;
335 	u32 fifo_status;
336 	unsigned i, count;
337 	unsigned int read_words = 0;
338 	unsigned len;
339 	u8 *rx_buf = (u8 *)t->rx_buf + tspi->cur_rx_pos;
340 
341 	fifo_status = tegra_slink_readl(tspi, SLINK_STATUS2);
342 	rx_full_count = SLINK_RX_FIFO_FULL_COUNT(fifo_status);
343 	if (tspi->is_packed) {
344 		len = tspi->curr_dma_words * tspi->bytes_per_word;
345 		for (count = 0; count < rx_full_count; count++) {
346 			u32 x = tegra_slink_readl(tspi, SLINK_RX_FIFO);
347 			for (i = 0; len && (i < 4); i++, len--)
348 				*rx_buf++ = (x >> i*8) & 0xFF;
349 		}
350 		tspi->cur_rx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
351 		read_words += tspi->curr_dma_words;
352 	} else {
353 		for (count = 0; count < rx_full_count; count++) {
354 			u32 x = tegra_slink_readl(tspi, SLINK_RX_FIFO);
355 			for (i = 0; (i < tspi->bytes_per_word); i++)
356 				*rx_buf++ = (x >> (i*8)) & 0xFF;
357 		}
358 		tspi->cur_rx_pos += rx_full_count * tspi->bytes_per_word;
359 		read_words += rx_full_count;
360 	}
361 	return read_words;
362 }
363 
364 static void tegra_slink_copy_client_txbuf_to_spi_txbuf(
365 		struct tegra_slink_data *tspi, struct spi_transfer *t)
366 {
367 	/* Make the dma buffer to read by cpu */
368 	dma_sync_single_for_cpu(tspi->dev, tspi->tx_dma_phys,
369 				tspi->dma_buf_size, DMA_TO_DEVICE);
370 
371 	if (tspi->is_packed) {
372 		unsigned len = tspi->curr_dma_words * tspi->bytes_per_word;
373 		memcpy(tspi->tx_dma_buf, t->tx_buf + tspi->cur_pos, len);
374 	} else {
375 		unsigned int i;
376 		unsigned int count;
377 		u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_tx_pos;
378 		unsigned consume = tspi->curr_dma_words * tspi->bytes_per_word;
379 
380 		for (count = 0; count < tspi->curr_dma_words; count++) {
381 			u32 x = 0;
382 			for (i = 0; consume && (i < tspi->bytes_per_word);
383 							i++, consume--)
384 				x |= (u32)(*tx_buf++) << (i * 8);
385 			tspi->tx_dma_buf[count] = x;
386 		}
387 	}
388 	tspi->cur_tx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
389 
390 	/* Make the dma buffer to read by dma */
391 	dma_sync_single_for_device(tspi->dev, tspi->tx_dma_phys,
392 				tspi->dma_buf_size, DMA_TO_DEVICE);
393 }
394 
395 static void tegra_slink_copy_spi_rxbuf_to_client_rxbuf(
396 		struct tegra_slink_data *tspi, struct spi_transfer *t)
397 {
398 	unsigned len;
399 
400 	/* Make the dma buffer to read by cpu */
401 	dma_sync_single_for_cpu(tspi->dev, tspi->rx_dma_phys,
402 		tspi->dma_buf_size, DMA_FROM_DEVICE);
403 
404 	if (tspi->is_packed) {
405 		len = tspi->curr_dma_words * tspi->bytes_per_word;
406 		memcpy(t->rx_buf + tspi->cur_rx_pos, tspi->rx_dma_buf, len);
407 	} else {
408 		unsigned int i;
409 		unsigned int count;
410 		unsigned char *rx_buf = t->rx_buf + tspi->cur_rx_pos;
411 		u32 rx_mask = ((u32)1 << t->bits_per_word) - 1;
412 
413 		for (count = 0; count < tspi->curr_dma_words; count++) {
414 			u32 x = tspi->rx_dma_buf[count] & rx_mask;
415 			for (i = 0; (i < tspi->bytes_per_word); i++)
416 				*rx_buf++ = (x >> (i*8)) & 0xFF;
417 		}
418 	}
419 	tspi->cur_rx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
420 
421 	/* Make the dma buffer to read by dma */
422 	dma_sync_single_for_device(tspi->dev, tspi->rx_dma_phys,
423 		tspi->dma_buf_size, DMA_FROM_DEVICE);
424 }
425 
426 static void tegra_slink_dma_complete(void *args)
427 {
428 	struct completion *dma_complete = args;
429 
430 	complete(dma_complete);
431 }
432 
433 static int tegra_slink_start_tx_dma(struct tegra_slink_data *tspi, int len)
434 {
435 	reinit_completion(&tspi->tx_dma_complete);
436 	tspi->tx_dma_desc = dmaengine_prep_slave_single(tspi->tx_dma_chan,
437 				tspi->tx_dma_phys, len, DMA_MEM_TO_DEV,
438 				DMA_PREP_INTERRUPT |  DMA_CTRL_ACK);
439 	if (!tspi->tx_dma_desc) {
440 		dev_err(tspi->dev, "Not able to get desc for Tx\n");
441 		return -EIO;
442 	}
443 
444 	tspi->tx_dma_desc->callback = tegra_slink_dma_complete;
445 	tspi->tx_dma_desc->callback_param = &tspi->tx_dma_complete;
446 
447 	dmaengine_submit(tspi->tx_dma_desc);
448 	dma_async_issue_pending(tspi->tx_dma_chan);
449 	return 0;
450 }
451 
452 static int tegra_slink_start_rx_dma(struct tegra_slink_data *tspi, int len)
453 {
454 	reinit_completion(&tspi->rx_dma_complete);
455 	tspi->rx_dma_desc = dmaengine_prep_slave_single(tspi->rx_dma_chan,
456 				tspi->rx_dma_phys, len, DMA_DEV_TO_MEM,
457 				DMA_PREP_INTERRUPT |  DMA_CTRL_ACK);
458 	if (!tspi->rx_dma_desc) {
459 		dev_err(tspi->dev, "Not able to get desc for Rx\n");
460 		return -EIO;
461 	}
462 
463 	tspi->rx_dma_desc->callback = tegra_slink_dma_complete;
464 	tspi->rx_dma_desc->callback_param = &tspi->rx_dma_complete;
465 
466 	dmaengine_submit(tspi->rx_dma_desc);
467 	dma_async_issue_pending(tspi->rx_dma_chan);
468 	return 0;
469 }
470 
471 static int tegra_slink_start_dma_based_transfer(
472 		struct tegra_slink_data *tspi, struct spi_transfer *t)
473 {
474 	u32 val;
475 	unsigned int len;
476 	int ret = 0;
477 	u32 status;
478 
479 	/* Make sure that Rx and Tx fifo are empty */
480 	status = tegra_slink_readl(tspi, SLINK_STATUS);
481 	if ((status & SLINK_FIFO_EMPTY) != SLINK_FIFO_EMPTY) {
482 		dev_err(tspi->dev, "Rx/Tx fifo are not empty status 0x%08x\n",
483 			(unsigned)status);
484 		return -EIO;
485 	}
486 
487 	val = SLINK_DMA_BLOCK_SIZE(tspi->curr_dma_words - 1);
488 	val |= tspi->packed_size;
489 	if (tspi->is_packed)
490 		len = DIV_ROUND_UP(tspi->curr_dma_words * tspi->bytes_per_word,
491 					4) * 4;
492 	else
493 		len = tspi->curr_dma_words * 4;
494 
495 	/* Set attention level based on length of transfer */
496 	if (len & 0xF)
497 		val |= SLINK_TX_TRIG_1 | SLINK_RX_TRIG_1;
498 	else if (((len) >> 4) & 0x1)
499 		val |= SLINK_TX_TRIG_4 | SLINK_RX_TRIG_4;
500 	else
501 		val |= SLINK_TX_TRIG_8 | SLINK_RX_TRIG_8;
502 
503 	if (tspi->cur_direction & DATA_DIR_TX)
504 		val |= SLINK_IE_TXC;
505 
506 	if (tspi->cur_direction & DATA_DIR_RX)
507 		val |= SLINK_IE_RXC;
508 
509 	tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
510 	tspi->dma_control_reg = val;
511 
512 	if (tspi->cur_direction & DATA_DIR_TX) {
513 		tegra_slink_copy_client_txbuf_to_spi_txbuf(tspi, t);
514 		wmb();
515 		ret = tegra_slink_start_tx_dma(tspi, len);
516 		if (ret < 0) {
517 			dev_err(tspi->dev,
518 				"Starting tx dma failed, err %d\n", ret);
519 			return ret;
520 		}
521 
522 		/* Wait for tx fifo to be fill before starting slink */
523 		status = tegra_slink_readl(tspi, SLINK_STATUS);
524 		while (!(status & SLINK_TX_FULL))
525 			status = tegra_slink_readl(tspi, SLINK_STATUS);
526 	}
527 
528 	if (tspi->cur_direction & DATA_DIR_RX) {
529 		/* Make the dma buffer to read by dma */
530 		dma_sync_single_for_device(tspi->dev, tspi->rx_dma_phys,
531 				tspi->dma_buf_size, DMA_FROM_DEVICE);
532 
533 		ret = tegra_slink_start_rx_dma(tspi, len);
534 		if (ret < 0) {
535 			dev_err(tspi->dev,
536 				"Starting rx dma failed, err %d\n", ret);
537 			if (tspi->cur_direction & DATA_DIR_TX)
538 				dmaengine_terminate_all(tspi->tx_dma_chan);
539 			return ret;
540 		}
541 	}
542 	tspi->is_curr_dma_xfer = true;
543 	if (tspi->is_packed) {
544 		val |= SLINK_PACKED;
545 		tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
546 		/* HW need small delay after settign Packed mode */
547 		udelay(1);
548 	}
549 	tspi->dma_control_reg = val;
550 
551 	val |= SLINK_DMA_EN;
552 	tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
553 	return ret;
554 }
555 
556 static int tegra_slink_start_cpu_based_transfer(
557 		struct tegra_slink_data *tspi, struct spi_transfer *t)
558 {
559 	u32 val;
560 	unsigned cur_words;
561 
562 	val = tspi->packed_size;
563 	if (tspi->cur_direction & DATA_DIR_TX)
564 		val |= SLINK_IE_TXC;
565 
566 	if (tspi->cur_direction & DATA_DIR_RX)
567 		val |= SLINK_IE_RXC;
568 
569 	tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
570 	tspi->dma_control_reg = val;
571 
572 	if (tspi->cur_direction & DATA_DIR_TX)
573 		cur_words = tegra_slink_fill_tx_fifo_from_client_txbuf(tspi, t);
574 	else
575 		cur_words = tspi->curr_dma_words;
576 	val |= SLINK_DMA_BLOCK_SIZE(cur_words - 1);
577 	tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
578 	tspi->dma_control_reg = val;
579 
580 	tspi->is_curr_dma_xfer = false;
581 	if (tspi->is_packed) {
582 		val |= SLINK_PACKED;
583 		tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
584 		udelay(1);
585 		wmb();
586 	}
587 	tspi->dma_control_reg = val;
588 	val |= SLINK_DMA_EN;
589 	tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
590 	return 0;
591 }
592 
593 static int tegra_slink_init_dma_param(struct tegra_slink_data *tspi,
594 			bool dma_to_memory)
595 {
596 	struct dma_chan *dma_chan;
597 	u32 *dma_buf;
598 	dma_addr_t dma_phys;
599 	int ret;
600 	struct dma_slave_config dma_sconfig;
601 
602 	dma_chan = dma_request_chan(tspi->dev, dma_to_memory ? "rx" : "tx");
603 	if (IS_ERR(dma_chan))
604 		return dev_err_probe(tspi->dev, PTR_ERR(dma_chan),
605 				     "Dma channel is not available\n");
606 
607 	dma_buf = dma_alloc_coherent(tspi->dev, tspi->dma_buf_size,
608 				&dma_phys, GFP_KERNEL);
609 	if (!dma_buf) {
610 		dev_err(tspi->dev, " Not able to allocate the dma buffer\n");
611 		dma_release_channel(dma_chan);
612 		return -ENOMEM;
613 	}
614 
615 	if (dma_to_memory) {
616 		dma_sconfig.src_addr = tspi->phys + SLINK_RX_FIFO;
617 		dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
618 		dma_sconfig.src_maxburst = 0;
619 	} else {
620 		dma_sconfig.dst_addr = tspi->phys + SLINK_TX_FIFO;
621 		dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
622 		dma_sconfig.dst_maxburst = 0;
623 	}
624 
625 	ret = dmaengine_slave_config(dma_chan, &dma_sconfig);
626 	if (ret)
627 		goto scrub;
628 	if (dma_to_memory) {
629 		tspi->rx_dma_chan = dma_chan;
630 		tspi->rx_dma_buf = dma_buf;
631 		tspi->rx_dma_phys = dma_phys;
632 	} else {
633 		tspi->tx_dma_chan = dma_chan;
634 		tspi->tx_dma_buf = dma_buf;
635 		tspi->tx_dma_phys = dma_phys;
636 	}
637 	return 0;
638 
639 scrub:
640 	dma_free_coherent(tspi->dev, tspi->dma_buf_size, dma_buf, dma_phys);
641 	dma_release_channel(dma_chan);
642 	return ret;
643 }
644 
645 static void tegra_slink_deinit_dma_param(struct tegra_slink_data *tspi,
646 	bool dma_to_memory)
647 {
648 	u32 *dma_buf;
649 	dma_addr_t dma_phys;
650 	struct dma_chan *dma_chan;
651 
652 	if (dma_to_memory) {
653 		dma_buf = tspi->rx_dma_buf;
654 		dma_chan = tspi->rx_dma_chan;
655 		dma_phys = tspi->rx_dma_phys;
656 		tspi->rx_dma_chan = NULL;
657 		tspi->rx_dma_buf = NULL;
658 	} else {
659 		dma_buf = tspi->tx_dma_buf;
660 		dma_chan = tspi->tx_dma_chan;
661 		dma_phys = tspi->tx_dma_phys;
662 		tspi->tx_dma_buf = NULL;
663 		tspi->tx_dma_chan = NULL;
664 	}
665 	if (!dma_chan)
666 		return;
667 
668 	dma_free_coherent(tspi->dev, tspi->dma_buf_size, dma_buf, dma_phys);
669 	dma_release_channel(dma_chan);
670 }
671 
672 static int tegra_slink_start_transfer_one(struct spi_device *spi,
673 		struct spi_transfer *t)
674 {
675 	struct tegra_slink_data *tspi = spi_master_get_devdata(spi->master);
676 	u32 speed;
677 	u8 bits_per_word;
678 	unsigned total_fifo_words;
679 	int ret;
680 	u32 command;
681 	u32 command2;
682 
683 	bits_per_word = t->bits_per_word;
684 	speed = t->speed_hz;
685 	if (speed != tspi->cur_speed) {
686 		clk_set_rate(tspi->clk, speed * 4);
687 		tspi->cur_speed = speed;
688 	}
689 
690 	tspi->cur_spi = spi;
691 	tspi->cur_pos = 0;
692 	tspi->cur_rx_pos = 0;
693 	tspi->cur_tx_pos = 0;
694 	tspi->curr_xfer = t;
695 	total_fifo_words = tegra_slink_calculate_curr_xfer_param(spi, tspi, t);
696 
697 	command = tspi->command_reg;
698 	command &= ~SLINK_BIT_LENGTH(~0);
699 	command |= SLINK_BIT_LENGTH(bits_per_word - 1);
700 
701 	command2 = tspi->command2_reg;
702 	command2 &= ~(SLINK_RXEN | SLINK_TXEN);
703 
704 	tspi->cur_direction = 0;
705 	if (t->rx_buf) {
706 		command2 |= SLINK_RXEN;
707 		tspi->cur_direction |= DATA_DIR_RX;
708 	}
709 	if (t->tx_buf) {
710 		command2 |= SLINK_TXEN;
711 		tspi->cur_direction |= DATA_DIR_TX;
712 	}
713 
714 	/*
715 	 * Writing to the command2 register bevore the command register prevents
716 	 * a spike in chip_select line 0. This selects the chip_select line
717 	 * before changing the chip_select value.
718 	 */
719 	tegra_slink_writel(tspi, command2, SLINK_COMMAND2);
720 	tspi->command2_reg = command2;
721 
722 	tegra_slink_writel(tspi, command, SLINK_COMMAND);
723 	tspi->command_reg = command;
724 
725 	if (total_fifo_words > SLINK_FIFO_DEPTH)
726 		ret = tegra_slink_start_dma_based_transfer(tspi, t);
727 	else
728 		ret = tegra_slink_start_cpu_based_transfer(tspi, t);
729 	return ret;
730 }
731 
732 static int tegra_slink_setup(struct spi_device *spi)
733 {
734 	static const u32 cs_pol_bit[MAX_CHIP_SELECT] = {
735 			SLINK_CS_POLARITY,
736 			SLINK_CS_POLARITY1,
737 			SLINK_CS_POLARITY2,
738 			SLINK_CS_POLARITY3,
739 	};
740 
741 	struct tegra_slink_data *tspi = spi_master_get_devdata(spi->master);
742 	u32 val;
743 	unsigned long flags;
744 	int ret;
745 
746 	dev_dbg(&spi->dev, "setup %d bpw, %scpol, %scpha, %dHz\n",
747 		spi->bits_per_word,
748 		spi->mode & SPI_CPOL ? "" : "~",
749 		spi->mode & SPI_CPHA ? "" : "~",
750 		spi->max_speed_hz);
751 
752 	ret = pm_runtime_get_sync(tspi->dev);
753 	if (ret < 0) {
754 		pm_runtime_put_noidle(tspi->dev);
755 		dev_err(tspi->dev, "pm runtime failed, e = %d\n", ret);
756 		return ret;
757 	}
758 
759 	spin_lock_irqsave(&tspi->lock, flags);
760 	val = tspi->def_command_reg;
761 	if (spi->mode & SPI_CS_HIGH)
762 		val |= cs_pol_bit[spi->chip_select];
763 	else
764 		val &= ~cs_pol_bit[spi->chip_select];
765 	tspi->def_command_reg = val;
766 	tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
767 	spin_unlock_irqrestore(&tspi->lock, flags);
768 
769 	pm_runtime_put(tspi->dev);
770 	return 0;
771 }
772 
773 static int tegra_slink_prepare_message(struct spi_master *master,
774 				       struct spi_message *msg)
775 {
776 	struct tegra_slink_data *tspi = spi_master_get_devdata(master);
777 	struct spi_device *spi = msg->spi;
778 
779 	tegra_slink_clear_status(tspi);
780 
781 	tspi->command_reg = tspi->def_command_reg;
782 	tspi->command_reg |= SLINK_CS_SW | SLINK_CS_VALUE;
783 
784 	tspi->command2_reg = tspi->def_command2_reg;
785 	tspi->command2_reg |= SLINK_SS_EN_CS(spi->chip_select);
786 
787 	tspi->command_reg &= ~SLINK_MODES;
788 	if (spi->mode & SPI_CPHA)
789 		tspi->command_reg |= SLINK_CK_SDA;
790 
791 	if (spi->mode & SPI_CPOL)
792 		tspi->command_reg |= SLINK_IDLE_SCLK_DRIVE_HIGH;
793 	else
794 		tspi->command_reg |= SLINK_IDLE_SCLK_DRIVE_LOW;
795 
796 	return 0;
797 }
798 
799 static int tegra_slink_transfer_one(struct spi_master *master,
800 				    struct spi_device *spi,
801 				    struct spi_transfer *xfer)
802 {
803 	struct tegra_slink_data *tspi = spi_master_get_devdata(master);
804 	int ret;
805 
806 	reinit_completion(&tspi->xfer_completion);
807 	ret = tegra_slink_start_transfer_one(spi, xfer);
808 	if (ret < 0) {
809 		dev_err(tspi->dev,
810 			"spi can not start transfer, err %d\n", ret);
811 		return ret;
812 	}
813 
814 	ret = wait_for_completion_timeout(&tspi->xfer_completion,
815 					  SLINK_DMA_TIMEOUT);
816 	if (WARN_ON(ret == 0)) {
817 		dev_err(tspi->dev,
818 			"spi transfer timeout, err %d\n", ret);
819 		return -EIO;
820 	}
821 
822 	if (tspi->tx_status)
823 		return tspi->tx_status;
824 	if (tspi->rx_status)
825 		return tspi->rx_status;
826 
827 	return 0;
828 }
829 
830 static int tegra_slink_unprepare_message(struct spi_master *master,
831 					 struct spi_message *msg)
832 {
833 	struct tegra_slink_data *tspi = spi_master_get_devdata(master);
834 
835 	tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
836 	tegra_slink_writel(tspi, tspi->def_command2_reg, SLINK_COMMAND2);
837 
838 	return 0;
839 }
840 
841 static irqreturn_t handle_cpu_based_xfer(struct tegra_slink_data *tspi)
842 {
843 	struct spi_transfer *t = tspi->curr_xfer;
844 	unsigned long flags;
845 
846 	spin_lock_irqsave(&tspi->lock, flags);
847 	if (tspi->tx_status ||  tspi->rx_status ||
848 				(tspi->status_reg & SLINK_BSY)) {
849 		dev_err(tspi->dev,
850 			"CpuXfer ERROR bit set 0x%x\n", tspi->status_reg);
851 		dev_err(tspi->dev,
852 			"CpuXfer 0x%08x:0x%08x:0x%08x\n", tspi->command_reg,
853 				tspi->command2_reg, tspi->dma_control_reg);
854 		reset_control_assert(tspi->rst);
855 		udelay(2);
856 		reset_control_deassert(tspi->rst);
857 		complete(&tspi->xfer_completion);
858 		goto exit;
859 	}
860 
861 	if (tspi->cur_direction & DATA_DIR_RX)
862 		tegra_slink_read_rx_fifo_to_client_rxbuf(tspi, t);
863 
864 	if (tspi->cur_direction & DATA_DIR_TX)
865 		tspi->cur_pos = tspi->cur_tx_pos;
866 	else
867 		tspi->cur_pos = tspi->cur_rx_pos;
868 
869 	if (tspi->cur_pos == t->len) {
870 		complete(&tspi->xfer_completion);
871 		goto exit;
872 	}
873 
874 	tegra_slink_calculate_curr_xfer_param(tspi->cur_spi, tspi, t);
875 	tegra_slink_start_cpu_based_transfer(tspi, t);
876 exit:
877 	spin_unlock_irqrestore(&tspi->lock, flags);
878 	return IRQ_HANDLED;
879 }
880 
881 static irqreturn_t handle_dma_based_xfer(struct tegra_slink_data *tspi)
882 {
883 	struct spi_transfer *t = tspi->curr_xfer;
884 	long wait_status;
885 	int err = 0;
886 	unsigned total_fifo_words;
887 	unsigned long flags;
888 
889 	/* Abort dmas if any error */
890 	if (tspi->cur_direction & DATA_DIR_TX) {
891 		if (tspi->tx_status) {
892 			dmaengine_terminate_all(tspi->tx_dma_chan);
893 			err += 1;
894 		} else {
895 			wait_status = wait_for_completion_interruptible_timeout(
896 				&tspi->tx_dma_complete, SLINK_DMA_TIMEOUT);
897 			if (wait_status <= 0) {
898 				dmaengine_terminate_all(tspi->tx_dma_chan);
899 				dev_err(tspi->dev, "TxDma Xfer failed\n");
900 				err += 1;
901 			}
902 		}
903 	}
904 
905 	if (tspi->cur_direction & DATA_DIR_RX) {
906 		if (tspi->rx_status) {
907 			dmaengine_terminate_all(tspi->rx_dma_chan);
908 			err += 2;
909 		} else {
910 			wait_status = wait_for_completion_interruptible_timeout(
911 				&tspi->rx_dma_complete, SLINK_DMA_TIMEOUT);
912 			if (wait_status <= 0) {
913 				dmaengine_terminate_all(tspi->rx_dma_chan);
914 				dev_err(tspi->dev, "RxDma Xfer failed\n");
915 				err += 2;
916 			}
917 		}
918 	}
919 
920 	spin_lock_irqsave(&tspi->lock, flags);
921 	if (err) {
922 		dev_err(tspi->dev,
923 			"DmaXfer: ERROR bit set 0x%x\n", tspi->status_reg);
924 		dev_err(tspi->dev,
925 			"DmaXfer 0x%08x:0x%08x:0x%08x\n", tspi->command_reg,
926 				tspi->command2_reg, tspi->dma_control_reg);
927 		reset_control_assert(tspi->rst);
928 		udelay(2);
929 		reset_control_assert(tspi->rst);
930 		complete(&tspi->xfer_completion);
931 		spin_unlock_irqrestore(&tspi->lock, flags);
932 		return IRQ_HANDLED;
933 	}
934 
935 	if (tspi->cur_direction & DATA_DIR_RX)
936 		tegra_slink_copy_spi_rxbuf_to_client_rxbuf(tspi, t);
937 
938 	if (tspi->cur_direction & DATA_DIR_TX)
939 		tspi->cur_pos = tspi->cur_tx_pos;
940 	else
941 		tspi->cur_pos = tspi->cur_rx_pos;
942 
943 	if (tspi->cur_pos == t->len) {
944 		complete(&tspi->xfer_completion);
945 		goto exit;
946 	}
947 
948 	/* Continue transfer in current message */
949 	total_fifo_words = tegra_slink_calculate_curr_xfer_param(tspi->cur_spi,
950 							tspi, t);
951 	if (total_fifo_words > SLINK_FIFO_DEPTH)
952 		err = tegra_slink_start_dma_based_transfer(tspi, t);
953 	else
954 		err = tegra_slink_start_cpu_based_transfer(tspi, t);
955 
956 exit:
957 	spin_unlock_irqrestore(&tspi->lock, flags);
958 	return IRQ_HANDLED;
959 }
960 
961 static irqreturn_t tegra_slink_isr_thread(int irq, void *context_data)
962 {
963 	struct tegra_slink_data *tspi = context_data;
964 
965 	if (!tspi->is_curr_dma_xfer)
966 		return handle_cpu_based_xfer(tspi);
967 	return handle_dma_based_xfer(tspi);
968 }
969 
970 static irqreturn_t tegra_slink_isr(int irq, void *context_data)
971 {
972 	struct tegra_slink_data *tspi = context_data;
973 
974 	tspi->status_reg = tegra_slink_readl(tspi, SLINK_STATUS);
975 	if (tspi->cur_direction & DATA_DIR_TX)
976 		tspi->tx_status = tspi->status_reg &
977 					(SLINK_TX_OVF | SLINK_TX_UNF);
978 
979 	if (tspi->cur_direction & DATA_DIR_RX)
980 		tspi->rx_status = tspi->status_reg &
981 					(SLINK_RX_OVF | SLINK_RX_UNF);
982 	tegra_slink_clear_status(tspi);
983 
984 	return IRQ_WAKE_THREAD;
985 }
986 
987 static const struct tegra_slink_chip_data tegra30_spi_cdata = {
988 	.cs_hold_time = true,
989 };
990 
991 static const struct tegra_slink_chip_data tegra20_spi_cdata = {
992 	.cs_hold_time = false,
993 };
994 
995 static const struct of_device_id tegra_slink_of_match[] = {
996 	{ .compatible = "nvidia,tegra30-slink", .data = &tegra30_spi_cdata, },
997 	{ .compatible = "nvidia,tegra20-slink", .data = &tegra20_spi_cdata, },
998 	{}
999 };
1000 MODULE_DEVICE_TABLE(of, tegra_slink_of_match);
1001 
1002 static int tegra_slink_probe(struct platform_device *pdev)
1003 {
1004 	struct spi_master	*master;
1005 	struct tegra_slink_data	*tspi;
1006 	struct resource		*r;
1007 	int ret, spi_irq;
1008 	const struct tegra_slink_chip_data *cdata = NULL;
1009 	const struct of_device_id *match;
1010 
1011 	match = of_match_device(tegra_slink_of_match, &pdev->dev);
1012 	if (!match) {
1013 		dev_err(&pdev->dev, "Error: No device match found\n");
1014 		return -ENODEV;
1015 	}
1016 	cdata = match->data;
1017 
1018 	master = spi_alloc_master(&pdev->dev, sizeof(*tspi));
1019 	if (!master) {
1020 		dev_err(&pdev->dev, "master allocation failed\n");
1021 		return -ENOMEM;
1022 	}
1023 
1024 	/* the spi->mode bits understood by this driver: */
1025 	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
1026 	master->setup = tegra_slink_setup;
1027 	master->prepare_message = tegra_slink_prepare_message;
1028 	master->transfer_one = tegra_slink_transfer_one;
1029 	master->unprepare_message = tegra_slink_unprepare_message;
1030 	master->auto_runtime_pm = true;
1031 	master->num_chipselect = MAX_CHIP_SELECT;
1032 
1033 	platform_set_drvdata(pdev, master);
1034 	tspi = spi_master_get_devdata(master);
1035 	tspi->master = master;
1036 	tspi->dev = &pdev->dev;
1037 	tspi->chip_data = cdata;
1038 	spin_lock_init(&tspi->lock);
1039 
1040 	if (of_property_read_u32(tspi->dev->of_node, "spi-max-frequency",
1041 				 &master->max_speed_hz))
1042 		master->max_speed_hz = 25000000; /* 25MHz */
1043 
1044 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1045 	if (!r) {
1046 		dev_err(&pdev->dev, "No IO memory resource\n");
1047 		ret = -ENODEV;
1048 		goto exit_free_master;
1049 	}
1050 	tspi->phys = r->start;
1051 	tspi->base = devm_ioremap_resource(&pdev->dev, r);
1052 	if (IS_ERR(tspi->base)) {
1053 		ret = PTR_ERR(tspi->base);
1054 		goto exit_free_master;
1055 	}
1056 
1057 	/* disabled clock may cause interrupt storm upon request */
1058 	tspi->clk = devm_clk_get(&pdev->dev, NULL);
1059 	if (IS_ERR(tspi->clk)) {
1060 		ret = PTR_ERR(tspi->clk);
1061 		dev_err(&pdev->dev, "Can not get clock %d\n", ret);
1062 		goto exit_free_master;
1063 	}
1064 	ret = clk_prepare(tspi->clk);
1065 	if (ret < 0) {
1066 		dev_err(&pdev->dev, "Clock prepare failed %d\n", ret);
1067 		goto exit_free_master;
1068 	}
1069 	ret = clk_enable(tspi->clk);
1070 	if (ret < 0) {
1071 		dev_err(&pdev->dev, "Clock enable failed %d\n", ret);
1072 		goto exit_clk_unprepare;
1073 	}
1074 
1075 	spi_irq = platform_get_irq(pdev, 0);
1076 	tspi->irq = spi_irq;
1077 	ret = request_threaded_irq(tspi->irq, tegra_slink_isr,
1078 			tegra_slink_isr_thread, IRQF_ONESHOT,
1079 			dev_name(&pdev->dev), tspi);
1080 	if (ret < 0) {
1081 		dev_err(&pdev->dev, "Failed to register ISR for IRQ %d\n",
1082 					tspi->irq);
1083 		goto exit_clk_disable;
1084 	}
1085 
1086 	tspi->rst = devm_reset_control_get_exclusive(&pdev->dev, "spi");
1087 	if (IS_ERR(tspi->rst)) {
1088 		dev_err(&pdev->dev, "can not get reset\n");
1089 		ret = PTR_ERR(tspi->rst);
1090 		goto exit_free_irq;
1091 	}
1092 
1093 	tspi->max_buf_size = SLINK_FIFO_DEPTH << 2;
1094 	tspi->dma_buf_size = DEFAULT_SPI_DMA_BUF_LEN;
1095 
1096 	ret = tegra_slink_init_dma_param(tspi, true);
1097 	if (ret < 0)
1098 		goto exit_free_irq;
1099 	ret = tegra_slink_init_dma_param(tspi, false);
1100 	if (ret < 0)
1101 		goto exit_rx_dma_free;
1102 	tspi->max_buf_size = tspi->dma_buf_size;
1103 	init_completion(&tspi->tx_dma_complete);
1104 	init_completion(&tspi->rx_dma_complete);
1105 
1106 	init_completion(&tspi->xfer_completion);
1107 
1108 	pm_runtime_enable(&pdev->dev);
1109 	if (!pm_runtime_enabled(&pdev->dev)) {
1110 		ret = tegra_slink_runtime_resume(&pdev->dev);
1111 		if (ret)
1112 			goto exit_pm_disable;
1113 	}
1114 
1115 	ret = pm_runtime_get_sync(&pdev->dev);
1116 	if (ret < 0) {
1117 		dev_err(&pdev->dev, "pm runtime get failed, e = %d\n", ret);
1118 		pm_runtime_put_noidle(&pdev->dev);
1119 		goto exit_pm_disable;
1120 	}
1121 	tspi->def_command_reg  = SLINK_M_S;
1122 	tspi->def_command2_reg = SLINK_CS_ACTIVE_BETWEEN;
1123 	tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
1124 	tegra_slink_writel(tspi, tspi->def_command2_reg, SLINK_COMMAND2);
1125 	pm_runtime_put(&pdev->dev);
1126 
1127 	master->dev.of_node = pdev->dev.of_node;
1128 	ret = devm_spi_register_master(&pdev->dev, master);
1129 	if (ret < 0) {
1130 		dev_err(&pdev->dev, "can not register to master err %d\n", ret);
1131 		goto exit_pm_disable;
1132 	}
1133 	return ret;
1134 
1135 exit_pm_disable:
1136 	pm_runtime_disable(&pdev->dev);
1137 	if (!pm_runtime_status_suspended(&pdev->dev))
1138 		tegra_slink_runtime_suspend(&pdev->dev);
1139 	tegra_slink_deinit_dma_param(tspi, false);
1140 exit_rx_dma_free:
1141 	tegra_slink_deinit_dma_param(tspi, true);
1142 exit_free_irq:
1143 	free_irq(spi_irq, tspi);
1144 exit_clk_disable:
1145 	clk_disable(tspi->clk);
1146 exit_clk_unprepare:
1147 	clk_unprepare(tspi->clk);
1148 exit_free_master:
1149 	spi_master_put(master);
1150 	return ret;
1151 }
1152 
1153 static int tegra_slink_remove(struct platform_device *pdev)
1154 {
1155 	struct spi_master *master = platform_get_drvdata(pdev);
1156 	struct tegra_slink_data	*tspi = spi_master_get_devdata(master);
1157 
1158 	free_irq(tspi->irq, tspi);
1159 
1160 	clk_disable(tspi->clk);
1161 	clk_unprepare(tspi->clk);
1162 
1163 	if (tspi->tx_dma_chan)
1164 		tegra_slink_deinit_dma_param(tspi, false);
1165 
1166 	if (tspi->rx_dma_chan)
1167 		tegra_slink_deinit_dma_param(tspi, true);
1168 
1169 	pm_runtime_disable(&pdev->dev);
1170 	if (!pm_runtime_status_suspended(&pdev->dev))
1171 		tegra_slink_runtime_suspend(&pdev->dev);
1172 
1173 	return 0;
1174 }
1175 
1176 #ifdef CONFIG_PM_SLEEP
1177 static int tegra_slink_suspend(struct device *dev)
1178 {
1179 	struct spi_master *master = dev_get_drvdata(dev);
1180 
1181 	return spi_master_suspend(master);
1182 }
1183 
1184 static int tegra_slink_resume(struct device *dev)
1185 {
1186 	struct spi_master *master = dev_get_drvdata(dev);
1187 	struct tegra_slink_data *tspi = spi_master_get_devdata(master);
1188 	int ret;
1189 
1190 	ret = pm_runtime_get_sync(dev);
1191 	if (ret < 0) {
1192 		pm_runtime_put_noidle(dev);
1193 		dev_err(dev, "pm runtime failed, e = %d\n", ret);
1194 		return ret;
1195 	}
1196 	tegra_slink_writel(tspi, tspi->command_reg, SLINK_COMMAND);
1197 	tegra_slink_writel(tspi, tspi->command2_reg, SLINK_COMMAND2);
1198 	pm_runtime_put(dev);
1199 
1200 	return spi_master_resume(master);
1201 }
1202 #endif
1203 
1204 static int tegra_slink_runtime_suspend(struct device *dev)
1205 {
1206 	struct spi_master *master = dev_get_drvdata(dev);
1207 	struct tegra_slink_data *tspi = spi_master_get_devdata(master);
1208 
1209 	/* Flush all write which are in PPSB queue by reading back */
1210 	tegra_slink_readl(tspi, SLINK_MAS_DATA);
1211 
1212 	clk_disable_unprepare(tspi->clk);
1213 	return 0;
1214 }
1215 
1216 static int tegra_slink_runtime_resume(struct device *dev)
1217 {
1218 	struct spi_master *master = dev_get_drvdata(dev);
1219 	struct tegra_slink_data *tspi = spi_master_get_devdata(master);
1220 	int ret;
1221 
1222 	ret = clk_prepare_enable(tspi->clk);
1223 	if (ret < 0) {
1224 		dev_err(tspi->dev, "clk_prepare failed: %d\n", ret);
1225 		return ret;
1226 	}
1227 	return 0;
1228 }
1229 
1230 static const struct dev_pm_ops slink_pm_ops = {
1231 	SET_RUNTIME_PM_OPS(tegra_slink_runtime_suspend,
1232 		tegra_slink_runtime_resume, NULL)
1233 	SET_SYSTEM_SLEEP_PM_OPS(tegra_slink_suspend, tegra_slink_resume)
1234 };
1235 static struct platform_driver tegra_slink_driver = {
1236 	.driver = {
1237 		.name		= "spi-tegra-slink",
1238 		.pm		= &slink_pm_ops,
1239 		.of_match_table	= tegra_slink_of_match,
1240 	},
1241 	.probe =	tegra_slink_probe,
1242 	.remove =	tegra_slink_remove,
1243 };
1244 module_platform_driver(tegra_slink_driver);
1245 
1246 MODULE_ALIAS("platform:spi-tegra-slink");
1247 MODULE_DESCRIPTION("NVIDIA Tegra20/Tegra30 SLINK Controller Driver");
1248 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
1249 MODULE_LICENSE("GPL v2");
1250