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