1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Driver for the Analog Devices AXI-DMAC core
4 *
5 * Copyright 2013-2019 Analog Devices Inc.
6 * Author: Lars-Peter Clausen <lars@metafoo.de>
7 */
8
9#include <linux/adi-axi-common.h>
10#include <linux/bitfield.h>
11#include <linux/clk.h>
12#include <linux/device.h>
13#include <linux/dma-mapping.h>
14#include <linux/dmaengine.h>
15#include <linux/err.h>
16#include <linux/interrupt.h>
17#include <linux/io.h>
18#include <linux/kernel.h>
19#include <linux/module.h>
20#include <linux/of.h>
21#include <linux/of_dma.h>
22#include <linux/of_address.h>
23#include <linux/platform_device.h>
24#include <linux/regmap.h>
25#include <linux/slab.h>
26
27#include <dt-bindings/dma/axi-dmac.h>
28
29#include "dmaengine.h"
30#include "virt-dma.h"
31
32/*
33 * The AXI-DMAC is a soft IP core that is used in FPGA designs. The core has
34 * various instantiation parameters which decided the exact feature set support
35 * by the core.
36 *
37 * Each channel of the core has a source interface and a destination interface.
38 * The number of channels and the type of the channel interfaces is selected at
39 * configuration time. A interface can either be a connected to a central memory
40 * interconnect, which allows access to system memory, or it can be connected to
41 * a dedicated bus which is directly connected to a data port on a peripheral.
42 * Given that those are configuration options of the core that are selected when
43 * it is instantiated this means that they can not be changed by software at
44 * runtime. By extension this means that each channel is uni-directional. It can
45 * either be device to memory or memory to device, but not both. Also since the
46 * device side is a dedicated data bus only connected to a single peripheral
47 * there is no address than can or needs to be configured for the device side.
48 */
49
50#define AXI_DMAC_REG_INTERFACE_DESC 0x10
51#define AXI_DMAC_DMA_SRC_TYPE_MSK GENMASK(13, 12)
52#define AXI_DMAC_DMA_SRC_TYPE_GET(x) FIELD_GET(AXI_DMAC_DMA_SRC_TYPE_MSK, x)
53#define AXI_DMAC_DMA_SRC_WIDTH_MSK GENMASK(11, 8)
54#define AXI_DMAC_DMA_SRC_WIDTH_GET(x) FIELD_GET(AXI_DMAC_DMA_SRC_WIDTH_MSK, x)
55#define AXI_DMAC_DMA_DST_TYPE_MSK GENMASK(5, 4)
56#define AXI_DMAC_DMA_DST_TYPE_GET(x) FIELD_GET(AXI_DMAC_DMA_DST_TYPE_MSK, x)
57#define AXI_DMAC_DMA_DST_WIDTH_MSK GENMASK(3, 0)
58#define AXI_DMAC_DMA_DST_WIDTH_GET(x) FIELD_GET(AXI_DMAC_DMA_DST_WIDTH_MSK, x)
59#define AXI_DMAC_REG_COHERENCY_DESC 0x14
60#define AXI_DMAC_DST_COHERENT_MSK BIT(0)
61#define AXI_DMAC_DST_COHERENT_GET(x) FIELD_GET(AXI_DMAC_DST_COHERENT_MSK, x)
62
63#define AXI_DMAC_REG_IRQ_MASK 0x80
64#define AXI_DMAC_REG_IRQ_PENDING 0x84
65#define AXI_DMAC_REG_IRQ_SOURCE 0x88
66
67#define AXI_DMAC_REG_CTRL 0x400
68#define AXI_DMAC_REG_TRANSFER_ID 0x404
69#define AXI_DMAC_REG_START_TRANSFER 0x408
70#define AXI_DMAC_REG_FLAGS 0x40c
71#define AXI_DMAC_REG_DEST_ADDRESS 0x410
72#define AXI_DMAC_REG_SRC_ADDRESS 0x414
73#define AXI_DMAC_REG_X_LENGTH 0x418
74#define AXI_DMAC_REG_Y_LENGTH 0x41c
75#define AXI_DMAC_REG_DEST_STRIDE 0x420
76#define AXI_DMAC_REG_SRC_STRIDE 0x424
77#define AXI_DMAC_REG_TRANSFER_DONE 0x428
78#define AXI_DMAC_REG_ACTIVE_TRANSFER_ID 0x42c
79#define AXI_DMAC_REG_STATUS 0x430
80#define AXI_DMAC_REG_CURRENT_SRC_ADDR 0x434
81#define AXI_DMAC_REG_CURRENT_DEST_ADDR 0x438
82#define AXI_DMAC_REG_PARTIAL_XFER_LEN 0x44c
83#define AXI_DMAC_REG_PARTIAL_XFER_ID 0x450
84#define AXI_DMAC_REG_CURRENT_SG_ID 0x454
85#define AXI_DMAC_REG_SG_ADDRESS 0x47c
86#define AXI_DMAC_REG_SG_ADDRESS_HIGH 0x4bc
87
88#define AXI_DMAC_CTRL_ENABLE BIT(0)
89#define AXI_DMAC_CTRL_PAUSE BIT(1)
90#define AXI_DMAC_CTRL_ENABLE_SG BIT(2)
91
92#define AXI_DMAC_IRQ_SOT BIT(0)
93#define AXI_DMAC_IRQ_EOT BIT(1)
94
95#define AXI_DMAC_FLAG_CYCLIC BIT(0)
96#define AXI_DMAC_FLAG_LAST BIT(1)
97#define AXI_DMAC_FLAG_PARTIAL_REPORT BIT(2)
98
99#define AXI_DMAC_FLAG_PARTIAL_XFER_DONE BIT(31)
100
101/* The maximum ID allocated by the hardware is 31 */
102#define AXI_DMAC_SG_UNUSED 32U
103
104/* Flags for axi_dmac_hw_desc.flags */
105#define AXI_DMAC_HW_FLAG_LAST BIT(0)
106#define AXI_DMAC_HW_FLAG_IRQ BIT(1)
107
108struct axi_dmac_hw_desc {
109 u32 flags;
110 u32 id;
111 u64 dest_addr;
112 u64 src_addr;
113 u64 next_sg_addr;
114 u32 y_len;
115 u32 x_len;
116 u32 src_stride;
117 u32 dst_stride;
118 u64 __pad[2];
119};
120
121struct axi_dmac_sg {
122 unsigned int partial_len;
123 bool schedule_when_free;
124
125 struct axi_dmac_hw_desc *hw;
126 dma_addr_t hw_phys;
127};
128
129struct axi_dmac_desc {
130 struct virt_dma_desc vdesc;
131 struct axi_dmac_chan *chan;
132
133 bool cyclic;
134 bool have_partial_xfer;
135
136 unsigned int num_submitted;
137 unsigned int num_completed;
138 unsigned int num_sgs;
139 struct axi_dmac_sg sg[] __counted_by(num_sgs);
140};
141
142struct axi_dmac_chan {
143 struct virt_dma_chan vchan;
144
145 struct axi_dmac_desc *next_desc;
146 struct list_head active_descs;
147 enum dma_transfer_direction direction;
148
149 unsigned int src_width;
150 unsigned int dest_width;
151 unsigned int src_type;
152 unsigned int dest_type;
153
154 unsigned int max_length;
155 unsigned int address_align_mask;
156 unsigned int length_align_mask;
157
158 bool hw_partial_xfer;
159 bool hw_cyclic;
160 bool hw_2d;
161 bool hw_sg;
162};
163
164struct axi_dmac {
165 void __iomem *base;
166 int irq;
167
168 struct clk *clk;
169
170 struct dma_device dma_dev;
171 struct axi_dmac_chan chan;
172};
173
174static struct axi_dmac *chan_to_axi_dmac(struct axi_dmac_chan *chan)
175{
176 return container_of(chan->vchan.chan.device, struct axi_dmac,
177 dma_dev);
178}
179
180static struct axi_dmac_chan *to_axi_dmac_chan(struct dma_chan *c)
181{
182 return container_of(c, struct axi_dmac_chan, vchan.chan);
183}
184
185static struct axi_dmac_desc *to_axi_dmac_desc(struct virt_dma_desc *vdesc)
186{
187 return container_of(vdesc, struct axi_dmac_desc, vdesc);
188}
189
190static void axi_dmac_write(struct axi_dmac *axi_dmac, unsigned int reg,
191 unsigned int val)
192{
193 writel(val, addr: axi_dmac->base + reg);
194}
195
196static int axi_dmac_read(struct axi_dmac *axi_dmac, unsigned int reg)
197{
198 return readl(addr: axi_dmac->base + reg);
199}
200
201static int axi_dmac_src_is_mem(struct axi_dmac_chan *chan)
202{
203 return chan->src_type == AXI_DMAC_BUS_TYPE_AXI_MM;
204}
205
206static int axi_dmac_dest_is_mem(struct axi_dmac_chan *chan)
207{
208 return chan->dest_type == AXI_DMAC_BUS_TYPE_AXI_MM;
209}
210
211static bool axi_dmac_check_len(struct axi_dmac_chan *chan, unsigned int len)
212{
213 if (len == 0)
214 return false;
215 if ((len & chan->length_align_mask) != 0) /* Not aligned */
216 return false;
217 return true;
218}
219
220static bool axi_dmac_check_addr(struct axi_dmac_chan *chan, dma_addr_t addr)
221{
222 if ((addr & chan->address_align_mask) != 0) /* Not aligned */
223 return false;
224 return true;
225}
226
227static void axi_dmac_start_transfer(struct axi_dmac_chan *chan)
228{
229 struct axi_dmac *dmac = chan_to_axi_dmac(chan);
230 struct virt_dma_desc *vdesc;
231 struct axi_dmac_desc *desc;
232 struct axi_dmac_sg *sg;
233 unsigned int flags = 0;
234 unsigned int val;
235
236 if (!chan->hw_sg) {
237 val = axi_dmac_read(axi_dmac: dmac, AXI_DMAC_REG_START_TRANSFER);
238 if (val) /* Queue is full, wait for the next SOT IRQ */
239 return;
240 }
241
242 desc = chan->next_desc;
243
244 if (!desc) {
245 vdesc = vchan_next_desc(vc: &chan->vchan);
246 if (!vdesc)
247 return;
248 list_move_tail(list: &vdesc->node, head: &chan->active_descs);
249 desc = to_axi_dmac_desc(vdesc);
250 }
251 sg = &desc->sg[desc->num_submitted];
252
253 /* Already queued in cyclic mode. Wait for it to finish */
254 if (sg->hw->id != AXI_DMAC_SG_UNUSED) {
255 sg->schedule_when_free = true;
256 return;
257 }
258
259 if (chan->hw_sg) {
260 chan->next_desc = NULL;
261 } else if (++desc->num_submitted == desc->num_sgs ||
262 desc->have_partial_xfer) {
263 if (desc->cyclic)
264 desc->num_submitted = 0; /* Start again */
265 else
266 chan->next_desc = NULL;
267 flags |= AXI_DMAC_FLAG_LAST;
268 } else {
269 chan->next_desc = desc;
270 }
271
272 sg->hw->id = axi_dmac_read(axi_dmac: dmac, AXI_DMAC_REG_TRANSFER_ID);
273
274 if (!chan->hw_sg) {
275 if (axi_dmac_dest_is_mem(chan)) {
276 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_DEST_ADDRESS, val: sg->hw->dest_addr);
277 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_DEST_STRIDE, val: sg->hw->dst_stride);
278 }
279
280 if (axi_dmac_src_is_mem(chan)) {
281 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_SRC_ADDRESS, val: sg->hw->src_addr);
282 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_SRC_STRIDE, val: sg->hw->src_stride);
283 }
284 }
285
286 /*
287 * If the hardware supports cyclic transfers and there is no callback to
288 * call, enable hw cyclic mode to avoid unnecessary interrupts.
289 */
290 if (chan->hw_cyclic && desc->cyclic && !desc->vdesc.tx.callback) {
291 if (chan->hw_sg)
292 desc->sg[desc->num_sgs - 1].hw->flags &= ~AXI_DMAC_HW_FLAG_IRQ;
293 else if (desc->num_sgs == 1)
294 flags |= AXI_DMAC_FLAG_CYCLIC;
295 }
296
297 if (chan->hw_partial_xfer)
298 flags |= AXI_DMAC_FLAG_PARTIAL_REPORT;
299
300 if (chan->hw_sg) {
301 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_SG_ADDRESS, val: (u32)sg->hw_phys);
302 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_SG_ADDRESS_HIGH,
303 val: (u64)sg->hw_phys >> 32);
304 } else {
305 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_X_LENGTH, val: sg->hw->x_len);
306 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_Y_LENGTH, val: sg->hw->y_len);
307 }
308 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_FLAGS, val: flags);
309 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_START_TRANSFER, val: 1);
310}
311
312static struct axi_dmac_desc *axi_dmac_active_desc(struct axi_dmac_chan *chan)
313{
314 return list_first_entry_or_null(&chan->active_descs,
315 struct axi_dmac_desc, vdesc.node);
316}
317
318static inline unsigned int axi_dmac_total_sg_bytes(struct axi_dmac_chan *chan,
319 struct axi_dmac_sg *sg)
320{
321 if (chan->hw_2d)
322 return (sg->hw->x_len + 1) * (sg->hw->y_len + 1);
323 else
324 return (sg->hw->x_len + 1);
325}
326
327static void axi_dmac_dequeue_partial_xfers(struct axi_dmac_chan *chan)
328{
329 struct axi_dmac *dmac = chan_to_axi_dmac(chan);
330 struct axi_dmac_desc *desc;
331 struct axi_dmac_sg *sg;
332 u32 xfer_done, len, id, i;
333 bool found_sg;
334
335 do {
336 len = axi_dmac_read(axi_dmac: dmac, AXI_DMAC_REG_PARTIAL_XFER_LEN);
337 id = axi_dmac_read(axi_dmac: dmac, AXI_DMAC_REG_PARTIAL_XFER_ID);
338
339 found_sg = false;
340 list_for_each_entry(desc, &chan->active_descs, vdesc.node) {
341 for (i = 0; i < desc->num_sgs; i++) {
342 sg = &desc->sg[i];
343 if (sg->hw->id == AXI_DMAC_SG_UNUSED)
344 continue;
345 if (sg->hw->id == id) {
346 desc->have_partial_xfer = true;
347 sg->partial_len = len;
348 found_sg = true;
349 break;
350 }
351 }
352 if (found_sg)
353 break;
354 }
355
356 if (found_sg) {
357 dev_dbg(dmac->dma_dev.dev,
358 "Found partial segment id=%u, len=%u\n",
359 id, len);
360 } else {
361 dev_warn(dmac->dma_dev.dev,
362 "Not found partial segment id=%u, len=%u\n",
363 id, len);
364 }
365
366 /* Check if we have any more partial transfers */
367 xfer_done = axi_dmac_read(axi_dmac: dmac, AXI_DMAC_REG_TRANSFER_DONE);
368 xfer_done = !(xfer_done & AXI_DMAC_FLAG_PARTIAL_XFER_DONE);
369
370 } while (!xfer_done);
371}
372
373static void axi_dmac_compute_residue(struct axi_dmac_chan *chan,
374 struct axi_dmac_desc *active)
375{
376 struct dmaengine_result *rslt = &active->vdesc.tx_result;
377 unsigned int start = active->num_completed - 1;
378 struct axi_dmac_sg *sg;
379 unsigned int i, total;
380
381 rslt->result = DMA_TRANS_NOERROR;
382 rslt->residue = 0;
383
384 if (chan->hw_sg)
385 return;
386
387 /*
388 * We get here if the last completed segment is partial, which
389 * means we can compute the residue from that segment onwards
390 */
391 for (i = start; i < active->num_sgs; i++) {
392 sg = &active->sg[i];
393 total = axi_dmac_total_sg_bytes(chan, sg);
394 rslt->residue += (total - sg->partial_len);
395 }
396}
397
398static bool axi_dmac_transfer_done(struct axi_dmac_chan *chan,
399 unsigned int completed_transfers)
400{
401 struct axi_dmac_desc *active;
402 struct axi_dmac_sg *sg;
403 bool start_next = false;
404
405 active = axi_dmac_active_desc(chan);
406 if (!active)
407 return false;
408
409 if (chan->hw_partial_xfer &&
410 (completed_transfers & AXI_DMAC_FLAG_PARTIAL_XFER_DONE))
411 axi_dmac_dequeue_partial_xfers(chan);
412
413 if (chan->hw_sg) {
414 if (active->cyclic) {
415 vchan_cyclic_callback(vd: &active->vdesc);
416 } else {
417 list_del(entry: &active->vdesc.node);
418 vchan_cookie_complete(vd: &active->vdesc);
419 active = axi_dmac_active_desc(chan);
420 start_next = !!active;
421 }
422 } else {
423 do {
424 sg = &active->sg[active->num_completed];
425 if (sg->hw->id == AXI_DMAC_SG_UNUSED) /* Not yet submitted */
426 break;
427 if (!(BIT(sg->hw->id) & completed_transfers))
428 break;
429 active->num_completed++;
430 sg->hw->id = AXI_DMAC_SG_UNUSED;
431 if (sg->schedule_when_free) {
432 sg->schedule_when_free = false;
433 start_next = true;
434 }
435
436 if (sg->partial_len)
437 axi_dmac_compute_residue(chan, active);
438
439 if (active->cyclic)
440 vchan_cyclic_callback(vd: &active->vdesc);
441
442 if (active->num_completed == active->num_sgs ||
443 sg->partial_len) {
444 if (active->cyclic) {
445 active->num_completed = 0; /* wrap around */
446 } else {
447 list_del(entry: &active->vdesc.node);
448 vchan_cookie_complete(vd: &active->vdesc);
449 active = axi_dmac_active_desc(chan);
450 }
451 }
452 } while (active);
453 }
454
455 return start_next;
456}
457
458static irqreturn_t axi_dmac_interrupt_handler(int irq, void *devid)
459{
460 struct axi_dmac *dmac = devid;
461 unsigned int pending;
462 bool start_next = false;
463
464 pending = axi_dmac_read(axi_dmac: dmac, AXI_DMAC_REG_IRQ_PENDING);
465 if (!pending)
466 return IRQ_NONE;
467
468 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_IRQ_PENDING, val: pending);
469
470 spin_lock(lock: &dmac->chan.vchan.lock);
471 /* One or more transfers have finished */
472 if (pending & AXI_DMAC_IRQ_EOT) {
473 unsigned int completed;
474
475 completed = axi_dmac_read(axi_dmac: dmac, AXI_DMAC_REG_TRANSFER_DONE);
476 start_next = axi_dmac_transfer_done(chan: &dmac->chan, completed_transfers: completed);
477 }
478 /* Space has become available in the descriptor queue */
479 if ((pending & AXI_DMAC_IRQ_SOT) || start_next)
480 axi_dmac_start_transfer(chan: &dmac->chan);
481 spin_unlock(lock: &dmac->chan.vchan.lock);
482
483 return IRQ_HANDLED;
484}
485
486static int axi_dmac_terminate_all(struct dma_chan *c)
487{
488 struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
489 struct axi_dmac *dmac = chan_to_axi_dmac(chan);
490 unsigned long flags;
491 LIST_HEAD(head);
492
493 spin_lock_irqsave(&chan->vchan.lock, flags);
494 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_CTRL, val: 0);
495 chan->next_desc = NULL;
496 vchan_get_all_descriptors(vc: &chan->vchan, head: &head);
497 list_splice_tail_init(list: &chan->active_descs, head: &head);
498 spin_unlock_irqrestore(lock: &chan->vchan.lock, flags);
499
500 vchan_dma_desc_free_list(vc: &chan->vchan, head: &head);
501
502 return 0;
503}
504
505static void axi_dmac_synchronize(struct dma_chan *c)
506{
507 struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
508
509 vchan_synchronize(vc: &chan->vchan);
510}
511
512static void axi_dmac_issue_pending(struct dma_chan *c)
513{
514 struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
515 struct axi_dmac *dmac = chan_to_axi_dmac(chan);
516 unsigned long flags;
517 u32 ctrl = AXI_DMAC_CTRL_ENABLE;
518
519 if (chan->hw_sg)
520 ctrl |= AXI_DMAC_CTRL_ENABLE_SG;
521
522 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_CTRL, val: ctrl);
523
524 spin_lock_irqsave(&chan->vchan.lock, flags);
525 if (vchan_issue_pending(vc: &chan->vchan))
526 axi_dmac_start_transfer(chan);
527 spin_unlock_irqrestore(lock: &chan->vchan.lock, flags);
528}
529
530static struct axi_dmac_desc *
531axi_dmac_alloc_desc(struct axi_dmac_chan *chan, unsigned int num_sgs)
532{
533 struct axi_dmac *dmac = chan_to_axi_dmac(chan);
534 struct device *dev = dmac->dma_dev.dev;
535 struct axi_dmac_hw_desc *hws;
536 struct axi_dmac_desc *desc;
537 dma_addr_t hw_phys;
538 unsigned int i;
539
540 desc = kzalloc(struct_size(desc, sg, num_sgs), GFP_NOWAIT);
541 if (!desc)
542 return NULL;
543 desc->num_sgs = num_sgs;
544 desc->chan = chan;
545
546 hws = dma_alloc_coherent(dev, PAGE_ALIGN(num_sgs * sizeof(*hws)),
547 dma_handle: &hw_phys, GFP_ATOMIC);
548 if (!hws) {
549 kfree(objp: desc);
550 return NULL;
551 }
552
553 for (i = 0; i < num_sgs; i++) {
554 desc->sg[i].hw = &hws[i];
555 desc->sg[i].hw_phys = hw_phys + i * sizeof(*hws);
556
557 hws[i].id = AXI_DMAC_SG_UNUSED;
558 hws[i].flags = 0;
559
560 /* Link hardware descriptors */
561 hws[i].next_sg_addr = hw_phys + (i + 1) * sizeof(*hws);
562 }
563
564 /* The last hardware descriptor will trigger an interrupt */
565 desc->sg[num_sgs - 1].hw->flags = AXI_DMAC_HW_FLAG_LAST | AXI_DMAC_HW_FLAG_IRQ;
566
567 return desc;
568}
569
570static void axi_dmac_free_desc(struct axi_dmac_desc *desc)
571{
572 struct axi_dmac *dmac = chan_to_axi_dmac(chan: desc->chan);
573 struct device *dev = dmac->dma_dev.dev;
574 struct axi_dmac_hw_desc *hw = desc->sg[0].hw;
575 dma_addr_t hw_phys = desc->sg[0].hw_phys;
576
577 dma_free_coherent(dev, PAGE_ALIGN(desc->num_sgs * sizeof(*hw)),
578 cpu_addr: hw, dma_handle: hw_phys);
579 kfree(objp: desc);
580}
581
582static struct axi_dmac_sg *axi_dmac_fill_linear_sg(struct axi_dmac_chan *chan,
583 enum dma_transfer_direction direction, dma_addr_t addr,
584 unsigned int num_periods, unsigned int period_len,
585 struct axi_dmac_sg *sg)
586{
587 unsigned int num_segments, i;
588 unsigned int segment_size;
589 unsigned int len;
590
591 /* Split into multiple equally sized segments if necessary */
592 num_segments = DIV_ROUND_UP(period_len, chan->max_length);
593 segment_size = DIV_ROUND_UP(period_len, num_segments);
594 /* Take care of alignment */
595 segment_size = ((segment_size - 1) | chan->length_align_mask) + 1;
596
597 for (i = 0; i < num_periods; i++) {
598 for (len = period_len; len > segment_size; sg++) {
599 if (direction == DMA_DEV_TO_MEM)
600 sg->hw->dest_addr = addr;
601 else
602 sg->hw->src_addr = addr;
603 sg->hw->x_len = segment_size - 1;
604 sg->hw->y_len = 0;
605 sg->hw->flags = 0;
606 addr += segment_size;
607 len -= segment_size;
608 }
609
610 if (direction == DMA_DEV_TO_MEM)
611 sg->hw->dest_addr = addr;
612 else
613 sg->hw->src_addr = addr;
614 sg->hw->x_len = len - 1;
615 sg->hw->y_len = 0;
616 sg++;
617 addr += len;
618 }
619
620 return sg;
621}
622
623static struct dma_async_tx_descriptor *
624axi_dmac_prep_peripheral_dma_vec(struct dma_chan *c, const struct dma_vec *vecs,
625 size_t nb, enum dma_transfer_direction direction,
626 unsigned long flags)
627{
628 struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
629 struct axi_dmac_desc *desc;
630 unsigned int num_sgs = 0;
631 struct axi_dmac_sg *dsg;
632 size_t i;
633
634 if (direction != chan->direction)
635 return NULL;
636
637 for (i = 0; i < nb; i++)
638 num_sgs += DIV_ROUND_UP(vecs[i].len, chan->max_length);
639
640 desc = axi_dmac_alloc_desc(chan, num_sgs);
641 if (!desc)
642 return NULL;
643
644 dsg = desc->sg;
645
646 for (i = 0; i < nb; i++) {
647 if (!axi_dmac_check_addr(chan, addr: vecs[i].addr) ||
648 !axi_dmac_check_len(chan, len: vecs[i].len)) {
649 kfree(objp: desc);
650 return NULL;
651 }
652
653 dsg = axi_dmac_fill_linear_sg(chan, direction, addr: vecs[i].addr, num_periods: 1,
654 period_len: vecs[i].len, sg: dsg);
655 }
656
657 desc->cyclic = false;
658
659 return vchan_tx_prep(vc: &chan->vchan, vd: &desc->vdesc, tx_flags: flags);
660}
661
662static struct dma_async_tx_descriptor *axi_dmac_prep_slave_sg(
663 struct dma_chan *c, struct scatterlist *sgl,
664 unsigned int sg_len, enum dma_transfer_direction direction,
665 unsigned long flags, void *context)
666{
667 struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
668 struct axi_dmac_desc *desc;
669 struct axi_dmac_sg *dsg;
670 struct scatterlist *sg;
671 unsigned int num_sgs;
672 unsigned int i;
673
674 if (direction != chan->direction)
675 return NULL;
676
677 num_sgs = 0;
678 for_each_sg(sgl, sg, sg_len, i)
679 num_sgs += DIV_ROUND_UP(sg_dma_len(sg), chan->max_length);
680
681 desc = axi_dmac_alloc_desc(chan, num_sgs);
682 if (!desc)
683 return NULL;
684
685 dsg = desc->sg;
686
687 for_each_sg(sgl, sg, sg_len, i) {
688 if (!axi_dmac_check_addr(chan, sg_dma_address(sg)) ||
689 !axi_dmac_check_len(chan, sg_dma_len(sg))) {
690 axi_dmac_free_desc(desc);
691 return NULL;
692 }
693
694 dsg = axi_dmac_fill_linear_sg(chan, direction, sg_dma_address(sg), num_periods: 1,
695 sg_dma_len(sg), sg: dsg);
696 }
697
698 desc->cyclic = false;
699
700 return vchan_tx_prep(vc: &chan->vchan, vd: &desc->vdesc, tx_flags: flags);
701}
702
703static struct dma_async_tx_descriptor *axi_dmac_prep_dma_cyclic(
704 struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len,
705 size_t period_len, enum dma_transfer_direction direction,
706 unsigned long flags)
707{
708 struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
709 struct axi_dmac_desc *desc;
710 unsigned int num_periods, num_segments, num_sgs;
711
712 if (direction != chan->direction)
713 return NULL;
714
715 if (!axi_dmac_check_len(chan, len: buf_len) ||
716 !axi_dmac_check_addr(chan, addr: buf_addr))
717 return NULL;
718
719 if (period_len == 0 || buf_len % period_len)
720 return NULL;
721
722 num_periods = buf_len / period_len;
723 num_segments = DIV_ROUND_UP(period_len, chan->max_length);
724 num_sgs = num_periods * num_segments;
725
726 desc = axi_dmac_alloc_desc(chan, num_sgs);
727 if (!desc)
728 return NULL;
729
730 /* Chain the last descriptor to the first, and remove its "last" flag */
731 desc->sg[num_sgs - 1].hw->next_sg_addr = desc->sg[0].hw_phys;
732 desc->sg[num_sgs - 1].hw->flags &= ~AXI_DMAC_HW_FLAG_LAST;
733
734 axi_dmac_fill_linear_sg(chan, direction, addr: buf_addr, num_periods,
735 period_len, sg: desc->sg);
736
737 desc->cyclic = true;
738
739 return vchan_tx_prep(vc: &chan->vchan, vd: &desc->vdesc, tx_flags: flags);
740}
741
742static struct dma_async_tx_descriptor *axi_dmac_prep_interleaved(
743 struct dma_chan *c, struct dma_interleaved_template *xt,
744 unsigned long flags)
745{
746 struct axi_dmac_chan *chan = to_axi_dmac_chan(c);
747 struct axi_dmac_desc *desc;
748 size_t dst_icg, src_icg;
749
750 if (xt->frame_size != 1)
751 return NULL;
752
753 if (xt->dir != chan->direction)
754 return NULL;
755
756 if (axi_dmac_src_is_mem(chan)) {
757 if (!xt->src_inc || !axi_dmac_check_addr(chan, addr: xt->src_start))
758 return NULL;
759 }
760
761 if (axi_dmac_dest_is_mem(chan)) {
762 if (!xt->dst_inc || !axi_dmac_check_addr(chan, addr: xt->dst_start))
763 return NULL;
764 }
765
766 dst_icg = dmaengine_get_dst_icg(xt, chunk: &xt->sgl[0]);
767 src_icg = dmaengine_get_src_icg(xt, chunk: &xt->sgl[0]);
768
769 if (chan->hw_2d) {
770 if (!axi_dmac_check_len(chan, len: xt->sgl[0].size) ||
771 xt->numf == 0)
772 return NULL;
773 if (xt->sgl[0].size + dst_icg > chan->max_length ||
774 xt->sgl[0].size + src_icg > chan->max_length)
775 return NULL;
776 } else {
777 if (dst_icg != 0 || src_icg != 0)
778 return NULL;
779 if (chan->max_length / xt->sgl[0].size < xt->numf)
780 return NULL;
781 if (!axi_dmac_check_len(chan, len: xt->sgl[0].size * xt->numf))
782 return NULL;
783 }
784
785 desc = axi_dmac_alloc_desc(chan, num_sgs: 1);
786 if (!desc)
787 return NULL;
788
789 if (axi_dmac_src_is_mem(chan)) {
790 desc->sg[0].hw->src_addr = xt->src_start;
791 desc->sg[0].hw->src_stride = xt->sgl[0].size + src_icg;
792 }
793
794 if (axi_dmac_dest_is_mem(chan)) {
795 desc->sg[0].hw->dest_addr = xt->dst_start;
796 desc->sg[0].hw->dst_stride = xt->sgl[0].size + dst_icg;
797 }
798
799 if (chan->hw_2d) {
800 desc->sg[0].hw->x_len = xt->sgl[0].size - 1;
801 desc->sg[0].hw->y_len = xt->numf - 1;
802 } else {
803 desc->sg[0].hw->x_len = xt->sgl[0].size * xt->numf - 1;
804 desc->sg[0].hw->y_len = 0;
805 }
806
807 if (flags & DMA_CYCLIC)
808 desc->cyclic = true;
809
810 return vchan_tx_prep(vc: &chan->vchan, vd: &desc->vdesc, tx_flags: flags);
811}
812
813static void axi_dmac_free_chan_resources(struct dma_chan *c)
814{
815 vchan_free_chan_resources(vc: to_virt_chan(chan: c));
816}
817
818static void axi_dmac_desc_free(struct virt_dma_desc *vdesc)
819{
820 axi_dmac_free_desc(desc: to_axi_dmac_desc(vdesc));
821}
822
823static bool axi_dmac_regmap_rdwr(struct device *dev, unsigned int reg)
824{
825 switch (reg) {
826 case AXI_DMAC_REG_IRQ_MASK:
827 case AXI_DMAC_REG_IRQ_SOURCE:
828 case AXI_DMAC_REG_IRQ_PENDING:
829 case AXI_DMAC_REG_CTRL:
830 case AXI_DMAC_REG_TRANSFER_ID:
831 case AXI_DMAC_REG_START_TRANSFER:
832 case AXI_DMAC_REG_FLAGS:
833 case AXI_DMAC_REG_DEST_ADDRESS:
834 case AXI_DMAC_REG_SRC_ADDRESS:
835 case AXI_DMAC_REG_X_LENGTH:
836 case AXI_DMAC_REG_Y_LENGTH:
837 case AXI_DMAC_REG_DEST_STRIDE:
838 case AXI_DMAC_REG_SRC_STRIDE:
839 case AXI_DMAC_REG_TRANSFER_DONE:
840 case AXI_DMAC_REG_ACTIVE_TRANSFER_ID:
841 case AXI_DMAC_REG_STATUS:
842 case AXI_DMAC_REG_CURRENT_SRC_ADDR:
843 case AXI_DMAC_REG_CURRENT_DEST_ADDR:
844 case AXI_DMAC_REG_PARTIAL_XFER_LEN:
845 case AXI_DMAC_REG_PARTIAL_XFER_ID:
846 case AXI_DMAC_REG_CURRENT_SG_ID:
847 case AXI_DMAC_REG_SG_ADDRESS:
848 case AXI_DMAC_REG_SG_ADDRESS_HIGH:
849 return true;
850 default:
851 return false;
852 }
853}
854
855static const struct regmap_config axi_dmac_regmap_config = {
856 .reg_bits = 32,
857 .val_bits = 32,
858 .reg_stride = 4,
859 .max_register = AXI_DMAC_REG_PARTIAL_XFER_ID,
860 .readable_reg = axi_dmac_regmap_rdwr,
861 .writeable_reg = axi_dmac_regmap_rdwr,
862};
863
864static void axi_dmac_adjust_chan_params(struct axi_dmac_chan *chan)
865{
866 chan->address_align_mask = max(chan->dest_width, chan->src_width) - 1;
867
868 if (axi_dmac_dest_is_mem(chan) && axi_dmac_src_is_mem(chan))
869 chan->direction = DMA_MEM_TO_MEM;
870 else if (!axi_dmac_dest_is_mem(chan) && axi_dmac_src_is_mem(chan))
871 chan->direction = DMA_MEM_TO_DEV;
872 else if (axi_dmac_dest_is_mem(chan) && !axi_dmac_src_is_mem(chan))
873 chan->direction = DMA_DEV_TO_MEM;
874 else
875 chan->direction = DMA_DEV_TO_DEV;
876}
877
878/*
879 * The configuration stored in the devicetree matches the configuration
880 * parameters of the peripheral instance and allows the driver to know which
881 * features are implemented and how it should behave.
882 */
883static int axi_dmac_parse_chan_dt(struct device_node *of_chan,
884 struct axi_dmac_chan *chan)
885{
886 u32 val;
887 int ret;
888
889 ret = of_property_read_u32(np: of_chan, propname: "reg", out_value: &val);
890 if (ret)
891 return ret;
892
893 /* We only support 1 channel for now */
894 if (val != 0)
895 return -EINVAL;
896
897 ret = of_property_read_u32(np: of_chan, propname: "adi,source-bus-type", out_value: &val);
898 if (ret)
899 return ret;
900 if (val > AXI_DMAC_BUS_TYPE_FIFO)
901 return -EINVAL;
902 chan->src_type = val;
903
904 ret = of_property_read_u32(np: of_chan, propname: "adi,destination-bus-type", out_value: &val);
905 if (ret)
906 return ret;
907 if (val > AXI_DMAC_BUS_TYPE_FIFO)
908 return -EINVAL;
909 chan->dest_type = val;
910
911 ret = of_property_read_u32(np: of_chan, propname: "adi,source-bus-width", out_value: &val);
912 if (ret)
913 return ret;
914 chan->src_width = val / 8;
915
916 ret = of_property_read_u32(np: of_chan, propname: "adi,destination-bus-width", out_value: &val);
917 if (ret)
918 return ret;
919 chan->dest_width = val / 8;
920
921 axi_dmac_adjust_chan_params(chan);
922
923 return 0;
924}
925
926static int axi_dmac_parse_dt(struct device *dev, struct axi_dmac *dmac)
927{
928 struct device_node *of_channels, *of_chan;
929 int ret;
930
931 of_channels = of_get_child_by_name(node: dev->of_node, name: "adi,channels");
932 if (of_channels == NULL)
933 return -ENODEV;
934
935 for_each_child_of_node(of_channels, of_chan) {
936 ret = axi_dmac_parse_chan_dt(of_chan, chan: &dmac->chan);
937 if (ret) {
938 of_node_put(node: of_chan);
939 of_node_put(node: of_channels);
940 return -EINVAL;
941 }
942 }
943 of_node_put(node: of_channels);
944
945 return 0;
946}
947
948static int axi_dmac_read_chan_config(struct device *dev, struct axi_dmac *dmac)
949{
950 struct axi_dmac_chan *chan = &dmac->chan;
951 unsigned int val, desc;
952
953 desc = axi_dmac_read(axi_dmac: dmac, AXI_DMAC_REG_INTERFACE_DESC);
954 if (desc == 0) {
955 dev_err(dev, "DMA interface register reads zero\n");
956 return -EFAULT;
957 }
958
959 val = AXI_DMAC_DMA_SRC_TYPE_GET(desc);
960 if (val > AXI_DMAC_BUS_TYPE_FIFO) {
961 dev_err(dev, "Invalid source bus type read: %d\n", val);
962 return -EINVAL;
963 }
964 chan->src_type = val;
965
966 val = AXI_DMAC_DMA_DST_TYPE_GET(desc);
967 if (val > AXI_DMAC_BUS_TYPE_FIFO) {
968 dev_err(dev, "Invalid destination bus type read: %d\n", val);
969 return -EINVAL;
970 }
971 chan->dest_type = val;
972
973 val = AXI_DMAC_DMA_SRC_WIDTH_GET(desc);
974 if (val == 0) {
975 dev_err(dev, "Source bus width is zero\n");
976 return -EINVAL;
977 }
978 /* widths are stored in log2 */
979 chan->src_width = 1 << val;
980
981 val = AXI_DMAC_DMA_DST_WIDTH_GET(desc);
982 if (val == 0) {
983 dev_err(dev, "Destination bus width is zero\n");
984 return -EINVAL;
985 }
986 chan->dest_width = 1 << val;
987
988 axi_dmac_adjust_chan_params(chan);
989
990 return 0;
991}
992
993static int axi_dmac_detect_caps(struct axi_dmac *dmac, unsigned int version)
994{
995 struct axi_dmac_chan *chan = &dmac->chan;
996
997 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_FLAGS, AXI_DMAC_FLAG_CYCLIC);
998 if (axi_dmac_read(axi_dmac: dmac, AXI_DMAC_REG_FLAGS) == AXI_DMAC_FLAG_CYCLIC)
999 chan->hw_cyclic = true;
1000
1001 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_SG_ADDRESS, val: 0xffffffff);
1002 if (axi_dmac_read(axi_dmac: dmac, AXI_DMAC_REG_SG_ADDRESS))
1003 chan->hw_sg = true;
1004
1005 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_Y_LENGTH, val: 1);
1006 if (axi_dmac_read(axi_dmac: dmac, AXI_DMAC_REG_Y_LENGTH) == 1)
1007 chan->hw_2d = true;
1008
1009 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_X_LENGTH, val: 0xffffffff);
1010 chan->max_length = axi_dmac_read(axi_dmac: dmac, AXI_DMAC_REG_X_LENGTH);
1011 if (chan->max_length != UINT_MAX)
1012 chan->max_length++;
1013
1014 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_DEST_ADDRESS, val: 0xffffffff);
1015 if (axi_dmac_read(axi_dmac: dmac, AXI_DMAC_REG_DEST_ADDRESS) == 0 &&
1016 chan->dest_type == AXI_DMAC_BUS_TYPE_AXI_MM) {
1017 dev_err(dmac->dma_dev.dev,
1018 "Destination memory-mapped interface not supported.");
1019 return -ENODEV;
1020 }
1021
1022 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_SRC_ADDRESS, val: 0xffffffff);
1023 if (axi_dmac_read(axi_dmac: dmac, AXI_DMAC_REG_SRC_ADDRESS) == 0 &&
1024 chan->src_type == AXI_DMAC_BUS_TYPE_AXI_MM) {
1025 dev_err(dmac->dma_dev.dev,
1026 "Source memory-mapped interface not supported.");
1027 return -ENODEV;
1028 }
1029
1030 if (version >= ADI_AXI_PCORE_VER(4, 2, 'a'))
1031 chan->hw_partial_xfer = true;
1032
1033 if (version >= ADI_AXI_PCORE_VER(4, 1, 'a')) {
1034 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_X_LENGTH, val: 0x00);
1035 chan->length_align_mask =
1036 axi_dmac_read(axi_dmac: dmac, AXI_DMAC_REG_X_LENGTH);
1037 } else {
1038 chan->length_align_mask = chan->address_align_mask;
1039 }
1040
1041 return 0;
1042}
1043
1044static void axi_dmac_tasklet_kill(void *task)
1045{
1046 tasklet_kill(t: task);
1047}
1048
1049static void axi_dmac_free_dma_controller(void *of_node)
1050{
1051 of_dma_controller_free(np: of_node);
1052}
1053
1054static int axi_dmac_probe(struct platform_device *pdev)
1055{
1056 struct dma_device *dma_dev;
1057 struct axi_dmac *dmac;
1058 struct regmap *regmap;
1059 unsigned int version;
1060 u32 irq_mask = 0;
1061 int ret;
1062
1063 dmac = devm_kzalloc(dev: &pdev->dev, size: sizeof(*dmac), GFP_KERNEL);
1064 if (!dmac)
1065 return -ENOMEM;
1066
1067 dmac->irq = platform_get_irq(pdev, 0);
1068 if (dmac->irq < 0)
1069 return dmac->irq;
1070 if (dmac->irq == 0)
1071 return -EINVAL;
1072
1073 dmac->base = devm_platform_ioremap_resource(pdev, index: 0);
1074 if (IS_ERR(ptr: dmac->base))
1075 return PTR_ERR(ptr: dmac->base);
1076
1077 dmac->clk = devm_clk_get_enabled(dev: &pdev->dev, NULL);
1078 if (IS_ERR(ptr: dmac->clk))
1079 return PTR_ERR(ptr: dmac->clk);
1080
1081 version = axi_dmac_read(axi_dmac: dmac, ADI_AXI_REG_VERSION);
1082
1083 if (version >= ADI_AXI_PCORE_VER(4, 3, 'a'))
1084 ret = axi_dmac_read_chan_config(dev: &pdev->dev, dmac);
1085 else
1086 ret = axi_dmac_parse_dt(dev: &pdev->dev, dmac);
1087
1088 if (ret < 0)
1089 return ret;
1090
1091 INIT_LIST_HEAD(list: &dmac->chan.active_descs);
1092
1093 dma_set_max_seg_size(dev: &pdev->dev, UINT_MAX);
1094
1095 dma_dev = &dmac->dma_dev;
1096 dma_cap_set(DMA_SLAVE, dma_dev->cap_mask);
1097 dma_cap_set(DMA_CYCLIC, dma_dev->cap_mask);
1098 dma_cap_set(DMA_INTERLEAVE, dma_dev->cap_mask);
1099 dma_dev->device_free_chan_resources = axi_dmac_free_chan_resources;
1100 dma_dev->device_tx_status = dma_cookie_status;
1101 dma_dev->device_issue_pending = axi_dmac_issue_pending;
1102 dma_dev->device_prep_slave_sg = axi_dmac_prep_slave_sg;
1103 dma_dev->device_prep_peripheral_dma_vec = axi_dmac_prep_peripheral_dma_vec;
1104 dma_dev->device_prep_dma_cyclic = axi_dmac_prep_dma_cyclic;
1105 dma_dev->device_prep_interleaved_dma = axi_dmac_prep_interleaved;
1106 dma_dev->device_terminate_all = axi_dmac_terminate_all;
1107 dma_dev->device_synchronize = axi_dmac_synchronize;
1108 dma_dev->dev = &pdev->dev;
1109 dma_dev->src_addr_widths = BIT(dmac->chan.src_width);
1110 dma_dev->dst_addr_widths = BIT(dmac->chan.dest_width);
1111 dma_dev->directions = BIT(dmac->chan.direction);
1112 dma_dev->residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
1113 dma_dev->max_sg_burst = 31; /* 31 SGs maximum in one burst */
1114 INIT_LIST_HEAD(list: &dma_dev->channels);
1115
1116 dmac->chan.vchan.desc_free = axi_dmac_desc_free;
1117 vchan_init(vc: &dmac->chan.vchan, dmadev: dma_dev);
1118
1119 ret = axi_dmac_detect_caps(dmac, version);
1120 if (ret)
1121 return ret;
1122
1123 dma_dev->copy_align = (dmac->chan.address_align_mask + 1);
1124
1125 if (dmac->chan.hw_sg)
1126 irq_mask |= AXI_DMAC_IRQ_SOT;
1127
1128 axi_dmac_write(axi_dmac: dmac, AXI_DMAC_REG_IRQ_MASK, val: irq_mask);
1129
1130 if (of_dma_is_coherent(np: pdev->dev.of_node)) {
1131 ret = axi_dmac_read(axi_dmac: dmac, AXI_DMAC_REG_COHERENCY_DESC);
1132
1133 if (version < ADI_AXI_PCORE_VER(4, 4, 'a') ||
1134 !AXI_DMAC_DST_COHERENT_GET(ret)) {
1135 dev_err(dmac->dma_dev.dev,
1136 "Coherent DMA not supported in hardware");
1137 return -EINVAL;
1138 }
1139 }
1140
1141 ret = dmaenginem_async_device_register(device: dma_dev);
1142 if (ret)
1143 return ret;
1144
1145 /*
1146 * Put the action in here so it get's done before unregistering the DMA
1147 * device.
1148 */
1149 ret = devm_add_action_or_reset(&pdev->dev, axi_dmac_tasklet_kill,
1150 &dmac->chan.vchan.task);
1151 if (ret)
1152 return ret;
1153
1154 ret = of_dma_controller_register(np: pdev->dev.of_node,
1155 of_dma_xlate: of_dma_xlate_by_chan_id, data: dma_dev);
1156 if (ret)
1157 return ret;
1158
1159 ret = devm_add_action_or_reset(&pdev->dev, axi_dmac_free_dma_controller,
1160 pdev->dev.of_node);
1161 if (ret)
1162 return ret;
1163
1164 ret = devm_request_irq(dev: &pdev->dev, irq: dmac->irq, handler: axi_dmac_interrupt_handler,
1165 IRQF_SHARED, devname: dev_name(dev: &pdev->dev), dev_id: dmac);
1166 if (ret)
1167 return ret;
1168
1169 regmap = devm_regmap_init_mmio(&pdev->dev, dmac->base,
1170 &axi_dmac_regmap_config);
1171
1172 return PTR_ERR_OR_ZERO(ptr: regmap);
1173}
1174
1175static const struct of_device_id axi_dmac_of_match_table[] = {
1176 { .compatible = "adi,axi-dmac-1.00.a" },
1177 { },
1178};
1179MODULE_DEVICE_TABLE(of, axi_dmac_of_match_table);
1180
1181static struct platform_driver axi_dmac_driver = {
1182 .driver = {
1183 .name = "dma-axi-dmac",
1184 .of_match_table = axi_dmac_of_match_table,
1185 },
1186 .probe = axi_dmac_probe,
1187};
1188module_platform_driver(axi_dmac_driver);
1189
1190MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
1191MODULE_DESCRIPTION("DMA controller driver for the AXI-DMAC controller");
1192MODULE_LICENSE("GPL v2");
1193

source code of linux/drivers/dma/dma-axi-dmac.c