1 // SPDX-License-Identifier: GPL-2.0
3 * Core driver for the Synopsys DesignWare DMA Controller
5 * Copyright (C) 2007-2008 Atmel Corporation
6 * Copyright (C) 2010-2011 ST Microelectronics
7 * Copyright (C) 2013 Intel Corporation
10 #include <linux/bitops.h>
11 #include <linux/delay.h>
12 #include <linux/dmaengine.h>
13 #include <linux/dma-mapping.h>
14 #include <linux/dmapool.h>
15 #include <linux/err.h>
16 #include <linux/init.h>
17 #include <linux/interrupt.h>
19 #include <linux/log2.h>
21 #include <linux/module.h>
22 #include <linux/slab.h>
23 #include <linux/pm_runtime.h>
25 #include "../dmaengine.h"
29 * This supports the Synopsys "DesignWare AHB Central DMA Controller",
30 * (DW_ahb_dmac) which is used with various AMBA 2.0 systems (not all
31 * of which use ARM any more). See the "Databook" from Synopsys for
32 * information beyond what licensees probably provide.
35 /* The set of bus widths supported by the DMA controller */
36 #define DW_DMA_BUSWIDTHS \
37 BIT(DMA_SLAVE_BUSWIDTH_UNDEFINED) | \
38 BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
39 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
40 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES)
42 /*----------------------------------------------------------------------*/
44 static struct device
*chan2dev(struct dma_chan
*chan
)
46 return &chan
->dev
->device
;
49 static struct dw_desc
*dwc_first_active(struct dw_dma_chan
*dwc
)
51 return to_dw_desc(dwc
->active_list
.next
);
54 static dma_cookie_t
dwc_tx_submit(struct dma_async_tx_descriptor
*tx
)
56 struct dw_desc
*desc
= txd_to_dw_desc(tx
);
57 struct dw_dma_chan
*dwc
= to_dw_dma_chan(tx
->chan
);
61 spin_lock_irqsave(&dwc
->lock
, flags
);
62 cookie
= dma_cookie_assign(tx
);
65 * REVISIT: We should attempt to chain as many descriptors as
66 * possible, perhaps even appending to those already submitted
67 * for DMA. But this is hard to do in a race-free manner.
70 list_add_tail(&desc
->desc_node
, &dwc
->queue
);
71 spin_unlock_irqrestore(&dwc
->lock
, flags
);
72 dev_vdbg(chan2dev(tx
->chan
), "%s: queued %u\n",
73 __func__
, desc
->txd
.cookie
);
78 static struct dw_desc
*dwc_desc_get(struct dw_dma_chan
*dwc
)
80 struct dw_dma
*dw
= to_dw_dma(dwc
->chan
.device
);
84 desc
= dma_pool_zalloc(dw
->desc_pool
, GFP_ATOMIC
, &phys
);
88 dwc
->descs_allocated
++;
89 INIT_LIST_HEAD(&desc
->tx_list
);
90 dma_async_tx_descriptor_init(&desc
->txd
, &dwc
->chan
);
91 desc
->txd
.tx_submit
= dwc_tx_submit
;
92 desc
->txd
.flags
= DMA_CTRL_ACK
;
93 desc
->txd
.phys
= phys
;
97 static void dwc_desc_put(struct dw_dma_chan
*dwc
, struct dw_desc
*desc
)
99 struct dw_dma
*dw
= to_dw_dma(dwc
->chan
.device
);
100 struct dw_desc
*child
, *_next
;
105 list_for_each_entry_safe(child
, _next
, &desc
->tx_list
, desc_node
) {
106 list_del(&child
->desc_node
);
107 dma_pool_free(dw
->desc_pool
, child
, child
->txd
.phys
);
108 dwc
->descs_allocated
--;
111 dma_pool_free(dw
->desc_pool
, desc
, desc
->txd
.phys
);
112 dwc
->descs_allocated
--;
115 static void dwc_initialize(struct dw_dma_chan
*dwc
)
117 struct dw_dma
*dw
= to_dw_dma(dwc
->chan
.device
);
119 dw
->initialize_chan(dwc
);
121 /* Enable interrupts */
122 channel_set_bit(dw
, MASK
.XFER
, dwc
->mask
);
123 channel_set_bit(dw
, MASK
.ERROR
, dwc
->mask
);
126 /*----------------------------------------------------------------------*/
128 static inline void dwc_dump_chan_regs(struct dw_dma_chan
*dwc
)
130 dev_err(chan2dev(&dwc
->chan
),
131 " SAR: 0x%x DAR: 0x%x LLP: 0x%x CTL: 0x%x:%08x\n",
132 channel_readl(dwc
, SAR
),
133 channel_readl(dwc
, DAR
),
134 channel_readl(dwc
, LLP
),
135 channel_readl(dwc
, CTL_HI
),
136 channel_readl(dwc
, CTL_LO
));
139 static inline void dwc_chan_disable(struct dw_dma
*dw
, struct dw_dma_chan
*dwc
)
141 channel_clear_bit(dw
, CH_EN
, dwc
->mask
);
142 while (dma_readl(dw
, CH_EN
) & dwc
->mask
)
146 /*----------------------------------------------------------------------*/
148 /* Perform single block transfer */
149 static inline void dwc_do_single_block(struct dw_dma_chan
*dwc
,
150 struct dw_desc
*desc
)
152 struct dw_dma
*dw
= to_dw_dma(dwc
->chan
.device
);
156 * Software emulation of LLP mode relies on interrupts to continue
157 * multi block transfer.
159 ctllo
= lli_read(desc
, ctllo
) | DWC_CTLL_INT_EN
;
161 channel_writel(dwc
, SAR
, lli_read(desc
, sar
));
162 channel_writel(dwc
, DAR
, lli_read(desc
, dar
));
163 channel_writel(dwc
, CTL_LO
, ctllo
);
164 channel_writel(dwc
, CTL_HI
, lli_read(desc
, ctlhi
));
165 channel_set_bit(dw
, CH_EN
, dwc
->mask
);
167 /* Move pointer to next descriptor */
168 dwc
->tx_node_active
= dwc
->tx_node_active
->next
;
171 /* Called with dwc->lock held and bh disabled */
172 static void dwc_dostart(struct dw_dma_chan
*dwc
, struct dw_desc
*first
)
174 struct dw_dma
*dw
= to_dw_dma(dwc
->chan
.device
);
175 u8 lms
= DWC_LLP_LMS(dwc
->dws
.m_master
);
176 unsigned long was_soft_llp
;
178 /* ASSERT: channel is idle */
179 if (dma_readl(dw
, CH_EN
) & dwc
->mask
) {
180 dev_err(chan2dev(&dwc
->chan
),
181 "%s: BUG: Attempted to start non-idle channel\n",
183 dwc_dump_chan_regs(dwc
);
185 /* The tasklet will hopefully advance the queue... */
190 was_soft_llp
= test_and_set_bit(DW_DMA_IS_SOFT_LLP
,
193 dev_err(chan2dev(&dwc
->chan
),
194 "BUG: Attempted to start new LLP transfer inside ongoing one\n");
200 first
->residue
= first
->total_len
;
201 dwc
->tx_node_active
= &first
->tx_list
;
203 /* Submit first block */
204 dwc_do_single_block(dwc
, first
);
211 channel_writel(dwc
, LLP
, first
->txd
.phys
| lms
);
212 channel_writel(dwc
, CTL_LO
, DWC_CTLL_LLP_D_EN
| DWC_CTLL_LLP_S_EN
);
213 channel_writel(dwc
, CTL_HI
, 0);
214 channel_set_bit(dw
, CH_EN
, dwc
->mask
);
217 static void dwc_dostart_first_queued(struct dw_dma_chan
*dwc
)
219 struct dw_desc
*desc
;
221 if (list_empty(&dwc
->queue
))
224 list_move(dwc
->queue
.next
, &dwc
->active_list
);
225 desc
= dwc_first_active(dwc
);
226 dev_vdbg(chan2dev(&dwc
->chan
), "%s: started %u\n", __func__
, desc
->txd
.cookie
);
227 dwc_dostart(dwc
, desc
);
230 /*----------------------------------------------------------------------*/
233 dwc_descriptor_complete(struct dw_dma_chan
*dwc
, struct dw_desc
*desc
,
234 bool callback_required
)
236 struct dma_async_tx_descriptor
*txd
= &desc
->txd
;
237 struct dw_desc
*child
;
239 struct dmaengine_desc_callback cb
;
241 dev_vdbg(chan2dev(&dwc
->chan
), "descriptor %u complete\n", txd
->cookie
);
243 spin_lock_irqsave(&dwc
->lock
, flags
);
244 dma_cookie_complete(txd
);
245 if (callback_required
)
246 dmaengine_desc_get_callback(txd
, &cb
);
248 memset(&cb
, 0, sizeof(cb
));
251 list_for_each_entry(child
, &desc
->tx_list
, desc_node
)
252 async_tx_ack(&child
->txd
);
253 async_tx_ack(&desc
->txd
);
254 dwc_desc_put(dwc
, desc
);
255 spin_unlock_irqrestore(&dwc
->lock
, flags
);
257 dmaengine_desc_callback_invoke(&cb
, NULL
);
260 static void dwc_complete_all(struct dw_dma
*dw
, struct dw_dma_chan
*dwc
)
262 struct dw_desc
*desc
, *_desc
;
266 spin_lock_irqsave(&dwc
->lock
, flags
);
267 if (dma_readl(dw
, CH_EN
) & dwc
->mask
) {
268 dev_err(chan2dev(&dwc
->chan
),
269 "BUG: XFER bit set, but channel not idle!\n");
271 /* Try to continue after resetting the channel... */
272 dwc_chan_disable(dw
, dwc
);
276 * Submit queued descriptors ASAP, i.e. before we go through
277 * the completed ones.
279 list_splice_init(&dwc
->active_list
, &list
);
280 dwc_dostart_first_queued(dwc
);
282 spin_unlock_irqrestore(&dwc
->lock
, flags
);
284 list_for_each_entry_safe(desc
, _desc
, &list
, desc_node
)
285 dwc_descriptor_complete(dwc
, desc
, true);
288 /* Returns how many bytes were already received from source */
289 static inline u32
dwc_get_sent(struct dw_dma_chan
*dwc
)
291 struct dw_dma
*dw
= to_dw_dma(dwc
->chan
.device
);
292 u32 ctlhi
= channel_readl(dwc
, CTL_HI
);
293 u32 ctllo
= channel_readl(dwc
, CTL_LO
);
295 return dw
->block2bytes(dwc
, ctlhi
, ctllo
>> 4 & 7);
298 static void dwc_scan_descriptors(struct dw_dma
*dw
, struct dw_dma_chan
*dwc
)
301 struct dw_desc
*desc
, *_desc
;
302 struct dw_desc
*child
;
306 spin_lock_irqsave(&dwc
->lock
, flags
);
307 llp
= channel_readl(dwc
, LLP
);
308 status_xfer
= dma_readl(dw
, RAW
.XFER
);
310 if (status_xfer
& dwc
->mask
) {
311 /* Everything we've submitted is done */
312 dma_writel(dw
, CLEAR
.XFER
, dwc
->mask
);
314 if (test_bit(DW_DMA_IS_SOFT_LLP
, &dwc
->flags
)) {
315 struct list_head
*head
, *active
= dwc
->tx_node_active
;
318 * We are inside first active descriptor.
319 * Otherwise something is really wrong.
321 desc
= dwc_first_active(dwc
);
323 head
= &desc
->tx_list
;
324 if (active
!= head
) {
325 /* Update residue to reflect last sent descriptor */
326 if (active
== head
->next
)
327 desc
->residue
-= desc
->len
;
329 desc
->residue
-= to_dw_desc(active
->prev
)->len
;
331 child
= to_dw_desc(active
);
333 /* Submit next block */
334 dwc_do_single_block(dwc
, child
);
336 spin_unlock_irqrestore(&dwc
->lock
, flags
);
340 /* We are done here */
341 clear_bit(DW_DMA_IS_SOFT_LLP
, &dwc
->flags
);
344 spin_unlock_irqrestore(&dwc
->lock
, flags
);
346 dwc_complete_all(dw
, dwc
);
350 if (list_empty(&dwc
->active_list
)) {
351 spin_unlock_irqrestore(&dwc
->lock
, flags
);
355 if (test_bit(DW_DMA_IS_SOFT_LLP
, &dwc
->flags
)) {
356 dev_vdbg(chan2dev(&dwc
->chan
), "%s: soft LLP mode\n", __func__
);
357 spin_unlock_irqrestore(&dwc
->lock
, flags
);
361 dev_vdbg(chan2dev(&dwc
->chan
), "%s: llp=%pad\n", __func__
, &llp
);
363 list_for_each_entry_safe(desc
, _desc
, &dwc
->active_list
, desc_node
) {
364 /* Initial residue value */
365 desc
->residue
= desc
->total_len
;
367 /* Check first descriptors addr */
368 if (desc
->txd
.phys
== DWC_LLP_LOC(llp
)) {
369 spin_unlock_irqrestore(&dwc
->lock
, flags
);
373 /* Check first descriptors llp */
374 if (lli_read(desc
, llp
) == llp
) {
375 /* This one is currently in progress */
376 desc
->residue
-= dwc_get_sent(dwc
);
377 spin_unlock_irqrestore(&dwc
->lock
, flags
);
381 desc
->residue
-= desc
->len
;
382 list_for_each_entry(child
, &desc
->tx_list
, desc_node
) {
383 if (lli_read(child
, llp
) == llp
) {
384 /* Currently in progress */
385 desc
->residue
-= dwc_get_sent(dwc
);
386 spin_unlock_irqrestore(&dwc
->lock
, flags
);
389 desc
->residue
-= child
->len
;
393 * No descriptors so far seem to be in progress, i.e.
394 * this one must be done.
396 spin_unlock_irqrestore(&dwc
->lock
, flags
);
397 dwc_descriptor_complete(dwc
, desc
, true);
398 spin_lock_irqsave(&dwc
->lock
, flags
);
401 dev_err(chan2dev(&dwc
->chan
),
402 "BUG: All descriptors done, but channel not idle!\n");
404 /* Try to continue after resetting the channel... */
405 dwc_chan_disable(dw
, dwc
);
407 dwc_dostart_first_queued(dwc
);
408 spin_unlock_irqrestore(&dwc
->lock
, flags
);
411 static inline void dwc_dump_lli(struct dw_dma_chan
*dwc
, struct dw_desc
*desc
)
413 dev_crit(chan2dev(&dwc
->chan
), " desc: s0x%x d0x%x l0x%x c0x%x:%x\n",
417 lli_read(desc
, ctlhi
),
418 lli_read(desc
, ctllo
));
421 static void dwc_handle_error(struct dw_dma
*dw
, struct dw_dma_chan
*dwc
)
423 struct dw_desc
*bad_desc
;
424 struct dw_desc
*child
;
427 dwc_scan_descriptors(dw
, dwc
);
429 spin_lock_irqsave(&dwc
->lock
, flags
);
432 * The descriptor currently at the head of the active list is
433 * borked. Since we don't have any way to report errors, we'll
434 * just have to scream loudly and try to carry on.
436 bad_desc
= dwc_first_active(dwc
);
437 list_del_init(&bad_desc
->desc_node
);
438 list_move(dwc
->queue
.next
, dwc
->active_list
.prev
);
440 /* Clear the error flag and try to restart the controller */
441 dma_writel(dw
, CLEAR
.ERROR
, dwc
->mask
);
442 if (!list_empty(&dwc
->active_list
))
443 dwc_dostart(dwc
, dwc_first_active(dwc
));
446 * WARN may seem harsh, but since this only happens
447 * when someone submits a bad physical address in a
448 * descriptor, we should consider ourselves lucky that the
449 * controller flagged an error instead of scribbling over
450 * random memory locations.
452 dev_WARN(chan2dev(&dwc
->chan
), "Bad descriptor submitted for DMA!\n"
453 " cookie: %d\n", bad_desc
->txd
.cookie
);
454 dwc_dump_lli(dwc
, bad_desc
);
455 list_for_each_entry(child
, &bad_desc
->tx_list
, desc_node
)
456 dwc_dump_lli(dwc
, child
);
458 spin_unlock_irqrestore(&dwc
->lock
, flags
);
460 /* Pretend the descriptor completed successfully */
461 dwc_descriptor_complete(dwc
, bad_desc
, true);
464 static void dw_dma_tasklet(struct tasklet_struct
*t
)
466 struct dw_dma
*dw
= from_tasklet(dw
, t
, tasklet
);
467 struct dw_dma_chan
*dwc
;
472 status_xfer
= dma_readl(dw
, RAW
.XFER
);
473 status_err
= dma_readl(dw
, RAW
.ERROR
);
475 dev_vdbg(dw
->dma
.dev
, "%s: status_err=%x\n", __func__
, status_err
);
477 for (i
= 0; i
< dw
->dma
.chancnt
; i
++) {
479 if (test_bit(DW_DMA_IS_CYCLIC
, &dwc
->flags
))
480 dev_vdbg(dw
->dma
.dev
, "Cyclic xfer is not implemented\n");
481 else if (status_err
& (1 << i
))
482 dwc_handle_error(dw
, dwc
);
483 else if (status_xfer
& (1 << i
))
484 dwc_scan_descriptors(dw
, dwc
);
487 /* Re-enable interrupts */
488 channel_set_bit(dw
, MASK
.XFER
, dw
->all_chan_mask
);
489 channel_set_bit(dw
, MASK
.ERROR
, dw
->all_chan_mask
);
492 static irqreturn_t
dw_dma_interrupt(int irq
, void *dev_id
)
494 struct dw_dma
*dw
= dev_id
;
497 /* Check if we have any interrupt from the DMAC which is not in use */
501 status
= dma_readl(dw
, STATUS_INT
);
502 dev_vdbg(dw
->dma
.dev
, "%s: status=0x%x\n", __func__
, status
);
504 /* Check if we have any interrupt from the DMAC */
509 * Just disable the interrupts. We'll turn them back on in the
512 channel_clear_bit(dw
, MASK
.XFER
, dw
->all_chan_mask
);
513 channel_clear_bit(dw
, MASK
.BLOCK
, dw
->all_chan_mask
);
514 channel_clear_bit(dw
, MASK
.ERROR
, dw
->all_chan_mask
);
516 status
= dma_readl(dw
, STATUS_INT
);
519 "BUG: Unexpected interrupts pending: 0x%x\n",
523 channel_clear_bit(dw
, MASK
.XFER
, (1 << 8) - 1);
524 channel_clear_bit(dw
, MASK
.BLOCK
, (1 << 8) - 1);
525 channel_clear_bit(dw
, MASK
.SRC_TRAN
, (1 << 8) - 1);
526 channel_clear_bit(dw
, MASK
.DST_TRAN
, (1 << 8) - 1);
527 channel_clear_bit(dw
, MASK
.ERROR
, (1 << 8) - 1);
530 tasklet_schedule(&dw
->tasklet
);
535 /*----------------------------------------------------------------------*/
537 static struct dma_async_tx_descriptor
*
538 dwc_prep_dma_memcpy(struct dma_chan
*chan
, dma_addr_t dest
, dma_addr_t src
,
539 size_t len
, unsigned long flags
)
541 struct dw_dma_chan
*dwc
= to_dw_dma_chan(chan
);
542 struct dw_dma
*dw
= to_dw_dma(chan
->device
);
543 struct dw_desc
*desc
;
544 struct dw_desc
*first
;
545 struct dw_desc
*prev
;
548 u8 m_master
= dwc
->dws
.m_master
;
549 unsigned int src_width
;
550 unsigned int dst_width
;
551 unsigned int data_width
= dw
->pdata
->data_width
[m_master
];
553 u8 lms
= DWC_LLP_LMS(m_master
);
555 dev_vdbg(chan2dev(chan
),
556 "%s: d%pad s%pad l0x%zx f0x%lx\n", __func__
,
557 &dest
, &src
, len
, flags
);
559 if (unlikely(!len
)) {
560 dev_dbg(chan2dev(chan
), "%s: length is zero!\n", __func__
);
564 dwc
->direction
= DMA_MEM_TO_MEM
;
566 src_width
= dst_width
= __ffs(data_width
| src
| dest
| len
);
568 ctllo
= dw
->prepare_ctllo(dwc
)
569 | DWC_CTLL_DST_WIDTH(dst_width
)
570 | DWC_CTLL_SRC_WIDTH(src_width
)
576 for (offset
= 0; offset
< len
; offset
+= xfer_count
) {
577 desc
= dwc_desc_get(dwc
);
581 ctlhi
= dw
->bytes2block(dwc
, len
- offset
, src_width
, &xfer_count
);
583 lli_write(desc
, sar
, src
+ offset
);
584 lli_write(desc
, dar
, dest
+ offset
);
585 lli_write(desc
, ctllo
, ctllo
);
586 lli_write(desc
, ctlhi
, ctlhi
);
587 desc
->len
= xfer_count
;
592 lli_write(prev
, llp
, desc
->txd
.phys
| lms
);
593 list_add_tail(&desc
->desc_node
, &first
->tx_list
);
598 if (flags
& DMA_PREP_INTERRUPT
)
599 /* Trigger interrupt after last block */
600 lli_set(prev
, ctllo
, DWC_CTLL_INT_EN
);
603 lli_clear(prev
, ctllo
, DWC_CTLL_LLP_D_EN
| DWC_CTLL_LLP_S_EN
);
604 first
->txd
.flags
= flags
;
605 first
->total_len
= len
;
610 dwc_desc_put(dwc
, first
);
614 static struct dma_async_tx_descriptor
*
615 dwc_prep_slave_sg(struct dma_chan
*chan
, struct scatterlist
*sgl
,
616 unsigned int sg_len
, enum dma_transfer_direction direction
,
617 unsigned long flags
, void *context
)
619 struct dw_dma_chan
*dwc
= to_dw_dma_chan(chan
);
620 struct dw_dma
*dw
= to_dw_dma(chan
->device
);
621 struct dma_slave_config
*sconfig
= &dwc
->dma_sconfig
;
622 struct dw_desc
*prev
;
623 struct dw_desc
*first
;
625 u8 lms
= DWC_LLP_LMS(dwc
->dws
.m_master
);
627 unsigned int reg_width
;
628 unsigned int mem_width
;
630 struct scatterlist
*sg
;
631 size_t total_len
= 0;
633 dev_vdbg(chan2dev(chan
), "%s\n", __func__
);
635 if (unlikely(!is_slave_direction(direction
) || !sg_len
))
638 dwc
->direction
= direction
;
644 reg_width
= __ffs(sconfig
->dst_addr_width
);
645 reg
= sconfig
->dst_addr
;
646 ctllo
= dw
->prepare_ctllo(dwc
)
647 | DWC_CTLL_DST_WIDTH(reg_width
)
651 ctllo
|= sconfig
->device_fc
? DWC_CTLL_FC(DW_DMA_FC_P_M2P
) :
652 DWC_CTLL_FC(DW_DMA_FC_D_M2P
);
654 for_each_sg(sgl
, sg
, sg_len
, i
) {
655 struct dw_desc
*desc
;
659 mem
= sg_dma_address(sg
);
660 len
= sg_dma_len(sg
);
662 mem_width
= __ffs(sconfig
->src_addr_width
| mem
| len
);
664 slave_sg_todev_fill_desc
:
665 desc
= dwc_desc_get(dwc
);
669 ctlhi
= dw
->bytes2block(dwc
, len
, mem_width
, &dlen
);
671 lli_write(desc
, sar
, mem
);
672 lli_write(desc
, dar
, reg
);
673 lli_write(desc
, ctlhi
, ctlhi
);
674 lli_write(desc
, ctllo
, ctllo
| DWC_CTLL_SRC_WIDTH(mem_width
));
680 lli_write(prev
, llp
, desc
->txd
.phys
| lms
);
681 list_add_tail(&desc
->desc_node
, &first
->tx_list
);
690 goto slave_sg_todev_fill_desc
;
694 reg_width
= __ffs(sconfig
->src_addr_width
);
695 reg
= sconfig
->src_addr
;
696 ctllo
= dw
->prepare_ctllo(dwc
)
697 | DWC_CTLL_SRC_WIDTH(reg_width
)
701 ctllo
|= sconfig
->device_fc
? DWC_CTLL_FC(DW_DMA_FC_P_P2M
) :
702 DWC_CTLL_FC(DW_DMA_FC_D_P2M
);
704 for_each_sg(sgl
, sg
, sg_len
, i
) {
705 struct dw_desc
*desc
;
709 mem
= sg_dma_address(sg
);
710 len
= sg_dma_len(sg
);
712 slave_sg_fromdev_fill_desc
:
713 desc
= dwc_desc_get(dwc
);
717 ctlhi
= dw
->bytes2block(dwc
, len
, reg_width
, &dlen
);
719 lli_write(desc
, sar
, reg
);
720 lli_write(desc
, dar
, mem
);
721 lli_write(desc
, ctlhi
, ctlhi
);
722 mem_width
= __ffs(sconfig
->dst_addr_width
| mem
);
723 lli_write(desc
, ctllo
, ctllo
| DWC_CTLL_DST_WIDTH(mem_width
));
729 lli_write(prev
, llp
, desc
->txd
.phys
| lms
);
730 list_add_tail(&desc
->desc_node
, &first
->tx_list
);
739 goto slave_sg_fromdev_fill_desc
;
746 if (flags
& DMA_PREP_INTERRUPT
)
747 /* Trigger interrupt after last block */
748 lli_set(prev
, ctllo
, DWC_CTLL_INT_EN
);
751 lli_clear(prev
, ctllo
, DWC_CTLL_LLP_D_EN
| DWC_CTLL_LLP_S_EN
);
752 first
->total_len
= total_len
;
757 dev_err(chan2dev(chan
),
758 "not enough descriptors available. Direction %d\n", direction
);
759 dwc_desc_put(dwc
, first
);
763 bool dw_dma_filter(struct dma_chan
*chan
, void *param
)
765 struct dw_dma_chan
*dwc
= to_dw_dma_chan(chan
);
766 struct dw_dma_slave
*dws
= param
;
768 if (dws
->dma_dev
!= chan
->device
->dev
)
771 /* permit channels in accordance with the channels mask */
772 if (dws
->channels
&& !(dws
->channels
& dwc
->mask
))
775 /* We have to copy data since dws can be temporary storage */
776 memcpy(&dwc
->dws
, dws
, sizeof(struct dw_dma_slave
));
780 EXPORT_SYMBOL_GPL(dw_dma_filter
);
782 static int dwc_verify_maxburst(struct dma_chan
*chan
)
784 struct dw_dma_chan
*dwc
= to_dw_dma_chan(chan
);
786 dwc
->dma_sconfig
.src_maxburst
=
787 clamp(dwc
->dma_sconfig
.src_maxburst
, 1U, dwc
->max_burst
);
788 dwc
->dma_sconfig
.dst_maxburst
=
789 clamp(dwc
->dma_sconfig
.dst_maxburst
, 1U, dwc
->max_burst
);
791 dwc
->dma_sconfig
.src_maxburst
=
792 rounddown_pow_of_two(dwc
->dma_sconfig
.src_maxburst
);
793 dwc
->dma_sconfig
.dst_maxburst
=
794 rounddown_pow_of_two(dwc
->dma_sconfig
.dst_maxburst
);
799 static int dwc_verify_p_buswidth(struct dma_chan
*chan
)
801 struct dw_dma_chan
*dwc
= to_dw_dma_chan(chan
);
802 struct dw_dma
*dw
= to_dw_dma(chan
->device
);
803 u32 reg_width
, max_width
;
805 if (dwc
->dma_sconfig
.direction
== DMA_MEM_TO_DEV
)
806 reg_width
= dwc
->dma_sconfig
.dst_addr_width
;
807 else if (dwc
->dma_sconfig
.direction
== DMA_DEV_TO_MEM
)
808 reg_width
= dwc
->dma_sconfig
.src_addr_width
;
809 else /* DMA_MEM_TO_MEM */
812 max_width
= dw
->pdata
->data_width
[dwc
->dws
.p_master
];
814 /* Fall-back to 1-byte transfer width if undefined */
815 if (reg_width
== DMA_SLAVE_BUSWIDTH_UNDEFINED
)
816 reg_width
= DMA_SLAVE_BUSWIDTH_1_BYTE
;
817 else if (!is_power_of_2(reg_width
) || reg_width
> max_width
)
819 else /* bus width is valid */
822 /* Update undefined addr width value */
823 if (dwc
->dma_sconfig
.direction
== DMA_MEM_TO_DEV
)
824 dwc
->dma_sconfig
.dst_addr_width
= reg_width
;
825 else /* DMA_DEV_TO_MEM */
826 dwc
->dma_sconfig
.src_addr_width
= reg_width
;
831 static int dwc_verify_m_buswidth(struct dma_chan
*chan
)
833 struct dw_dma_chan
*dwc
= to_dw_dma_chan(chan
);
834 struct dw_dma
*dw
= to_dw_dma(chan
->device
);
835 u32 reg_width
, reg_burst
, mem_width
;
837 mem_width
= dw
->pdata
->data_width
[dwc
->dws
.m_master
];
840 * It's possible to have a data portion locked in the DMA FIFO in case
841 * of the channel suspension. Subsequent channel disabling will cause
842 * that data silent loss. In order to prevent that maintain the src and
843 * dst transfer widths coherency by means of the relation:
844 * (CTLx.SRC_TR_WIDTH * CTLx.SRC_MSIZE >= CTLx.DST_TR_WIDTH)
845 * Look for the details in the commit message that brings this change.
847 * Note the DMA configs utilized in the calculations below must have
848 * been verified to have correct values by this method call.
850 if (dwc
->dma_sconfig
.direction
== DMA_MEM_TO_DEV
) {
851 reg_width
= dwc
->dma_sconfig
.dst_addr_width
;
852 if (mem_width
< reg_width
)
855 dwc
->dma_sconfig
.src_addr_width
= mem_width
;
856 } else if (dwc
->dma_sconfig
.direction
== DMA_DEV_TO_MEM
) {
857 reg_width
= dwc
->dma_sconfig
.src_addr_width
;
858 reg_burst
= dwc
->dma_sconfig
.src_maxburst
;
860 dwc
->dma_sconfig
.dst_addr_width
= min(mem_width
, reg_width
* reg_burst
);
866 static int dwc_config(struct dma_chan
*chan
, struct dma_slave_config
*sconfig
)
868 struct dw_dma_chan
*dwc
= to_dw_dma_chan(chan
);
871 memcpy(&dwc
->dma_sconfig
, sconfig
, sizeof(*sconfig
));
873 ret
= dwc_verify_maxburst(chan
);
877 ret
= dwc_verify_p_buswidth(chan
);
881 ret
= dwc_verify_m_buswidth(chan
);
888 static void dwc_chan_pause(struct dw_dma_chan
*dwc
, bool drain
)
890 struct dw_dma
*dw
= to_dw_dma(dwc
->chan
.device
);
891 unsigned int count
= 20; /* timeout iterations */
893 dw
->suspend_chan(dwc
, drain
);
895 while (!(channel_readl(dwc
, CFG_LO
) & DWC_CFGL_FIFO_EMPTY
) && count
--)
898 set_bit(DW_DMA_IS_PAUSED
, &dwc
->flags
);
901 static int dwc_pause(struct dma_chan
*chan
)
903 struct dw_dma_chan
*dwc
= to_dw_dma_chan(chan
);
906 spin_lock_irqsave(&dwc
->lock
, flags
);
907 dwc_chan_pause(dwc
, false);
908 spin_unlock_irqrestore(&dwc
->lock
, flags
);
913 static inline void dwc_chan_resume(struct dw_dma_chan
*dwc
, bool drain
)
915 struct dw_dma
*dw
= to_dw_dma(dwc
->chan
.device
);
917 dw
->resume_chan(dwc
, drain
);
919 clear_bit(DW_DMA_IS_PAUSED
, &dwc
->flags
);
922 static int dwc_resume(struct dma_chan
*chan
)
924 struct dw_dma_chan
*dwc
= to_dw_dma_chan(chan
);
927 spin_lock_irqsave(&dwc
->lock
, flags
);
929 if (test_bit(DW_DMA_IS_PAUSED
, &dwc
->flags
))
930 dwc_chan_resume(dwc
, false);
932 spin_unlock_irqrestore(&dwc
->lock
, flags
);
937 static int dwc_terminate_all(struct dma_chan
*chan
)
939 struct dw_dma_chan
*dwc
= to_dw_dma_chan(chan
);
940 struct dw_dma
*dw
= to_dw_dma(chan
->device
);
941 struct dw_desc
*desc
, *_desc
;
945 spin_lock_irqsave(&dwc
->lock
, flags
);
947 clear_bit(DW_DMA_IS_SOFT_LLP
, &dwc
->flags
);
949 dwc_chan_pause(dwc
, true);
951 dwc_chan_disable(dw
, dwc
);
953 dwc_chan_resume(dwc
, true);
955 /* active_list entries will end up before queued entries */
956 list_splice_init(&dwc
->queue
, &list
);
957 list_splice_init(&dwc
->active_list
, &list
);
959 spin_unlock_irqrestore(&dwc
->lock
, flags
);
961 /* Flush all pending and queued descriptors */
962 list_for_each_entry_safe(desc
, _desc
, &list
, desc_node
)
963 dwc_descriptor_complete(dwc
, desc
, false);
968 static struct dw_desc
*dwc_find_desc(struct dw_dma_chan
*dwc
, dma_cookie_t c
)
970 struct dw_desc
*desc
;
972 list_for_each_entry(desc
, &dwc
->active_list
, desc_node
)
973 if (desc
->txd
.cookie
== c
)
979 static u32
dwc_get_residue_and_status(struct dw_dma_chan
*dwc
, dma_cookie_t cookie
,
980 enum dma_status
*status
)
982 struct dw_desc
*desc
;
986 spin_lock_irqsave(&dwc
->lock
, flags
);
988 desc
= dwc_find_desc(dwc
, cookie
);
990 if (desc
== dwc_first_active(dwc
)) {
991 residue
= desc
->residue
;
992 if (test_bit(DW_DMA_IS_SOFT_LLP
, &dwc
->flags
) && residue
)
993 residue
-= dwc_get_sent(dwc
);
994 if (test_bit(DW_DMA_IS_PAUSED
, &dwc
->flags
))
995 *status
= DMA_PAUSED
;
997 residue
= desc
->total_len
;
1003 spin_unlock_irqrestore(&dwc
->lock
, flags
);
1007 static enum dma_status
1008 dwc_tx_status(struct dma_chan
*chan
,
1009 dma_cookie_t cookie
,
1010 struct dma_tx_state
*txstate
)
1012 struct dw_dma_chan
*dwc
= to_dw_dma_chan(chan
);
1013 enum dma_status ret
;
1015 ret
= dma_cookie_status(chan
, cookie
, txstate
);
1016 if (ret
== DMA_COMPLETE
)
1019 dwc_scan_descriptors(to_dw_dma(chan
->device
), dwc
);
1021 ret
= dma_cookie_status(chan
, cookie
, txstate
);
1022 if (ret
== DMA_COMPLETE
)
1025 dma_set_residue(txstate
, dwc_get_residue_and_status(dwc
, cookie
, &ret
));
1029 static void dwc_issue_pending(struct dma_chan
*chan
)
1031 struct dw_dma_chan
*dwc
= to_dw_dma_chan(chan
);
1032 unsigned long flags
;
1034 spin_lock_irqsave(&dwc
->lock
, flags
);
1035 if (list_empty(&dwc
->active_list
))
1036 dwc_dostart_first_queued(dwc
);
1037 spin_unlock_irqrestore(&dwc
->lock
, flags
);
1040 /*----------------------------------------------------------------------*/
1042 void do_dw_dma_off(struct dw_dma
*dw
)
1044 dma_writel(dw
, CFG
, 0);
1046 channel_clear_bit(dw
, MASK
.XFER
, dw
->all_chan_mask
);
1047 channel_clear_bit(dw
, MASK
.BLOCK
, dw
->all_chan_mask
);
1048 channel_clear_bit(dw
, MASK
.SRC_TRAN
, dw
->all_chan_mask
);
1049 channel_clear_bit(dw
, MASK
.DST_TRAN
, dw
->all_chan_mask
);
1050 channel_clear_bit(dw
, MASK
.ERROR
, dw
->all_chan_mask
);
1052 while (dma_readl(dw
, CFG
) & DW_CFG_DMA_EN
)
1056 void do_dw_dma_on(struct dw_dma
*dw
)
1058 dma_writel(dw
, CFG
, DW_CFG_DMA_EN
);
1061 static int dwc_alloc_chan_resources(struct dma_chan
*chan
)
1063 struct dw_dma_chan
*dwc
= to_dw_dma_chan(chan
);
1064 struct dw_dma
*dw
= to_dw_dma(chan
->device
);
1066 dev_vdbg(chan2dev(chan
), "%s\n", __func__
);
1068 /* ASSERT: channel is idle */
1069 if (dma_readl(dw
, CH_EN
) & dwc
->mask
) {
1070 dev_dbg(chan2dev(chan
), "DMA channel not idle?\n");
1074 dma_cookie_init(chan
);
1077 * NOTE: some controllers may have additional features that we
1078 * need to initialize here, like "scatter-gather" (which
1079 * doesn't mean what you think it means), and status writeback.
1083 * We need controller-specific data to set up slave transfers.
1085 if (chan
->private && !dw_dma_filter(chan
, chan
->private)) {
1086 dev_warn(chan2dev(chan
), "Wrong controller-specific data\n");
1090 /* Enable controller here if needed */
1093 dw
->in_use
|= dwc
->mask
;
1098 static void dwc_free_chan_resources(struct dma_chan
*chan
)
1100 struct dw_dma_chan
*dwc
= to_dw_dma_chan(chan
);
1101 struct dw_dma
*dw
= to_dw_dma(chan
->device
);
1102 unsigned long flags
;
1104 dev_dbg(chan2dev(chan
), "%s: descs allocated=%u\n", __func__
,
1105 dwc
->descs_allocated
);
1107 /* ASSERT: channel is idle */
1108 BUG_ON(!list_empty(&dwc
->active_list
));
1109 BUG_ON(!list_empty(&dwc
->queue
));
1110 BUG_ON(dma_readl(to_dw_dma(chan
->device
), CH_EN
) & dwc
->mask
);
1112 spin_lock_irqsave(&dwc
->lock
, flags
);
1114 /* Clear custom channel configuration */
1115 memset(&dwc
->dws
, 0, sizeof(struct dw_dma_slave
));
1117 /* Disable interrupts */
1118 channel_clear_bit(dw
, MASK
.XFER
, dwc
->mask
);
1119 channel_clear_bit(dw
, MASK
.BLOCK
, dwc
->mask
);
1120 channel_clear_bit(dw
, MASK
.ERROR
, dwc
->mask
);
1122 spin_unlock_irqrestore(&dwc
->lock
, flags
);
1124 /* Disable controller in case it was a last user */
1125 dw
->in_use
&= ~dwc
->mask
;
1129 dev_vdbg(chan2dev(chan
), "%s: done\n", __func__
);
1132 static void dwc_caps(struct dma_chan
*chan
, struct dma_slave_caps
*caps
)
1134 struct dw_dma_chan
*dwc
= to_dw_dma_chan(chan
);
1136 caps
->max_burst
= dwc
->max_burst
;
1139 * It might be crucial for some devices to have the hardware
1140 * accelerated multi-block transfers supported, aka LLPs in DW DMAC
1141 * notation. So if LLPs are supported then max_sg_burst is set to
1142 * zero which means unlimited number of SG entries can be handled in a
1143 * single DMA transaction, otherwise it's just one SG entry.
1146 caps
->max_sg_burst
= 1;
1148 caps
->max_sg_burst
= 0;
1151 int do_dma_probe(struct dw_dma_chip
*chip
)
1153 struct dw_dma
*dw
= chip
->dw
;
1154 struct dw_dma_platform_data
*pdata
;
1155 bool autocfg
= false;
1156 unsigned int dw_params
;
1160 dw
->pdata
= devm_kzalloc(chip
->dev
, sizeof(*dw
->pdata
), GFP_KERNEL
);
1164 dw
->regs
= chip
->regs
;
1166 pm_runtime_get_sync(chip
->dev
);
1169 dw_params
= dma_readl(dw
, DW_PARAMS
);
1170 dev_dbg(chip
->dev
, "DW_PARAMS: 0x%08x\n", dw_params
);
1172 autocfg
= dw_params
>> DW_PARAMS_EN
& 1;
1178 /* Reassign the platform data pointer */
1181 /* Get hardware configuration parameters */
1182 pdata
->nr_channels
= (dw_params
>> DW_PARAMS_NR_CHAN
& 7) + 1;
1183 pdata
->nr_masters
= (dw_params
>> DW_PARAMS_NR_MASTER
& 3) + 1;
1184 for (i
= 0; i
< pdata
->nr_masters
; i
++) {
1185 pdata
->data_width
[i
] =
1186 4 << (dw_params
>> DW_PARAMS_DATA_WIDTH(i
) & 3);
1188 pdata
->block_size
= dma_readl(dw
, MAX_BLK_SIZE
);
1190 /* Fill platform data with the default values */
1191 pdata
->chan_allocation_order
= CHAN_ALLOCATION_ASCENDING
;
1192 pdata
->chan_priority
= CHAN_PRIORITY_ASCENDING
;
1193 } else if (chip
->pdata
->nr_channels
> DW_DMA_MAX_NR_CHANNELS
) {
1197 memcpy(dw
->pdata
, chip
->pdata
, sizeof(*dw
->pdata
));
1199 /* Reassign the platform data pointer */
1203 dw
->chan
= devm_kcalloc(chip
->dev
, pdata
->nr_channels
, sizeof(*dw
->chan
),
1210 /* Calculate all channel mask before DMA setup */
1211 dw
->all_chan_mask
= (1 << pdata
->nr_channels
) - 1;
1213 /* Force dma off, just in case */
1216 /* Device and instance ID for IRQ and DMA pool */
1217 dw
->set_device_name(dw
, chip
->id
);
1219 /* Create a pool of consistent memory blocks for hardware descriptors */
1220 dw
->desc_pool
= dmam_pool_create(dw
->name
, chip
->dev
,
1221 sizeof(struct dw_desc
), 4, 0);
1222 if (!dw
->desc_pool
) {
1223 dev_err(chip
->dev
, "No memory for descriptors dma pool\n");
1228 tasklet_setup(&dw
->tasklet
, dw_dma_tasklet
);
1230 ret
= request_irq(chip
->irq
, dw_dma_interrupt
, IRQF_SHARED
,
1235 INIT_LIST_HEAD(&dw
->dma
.channels
);
1236 for (i
= 0; i
< pdata
->nr_channels
; i
++) {
1237 struct dw_dma_chan
*dwc
= &dw
->chan
[i
];
1239 dwc
->chan
.device
= &dw
->dma
;
1240 dma_cookie_init(&dwc
->chan
);
1241 if (pdata
->chan_allocation_order
== CHAN_ALLOCATION_ASCENDING
)
1242 list_add_tail(&dwc
->chan
.device_node
,
1245 list_add(&dwc
->chan
.device_node
, &dw
->dma
.channels
);
1247 /* 7 is highest priority & 0 is lowest. */
1248 if (pdata
->chan_priority
== CHAN_PRIORITY_ASCENDING
)
1249 dwc
->priority
= pdata
->nr_channels
- i
- 1;
1253 dwc
->ch_regs
= &__dw_regs(dw
)->CHAN
[i
];
1254 spin_lock_init(&dwc
->lock
);
1257 INIT_LIST_HEAD(&dwc
->active_list
);
1258 INIT_LIST_HEAD(&dwc
->queue
);
1260 channel_clear_bit(dw
, CH_EN
, dwc
->mask
);
1262 dwc
->direction
= DMA_TRANS_NONE
;
1264 /* Hardware configuration */
1266 unsigned int r
= DW_DMA_MAX_NR_CHANNELS
- i
- 1;
1267 void __iomem
*addr
= &__dw_regs(dw
)->DWC_PARAMS
[r
];
1268 unsigned int dwc_params
= readl(addr
);
1270 dev_dbg(chip
->dev
, "DWC_PARAMS[%d]: 0x%08x\n", i
,
1274 * Decode maximum block size for given channel. The
1275 * stored 4 bit value represents blocks from 0x00 for 3
1276 * up to 0x0a for 4095.
1279 (4 << ((pdata
->block_size
>> 4 * i
) & 0xf)) - 1;
1282 * According to the DW DMA databook the true scatter-
1283 * gether LLPs aren't available if either multi-block
1284 * config is disabled (CHx_MULTI_BLK_EN == 0) or the
1285 * LLP register is hard-coded to zeros
1286 * (CHx_HC_LLP == 1).
1289 (dwc_params
>> DWC_PARAMS_MBLK_EN
& 0x1) == 0 ||
1290 (dwc_params
>> DWC_PARAMS_HC_LLP
& 0x1) == 1;
1292 (0x4 << (dwc_params
>> DWC_PARAMS_MSIZE
& 0x7));
1294 dwc
->block_size
= pdata
->block_size
;
1295 dwc
->nollp
= !pdata
->multi_block
[i
];
1296 dwc
->max_burst
= pdata
->max_burst
[i
] ?: DW_DMA_MAX_BURST
;
1300 /* Clear all interrupts on all channels. */
1301 dma_writel(dw
, CLEAR
.XFER
, dw
->all_chan_mask
);
1302 dma_writel(dw
, CLEAR
.BLOCK
, dw
->all_chan_mask
);
1303 dma_writel(dw
, CLEAR
.SRC_TRAN
, dw
->all_chan_mask
);
1304 dma_writel(dw
, CLEAR
.DST_TRAN
, dw
->all_chan_mask
);
1305 dma_writel(dw
, CLEAR
.ERROR
, dw
->all_chan_mask
);
1307 /* Set capabilities */
1308 dma_cap_set(DMA_SLAVE
, dw
->dma
.cap_mask
);
1309 dma_cap_set(DMA_PRIVATE
, dw
->dma
.cap_mask
);
1310 dma_cap_set(DMA_MEMCPY
, dw
->dma
.cap_mask
);
1312 dw
->dma
.dev
= chip
->dev
;
1313 dw
->dma
.device_alloc_chan_resources
= dwc_alloc_chan_resources
;
1314 dw
->dma
.device_free_chan_resources
= dwc_free_chan_resources
;
1316 dw
->dma
.device_prep_dma_memcpy
= dwc_prep_dma_memcpy
;
1317 dw
->dma
.device_prep_slave_sg
= dwc_prep_slave_sg
;
1319 dw
->dma
.device_caps
= dwc_caps
;
1320 dw
->dma
.device_config
= dwc_config
;
1321 dw
->dma
.device_pause
= dwc_pause
;
1322 dw
->dma
.device_resume
= dwc_resume
;
1323 dw
->dma
.device_terminate_all
= dwc_terminate_all
;
1325 dw
->dma
.device_tx_status
= dwc_tx_status
;
1326 dw
->dma
.device_issue_pending
= dwc_issue_pending
;
1328 /* DMA capabilities */
1329 dw
->dma
.min_burst
= DW_DMA_MIN_BURST
;
1330 dw
->dma
.max_burst
= DW_DMA_MAX_BURST
;
1331 dw
->dma
.src_addr_widths
= DW_DMA_BUSWIDTHS
;
1332 dw
->dma
.dst_addr_widths
= DW_DMA_BUSWIDTHS
;
1333 dw
->dma
.directions
= BIT(DMA_DEV_TO_MEM
) | BIT(DMA_MEM_TO_DEV
) |
1334 BIT(DMA_MEM_TO_MEM
);
1335 dw
->dma
.residue_granularity
= DMA_RESIDUE_GRANULARITY_BURST
;
1338 * For now there is no hardware with non uniform maximum block size
1339 * across all of the device channels, so we set the maximum segment
1340 * size as the block size found for the very first channel.
1342 dma_set_max_seg_size(dw
->dma
.dev
, dw
->chan
[0].block_size
);
1344 ret
= dma_async_device_register(&dw
->dma
);
1346 goto err_dma_register
;
1348 dev_info(chip
->dev
, "DesignWare DMA Controller, %d channels\n",
1349 pdata
->nr_channels
);
1351 pm_runtime_put_sync_suspend(chip
->dev
);
1356 free_irq(chip
->irq
, dw
);
1358 pm_runtime_put_sync_suspend(chip
->dev
);
1362 int do_dma_remove(struct dw_dma_chip
*chip
)
1364 struct dw_dma
*dw
= chip
->dw
;
1365 struct dw_dma_chan
*dwc
, *_dwc
;
1367 pm_runtime_get_sync(chip
->dev
);
1370 dma_async_device_unregister(&dw
->dma
);
1372 free_irq(chip
->irq
, dw
);
1373 tasklet_kill(&dw
->tasklet
);
1375 list_for_each_entry_safe(dwc
, _dwc
, &dw
->dma
.channels
,
1377 list_del(&dwc
->chan
.device_node
);
1378 channel_clear_bit(dw
, CH_EN
, dwc
->mask
);
1381 pm_runtime_put_sync_suspend(chip
->dev
);
1385 int do_dw_dma_disable(struct dw_dma_chip
*chip
)
1387 struct dw_dma
*dw
= chip
->dw
;
1392 EXPORT_SYMBOL_GPL(do_dw_dma_disable
);
1394 int do_dw_dma_enable(struct dw_dma_chip
*chip
)
1396 struct dw_dma
*dw
= chip
->dw
;
1401 EXPORT_SYMBOL_GPL(do_dw_dma_enable
);
1403 MODULE_LICENSE("GPL v2");
1404 MODULE_DESCRIPTION("Synopsys DesignWare DMA Controller core driver");
1405 MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
1406 MODULE_AUTHOR("Viresh Kumar <vireshk@kernel.org>");