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