xref: /openbmc/linux/drivers/dma/tegra20-apb-dma.c (revision 5b628549)
1 /*
2  * DMA driver for Nvidia's Tegra20 APB DMA controller.
3  *
4  * Copyright (c) 2012-2013, 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/bitops.h>
20 #include <linux/clk.h>
21 #include <linux/delay.h>
22 #include <linux/dmaengine.h>
23 #include <linux/dma-mapping.h>
24 #include <linux/err.h>
25 #include <linux/init.h>
26 #include <linux/interrupt.h>
27 #include <linux/io.h>
28 #include <linux/mm.h>
29 #include <linux/module.h>
30 #include <linux/of.h>
31 #include <linux/of_device.h>
32 #include <linux/of_dma.h>
33 #include <linux/platform_device.h>
34 #include <linux/pm.h>
35 #include <linux/pm_runtime.h>
36 #include <linux/reset.h>
37 #include <linux/slab.h>
38 
39 #include "dmaengine.h"
40 
41 #define CREATE_TRACE_POINTS
42 #include <trace/events/tegra_apb_dma.h>
43 
44 #define TEGRA_APBDMA_GENERAL			0x0
45 #define TEGRA_APBDMA_GENERAL_ENABLE		BIT(31)
46 
47 #define TEGRA_APBDMA_CONTROL			0x010
48 #define TEGRA_APBDMA_IRQ_MASK			0x01c
49 #define TEGRA_APBDMA_IRQ_MASK_SET		0x020
50 
51 /* CSR register */
52 #define TEGRA_APBDMA_CHAN_CSR			0x00
53 #define TEGRA_APBDMA_CSR_ENB			BIT(31)
54 #define TEGRA_APBDMA_CSR_IE_EOC			BIT(30)
55 #define TEGRA_APBDMA_CSR_HOLD			BIT(29)
56 #define TEGRA_APBDMA_CSR_DIR			BIT(28)
57 #define TEGRA_APBDMA_CSR_ONCE			BIT(27)
58 #define TEGRA_APBDMA_CSR_FLOW			BIT(21)
59 #define TEGRA_APBDMA_CSR_REQ_SEL_SHIFT		16
60 #define TEGRA_APBDMA_CSR_REQ_SEL_MASK		0x1F
61 #define TEGRA_APBDMA_CSR_WCOUNT_MASK		0xFFFC
62 
63 /* STATUS register */
64 #define TEGRA_APBDMA_CHAN_STATUS		0x004
65 #define TEGRA_APBDMA_STATUS_BUSY		BIT(31)
66 #define TEGRA_APBDMA_STATUS_ISE_EOC		BIT(30)
67 #define TEGRA_APBDMA_STATUS_HALT		BIT(29)
68 #define TEGRA_APBDMA_STATUS_PING_PONG		BIT(28)
69 #define TEGRA_APBDMA_STATUS_COUNT_SHIFT		2
70 #define TEGRA_APBDMA_STATUS_COUNT_MASK		0xFFFC
71 
72 #define TEGRA_APBDMA_CHAN_CSRE			0x00C
73 #define TEGRA_APBDMA_CHAN_CSRE_PAUSE		(1 << 31)
74 
75 /* AHB memory address */
76 #define TEGRA_APBDMA_CHAN_AHBPTR		0x010
77 
78 /* AHB sequence register */
79 #define TEGRA_APBDMA_CHAN_AHBSEQ		0x14
80 #define TEGRA_APBDMA_AHBSEQ_INTR_ENB		BIT(31)
81 #define TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_8		(0 << 28)
82 #define TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_16	(1 << 28)
83 #define TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32	(2 << 28)
84 #define TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_64	(3 << 28)
85 #define TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_128	(4 << 28)
86 #define TEGRA_APBDMA_AHBSEQ_DATA_SWAP		BIT(27)
87 #define TEGRA_APBDMA_AHBSEQ_BURST_1		(4 << 24)
88 #define TEGRA_APBDMA_AHBSEQ_BURST_4		(5 << 24)
89 #define TEGRA_APBDMA_AHBSEQ_BURST_8		(6 << 24)
90 #define TEGRA_APBDMA_AHBSEQ_DBL_BUF		BIT(19)
91 #define TEGRA_APBDMA_AHBSEQ_WRAP_SHIFT		16
92 #define TEGRA_APBDMA_AHBSEQ_WRAP_NONE		0
93 
94 /* APB address */
95 #define TEGRA_APBDMA_CHAN_APBPTR		0x018
96 
97 /* APB sequence register */
98 #define TEGRA_APBDMA_CHAN_APBSEQ		0x01c
99 #define TEGRA_APBDMA_APBSEQ_BUS_WIDTH_8		(0 << 28)
100 #define TEGRA_APBDMA_APBSEQ_BUS_WIDTH_16	(1 << 28)
101 #define TEGRA_APBDMA_APBSEQ_BUS_WIDTH_32	(2 << 28)
102 #define TEGRA_APBDMA_APBSEQ_BUS_WIDTH_64	(3 << 28)
103 #define TEGRA_APBDMA_APBSEQ_BUS_WIDTH_128	(4 << 28)
104 #define TEGRA_APBDMA_APBSEQ_DATA_SWAP		BIT(27)
105 #define TEGRA_APBDMA_APBSEQ_WRAP_WORD_1		(1 << 16)
106 
107 /* Tegra148 specific registers */
108 #define TEGRA_APBDMA_CHAN_WCOUNT		0x20
109 
110 #define TEGRA_APBDMA_CHAN_WORD_TRANSFER		0x24
111 
112 /*
113  * If any burst is in flight and DMA paused then this is the time to complete
114  * on-flight burst and update DMA status register.
115  */
116 #define TEGRA_APBDMA_BURST_COMPLETE_TIME	20
117 
118 /* Channel base address offset from APBDMA base address */
119 #define TEGRA_APBDMA_CHANNEL_BASE_ADD_OFFSET	0x1000
120 
121 #define TEGRA_APBDMA_SLAVE_ID_INVALID	(TEGRA_APBDMA_CSR_REQ_SEL_MASK + 1)
122 
123 struct tegra_dma;
124 
125 /*
126  * tegra_dma_chip_data Tegra chip specific DMA data
127  * @nr_channels: Number of channels available in the controller.
128  * @channel_reg_size: Channel register size/stride.
129  * @max_dma_count: Maximum DMA transfer count supported by DMA controller.
130  * @support_channel_pause: Support channel wise pause of dma.
131  * @support_separate_wcount_reg: Support separate word count register.
132  */
133 struct tegra_dma_chip_data {
134 	int nr_channels;
135 	int channel_reg_size;
136 	int max_dma_count;
137 	bool support_channel_pause;
138 	bool support_separate_wcount_reg;
139 };
140 
141 /* DMA channel registers */
142 struct tegra_dma_channel_regs {
143 	unsigned long	csr;
144 	unsigned long	ahb_ptr;
145 	unsigned long	apb_ptr;
146 	unsigned long	ahb_seq;
147 	unsigned long	apb_seq;
148 	unsigned long	wcount;
149 };
150 
151 /*
152  * tegra_dma_sg_req: DMA request details to configure hardware. This
153  * contains the details for one transfer to configure DMA hw.
154  * The client's request for data transfer can be broken into multiple
155  * sub-transfer as per requester details and hw support.
156  * This sub transfer get added in the list of transfer and point to Tegra
157  * DMA descriptor which manages the transfer details.
158  */
159 struct tegra_dma_sg_req {
160 	struct tegra_dma_channel_regs	ch_regs;
161 	unsigned int			req_len;
162 	bool				configured;
163 	bool				last_sg;
164 	struct list_head		node;
165 	struct tegra_dma_desc		*dma_desc;
166 };
167 
168 /*
169  * tegra_dma_desc: Tegra DMA descriptors which manages the client requests.
170  * This descriptor keep track of transfer status, callbacks and request
171  * counts etc.
172  */
173 struct tegra_dma_desc {
174 	struct dma_async_tx_descriptor	txd;
175 	unsigned int			bytes_requested;
176 	unsigned int			bytes_transferred;
177 	enum dma_status			dma_status;
178 	struct list_head		node;
179 	struct list_head		tx_list;
180 	struct list_head		cb_node;
181 	int				cb_count;
182 };
183 
184 struct tegra_dma_channel;
185 
186 typedef void (*dma_isr_handler)(struct tegra_dma_channel *tdc,
187 				bool to_terminate);
188 
189 /* tegra_dma_channel: Channel specific information */
190 struct tegra_dma_channel {
191 	struct dma_chan		dma_chan;
192 	char			name[12];
193 	bool			config_init;
194 	int			id;
195 	int			irq;
196 	void __iomem		*chan_addr;
197 	spinlock_t		lock;
198 	bool			busy;
199 	struct tegra_dma	*tdma;
200 	bool			cyclic;
201 
202 	/* Different lists for managing the requests */
203 	struct list_head	free_sg_req;
204 	struct list_head	pending_sg_req;
205 	struct list_head	free_dma_desc;
206 	struct list_head	cb_desc;
207 
208 	/* ISR handler and tasklet for bottom half of isr handling */
209 	dma_isr_handler		isr_handler;
210 	struct tasklet_struct	tasklet;
211 
212 	/* Channel-slave specific configuration */
213 	unsigned int slave_id;
214 	struct dma_slave_config dma_sconfig;
215 	struct tegra_dma_channel_regs	channel_reg;
216 };
217 
218 /* tegra_dma: Tegra DMA specific information */
219 struct tegra_dma {
220 	struct dma_device		dma_dev;
221 	struct device			*dev;
222 	struct clk			*dma_clk;
223 	struct reset_control		*rst;
224 	spinlock_t			global_lock;
225 	void __iomem			*base_addr;
226 	const struct tegra_dma_chip_data *chip_data;
227 
228 	/*
229 	 * Counter for managing global pausing of the DMA controller.
230 	 * Only applicable for devices that don't support individual
231 	 * channel pausing.
232 	 */
233 	u32				global_pause_count;
234 
235 	/* Some register need to be cache before suspend */
236 	u32				reg_gen;
237 
238 	/* Last member of the structure */
239 	struct tegra_dma_channel channels[0];
240 };
241 
242 static inline void tdma_write(struct tegra_dma *tdma, u32 reg, u32 val)
243 {
244 	writel(val, tdma->base_addr + reg);
245 }
246 
247 static inline u32 tdma_read(struct tegra_dma *tdma, u32 reg)
248 {
249 	return readl(tdma->base_addr + reg);
250 }
251 
252 static inline void tdc_write(struct tegra_dma_channel *tdc,
253 		u32 reg, u32 val)
254 {
255 	writel(val, tdc->chan_addr + reg);
256 }
257 
258 static inline u32 tdc_read(struct tegra_dma_channel *tdc, u32 reg)
259 {
260 	return readl(tdc->chan_addr + reg);
261 }
262 
263 static inline struct tegra_dma_channel *to_tegra_dma_chan(struct dma_chan *dc)
264 {
265 	return container_of(dc, struct tegra_dma_channel, dma_chan);
266 }
267 
268 static inline struct tegra_dma_desc *txd_to_tegra_dma_desc(
269 		struct dma_async_tx_descriptor *td)
270 {
271 	return container_of(td, struct tegra_dma_desc, txd);
272 }
273 
274 static inline struct device *tdc2dev(struct tegra_dma_channel *tdc)
275 {
276 	return &tdc->dma_chan.dev->device;
277 }
278 
279 static dma_cookie_t tegra_dma_tx_submit(struct dma_async_tx_descriptor *tx);
280 static int tegra_dma_runtime_suspend(struct device *dev);
281 static int tegra_dma_runtime_resume(struct device *dev);
282 
283 /* Get DMA desc from free list, if not there then allocate it.  */
284 static struct tegra_dma_desc *tegra_dma_desc_get(
285 		struct tegra_dma_channel *tdc)
286 {
287 	struct tegra_dma_desc *dma_desc;
288 	unsigned long flags;
289 
290 	spin_lock_irqsave(&tdc->lock, flags);
291 
292 	/* Do not allocate if desc are waiting for ack */
293 	list_for_each_entry(dma_desc, &tdc->free_dma_desc, node) {
294 		if (async_tx_test_ack(&dma_desc->txd)) {
295 			list_del(&dma_desc->node);
296 			spin_unlock_irqrestore(&tdc->lock, flags);
297 			dma_desc->txd.flags = 0;
298 			return dma_desc;
299 		}
300 	}
301 
302 	spin_unlock_irqrestore(&tdc->lock, flags);
303 
304 	/* Allocate DMA desc */
305 	dma_desc = kzalloc(sizeof(*dma_desc), GFP_NOWAIT);
306 	if (!dma_desc)
307 		return NULL;
308 
309 	dma_async_tx_descriptor_init(&dma_desc->txd, &tdc->dma_chan);
310 	dma_desc->txd.tx_submit = tegra_dma_tx_submit;
311 	dma_desc->txd.flags = 0;
312 	return dma_desc;
313 }
314 
315 static void tegra_dma_desc_put(struct tegra_dma_channel *tdc,
316 		struct tegra_dma_desc *dma_desc)
317 {
318 	unsigned long flags;
319 
320 	spin_lock_irqsave(&tdc->lock, flags);
321 	if (!list_empty(&dma_desc->tx_list))
322 		list_splice_init(&dma_desc->tx_list, &tdc->free_sg_req);
323 	list_add_tail(&dma_desc->node, &tdc->free_dma_desc);
324 	spin_unlock_irqrestore(&tdc->lock, flags);
325 }
326 
327 static struct tegra_dma_sg_req *tegra_dma_sg_req_get(
328 		struct tegra_dma_channel *tdc)
329 {
330 	struct tegra_dma_sg_req *sg_req = NULL;
331 	unsigned long flags;
332 
333 	spin_lock_irqsave(&tdc->lock, flags);
334 	if (!list_empty(&tdc->free_sg_req)) {
335 		sg_req = list_first_entry(&tdc->free_sg_req,
336 					typeof(*sg_req), node);
337 		list_del(&sg_req->node);
338 		spin_unlock_irqrestore(&tdc->lock, flags);
339 		return sg_req;
340 	}
341 	spin_unlock_irqrestore(&tdc->lock, flags);
342 
343 	sg_req = kzalloc(sizeof(struct tegra_dma_sg_req), GFP_NOWAIT);
344 
345 	return sg_req;
346 }
347 
348 static int tegra_dma_slave_config(struct dma_chan *dc,
349 		struct dma_slave_config *sconfig)
350 {
351 	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
352 
353 	if (!list_empty(&tdc->pending_sg_req)) {
354 		dev_err(tdc2dev(tdc), "Configuration not allowed\n");
355 		return -EBUSY;
356 	}
357 
358 	memcpy(&tdc->dma_sconfig, sconfig, sizeof(*sconfig));
359 	if (tdc->slave_id == TEGRA_APBDMA_SLAVE_ID_INVALID &&
360 	    sconfig->device_fc) {
361 		if (sconfig->slave_id > TEGRA_APBDMA_CSR_REQ_SEL_MASK)
362 			return -EINVAL;
363 		tdc->slave_id = sconfig->slave_id;
364 	}
365 	tdc->config_init = true;
366 	return 0;
367 }
368 
369 static void tegra_dma_global_pause(struct tegra_dma_channel *tdc,
370 	bool wait_for_burst_complete)
371 {
372 	struct tegra_dma *tdma = tdc->tdma;
373 
374 	spin_lock(&tdma->global_lock);
375 
376 	if (tdc->tdma->global_pause_count == 0) {
377 		tdma_write(tdma, TEGRA_APBDMA_GENERAL, 0);
378 		if (wait_for_burst_complete)
379 			udelay(TEGRA_APBDMA_BURST_COMPLETE_TIME);
380 	}
381 
382 	tdc->tdma->global_pause_count++;
383 
384 	spin_unlock(&tdma->global_lock);
385 }
386 
387 static void tegra_dma_global_resume(struct tegra_dma_channel *tdc)
388 {
389 	struct tegra_dma *tdma = tdc->tdma;
390 
391 	spin_lock(&tdma->global_lock);
392 
393 	if (WARN_ON(tdc->tdma->global_pause_count == 0))
394 		goto out;
395 
396 	if (--tdc->tdma->global_pause_count == 0)
397 		tdma_write(tdma, TEGRA_APBDMA_GENERAL,
398 			   TEGRA_APBDMA_GENERAL_ENABLE);
399 
400 out:
401 	spin_unlock(&tdma->global_lock);
402 }
403 
404 static void tegra_dma_pause(struct tegra_dma_channel *tdc,
405 	bool wait_for_burst_complete)
406 {
407 	struct tegra_dma *tdma = tdc->tdma;
408 
409 	if (tdma->chip_data->support_channel_pause) {
410 		tdc_write(tdc, TEGRA_APBDMA_CHAN_CSRE,
411 				TEGRA_APBDMA_CHAN_CSRE_PAUSE);
412 		if (wait_for_burst_complete)
413 			udelay(TEGRA_APBDMA_BURST_COMPLETE_TIME);
414 	} else {
415 		tegra_dma_global_pause(tdc, wait_for_burst_complete);
416 	}
417 }
418 
419 static void tegra_dma_resume(struct tegra_dma_channel *tdc)
420 {
421 	struct tegra_dma *tdma = tdc->tdma;
422 
423 	if (tdma->chip_data->support_channel_pause) {
424 		tdc_write(tdc, TEGRA_APBDMA_CHAN_CSRE, 0);
425 	} else {
426 		tegra_dma_global_resume(tdc);
427 	}
428 }
429 
430 static void tegra_dma_stop(struct tegra_dma_channel *tdc)
431 {
432 	u32 csr;
433 	u32 status;
434 
435 	/* Disable interrupts */
436 	csr = tdc_read(tdc, TEGRA_APBDMA_CHAN_CSR);
437 	csr &= ~TEGRA_APBDMA_CSR_IE_EOC;
438 	tdc_write(tdc, TEGRA_APBDMA_CHAN_CSR, csr);
439 
440 	/* Disable DMA */
441 	csr &= ~TEGRA_APBDMA_CSR_ENB;
442 	tdc_write(tdc, TEGRA_APBDMA_CHAN_CSR, csr);
443 
444 	/* Clear interrupt status if it is there */
445 	status = tdc_read(tdc, TEGRA_APBDMA_CHAN_STATUS);
446 	if (status & TEGRA_APBDMA_STATUS_ISE_EOC) {
447 		dev_dbg(tdc2dev(tdc), "%s():clearing interrupt\n", __func__);
448 		tdc_write(tdc, TEGRA_APBDMA_CHAN_STATUS, status);
449 	}
450 	tdc->busy = false;
451 }
452 
453 static void tegra_dma_start(struct tegra_dma_channel *tdc,
454 		struct tegra_dma_sg_req *sg_req)
455 {
456 	struct tegra_dma_channel_regs *ch_regs = &sg_req->ch_regs;
457 
458 	tdc_write(tdc, TEGRA_APBDMA_CHAN_CSR, ch_regs->csr);
459 	tdc_write(tdc, TEGRA_APBDMA_CHAN_APBSEQ, ch_regs->apb_seq);
460 	tdc_write(tdc, TEGRA_APBDMA_CHAN_APBPTR, ch_regs->apb_ptr);
461 	tdc_write(tdc, TEGRA_APBDMA_CHAN_AHBSEQ, ch_regs->ahb_seq);
462 	tdc_write(tdc, TEGRA_APBDMA_CHAN_AHBPTR, ch_regs->ahb_ptr);
463 	if (tdc->tdma->chip_data->support_separate_wcount_reg)
464 		tdc_write(tdc, TEGRA_APBDMA_CHAN_WCOUNT, ch_regs->wcount);
465 
466 	/* Start DMA */
467 	tdc_write(tdc, TEGRA_APBDMA_CHAN_CSR,
468 				ch_regs->csr | TEGRA_APBDMA_CSR_ENB);
469 }
470 
471 static void tegra_dma_configure_for_next(struct tegra_dma_channel *tdc,
472 		struct tegra_dma_sg_req *nsg_req)
473 {
474 	unsigned long status;
475 
476 	/*
477 	 * The DMA controller reloads the new configuration for next transfer
478 	 * after last burst of current transfer completes.
479 	 * If there is no IEC status then this makes sure that last burst
480 	 * has not be completed. There may be case that last burst is on
481 	 * flight and so it can complete but because DMA is paused, it
482 	 * will not generates interrupt as well as not reload the new
483 	 * configuration.
484 	 * If there is already IEC status then interrupt handler need to
485 	 * load new configuration.
486 	 */
487 	tegra_dma_pause(tdc, false);
488 	status = tdc_read(tdc, TEGRA_APBDMA_CHAN_STATUS);
489 
490 	/*
491 	 * If interrupt is pending then do nothing as the ISR will handle
492 	 * the programing for new request.
493 	 */
494 	if (status & TEGRA_APBDMA_STATUS_ISE_EOC) {
495 		dev_err(tdc2dev(tdc),
496 			"Skipping new configuration as interrupt is pending\n");
497 		tegra_dma_resume(tdc);
498 		return;
499 	}
500 
501 	/* Safe to program new configuration */
502 	tdc_write(tdc, TEGRA_APBDMA_CHAN_APBPTR, nsg_req->ch_regs.apb_ptr);
503 	tdc_write(tdc, TEGRA_APBDMA_CHAN_AHBPTR, nsg_req->ch_regs.ahb_ptr);
504 	if (tdc->tdma->chip_data->support_separate_wcount_reg)
505 		tdc_write(tdc, TEGRA_APBDMA_CHAN_WCOUNT,
506 						nsg_req->ch_regs.wcount);
507 	tdc_write(tdc, TEGRA_APBDMA_CHAN_CSR,
508 				nsg_req->ch_regs.csr | TEGRA_APBDMA_CSR_ENB);
509 	nsg_req->configured = true;
510 
511 	tegra_dma_resume(tdc);
512 }
513 
514 static void tdc_start_head_req(struct tegra_dma_channel *tdc)
515 {
516 	struct tegra_dma_sg_req *sg_req;
517 
518 	if (list_empty(&tdc->pending_sg_req))
519 		return;
520 
521 	sg_req = list_first_entry(&tdc->pending_sg_req,
522 					typeof(*sg_req), node);
523 	tegra_dma_start(tdc, sg_req);
524 	sg_req->configured = true;
525 	tdc->busy = true;
526 }
527 
528 static void tdc_configure_next_head_desc(struct tegra_dma_channel *tdc)
529 {
530 	struct tegra_dma_sg_req *hsgreq;
531 	struct tegra_dma_sg_req *hnsgreq;
532 
533 	if (list_empty(&tdc->pending_sg_req))
534 		return;
535 
536 	hsgreq = list_first_entry(&tdc->pending_sg_req, typeof(*hsgreq), node);
537 	if (!list_is_last(&hsgreq->node, &tdc->pending_sg_req)) {
538 		hnsgreq = list_first_entry(&hsgreq->node,
539 					typeof(*hnsgreq), node);
540 		tegra_dma_configure_for_next(tdc, hnsgreq);
541 	}
542 }
543 
544 static inline int get_current_xferred_count(struct tegra_dma_channel *tdc,
545 	struct tegra_dma_sg_req *sg_req, unsigned long status)
546 {
547 	return sg_req->req_len - (status & TEGRA_APBDMA_STATUS_COUNT_MASK) - 4;
548 }
549 
550 static void tegra_dma_abort_all(struct tegra_dma_channel *tdc)
551 {
552 	struct tegra_dma_sg_req *sgreq;
553 	struct tegra_dma_desc *dma_desc;
554 
555 	while (!list_empty(&tdc->pending_sg_req)) {
556 		sgreq = list_first_entry(&tdc->pending_sg_req,
557 						typeof(*sgreq), node);
558 		list_move_tail(&sgreq->node, &tdc->free_sg_req);
559 		if (sgreq->last_sg) {
560 			dma_desc = sgreq->dma_desc;
561 			dma_desc->dma_status = DMA_ERROR;
562 			list_add_tail(&dma_desc->node, &tdc->free_dma_desc);
563 
564 			/* Add in cb list if it is not there. */
565 			if (!dma_desc->cb_count)
566 				list_add_tail(&dma_desc->cb_node,
567 							&tdc->cb_desc);
568 			dma_desc->cb_count++;
569 		}
570 	}
571 	tdc->isr_handler = NULL;
572 }
573 
574 static bool handle_continuous_head_request(struct tegra_dma_channel *tdc,
575 		struct tegra_dma_sg_req *last_sg_req, bool to_terminate)
576 {
577 	struct tegra_dma_sg_req *hsgreq = NULL;
578 
579 	if (list_empty(&tdc->pending_sg_req)) {
580 		dev_err(tdc2dev(tdc), "DMA is running without req\n");
581 		tegra_dma_stop(tdc);
582 		return false;
583 	}
584 
585 	/*
586 	 * Check that head req on list should be in flight.
587 	 * If it is not in flight then abort transfer as
588 	 * looping of transfer can not continue.
589 	 */
590 	hsgreq = list_first_entry(&tdc->pending_sg_req, typeof(*hsgreq), node);
591 	if (!hsgreq->configured) {
592 		tegra_dma_stop(tdc);
593 		dev_err(tdc2dev(tdc), "Error in DMA transfer, aborting DMA\n");
594 		tegra_dma_abort_all(tdc);
595 		return false;
596 	}
597 
598 	/* Configure next request */
599 	if (!to_terminate)
600 		tdc_configure_next_head_desc(tdc);
601 	return true;
602 }
603 
604 static void handle_once_dma_done(struct tegra_dma_channel *tdc,
605 	bool to_terminate)
606 {
607 	struct tegra_dma_sg_req *sgreq;
608 	struct tegra_dma_desc *dma_desc;
609 
610 	tdc->busy = false;
611 	sgreq = list_first_entry(&tdc->pending_sg_req, typeof(*sgreq), node);
612 	dma_desc = sgreq->dma_desc;
613 	dma_desc->bytes_transferred += sgreq->req_len;
614 
615 	list_del(&sgreq->node);
616 	if (sgreq->last_sg) {
617 		dma_desc->dma_status = DMA_COMPLETE;
618 		dma_cookie_complete(&dma_desc->txd);
619 		if (!dma_desc->cb_count)
620 			list_add_tail(&dma_desc->cb_node, &tdc->cb_desc);
621 		dma_desc->cb_count++;
622 		list_add_tail(&dma_desc->node, &tdc->free_dma_desc);
623 	}
624 	list_add_tail(&sgreq->node, &tdc->free_sg_req);
625 
626 	/* Do not start DMA if it is going to be terminate */
627 	if (to_terminate || list_empty(&tdc->pending_sg_req))
628 		return;
629 
630 	tdc_start_head_req(tdc);
631 }
632 
633 static void handle_cont_sngl_cycle_dma_done(struct tegra_dma_channel *tdc,
634 		bool to_terminate)
635 {
636 	struct tegra_dma_sg_req *sgreq;
637 	struct tegra_dma_desc *dma_desc;
638 	bool st;
639 
640 	sgreq = list_first_entry(&tdc->pending_sg_req, typeof(*sgreq), node);
641 	dma_desc = sgreq->dma_desc;
642 	/* if we dma for long enough the transfer count will wrap */
643 	dma_desc->bytes_transferred =
644 		(dma_desc->bytes_transferred + sgreq->req_len) %
645 		dma_desc->bytes_requested;
646 
647 	/* Callback need to be call */
648 	if (!dma_desc->cb_count)
649 		list_add_tail(&dma_desc->cb_node, &tdc->cb_desc);
650 	dma_desc->cb_count++;
651 
652 	/* If not last req then put at end of pending list */
653 	if (!list_is_last(&sgreq->node, &tdc->pending_sg_req)) {
654 		list_move_tail(&sgreq->node, &tdc->pending_sg_req);
655 		sgreq->configured = false;
656 		st = handle_continuous_head_request(tdc, sgreq, to_terminate);
657 		if (!st)
658 			dma_desc->dma_status = DMA_ERROR;
659 	}
660 }
661 
662 static void tegra_dma_tasklet(unsigned long data)
663 {
664 	struct tegra_dma_channel *tdc = (struct tegra_dma_channel *)data;
665 	struct dmaengine_desc_callback cb;
666 	struct tegra_dma_desc *dma_desc;
667 	unsigned long flags;
668 	int cb_count;
669 
670 	spin_lock_irqsave(&tdc->lock, flags);
671 	while (!list_empty(&tdc->cb_desc)) {
672 		dma_desc  = list_first_entry(&tdc->cb_desc,
673 					typeof(*dma_desc), cb_node);
674 		list_del(&dma_desc->cb_node);
675 		dmaengine_desc_get_callback(&dma_desc->txd, &cb);
676 		cb_count = dma_desc->cb_count;
677 		dma_desc->cb_count = 0;
678 		trace_tegra_dma_complete_cb(&tdc->dma_chan, cb_count,
679 					    cb.callback);
680 		spin_unlock_irqrestore(&tdc->lock, flags);
681 		while (cb_count--)
682 			dmaengine_desc_callback_invoke(&cb, NULL);
683 		spin_lock_irqsave(&tdc->lock, flags);
684 	}
685 	spin_unlock_irqrestore(&tdc->lock, flags);
686 }
687 
688 static irqreturn_t tegra_dma_isr(int irq, void *dev_id)
689 {
690 	struct tegra_dma_channel *tdc = dev_id;
691 	unsigned long status;
692 	unsigned long flags;
693 
694 	spin_lock_irqsave(&tdc->lock, flags);
695 
696 	trace_tegra_dma_isr(&tdc->dma_chan, irq);
697 	status = tdc_read(tdc, TEGRA_APBDMA_CHAN_STATUS);
698 	if (status & TEGRA_APBDMA_STATUS_ISE_EOC) {
699 		tdc_write(tdc, TEGRA_APBDMA_CHAN_STATUS, status);
700 		tdc->isr_handler(tdc, false);
701 		tasklet_schedule(&tdc->tasklet);
702 		spin_unlock_irqrestore(&tdc->lock, flags);
703 		return IRQ_HANDLED;
704 	}
705 
706 	spin_unlock_irqrestore(&tdc->lock, flags);
707 	dev_info(tdc2dev(tdc),
708 		"Interrupt already served status 0x%08lx\n", status);
709 	return IRQ_NONE;
710 }
711 
712 static dma_cookie_t tegra_dma_tx_submit(struct dma_async_tx_descriptor *txd)
713 {
714 	struct tegra_dma_desc *dma_desc = txd_to_tegra_dma_desc(txd);
715 	struct tegra_dma_channel *tdc = to_tegra_dma_chan(txd->chan);
716 	unsigned long flags;
717 	dma_cookie_t cookie;
718 
719 	spin_lock_irqsave(&tdc->lock, flags);
720 	dma_desc->dma_status = DMA_IN_PROGRESS;
721 	cookie = dma_cookie_assign(&dma_desc->txd);
722 	list_splice_tail_init(&dma_desc->tx_list, &tdc->pending_sg_req);
723 	spin_unlock_irqrestore(&tdc->lock, flags);
724 	return cookie;
725 }
726 
727 static void tegra_dma_issue_pending(struct dma_chan *dc)
728 {
729 	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
730 	unsigned long flags;
731 
732 	spin_lock_irqsave(&tdc->lock, flags);
733 	if (list_empty(&tdc->pending_sg_req)) {
734 		dev_err(tdc2dev(tdc), "No DMA request\n");
735 		goto end;
736 	}
737 	if (!tdc->busy) {
738 		tdc_start_head_req(tdc);
739 
740 		/* Continuous single mode: Configure next req */
741 		if (tdc->cyclic) {
742 			/*
743 			 * Wait for 1 burst time for configure DMA for
744 			 * next transfer.
745 			 */
746 			udelay(TEGRA_APBDMA_BURST_COMPLETE_TIME);
747 			tdc_configure_next_head_desc(tdc);
748 		}
749 	}
750 end:
751 	spin_unlock_irqrestore(&tdc->lock, flags);
752 }
753 
754 static int tegra_dma_terminate_all(struct dma_chan *dc)
755 {
756 	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
757 	struct tegra_dma_sg_req *sgreq;
758 	struct tegra_dma_desc *dma_desc;
759 	unsigned long flags;
760 	unsigned long status;
761 	unsigned long wcount;
762 	bool was_busy;
763 
764 	spin_lock_irqsave(&tdc->lock, flags);
765 	if (list_empty(&tdc->pending_sg_req)) {
766 		spin_unlock_irqrestore(&tdc->lock, flags);
767 		return 0;
768 	}
769 
770 	if (!tdc->busy)
771 		goto skip_dma_stop;
772 
773 	/* Pause DMA before checking the queue status */
774 	tegra_dma_pause(tdc, true);
775 
776 	status = tdc_read(tdc, TEGRA_APBDMA_CHAN_STATUS);
777 	if (status & TEGRA_APBDMA_STATUS_ISE_EOC) {
778 		dev_dbg(tdc2dev(tdc), "%s():handling isr\n", __func__);
779 		tdc->isr_handler(tdc, true);
780 		status = tdc_read(tdc, TEGRA_APBDMA_CHAN_STATUS);
781 	}
782 	if (tdc->tdma->chip_data->support_separate_wcount_reg)
783 		wcount = tdc_read(tdc, TEGRA_APBDMA_CHAN_WORD_TRANSFER);
784 	else
785 		wcount = status;
786 
787 	was_busy = tdc->busy;
788 	tegra_dma_stop(tdc);
789 
790 	if (!list_empty(&tdc->pending_sg_req) && was_busy) {
791 		sgreq = list_first_entry(&tdc->pending_sg_req,
792 					typeof(*sgreq), node);
793 		sgreq->dma_desc->bytes_transferred +=
794 				get_current_xferred_count(tdc, sgreq, wcount);
795 	}
796 	tegra_dma_resume(tdc);
797 
798 skip_dma_stop:
799 	tegra_dma_abort_all(tdc);
800 
801 	while (!list_empty(&tdc->cb_desc)) {
802 		dma_desc  = list_first_entry(&tdc->cb_desc,
803 					typeof(*dma_desc), cb_node);
804 		list_del(&dma_desc->cb_node);
805 		dma_desc->cb_count = 0;
806 	}
807 	spin_unlock_irqrestore(&tdc->lock, flags);
808 	return 0;
809 }
810 
811 static enum dma_status tegra_dma_tx_status(struct dma_chan *dc,
812 	dma_cookie_t cookie, struct dma_tx_state *txstate)
813 {
814 	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
815 	struct tegra_dma_desc *dma_desc;
816 	struct tegra_dma_sg_req *sg_req;
817 	enum dma_status ret;
818 	unsigned long flags;
819 	unsigned int residual;
820 
821 	ret = dma_cookie_status(dc, cookie, txstate);
822 	if (ret == DMA_COMPLETE)
823 		return ret;
824 
825 	spin_lock_irqsave(&tdc->lock, flags);
826 
827 	/* Check on wait_ack desc status */
828 	list_for_each_entry(dma_desc, &tdc->free_dma_desc, node) {
829 		if (dma_desc->txd.cookie == cookie) {
830 			ret = dma_desc->dma_status;
831 			goto found;
832 		}
833 	}
834 
835 	/* Check in pending list */
836 	list_for_each_entry(sg_req, &tdc->pending_sg_req, node) {
837 		dma_desc = sg_req->dma_desc;
838 		if (dma_desc->txd.cookie == cookie) {
839 			ret = dma_desc->dma_status;
840 			goto found;
841 		}
842 	}
843 
844 	dev_dbg(tdc2dev(tdc), "cookie %d not found\n", cookie);
845 	dma_desc = NULL;
846 
847 found:
848 	if (dma_desc && txstate) {
849 		residual = dma_desc->bytes_requested -
850 			   (dma_desc->bytes_transferred %
851 			    dma_desc->bytes_requested);
852 		dma_set_residue(txstate, residual);
853 	}
854 
855 	trace_tegra_dma_tx_status(&tdc->dma_chan, cookie, txstate);
856 	spin_unlock_irqrestore(&tdc->lock, flags);
857 	return ret;
858 }
859 
860 static inline int get_bus_width(struct tegra_dma_channel *tdc,
861 		enum dma_slave_buswidth slave_bw)
862 {
863 	switch (slave_bw) {
864 	case DMA_SLAVE_BUSWIDTH_1_BYTE:
865 		return TEGRA_APBDMA_APBSEQ_BUS_WIDTH_8;
866 	case DMA_SLAVE_BUSWIDTH_2_BYTES:
867 		return TEGRA_APBDMA_APBSEQ_BUS_WIDTH_16;
868 	case DMA_SLAVE_BUSWIDTH_4_BYTES:
869 		return TEGRA_APBDMA_APBSEQ_BUS_WIDTH_32;
870 	case DMA_SLAVE_BUSWIDTH_8_BYTES:
871 		return TEGRA_APBDMA_APBSEQ_BUS_WIDTH_64;
872 	default:
873 		dev_warn(tdc2dev(tdc),
874 			"slave bw is not supported, using 32bits\n");
875 		return TEGRA_APBDMA_APBSEQ_BUS_WIDTH_32;
876 	}
877 }
878 
879 static inline int get_burst_size(struct tegra_dma_channel *tdc,
880 	u32 burst_size, enum dma_slave_buswidth slave_bw, int len)
881 {
882 	int burst_byte;
883 	int burst_ahb_width;
884 
885 	/*
886 	 * burst_size from client is in terms of the bus_width.
887 	 * convert them into AHB memory width which is 4 byte.
888 	 */
889 	burst_byte = burst_size * slave_bw;
890 	burst_ahb_width = burst_byte / 4;
891 
892 	/* If burst size is 0 then calculate the burst size based on length */
893 	if (!burst_ahb_width) {
894 		if (len & 0xF)
895 			return TEGRA_APBDMA_AHBSEQ_BURST_1;
896 		else if ((len >> 4) & 0x1)
897 			return TEGRA_APBDMA_AHBSEQ_BURST_4;
898 		else
899 			return TEGRA_APBDMA_AHBSEQ_BURST_8;
900 	}
901 	if (burst_ahb_width < 4)
902 		return TEGRA_APBDMA_AHBSEQ_BURST_1;
903 	else if (burst_ahb_width < 8)
904 		return TEGRA_APBDMA_AHBSEQ_BURST_4;
905 	else
906 		return TEGRA_APBDMA_AHBSEQ_BURST_8;
907 }
908 
909 static int get_transfer_param(struct tegra_dma_channel *tdc,
910 	enum dma_transfer_direction direction, unsigned long *apb_addr,
911 	unsigned long *apb_seq,	unsigned long *csr, unsigned int *burst_size,
912 	enum dma_slave_buswidth *slave_bw)
913 {
914 	switch (direction) {
915 	case DMA_MEM_TO_DEV:
916 		*apb_addr = tdc->dma_sconfig.dst_addr;
917 		*apb_seq = get_bus_width(tdc, tdc->dma_sconfig.dst_addr_width);
918 		*burst_size = tdc->dma_sconfig.dst_maxburst;
919 		*slave_bw = tdc->dma_sconfig.dst_addr_width;
920 		*csr = TEGRA_APBDMA_CSR_DIR;
921 		return 0;
922 
923 	case DMA_DEV_TO_MEM:
924 		*apb_addr = tdc->dma_sconfig.src_addr;
925 		*apb_seq = get_bus_width(tdc, tdc->dma_sconfig.src_addr_width);
926 		*burst_size = tdc->dma_sconfig.src_maxburst;
927 		*slave_bw = tdc->dma_sconfig.src_addr_width;
928 		*csr = 0;
929 		return 0;
930 
931 	default:
932 		dev_err(tdc2dev(tdc), "DMA direction is not supported\n");
933 		return -EINVAL;
934 	}
935 	return -EINVAL;
936 }
937 
938 static void tegra_dma_prep_wcount(struct tegra_dma_channel *tdc,
939 	struct tegra_dma_channel_regs *ch_regs, u32 len)
940 {
941 	u32 len_field = (len - 4) & 0xFFFC;
942 
943 	if (tdc->tdma->chip_data->support_separate_wcount_reg)
944 		ch_regs->wcount = len_field;
945 	else
946 		ch_regs->csr |= len_field;
947 }
948 
949 static struct dma_async_tx_descriptor *tegra_dma_prep_slave_sg(
950 	struct dma_chan *dc, struct scatterlist *sgl, unsigned int sg_len,
951 	enum dma_transfer_direction direction, unsigned long flags,
952 	void *context)
953 {
954 	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
955 	struct tegra_dma_desc *dma_desc;
956 	unsigned int i;
957 	struct scatterlist *sg;
958 	unsigned long csr, ahb_seq, apb_ptr, apb_seq;
959 	struct list_head req_list;
960 	struct tegra_dma_sg_req  *sg_req = NULL;
961 	u32 burst_size;
962 	enum dma_slave_buswidth slave_bw;
963 
964 	if (!tdc->config_init) {
965 		dev_err(tdc2dev(tdc), "DMA channel is not configured\n");
966 		return NULL;
967 	}
968 	if (sg_len < 1) {
969 		dev_err(tdc2dev(tdc), "Invalid segment length %d\n", sg_len);
970 		return NULL;
971 	}
972 
973 	if (get_transfer_param(tdc, direction, &apb_ptr, &apb_seq, &csr,
974 				&burst_size, &slave_bw) < 0)
975 		return NULL;
976 
977 	INIT_LIST_HEAD(&req_list);
978 
979 	ahb_seq = TEGRA_APBDMA_AHBSEQ_INTR_ENB;
980 	ahb_seq |= TEGRA_APBDMA_AHBSEQ_WRAP_NONE <<
981 					TEGRA_APBDMA_AHBSEQ_WRAP_SHIFT;
982 	ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32;
983 
984 	csr |= TEGRA_APBDMA_CSR_ONCE;
985 
986 	if (tdc->slave_id != TEGRA_APBDMA_SLAVE_ID_INVALID) {
987 		csr |= TEGRA_APBDMA_CSR_FLOW;
988 		csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
989 	}
990 
991 	if (flags & DMA_PREP_INTERRUPT)
992 		csr |= TEGRA_APBDMA_CSR_IE_EOC;
993 
994 	apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;
995 
996 	dma_desc = tegra_dma_desc_get(tdc);
997 	if (!dma_desc) {
998 		dev_err(tdc2dev(tdc), "DMA descriptors not available\n");
999 		return NULL;
1000 	}
1001 	INIT_LIST_HEAD(&dma_desc->tx_list);
1002 	INIT_LIST_HEAD(&dma_desc->cb_node);
1003 	dma_desc->cb_count = 0;
1004 	dma_desc->bytes_requested = 0;
1005 	dma_desc->bytes_transferred = 0;
1006 	dma_desc->dma_status = DMA_IN_PROGRESS;
1007 
1008 	/* Make transfer requests */
1009 	for_each_sg(sgl, sg, sg_len, i) {
1010 		u32 len, mem;
1011 
1012 		mem = sg_dma_address(sg);
1013 		len = sg_dma_len(sg);
1014 
1015 		if ((len & 3) || (mem & 3) ||
1016 				(len > tdc->tdma->chip_data->max_dma_count)) {
1017 			dev_err(tdc2dev(tdc),
1018 				"DMA length/memory address is not supported\n");
1019 			tegra_dma_desc_put(tdc, dma_desc);
1020 			return NULL;
1021 		}
1022 
1023 		sg_req = tegra_dma_sg_req_get(tdc);
1024 		if (!sg_req) {
1025 			dev_err(tdc2dev(tdc), "DMA sg-req not available\n");
1026 			tegra_dma_desc_put(tdc, dma_desc);
1027 			return NULL;
1028 		}
1029 
1030 		ahb_seq |= get_burst_size(tdc, burst_size, slave_bw, len);
1031 		dma_desc->bytes_requested += len;
1032 
1033 		sg_req->ch_regs.apb_ptr = apb_ptr;
1034 		sg_req->ch_regs.ahb_ptr = mem;
1035 		sg_req->ch_regs.csr = csr;
1036 		tegra_dma_prep_wcount(tdc, &sg_req->ch_regs, len);
1037 		sg_req->ch_regs.apb_seq = apb_seq;
1038 		sg_req->ch_regs.ahb_seq = ahb_seq;
1039 		sg_req->configured = false;
1040 		sg_req->last_sg = false;
1041 		sg_req->dma_desc = dma_desc;
1042 		sg_req->req_len = len;
1043 
1044 		list_add_tail(&sg_req->node, &dma_desc->tx_list);
1045 	}
1046 	sg_req->last_sg = true;
1047 	if (flags & DMA_CTRL_ACK)
1048 		dma_desc->txd.flags = DMA_CTRL_ACK;
1049 
1050 	/*
1051 	 * Make sure that mode should not be conflicting with currently
1052 	 * configured mode.
1053 	 */
1054 	if (!tdc->isr_handler) {
1055 		tdc->isr_handler = handle_once_dma_done;
1056 		tdc->cyclic = false;
1057 	} else {
1058 		if (tdc->cyclic) {
1059 			dev_err(tdc2dev(tdc), "DMA configured in cyclic mode\n");
1060 			tegra_dma_desc_put(tdc, dma_desc);
1061 			return NULL;
1062 		}
1063 	}
1064 
1065 	return &dma_desc->txd;
1066 }
1067 
1068 static struct dma_async_tx_descriptor *tegra_dma_prep_dma_cyclic(
1069 	struct dma_chan *dc, dma_addr_t buf_addr, size_t buf_len,
1070 	size_t period_len, enum dma_transfer_direction direction,
1071 	unsigned long flags)
1072 {
1073 	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
1074 	struct tegra_dma_desc *dma_desc = NULL;
1075 	struct tegra_dma_sg_req *sg_req = NULL;
1076 	unsigned long csr, ahb_seq, apb_ptr, apb_seq;
1077 	int len;
1078 	size_t remain_len;
1079 	dma_addr_t mem = buf_addr;
1080 	u32 burst_size;
1081 	enum dma_slave_buswidth slave_bw;
1082 
1083 	if (!buf_len || !period_len) {
1084 		dev_err(tdc2dev(tdc), "Invalid buffer/period len\n");
1085 		return NULL;
1086 	}
1087 
1088 	if (!tdc->config_init) {
1089 		dev_err(tdc2dev(tdc), "DMA slave is not configured\n");
1090 		return NULL;
1091 	}
1092 
1093 	/*
1094 	 * We allow to take more number of requests till DMA is
1095 	 * not started. The driver will loop over all requests.
1096 	 * Once DMA is started then new requests can be queued only after
1097 	 * terminating the DMA.
1098 	 */
1099 	if (tdc->busy) {
1100 		dev_err(tdc2dev(tdc), "Request not allowed when DMA running\n");
1101 		return NULL;
1102 	}
1103 
1104 	/*
1105 	 * We only support cycle transfer when buf_len is multiple of
1106 	 * period_len.
1107 	 */
1108 	if (buf_len % period_len) {
1109 		dev_err(tdc2dev(tdc), "buf_len is not multiple of period_len\n");
1110 		return NULL;
1111 	}
1112 
1113 	len = period_len;
1114 	if ((len & 3) || (buf_addr & 3) ||
1115 			(len > tdc->tdma->chip_data->max_dma_count)) {
1116 		dev_err(tdc2dev(tdc), "Req len/mem address is not correct\n");
1117 		return NULL;
1118 	}
1119 
1120 	if (get_transfer_param(tdc, direction, &apb_ptr, &apb_seq, &csr,
1121 				&burst_size, &slave_bw) < 0)
1122 		return NULL;
1123 
1124 	ahb_seq = TEGRA_APBDMA_AHBSEQ_INTR_ENB;
1125 	ahb_seq |= TEGRA_APBDMA_AHBSEQ_WRAP_NONE <<
1126 					TEGRA_APBDMA_AHBSEQ_WRAP_SHIFT;
1127 	ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32;
1128 
1129 	if (tdc->slave_id != TEGRA_APBDMA_SLAVE_ID_INVALID) {
1130 		csr |= TEGRA_APBDMA_CSR_FLOW;
1131 		csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
1132 	}
1133 
1134 	if (flags & DMA_PREP_INTERRUPT)
1135 		csr |= TEGRA_APBDMA_CSR_IE_EOC;
1136 
1137 	apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;
1138 
1139 	dma_desc = tegra_dma_desc_get(tdc);
1140 	if (!dma_desc) {
1141 		dev_err(tdc2dev(tdc), "not enough descriptors available\n");
1142 		return NULL;
1143 	}
1144 
1145 	INIT_LIST_HEAD(&dma_desc->tx_list);
1146 	INIT_LIST_HEAD(&dma_desc->cb_node);
1147 	dma_desc->cb_count = 0;
1148 
1149 	dma_desc->bytes_transferred = 0;
1150 	dma_desc->bytes_requested = buf_len;
1151 	remain_len = buf_len;
1152 
1153 	/* Split transfer equal to period size */
1154 	while (remain_len) {
1155 		sg_req = tegra_dma_sg_req_get(tdc);
1156 		if (!sg_req) {
1157 			dev_err(tdc2dev(tdc), "DMA sg-req not available\n");
1158 			tegra_dma_desc_put(tdc, dma_desc);
1159 			return NULL;
1160 		}
1161 
1162 		ahb_seq |= get_burst_size(tdc, burst_size, slave_bw, len);
1163 		sg_req->ch_regs.apb_ptr = apb_ptr;
1164 		sg_req->ch_regs.ahb_ptr = mem;
1165 		sg_req->ch_regs.csr = csr;
1166 		tegra_dma_prep_wcount(tdc, &sg_req->ch_regs, len);
1167 		sg_req->ch_regs.apb_seq = apb_seq;
1168 		sg_req->ch_regs.ahb_seq = ahb_seq;
1169 		sg_req->configured = false;
1170 		sg_req->last_sg = false;
1171 		sg_req->dma_desc = dma_desc;
1172 		sg_req->req_len = len;
1173 
1174 		list_add_tail(&sg_req->node, &dma_desc->tx_list);
1175 		remain_len -= len;
1176 		mem += len;
1177 	}
1178 	sg_req->last_sg = true;
1179 	if (flags & DMA_CTRL_ACK)
1180 		dma_desc->txd.flags = DMA_CTRL_ACK;
1181 
1182 	/*
1183 	 * Make sure that mode should not be conflicting with currently
1184 	 * configured mode.
1185 	 */
1186 	if (!tdc->isr_handler) {
1187 		tdc->isr_handler = handle_cont_sngl_cycle_dma_done;
1188 		tdc->cyclic = true;
1189 	} else {
1190 		if (!tdc->cyclic) {
1191 			dev_err(tdc2dev(tdc), "DMA configuration conflict\n");
1192 			tegra_dma_desc_put(tdc, dma_desc);
1193 			return NULL;
1194 		}
1195 	}
1196 
1197 	return &dma_desc->txd;
1198 }
1199 
1200 static int tegra_dma_alloc_chan_resources(struct dma_chan *dc)
1201 {
1202 	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
1203 	struct tegra_dma *tdma = tdc->tdma;
1204 	int ret;
1205 
1206 	dma_cookie_init(&tdc->dma_chan);
1207 	tdc->config_init = false;
1208 
1209 	ret = pm_runtime_get_sync(tdma->dev);
1210 	if (ret < 0)
1211 		return ret;
1212 
1213 	return 0;
1214 }
1215 
1216 static void tegra_dma_free_chan_resources(struct dma_chan *dc)
1217 {
1218 	struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
1219 	struct tegra_dma *tdma = tdc->tdma;
1220 	struct tegra_dma_desc *dma_desc;
1221 	struct tegra_dma_sg_req *sg_req;
1222 	struct list_head dma_desc_list;
1223 	struct list_head sg_req_list;
1224 	unsigned long flags;
1225 
1226 	INIT_LIST_HEAD(&dma_desc_list);
1227 	INIT_LIST_HEAD(&sg_req_list);
1228 
1229 	dev_dbg(tdc2dev(tdc), "Freeing channel %d\n", tdc->id);
1230 
1231 	if (tdc->busy)
1232 		tegra_dma_terminate_all(dc);
1233 
1234 	spin_lock_irqsave(&tdc->lock, flags);
1235 	list_splice_init(&tdc->pending_sg_req, &sg_req_list);
1236 	list_splice_init(&tdc->free_sg_req, &sg_req_list);
1237 	list_splice_init(&tdc->free_dma_desc, &dma_desc_list);
1238 	INIT_LIST_HEAD(&tdc->cb_desc);
1239 	tdc->config_init = false;
1240 	tdc->isr_handler = NULL;
1241 	spin_unlock_irqrestore(&tdc->lock, flags);
1242 
1243 	while (!list_empty(&dma_desc_list)) {
1244 		dma_desc = list_first_entry(&dma_desc_list,
1245 					typeof(*dma_desc), node);
1246 		list_del(&dma_desc->node);
1247 		kfree(dma_desc);
1248 	}
1249 
1250 	while (!list_empty(&sg_req_list)) {
1251 		sg_req = list_first_entry(&sg_req_list, typeof(*sg_req), node);
1252 		list_del(&sg_req->node);
1253 		kfree(sg_req);
1254 	}
1255 	pm_runtime_put(tdma->dev);
1256 
1257 	tdc->slave_id = TEGRA_APBDMA_SLAVE_ID_INVALID;
1258 }
1259 
1260 static struct dma_chan *tegra_dma_of_xlate(struct of_phandle_args *dma_spec,
1261 					   struct of_dma *ofdma)
1262 {
1263 	struct tegra_dma *tdma = ofdma->of_dma_data;
1264 	struct dma_chan *chan;
1265 	struct tegra_dma_channel *tdc;
1266 
1267 	if (dma_spec->args[0] > TEGRA_APBDMA_CSR_REQ_SEL_MASK) {
1268 		dev_err(tdma->dev, "Invalid slave id: %d\n", dma_spec->args[0]);
1269 		return NULL;
1270 	}
1271 
1272 	chan = dma_get_any_slave_channel(&tdma->dma_dev);
1273 	if (!chan)
1274 		return NULL;
1275 
1276 	tdc = to_tegra_dma_chan(chan);
1277 	tdc->slave_id = dma_spec->args[0];
1278 
1279 	return chan;
1280 }
1281 
1282 /* Tegra20 specific DMA controller information */
1283 static const struct tegra_dma_chip_data tegra20_dma_chip_data = {
1284 	.nr_channels		= 16,
1285 	.channel_reg_size	= 0x20,
1286 	.max_dma_count		= 1024UL * 64,
1287 	.support_channel_pause	= false,
1288 	.support_separate_wcount_reg = false,
1289 };
1290 
1291 /* Tegra30 specific DMA controller information */
1292 static const struct tegra_dma_chip_data tegra30_dma_chip_data = {
1293 	.nr_channels		= 32,
1294 	.channel_reg_size	= 0x20,
1295 	.max_dma_count		= 1024UL * 64,
1296 	.support_channel_pause	= false,
1297 	.support_separate_wcount_reg = false,
1298 };
1299 
1300 /* Tegra114 specific DMA controller information */
1301 static const struct tegra_dma_chip_data tegra114_dma_chip_data = {
1302 	.nr_channels		= 32,
1303 	.channel_reg_size	= 0x20,
1304 	.max_dma_count		= 1024UL * 64,
1305 	.support_channel_pause	= true,
1306 	.support_separate_wcount_reg = false,
1307 };
1308 
1309 /* Tegra148 specific DMA controller information */
1310 static const struct tegra_dma_chip_data tegra148_dma_chip_data = {
1311 	.nr_channels		= 32,
1312 	.channel_reg_size	= 0x40,
1313 	.max_dma_count		= 1024UL * 64,
1314 	.support_channel_pause	= true,
1315 	.support_separate_wcount_reg = true,
1316 };
1317 
1318 static int tegra_dma_probe(struct platform_device *pdev)
1319 {
1320 	struct resource *res;
1321 	struct tegra_dma *tdma;
1322 	int ret;
1323 	int i;
1324 	const struct tegra_dma_chip_data *cdata;
1325 
1326 	cdata = of_device_get_match_data(&pdev->dev);
1327 	if (!cdata) {
1328 		dev_err(&pdev->dev, "Error: No device match data found\n");
1329 		return -ENODEV;
1330 	}
1331 
1332 	tdma = devm_kzalloc(&pdev->dev,
1333 			    struct_size(tdma, channels, cdata->nr_channels),
1334 			    GFP_KERNEL);
1335 	if (!tdma)
1336 		return -ENOMEM;
1337 
1338 	tdma->dev = &pdev->dev;
1339 	tdma->chip_data = cdata;
1340 	platform_set_drvdata(pdev, tdma);
1341 
1342 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1343 	tdma->base_addr = devm_ioremap_resource(&pdev->dev, res);
1344 	if (IS_ERR(tdma->base_addr))
1345 		return PTR_ERR(tdma->base_addr);
1346 
1347 	tdma->dma_clk = devm_clk_get(&pdev->dev, NULL);
1348 	if (IS_ERR(tdma->dma_clk)) {
1349 		dev_err(&pdev->dev, "Error: Missing controller clock\n");
1350 		return PTR_ERR(tdma->dma_clk);
1351 	}
1352 
1353 	tdma->rst = devm_reset_control_get(&pdev->dev, "dma");
1354 	if (IS_ERR(tdma->rst)) {
1355 		dev_err(&pdev->dev, "Error: Missing reset\n");
1356 		return PTR_ERR(tdma->rst);
1357 	}
1358 
1359 	spin_lock_init(&tdma->global_lock);
1360 
1361 	pm_runtime_enable(&pdev->dev);
1362 	if (!pm_runtime_enabled(&pdev->dev))
1363 		ret = tegra_dma_runtime_resume(&pdev->dev);
1364 	else
1365 		ret = pm_runtime_get_sync(&pdev->dev);
1366 
1367 	if (ret < 0) {
1368 		pm_runtime_disable(&pdev->dev);
1369 		return ret;
1370 	}
1371 
1372 	/* Reset DMA controller */
1373 	reset_control_assert(tdma->rst);
1374 	udelay(2);
1375 	reset_control_deassert(tdma->rst);
1376 
1377 	/* Enable global DMA registers */
1378 	tdma_write(tdma, TEGRA_APBDMA_GENERAL, TEGRA_APBDMA_GENERAL_ENABLE);
1379 	tdma_write(tdma, TEGRA_APBDMA_CONTROL, 0);
1380 	tdma_write(tdma, TEGRA_APBDMA_IRQ_MASK_SET, 0xFFFFFFFFul);
1381 
1382 	pm_runtime_put(&pdev->dev);
1383 
1384 	INIT_LIST_HEAD(&tdma->dma_dev.channels);
1385 	for (i = 0; i < cdata->nr_channels; i++) {
1386 		struct tegra_dma_channel *tdc = &tdma->channels[i];
1387 
1388 		tdc->chan_addr = tdma->base_addr +
1389 				 TEGRA_APBDMA_CHANNEL_BASE_ADD_OFFSET +
1390 				 (i * cdata->channel_reg_size);
1391 
1392 		res = platform_get_resource(pdev, IORESOURCE_IRQ, i);
1393 		if (!res) {
1394 			ret = -EINVAL;
1395 			dev_err(&pdev->dev, "No irq resource for chan %d\n", i);
1396 			goto err_irq;
1397 		}
1398 		tdc->irq = res->start;
1399 		snprintf(tdc->name, sizeof(tdc->name), "apbdma.%d", i);
1400 		ret = request_irq(tdc->irq, tegra_dma_isr, 0, tdc->name, tdc);
1401 		if (ret) {
1402 			dev_err(&pdev->dev,
1403 				"request_irq failed with err %d channel %d\n",
1404 				ret, i);
1405 			goto err_irq;
1406 		}
1407 
1408 		tdc->dma_chan.device = &tdma->dma_dev;
1409 		dma_cookie_init(&tdc->dma_chan);
1410 		list_add_tail(&tdc->dma_chan.device_node,
1411 				&tdma->dma_dev.channels);
1412 		tdc->tdma = tdma;
1413 		tdc->id = i;
1414 		tdc->slave_id = TEGRA_APBDMA_SLAVE_ID_INVALID;
1415 
1416 		tasklet_init(&tdc->tasklet, tegra_dma_tasklet,
1417 				(unsigned long)tdc);
1418 		spin_lock_init(&tdc->lock);
1419 
1420 		INIT_LIST_HEAD(&tdc->pending_sg_req);
1421 		INIT_LIST_HEAD(&tdc->free_sg_req);
1422 		INIT_LIST_HEAD(&tdc->free_dma_desc);
1423 		INIT_LIST_HEAD(&tdc->cb_desc);
1424 	}
1425 
1426 	dma_cap_set(DMA_SLAVE, tdma->dma_dev.cap_mask);
1427 	dma_cap_set(DMA_PRIVATE, tdma->dma_dev.cap_mask);
1428 	dma_cap_set(DMA_CYCLIC, tdma->dma_dev.cap_mask);
1429 
1430 	tdma->global_pause_count = 0;
1431 	tdma->dma_dev.dev = &pdev->dev;
1432 	tdma->dma_dev.device_alloc_chan_resources =
1433 					tegra_dma_alloc_chan_resources;
1434 	tdma->dma_dev.device_free_chan_resources =
1435 					tegra_dma_free_chan_resources;
1436 	tdma->dma_dev.device_prep_slave_sg = tegra_dma_prep_slave_sg;
1437 	tdma->dma_dev.device_prep_dma_cyclic = tegra_dma_prep_dma_cyclic;
1438 	tdma->dma_dev.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
1439 		BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
1440 		BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) |
1441 		BIT(DMA_SLAVE_BUSWIDTH_8_BYTES);
1442 	tdma->dma_dev.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
1443 		BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
1444 		BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) |
1445 		BIT(DMA_SLAVE_BUSWIDTH_8_BYTES);
1446 	tdma->dma_dev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
1447 	/*
1448 	 * XXX The hardware appears to support
1449 	 * DMA_RESIDUE_GRANULARITY_BURST-level reporting, but it's
1450 	 * only used by this driver during tegra_dma_terminate_all()
1451 	 */
1452 	tdma->dma_dev.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
1453 	tdma->dma_dev.device_config = tegra_dma_slave_config;
1454 	tdma->dma_dev.device_terminate_all = tegra_dma_terminate_all;
1455 	tdma->dma_dev.device_tx_status = tegra_dma_tx_status;
1456 	tdma->dma_dev.device_issue_pending = tegra_dma_issue_pending;
1457 
1458 	ret = dma_async_device_register(&tdma->dma_dev);
1459 	if (ret < 0) {
1460 		dev_err(&pdev->dev,
1461 			"Tegra20 APB DMA driver registration failed %d\n", ret);
1462 		goto err_irq;
1463 	}
1464 
1465 	ret = of_dma_controller_register(pdev->dev.of_node,
1466 					 tegra_dma_of_xlate, tdma);
1467 	if (ret < 0) {
1468 		dev_err(&pdev->dev,
1469 			"Tegra20 APB DMA OF registration failed %d\n", ret);
1470 		goto err_unregister_dma_dev;
1471 	}
1472 
1473 	dev_info(&pdev->dev, "Tegra20 APB DMA driver register %d channels\n",
1474 			cdata->nr_channels);
1475 	return 0;
1476 
1477 err_unregister_dma_dev:
1478 	dma_async_device_unregister(&tdma->dma_dev);
1479 err_irq:
1480 	while (--i >= 0) {
1481 		struct tegra_dma_channel *tdc = &tdma->channels[i];
1482 
1483 		free_irq(tdc->irq, tdc);
1484 		tasklet_kill(&tdc->tasklet);
1485 	}
1486 
1487 	pm_runtime_disable(&pdev->dev);
1488 	if (!pm_runtime_status_suspended(&pdev->dev))
1489 		tegra_dma_runtime_suspend(&pdev->dev);
1490 	return ret;
1491 }
1492 
1493 static int tegra_dma_remove(struct platform_device *pdev)
1494 {
1495 	struct tegra_dma *tdma = platform_get_drvdata(pdev);
1496 	int i;
1497 	struct tegra_dma_channel *tdc;
1498 
1499 	dma_async_device_unregister(&tdma->dma_dev);
1500 
1501 	for (i = 0; i < tdma->chip_data->nr_channels; ++i) {
1502 		tdc = &tdma->channels[i];
1503 		free_irq(tdc->irq, tdc);
1504 		tasklet_kill(&tdc->tasklet);
1505 	}
1506 
1507 	pm_runtime_disable(&pdev->dev);
1508 	if (!pm_runtime_status_suspended(&pdev->dev))
1509 		tegra_dma_runtime_suspend(&pdev->dev);
1510 
1511 	return 0;
1512 }
1513 
1514 static int tegra_dma_runtime_suspend(struct device *dev)
1515 {
1516 	struct tegra_dma *tdma = dev_get_drvdata(dev);
1517 	int i;
1518 
1519 	tdma->reg_gen = tdma_read(tdma, TEGRA_APBDMA_GENERAL);
1520 	for (i = 0; i < tdma->chip_data->nr_channels; i++) {
1521 		struct tegra_dma_channel *tdc = &tdma->channels[i];
1522 		struct tegra_dma_channel_regs *ch_reg = &tdc->channel_reg;
1523 
1524 		/* Only save the state of DMA channels that are in use */
1525 		if (!tdc->config_init)
1526 			continue;
1527 
1528 		ch_reg->csr = tdc_read(tdc, TEGRA_APBDMA_CHAN_CSR);
1529 		ch_reg->ahb_ptr = tdc_read(tdc, TEGRA_APBDMA_CHAN_AHBPTR);
1530 		ch_reg->apb_ptr = tdc_read(tdc, TEGRA_APBDMA_CHAN_APBPTR);
1531 		ch_reg->ahb_seq = tdc_read(tdc, TEGRA_APBDMA_CHAN_AHBSEQ);
1532 		ch_reg->apb_seq = tdc_read(tdc, TEGRA_APBDMA_CHAN_APBSEQ);
1533 		if (tdma->chip_data->support_separate_wcount_reg)
1534 			ch_reg->wcount = tdc_read(tdc,
1535 						  TEGRA_APBDMA_CHAN_WCOUNT);
1536 	}
1537 
1538 	clk_disable_unprepare(tdma->dma_clk);
1539 
1540 	return 0;
1541 }
1542 
1543 static int tegra_dma_runtime_resume(struct device *dev)
1544 {
1545 	struct tegra_dma *tdma = dev_get_drvdata(dev);
1546 	int i, ret;
1547 
1548 	ret = clk_prepare_enable(tdma->dma_clk);
1549 	if (ret < 0) {
1550 		dev_err(dev, "clk_enable failed: %d\n", ret);
1551 		return ret;
1552 	}
1553 
1554 	tdma_write(tdma, TEGRA_APBDMA_GENERAL, tdma->reg_gen);
1555 	tdma_write(tdma, TEGRA_APBDMA_CONTROL, 0);
1556 	tdma_write(tdma, TEGRA_APBDMA_IRQ_MASK_SET, 0xFFFFFFFFul);
1557 
1558 	for (i = 0; i < tdma->chip_data->nr_channels; i++) {
1559 		struct tegra_dma_channel *tdc = &tdma->channels[i];
1560 		struct tegra_dma_channel_regs *ch_reg = &tdc->channel_reg;
1561 
1562 		/* Only restore the state of DMA channels that are in use */
1563 		if (!tdc->config_init)
1564 			continue;
1565 
1566 		if (tdma->chip_data->support_separate_wcount_reg)
1567 			tdc_write(tdc, TEGRA_APBDMA_CHAN_WCOUNT,
1568 				  ch_reg->wcount);
1569 		tdc_write(tdc, TEGRA_APBDMA_CHAN_APBSEQ, ch_reg->apb_seq);
1570 		tdc_write(tdc, TEGRA_APBDMA_CHAN_APBPTR, ch_reg->apb_ptr);
1571 		tdc_write(tdc, TEGRA_APBDMA_CHAN_AHBSEQ, ch_reg->ahb_seq);
1572 		tdc_write(tdc, TEGRA_APBDMA_CHAN_AHBPTR, ch_reg->ahb_ptr);
1573 		tdc_write(tdc, TEGRA_APBDMA_CHAN_CSR,
1574 			(ch_reg->csr & ~TEGRA_APBDMA_CSR_ENB));
1575 	}
1576 
1577 	return 0;
1578 }
1579 
1580 static const struct dev_pm_ops tegra_dma_dev_pm_ops = {
1581 	SET_RUNTIME_PM_OPS(tegra_dma_runtime_suspend, tegra_dma_runtime_resume,
1582 			   NULL)
1583 	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
1584 				pm_runtime_force_resume)
1585 };
1586 
1587 static const struct of_device_id tegra_dma_of_match[] = {
1588 	{
1589 		.compatible = "nvidia,tegra148-apbdma",
1590 		.data = &tegra148_dma_chip_data,
1591 	}, {
1592 		.compatible = "nvidia,tegra114-apbdma",
1593 		.data = &tegra114_dma_chip_data,
1594 	}, {
1595 		.compatible = "nvidia,tegra30-apbdma",
1596 		.data = &tegra30_dma_chip_data,
1597 	}, {
1598 		.compatible = "nvidia,tegra20-apbdma",
1599 		.data = &tegra20_dma_chip_data,
1600 	}, {
1601 	},
1602 };
1603 MODULE_DEVICE_TABLE(of, tegra_dma_of_match);
1604 
1605 static struct platform_driver tegra_dmac_driver = {
1606 	.driver = {
1607 		.name	= "tegra-apbdma",
1608 		.pm	= &tegra_dma_dev_pm_ops,
1609 		.of_match_table = tegra_dma_of_match,
1610 	},
1611 	.probe		= tegra_dma_probe,
1612 	.remove		= tegra_dma_remove,
1613 };
1614 
1615 module_platform_driver(tegra_dmac_driver);
1616 
1617 MODULE_ALIAS("platform:tegra20-apbdma");
1618 MODULE_DESCRIPTION("NVIDIA Tegra APB DMA Controller driver");
1619 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
1620 MODULE_LICENSE("GPL v2");
1621