usb-dmac.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Renesas USB DMA Controller Driver
  4 *
  5 * Copyright (C) 2015 Renesas Electronics Corporation
  6 *
  7 * based on rcar-dmac.c
  8 * Copyright (C) 2014 Renesas Electronics Inc.
  9 * Author: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 10 */
 11
 12#include <linux/delay.h>
 13#include <linux/dma-mapping.h>
 14#include <linux/dmaengine.h>
 15#include <linux/interrupt.h>
 16#include <linux/list.h>
 17#include <linux/module.h>
 18#include <linux/of.h>
 19#include <linux/of_dma.h>
 20#include <linux/of_platform.h>
 21#include <linux/platform_device.h>
 22#include <linux/pm_runtime.h>
 23#include <linux/slab.h>
 24#include <linux/spinlock.h>
 25
 26#include "../dmaengine.h"
 27#include "../virt-dma.h"
 28
 29/*
 30 * struct usb_dmac_sg - Descriptor for a hardware transfer
 31 * @mem_addr: memory address
 32 * @size: transfer size in bytes
 33 */
 34struct usb_dmac_sg {
 35	dma_addr_t mem_addr;
 36	u32 size;
 37};
 38
 39/*
 40 * struct usb_dmac_desc - USB DMA Transfer Descriptor
 41 * @vd: base virtual channel DMA transaction descriptor
 42 * @direction: direction of the DMA transfer
 43 * @sg_allocated_len: length of allocated sg
 44 * @sg_len: length of sg
 45 * @sg_index: index of sg
 46 * @residue: residue after the DMAC completed a transfer
 47 * @node: node for desc_got and desc_freed
 48 * @done_cookie: cookie after the DMAC completed a transfer
 49 * @sg: information for the transfer
 50 */
 51struct usb_dmac_desc {
 52	struct virt_dma_desc vd;
 53	enum dma_transfer_direction direction;
 54	unsigned int sg_allocated_len;
 55	unsigned int sg_len;
 56	unsigned int sg_index;
 57	u32 residue;
 58	struct list_head node;
 59	dma_cookie_t done_cookie;
 60	struct usb_dmac_sg sg[] __counted_by(sg_allocated_len);
 61};
 62
 63#define to_usb_dmac_desc(vd)	container_of(vd, struct usb_dmac_desc, vd)
 64
 65/*
 66 * struct usb_dmac_chan - USB DMA Controller Channel
 67 * @vc: base virtual DMA channel object
 68 * @iomem: channel I/O memory base
 69 * @index: index of this channel in the controller
 70 * @irq: irq number of this channel
 71 * @desc: the current descriptor
 72 * @descs_allocated: number of descriptors allocated
 73 * @desc_got: got descriptors
 74 * @desc_freed: freed descriptors after the DMAC completed a transfer
 75 */
 76struct usb_dmac_chan {
 77	struct virt_dma_chan vc;
 78	void __iomem *iomem;
 79	unsigned int index;
 80	int irq;
 81	struct usb_dmac_desc *desc;
 82	int descs_allocated;
 83	struct list_head desc_got;
 84	struct list_head desc_freed;
 85};
 86
 87#define to_usb_dmac_chan(c) container_of(c, struct usb_dmac_chan, vc.chan)
 88
 89/*
 90 * struct usb_dmac - USB DMA Controller
 91 * @engine: base DMA engine object
 92 * @dev: the hardware device
 93 * @iomem: remapped I/O memory base
 94 * @n_channels: number of available channels
 95 * @channels: array of DMAC channels
 96 */
 97struct usb_dmac {
 98	struct dma_device engine;
 99	struct device *dev;
100	void __iomem *iomem;
101
102	unsigned int n_channels;
103	struct usb_dmac_chan *channels;
104};
105
106#define to_usb_dmac(d)		container_of(d, struct usb_dmac, engine)
107
108/* -----------------------------------------------------------------------------
109 * Registers
110 */
111
112#define USB_DMAC_CHAN_OFFSET(i)		(0x20 + 0x20 * (i))
113
114#define USB_DMASWR			0x0008
115#define USB_DMASWR_SWR			(1 << 0)
116#define USB_DMAOR			0x0060
117#define USB_DMAOR_AE			(1 << 1)
118#define USB_DMAOR_DME			(1 << 0)
119
120#define USB_DMASAR			0x0000
121#define USB_DMADAR			0x0004
122#define USB_DMATCR			0x0008
123#define USB_DMATCR_MASK			0x00ffffff
124#define USB_DMACHCR			0x0014
125#define USB_DMACHCR_FTE			(1 << 24)
126#define USB_DMACHCR_NULLE		(1 << 16)
127#define USB_DMACHCR_NULL		(1 << 12)
128#define USB_DMACHCR_TS_8B		((0 << 7) | (0 << 6))
129#define USB_DMACHCR_TS_16B		((0 << 7) | (1 << 6))
130#define USB_DMACHCR_TS_32B		((1 << 7) | (0 << 6))
131#define USB_DMACHCR_IE			(1 << 5)
132#define USB_DMACHCR_SP			(1 << 2)
133#define USB_DMACHCR_TE			(1 << 1)
134#define USB_DMACHCR_DE			(1 << 0)
135#define USB_DMATEND			0x0018
136
137/* Hardcode the xfer_shift to 5 (32bytes) */
138#define USB_DMAC_XFER_SHIFT	5
139#define USB_DMAC_XFER_SIZE	(1 << USB_DMAC_XFER_SHIFT)
140#define USB_DMAC_CHCR_TS	USB_DMACHCR_TS_32B
141#define USB_DMAC_SLAVE_BUSWIDTH	DMA_SLAVE_BUSWIDTH_32_BYTES
142
143/* for descriptors */
144#define USB_DMAC_INITIAL_NR_DESC	16
145#define USB_DMAC_INITIAL_NR_SG		8
146
147/* -----------------------------------------------------------------------------
148 * Device access
149 */
150
151static void usb_dmac_write(struct usb_dmac *dmac, u32 reg, u32 data)
152{
153	writel(data, dmac->iomem + reg);
154}
155
156static u32 usb_dmac_read(struct usb_dmac *dmac, u32 reg)
157{
158	return readl(dmac->iomem + reg);
159}
160
161static u32 usb_dmac_chan_read(struct usb_dmac_chan *chan, u32 reg)
162{
163	return readl(chan->iomem + reg);
164}
165
166static void usb_dmac_chan_write(struct usb_dmac_chan *chan, u32 reg, u32 data)
167{
168	writel(data, chan->iomem + reg);
169}
170
171/* -----------------------------------------------------------------------------
172 * Initialization and configuration
173 */
174
175static bool usb_dmac_chan_is_busy(struct usb_dmac_chan *chan)
176{
177	u32 chcr = usb_dmac_chan_read(chan, USB_DMACHCR);
178
179	return (chcr & (USB_DMACHCR_DE | USB_DMACHCR_TE)) == USB_DMACHCR_DE;
180}
181
182static u32 usb_dmac_calc_tend(u32 size)
183{
184	/*
185	 * Please refer to the Figure "Example of Final Transaction Valid
186	 * Data Transfer Enable (EDTEN) Setting" in the data sheet.
187	 */
188	return 0xffffffff << (32 - (size % USB_DMAC_XFER_SIZE ?	:
189						USB_DMAC_XFER_SIZE));
190}
191
192/* This function is already held by vc.lock */
193static void usb_dmac_chan_start_sg(struct usb_dmac_chan *chan,
194				   unsigned int index)
195{
196	struct usb_dmac_desc *desc = chan->desc;
197	struct usb_dmac_sg *sg = desc->sg + index;
198	dma_addr_t src_addr = 0, dst_addr = 0;
199
200	WARN_ON_ONCE(usb_dmac_chan_is_busy(chan));
201
202	if (desc->direction == DMA_DEV_TO_MEM)
203		dst_addr = sg->mem_addr;
204	else
205		src_addr = sg->mem_addr;
206
207	dev_dbg(chan->vc.chan.device->dev,
208		"chan%u: queue sg %p: %u@%pad -> %pad\n",
209		chan->index, sg, sg->size, &src_addr, &dst_addr);
210
211	usb_dmac_chan_write(chan, USB_DMASAR, src_addr & 0xffffffff);
212	usb_dmac_chan_write(chan, USB_DMADAR, dst_addr & 0xffffffff);
213	usb_dmac_chan_write(chan, USB_DMATCR,
214			    DIV_ROUND_UP(sg->size, USB_DMAC_XFER_SIZE));
215	usb_dmac_chan_write(chan, USB_DMATEND, usb_dmac_calc_tend(sg->size));
216
217	usb_dmac_chan_write(chan, USB_DMACHCR, USB_DMAC_CHCR_TS |
218			USB_DMACHCR_NULLE | USB_DMACHCR_IE | USB_DMACHCR_DE);
219}
220
221/* This function is already held by vc.lock */
222static void usb_dmac_chan_start_desc(struct usb_dmac_chan *chan)
223{
224	struct virt_dma_desc *vd;
225
226	vd = vchan_next_desc(&chan->vc);
227	if (!vd) {
228		chan->desc = NULL;
229		return;
230	}
231
232	/*
233	 * Remove this request from vc->desc_issued. Otherwise, this driver
234	 * will get the previous value from vchan_next_desc() after a transfer
235	 * was completed.
236	 */
237	list_del(&vd->node);
238
239	chan->desc = to_usb_dmac_desc(vd);
240	chan->desc->sg_index = 0;
241	usb_dmac_chan_start_sg(chan, 0);
242}
243
244static int usb_dmac_init(struct usb_dmac *dmac)
245{
246	u16 dmaor;
247
248	/* Clear all channels and enable the DMAC globally. */
249	usb_dmac_write(dmac, USB_DMAOR, USB_DMAOR_DME);
250
251	dmaor = usb_dmac_read(dmac, USB_DMAOR);
252	if ((dmaor & (USB_DMAOR_AE | USB_DMAOR_DME)) != USB_DMAOR_DME) {
253		dev_warn(dmac->dev, "DMAOR initialization failed.\n");
254		return -EIO;
255	}
256
257	return 0;
258}
259
260/* -----------------------------------------------------------------------------
261 * Descriptors allocation and free
262 */
263static int usb_dmac_desc_alloc(struct usb_dmac_chan *chan, unsigned int sg_len,
264			       gfp_t gfp)
265{
266	struct usb_dmac_desc *desc;
267	unsigned long flags;
268
269	desc = kzalloc(struct_size(desc, sg, sg_len), gfp);
270	if (!desc)
271		return -ENOMEM;
272
273	desc->sg_allocated_len = sg_len;
274	INIT_LIST_HEAD(&desc->node);
275
276	spin_lock_irqsave(&chan->vc.lock, flags);
277	list_add_tail(&desc->node, &chan->desc_freed);
278	spin_unlock_irqrestore(&chan->vc.lock, flags);
279
280	return 0;
281}
282
283static void usb_dmac_desc_free(struct usb_dmac_chan *chan)
284{
285	struct usb_dmac_desc *desc, *_desc;
286	LIST_HEAD(list);
287
288	list_splice_init(&chan->desc_freed, &list);
289	list_splice_init(&chan->desc_got, &list);
290
291	list_for_each_entry_safe(desc, _desc, &list, node) {
292		list_del(&desc->node);
293		kfree(desc);
294	}
295	chan->descs_allocated = 0;
296}
297
298static struct usb_dmac_desc *usb_dmac_desc_get(struct usb_dmac_chan *chan,
299					       unsigned int sg_len, gfp_t gfp)
300{
301	struct usb_dmac_desc *desc = NULL;
302	unsigned long flags;
303
304	/* Get a freed descriptor */
305	spin_lock_irqsave(&chan->vc.lock, flags);
306	list_for_each_entry(desc, &chan->desc_freed, node) {
307		if (sg_len <= desc->sg_allocated_len) {
308			list_move_tail(&desc->node, &chan->desc_got);
309			spin_unlock_irqrestore(&chan->vc.lock, flags);
310			return desc;
311		}
312	}
313	spin_unlock_irqrestore(&chan->vc.lock, flags);
314
315	/* Allocate a new descriptor */
316	if (!usb_dmac_desc_alloc(chan, sg_len, gfp)) {
317		/* If allocated the desc, it was added to tail of the list */
318		spin_lock_irqsave(&chan->vc.lock, flags);
319		desc = list_last_entry(&chan->desc_freed, struct usb_dmac_desc,
320				       node);
321		list_move_tail(&desc->node, &chan->desc_got);
322		spin_unlock_irqrestore(&chan->vc.lock, flags);
323		return desc;
324	}
325
326	return NULL;
327}
328
329static void usb_dmac_desc_put(struct usb_dmac_chan *chan,
330			      struct usb_dmac_desc *desc)
331{
332	unsigned long flags;
333
334	spin_lock_irqsave(&chan->vc.lock, flags);
335	list_move_tail(&desc->node, &chan->desc_freed);
336	spin_unlock_irqrestore(&chan->vc.lock, flags);
337}
338
339/* -----------------------------------------------------------------------------
340 * Stop and reset
341 */
342
343static void usb_dmac_soft_reset(struct usb_dmac_chan *uchan)
344{
345	struct dma_chan *chan = &uchan->vc.chan;
346	struct usb_dmac *dmac = to_usb_dmac(chan->device);
347	int i;
348
349	/* Don't issue soft reset if any one of channels is busy */
350	for (i = 0; i < dmac->n_channels; ++i) {
351		if (usb_dmac_chan_is_busy(uchan))
352			return;
353	}
354
355	usb_dmac_write(dmac, USB_DMAOR, 0);
356	usb_dmac_write(dmac, USB_DMASWR, USB_DMASWR_SWR);
357	udelay(100);
358	usb_dmac_write(dmac, USB_DMASWR, 0);
359	usb_dmac_write(dmac, USB_DMAOR, 1);
360}
361
362static void usb_dmac_chan_halt(struct usb_dmac_chan *chan)
363{
364	u32 chcr = usb_dmac_chan_read(chan, USB_DMACHCR);
365
366	chcr &= ~(USB_DMACHCR_IE | USB_DMACHCR_TE | USB_DMACHCR_DE);
367	usb_dmac_chan_write(chan, USB_DMACHCR, chcr);
368
369	usb_dmac_soft_reset(chan);
370}
371
372static void usb_dmac_stop(struct usb_dmac *dmac)
373{
374	usb_dmac_write(dmac, USB_DMAOR, 0);
375}
376
377/* -----------------------------------------------------------------------------
378 * DMA engine operations
379 */
380
381static int usb_dmac_alloc_chan_resources(struct dma_chan *chan)
382{
383	struct usb_dmac_chan *uchan = to_usb_dmac_chan(chan);
384	int ret;
385
386	while (uchan->descs_allocated < USB_DMAC_INITIAL_NR_DESC) {
387		ret = usb_dmac_desc_alloc(uchan, USB_DMAC_INITIAL_NR_SG,
388					  GFP_KERNEL);
389		if (ret < 0) {
390			usb_dmac_desc_free(uchan);
391			return ret;
392		}
393		uchan->descs_allocated++;
394	}
395
396	return pm_runtime_get_sync(chan->device->dev);
397}
398
399static void usb_dmac_free_chan_resources(struct dma_chan *chan)
400{
401	struct usb_dmac_chan *uchan = to_usb_dmac_chan(chan);
402	unsigned long flags;
403
404	/* Protect against ISR */
405	spin_lock_irqsave(&uchan->vc.lock, flags);
406	usb_dmac_chan_halt(uchan);
407	spin_unlock_irqrestore(&uchan->vc.lock, flags);
408
409	usb_dmac_desc_free(uchan);
410	vchan_free_chan_resources(&uchan->vc);
411
412	pm_runtime_put(chan->device->dev);
413}
414
415static struct dma_async_tx_descriptor *
416usb_dmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
417		       unsigned int sg_len, enum dma_transfer_direction dir,
418		       unsigned long dma_flags, void *context)
419{
420	struct usb_dmac_chan *uchan = to_usb_dmac_chan(chan);
421	struct usb_dmac_desc *desc;
422	struct scatterlist *sg;
423	int i;
424
425	if (!sg_len) {
426		dev_warn(chan->device->dev,
427			 "%s: bad parameter: len=%d\n", __func__, sg_len);
428		return NULL;
429	}
430
431	desc = usb_dmac_desc_get(uchan, sg_len, GFP_NOWAIT);
432	if (!desc)
433		return NULL;
434
435	desc->direction = dir;
436	desc->sg_len = sg_len;
437	for_each_sg(sgl, sg, sg_len, i) {
438		desc->sg[i].mem_addr = sg_dma_address(sg);
439		desc->sg[i].size = sg_dma_len(sg);
440	}
441
442	return vchan_tx_prep(&uchan->vc, &desc->vd, dma_flags);
443}
444
445static int usb_dmac_chan_terminate_all(struct dma_chan *chan)
446{
447	struct usb_dmac_chan *uchan = to_usb_dmac_chan(chan);
448	struct usb_dmac_desc *desc, *_desc;
449	unsigned long flags;
450	LIST_HEAD(head);
451	LIST_HEAD(list);
452
453	spin_lock_irqsave(&uchan->vc.lock, flags);
454	usb_dmac_chan_halt(uchan);
455	vchan_get_all_descriptors(&uchan->vc, &head);
456	if (uchan->desc)
457		uchan->desc = NULL;
458	list_splice_init(&uchan->desc_got, &list);
459	list_for_each_entry_safe(desc, _desc, &list, node)
460		list_move_tail(&desc->node, &uchan->desc_freed);
461	spin_unlock_irqrestore(&uchan->vc.lock, flags);
462	vchan_dma_desc_free_list(&uchan->vc, &head);
463
464	return 0;
465}
466
467static unsigned int usb_dmac_get_current_residue(struct usb_dmac_chan *chan,
468						 struct usb_dmac_desc *desc,
469						 unsigned int sg_index)
470{
471	struct usb_dmac_sg *sg = desc->sg + sg_index;
472	u32 mem_addr = sg->mem_addr & 0xffffffff;
473	unsigned int residue = sg->size;
474
475	/*
476	 * We cannot use USB_DMATCR to calculate residue because USB_DMATCR
477	 * has unsuited value to calculate.
478	 */
479	if (desc->direction == DMA_DEV_TO_MEM)
480		residue -= usb_dmac_chan_read(chan, USB_DMADAR) - mem_addr;
481	else
482		residue -= usb_dmac_chan_read(chan, USB_DMASAR) - mem_addr;
483
484	return residue;
485}
486
487static u32 usb_dmac_chan_get_residue_if_complete(struct usb_dmac_chan *chan,
488						 dma_cookie_t cookie)
489{
490	struct usb_dmac_desc *desc;
491	u32 residue = 0;
492
493	list_for_each_entry_reverse(desc, &chan->desc_freed, node) {
494		if (desc->done_cookie == cookie) {
495			residue = desc->residue;
496			break;
497		}
498	}
499
500	return residue;
501}
502
503static u32 usb_dmac_chan_get_residue(struct usb_dmac_chan *chan,
504				     dma_cookie_t cookie)
505{
506	u32 residue = 0;
507	struct virt_dma_desc *vd;
508	struct usb_dmac_desc *desc = chan->desc;
509	int i;
510
511	if (!desc) {
512		vd = vchan_find_desc(&chan->vc, cookie);
513		if (!vd)
514			return 0;
515		desc = to_usb_dmac_desc(vd);
516	}
517
518	/* Compute the size of all usb_dmac_sg still to be transferred */
519	for (i = desc->sg_index + 1; i < desc->sg_len; i++)
520		residue += desc->sg[i].size;
521
522	/* Add the residue for the current sg */
523	residue += usb_dmac_get_current_residue(chan, desc, desc->sg_index);
524
525	return residue;
526}
527
528static enum dma_status usb_dmac_tx_status(struct dma_chan *chan,
529					  dma_cookie_t cookie,
530					  struct dma_tx_state *txstate)
531{
532	struct usb_dmac_chan *uchan = to_usb_dmac_chan(chan);
533	enum dma_status status;
534	unsigned int residue = 0;
535	unsigned long flags;
536
537	status = dma_cookie_status(chan, cookie, txstate);
538	/* a client driver will get residue after DMA_COMPLETE */
539	if (!txstate)
540		return status;
541
542	spin_lock_irqsave(&uchan->vc.lock, flags);
543	if (status == DMA_COMPLETE)
544		residue = usb_dmac_chan_get_residue_if_complete(uchan, cookie);
545	else
546		residue = usb_dmac_chan_get_residue(uchan, cookie);
547	spin_unlock_irqrestore(&uchan->vc.lock, flags);
548
549	dma_set_residue(txstate, residue);
550
551	return status;
552}
553
554static void usb_dmac_issue_pending(struct dma_chan *chan)
555{
556	struct usb_dmac_chan *uchan = to_usb_dmac_chan(chan);
557	unsigned long flags;
558
559	spin_lock_irqsave(&uchan->vc.lock, flags);
560	if (vchan_issue_pending(&uchan->vc) && !uchan->desc)
561		usb_dmac_chan_start_desc(uchan);
562	spin_unlock_irqrestore(&uchan->vc.lock, flags);
563}
564
565static void usb_dmac_virt_desc_free(struct virt_dma_desc *vd)
566{
567	struct usb_dmac_desc *desc = to_usb_dmac_desc(vd);
568	struct usb_dmac_chan *chan = to_usb_dmac_chan(vd->tx.chan);
569
570	usb_dmac_desc_put(chan, desc);
571}
572
573/* -----------------------------------------------------------------------------
574 * IRQ handling
575 */
576
577static void usb_dmac_isr_transfer_end(struct usb_dmac_chan *chan)
578{
579	struct usb_dmac_desc *desc = chan->desc;
580
581	BUG_ON(!desc);
582
583	if (++desc->sg_index < desc->sg_len) {
584		usb_dmac_chan_start_sg(chan, desc->sg_index);
585	} else {
586		desc->residue = usb_dmac_get_current_residue(chan, desc,
587							desc->sg_index - 1);
588		desc->done_cookie = desc->vd.tx.cookie;
589		desc->vd.tx_result.result = DMA_TRANS_NOERROR;
590		desc->vd.tx_result.residue = desc->residue;
591		vchan_cookie_complete(&desc->vd);
592
593		/* Restart the next transfer if this driver has a next desc */
594		usb_dmac_chan_start_desc(chan);
595	}
596}
597
598static irqreturn_t usb_dmac_isr_channel(int irq, void *dev)
599{
600	struct usb_dmac_chan *chan = dev;
601	irqreturn_t ret = IRQ_NONE;
602	u32 mask = 0;
603	u32 chcr;
604	bool xfer_end = false;
605
606	spin_lock(&chan->vc.lock);
607
608	chcr = usb_dmac_chan_read(chan, USB_DMACHCR);
609	if (chcr & (USB_DMACHCR_TE | USB_DMACHCR_SP)) {
610		mask |= USB_DMACHCR_DE | USB_DMACHCR_TE | USB_DMACHCR_SP;
611		if (chcr & USB_DMACHCR_DE)
612			xfer_end = true;
613		ret |= IRQ_HANDLED;
614	}
615	if (chcr & USB_DMACHCR_NULL) {
616		/* An interruption of TE will happen after we set FTE */
617		mask |= USB_DMACHCR_NULL;
618		chcr |= USB_DMACHCR_FTE;
619		ret |= IRQ_HANDLED;
620	}
621	if (mask)
622		usb_dmac_chan_write(chan, USB_DMACHCR, chcr & ~mask);
623
624	if (xfer_end)
625		usb_dmac_isr_transfer_end(chan);
626
627	spin_unlock(&chan->vc.lock);
628
629	return ret;
630}
631
632/* -----------------------------------------------------------------------------
633 * OF xlate and channel filter
634 */
635
636static bool usb_dmac_chan_filter(struct dma_chan *chan, void *arg)
637{
638	struct usb_dmac_chan *uchan = to_usb_dmac_chan(chan);
639	struct of_phandle_args *dma_spec = arg;
640
641	/* USB-DMAC should be used with fixed usb controller's FIFO */
642	if (uchan->index != dma_spec->args[0])
643		return false;
644
645	return true;
646}
647
648static struct dma_chan *usb_dmac_of_xlate(struct of_phandle_args *dma_spec,
649					  struct of_dma *ofdma)
650{
651	struct dma_chan *chan;
652	dma_cap_mask_t mask;
653
654	if (dma_spec->args_count != 1)
655		return NULL;
656
657	/* Only slave DMA channels can be allocated via DT */
658	dma_cap_zero(mask);
659	dma_cap_set(DMA_SLAVE, mask);
660
661	chan = __dma_request_channel(&mask, usb_dmac_chan_filter, dma_spec,
662				     ofdma->of_node);
663	if (!chan)
664		return NULL;
665
666	return chan;
667}
668
669/* -----------------------------------------------------------------------------
670 * Power management
671 */
672
673static int usb_dmac_runtime_suspend(struct device *dev)
674{
675	struct usb_dmac *dmac = dev_get_drvdata(dev);
676	int i;
677
678	for (i = 0; i < dmac->n_channels; ++i) {
679		if (!dmac->channels[i].iomem)
680			break;
681		usb_dmac_chan_halt(&dmac->channels[i]);
682	}
683
684	return 0;
685}
686
687static int usb_dmac_runtime_resume(struct device *dev)
688{
689	struct usb_dmac *dmac = dev_get_drvdata(dev);
690
691	return usb_dmac_init(dmac);
692}
693
694static const struct dev_pm_ops usb_dmac_pm = {
695	NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
696				  pm_runtime_force_resume)
697	RUNTIME_PM_OPS(usb_dmac_runtime_suspend, usb_dmac_runtime_resume, NULL)
698};
699
700/* -----------------------------------------------------------------------------
701 * Probe and remove
702 */
703
704static int usb_dmac_chan_probe(struct usb_dmac *dmac,
705			       struct usb_dmac_chan *uchan,
706			       u8 index)
707{
708	struct platform_device *pdev = to_platform_device(dmac->dev);
709	char pdev_irqname[6];
710	char *irqname;
711	int ret;
712
713	uchan->index = index;
714	uchan->iomem = dmac->iomem + USB_DMAC_CHAN_OFFSET(index);
715
716	/* Request the channel interrupt. */
717	scnprintf(pdev_irqname, sizeof(pdev_irqname), "ch%u", index);
718	uchan->irq = platform_get_irq_byname(pdev, pdev_irqname);
719	if (uchan->irq < 0)
720		return -ENODEV;
721
722	irqname = devm_kasprintf(dmac->dev, GFP_KERNEL, "%s:%u",
723				 dev_name(dmac->dev), index);
724	if (!irqname)
725		return -ENOMEM;
726
727	ret = devm_request_irq(dmac->dev, uchan->irq, usb_dmac_isr_channel,
728			       IRQF_SHARED, irqname, uchan);
729	if (ret) {
730		dev_err(dmac->dev, "failed to request IRQ %u (%d)\n",
731			uchan->irq, ret);
732		return ret;
733	}
734
735	uchan->vc.desc_free = usb_dmac_virt_desc_free;
736	vchan_init(&uchan->vc, &dmac->engine);
737	INIT_LIST_HEAD(&uchan->desc_freed);
738	INIT_LIST_HEAD(&uchan->desc_got);
739
740	return 0;
741}
742
743static int usb_dmac_parse_of(struct device *dev, struct usb_dmac *dmac)
744{
745	struct device_node *np = dev->of_node;
746	int ret;
747
748	ret = of_property_read_u32(np, "dma-channels", &dmac->n_channels);
749	if (ret < 0) {
750		dev_err(dev, "unable to read dma-channels property\n");
751		return ret;
752	}
753
754	if (dmac->n_channels <= 0 || dmac->n_channels >= 100) {
755		dev_err(dev, "invalid number of channels %u\n",
756			dmac->n_channels);
757		return -EINVAL;
758	}
759
760	return 0;
761}
762
763static int usb_dmac_probe(struct platform_device *pdev)
764{
765	const enum dma_slave_buswidth widths = USB_DMAC_SLAVE_BUSWIDTH;
766	struct dma_device *engine;
767	struct usb_dmac *dmac;
768	int ret;
769	u8 i;
770
771	dmac = devm_kzalloc(&pdev->dev, sizeof(*dmac), GFP_KERNEL);
772	if (!dmac)
773		return -ENOMEM;
774
775	dmac->dev = &pdev->dev;
776	platform_set_drvdata(pdev, dmac);
777
778	ret = usb_dmac_parse_of(&pdev->dev, dmac);
779	if (ret < 0)
780		return ret;
781
782	dmac->channels = devm_kcalloc(&pdev->dev, dmac->n_channels,
783				      sizeof(*dmac->channels), GFP_KERNEL);
784	if (!dmac->channels)
785		return -ENOMEM;
786
787	/* Request resources. */
788	dmac->iomem = devm_platform_ioremap_resource(pdev, 0);
789	if (IS_ERR(dmac->iomem))
790		return PTR_ERR(dmac->iomem);
791
792	/* Enable runtime PM and initialize the device. */
793	pm_runtime_enable(&pdev->dev);
794	ret = pm_runtime_get_sync(&pdev->dev);
795	if (ret < 0) {
796		dev_err(&pdev->dev, "runtime PM get sync failed (%d)\n", ret);
797		goto error_pm;
798	}
799
800	ret = usb_dmac_init(dmac);
801
802	if (ret) {
803		dev_err(&pdev->dev, "failed to reset device\n");
804		goto error;
805	}
806
807	/* Initialize the channels. */
808	INIT_LIST_HEAD(&dmac->engine.channels);
809
810	for (i = 0; i < dmac->n_channels; ++i) {
811		ret = usb_dmac_chan_probe(dmac, &dmac->channels[i], i);
812		if (ret < 0)
813			goto error;
814	}
815
816	/* Register the DMAC as a DMA provider for DT. */
817	ret = of_dma_controller_register(pdev->dev.of_node, usb_dmac_of_xlate,
818					 NULL);
819	if (ret < 0)
820		goto error;
821
822	/*
823	 * Register the DMA engine device.
824	 *
825	 * Default transfer size of 32 bytes requires 32-byte alignment.
826	 */
827	engine = &dmac->engine;
828	dma_cap_set(DMA_SLAVE, engine->cap_mask);
829
830	engine->dev = &pdev->dev;
831
832	engine->src_addr_widths = widths;
833	engine->dst_addr_widths = widths;
834	engine->directions = BIT(DMA_MEM_TO_DEV) | BIT(DMA_DEV_TO_MEM);
835	engine->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
836
837	engine->device_alloc_chan_resources = usb_dmac_alloc_chan_resources;
838	engine->device_free_chan_resources = usb_dmac_free_chan_resources;
839	engine->device_prep_slave_sg = usb_dmac_prep_slave_sg;
840	engine->device_terminate_all = usb_dmac_chan_terminate_all;
841	engine->device_tx_status = usb_dmac_tx_status;
842	engine->device_issue_pending = usb_dmac_issue_pending;
843
844	ret = dma_async_device_register(engine);
845	if (ret < 0)
846		goto error;
847
848	pm_runtime_put(&pdev->dev);
849	return 0;
850
851error:
852	of_dma_controller_free(pdev->dev.of_node);
853error_pm:
854	pm_runtime_put(&pdev->dev);
855	pm_runtime_disable(&pdev->dev);
856	return ret;
857}
858
859static void usb_dmac_chan_remove(struct usb_dmac *dmac,
860				 struct usb_dmac_chan *uchan)
861{
862	usb_dmac_chan_halt(uchan);
863	devm_free_irq(dmac->dev, uchan->irq, uchan);
864}
865
866static void usb_dmac_remove(struct platform_device *pdev)
867{
868	struct usb_dmac *dmac = platform_get_drvdata(pdev);
869	u8 i;
870
871	for (i = 0; i < dmac->n_channels; ++i)
872		usb_dmac_chan_remove(dmac, &dmac->channels[i]);
873	of_dma_controller_free(pdev->dev.of_node);
874	dma_async_device_unregister(&dmac->engine);
875
876	pm_runtime_disable(&pdev->dev);
877}
878
879static void usb_dmac_shutdown(struct platform_device *pdev)
880{
881	struct usb_dmac *dmac = platform_get_drvdata(pdev);
882
883	usb_dmac_stop(dmac);
884}
885
886static const struct of_device_id usb_dmac_of_ids[] = {
887	{ .compatible = "renesas,usb-dmac", },
888	{ /* Sentinel */ }
889};
890MODULE_DEVICE_TABLE(of, usb_dmac_of_ids);
891
892static struct platform_driver usb_dmac_driver = {
893	.driver		= {
894		.pm	= pm_ptr(&usb_dmac_pm),
895		.name	= "usb-dmac",
896		.of_match_table = usb_dmac_of_ids,
897	},
898	.probe		= usb_dmac_probe,
899	.remove		= usb_dmac_remove,
900	.shutdown	= usb_dmac_shutdown,
901};
902
903module_platform_driver(usb_dmac_driver);
904
905MODULE_DESCRIPTION("Renesas USB DMA Controller Driver");
906MODULE_AUTHOR("Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>");
907MODULE_LICENSE("GPL v2");