1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * MediaTek UART APDMA driver.
4  *
5  * Copyright (c) 2019 MediaTek Inc.
6  * Author: Long Cheng <long.cheng@mediatek.com>
7  */
8 
9 #include <linux/clk.h>
10 #include <linux/dmaengine.h>
11 #include <linux/dma-mapping.h>
12 #include <linux/err.h>
13 #include <linux/init.h>
14 #include <linux/interrupt.h>
15 #include <linux/iopoll.h>
16 #include <linux/kernel.h>
17 #include <linux/list.h>
18 #include <linux/module.h>
19 #include <linux/of_device.h>
20 #include <linux/of_dma.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 "../virt-dma.h"
27 
28 /* The default number of virtual channel */
29 #define MTK_UART_APDMA_NR_VCHANS	8
30 
31 #define VFF_EN_B		BIT(0)
32 #define VFF_STOP_B		BIT(0)
33 #define VFF_FLUSH_B		BIT(0)
34 #define VFF_4G_EN_B		BIT(0)
35 /* rx valid size >=  vff thre */
36 #define VFF_RX_INT_EN_B		(BIT(0) | BIT(1))
37 /* tx left size >= vff thre */
38 #define VFF_TX_INT_EN_B		BIT(0)
39 #define VFF_WARM_RST_B		BIT(0)
40 #define VFF_RX_INT_CLR_B	(BIT(0) | BIT(1))
41 #define VFF_TX_INT_CLR_B	0
42 #define VFF_STOP_CLR_B		0
43 #define VFF_EN_CLR_B		0
44 #define VFF_INT_EN_CLR_B	0
45 #define VFF_4G_SUPPORT_CLR_B	0
46 
47 /*
48  * interrupt trigger level for tx
49  * if threshold is n, no polling is required to start tx.
50  * otherwise need polling VFF_FLUSH.
51  */
52 #define VFF_TX_THRE(n)		(n)
53 /* interrupt trigger level for rx */
54 #define VFF_RX_THRE(n)		((n) * 3 / 4)
55 
56 #define VFF_RING_SIZE	0xffff
57 /* invert this bit when wrap ring head again */
58 #define VFF_RING_WRAP	0x10000
59 
60 #define VFF_INT_FLAG		0x00
61 #define VFF_INT_EN		0x04
62 #define VFF_EN			0x08
63 #define VFF_RST			0x0c
64 #define VFF_STOP		0x10
65 #define VFF_FLUSH		0x14
66 #define VFF_ADDR		0x1c
67 #define VFF_LEN			0x24
68 #define VFF_THRE		0x28
69 #define VFF_WPT			0x2c
70 #define VFF_RPT			0x30
71 /* TX: the buffer size HW can read. RX: the buffer size SW can read. */
72 #define VFF_VALID_SIZE		0x3c
73 /* TX: the buffer size SW can write. RX: the buffer size HW can write. */
74 #define VFF_LEFT_SIZE		0x40
75 #define VFF_DEBUG_STATUS	0x50
76 #define VFF_4G_SUPPORT		0x54
77 
78 struct mtk_uart_apdmadev {
79 	struct dma_device ddev;
80 	struct clk *clk;
81 	bool support_33bits;
82 	unsigned int dma_requests;
83 };
84 
85 struct mtk_uart_apdma_desc {
86 	struct virt_dma_desc vd;
87 
88 	dma_addr_t addr;
89 	unsigned int avail_len;
90 };
91 
92 struct mtk_chan {
93 	struct virt_dma_chan vc;
94 	struct dma_slave_config	cfg;
95 	struct mtk_uart_apdma_desc *desc;
96 	enum dma_transfer_direction dir;
97 
98 	void __iomem *base;
99 	unsigned int irq;
100 
101 	unsigned int rx_status;
102 };
103 
104 static inline struct mtk_uart_apdmadev *
105 to_mtk_uart_apdma_dev(struct dma_device *d)
106 {
107 	return container_of(d, struct mtk_uart_apdmadev, ddev);
108 }
109 
110 static inline struct mtk_chan *to_mtk_uart_apdma_chan(struct dma_chan *c)
111 {
112 	return container_of(c, struct mtk_chan, vc.chan);
113 }
114 
115 static inline struct mtk_uart_apdma_desc *to_mtk_uart_apdma_desc
116 	(struct dma_async_tx_descriptor *t)
117 {
118 	return container_of(t, struct mtk_uart_apdma_desc, vd.tx);
119 }
120 
121 static void mtk_uart_apdma_write(struct mtk_chan *c,
122 			       unsigned int reg, unsigned int val)
123 {
124 	writel(val, c->base + reg);
125 }
126 
127 static unsigned int mtk_uart_apdma_read(struct mtk_chan *c, unsigned int reg)
128 {
129 	return readl(c->base + reg);
130 }
131 
132 static void mtk_uart_apdma_desc_free(struct virt_dma_desc *vd)
133 {
134 	struct dma_chan *chan = vd->tx.chan;
135 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
136 
137 	kfree(c->desc);
138 }
139 
140 static void mtk_uart_apdma_start_tx(struct mtk_chan *c)
141 {
142 	struct mtk_uart_apdmadev *mtkd =
143 				to_mtk_uart_apdma_dev(c->vc.chan.device);
144 	struct mtk_uart_apdma_desc *d = c->desc;
145 	unsigned int wpt, vff_sz;
146 
147 	vff_sz = c->cfg.dst_port_window_size;
148 	if (!mtk_uart_apdma_read(c, VFF_LEN)) {
149 		mtk_uart_apdma_write(c, VFF_ADDR, d->addr);
150 		mtk_uart_apdma_write(c, VFF_LEN, vff_sz);
151 		mtk_uart_apdma_write(c, VFF_THRE, VFF_TX_THRE(vff_sz));
152 		mtk_uart_apdma_write(c, VFF_WPT, 0);
153 		mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);
154 
155 		if (mtkd->support_33bits)
156 			mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_EN_B);
157 	}
158 
159 	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_B);
160 	if (mtk_uart_apdma_read(c, VFF_EN) != VFF_EN_B)
161 		dev_err(c->vc.chan.device->dev, "Enable TX fail\n");
162 
163 	if (!mtk_uart_apdma_read(c, VFF_LEFT_SIZE)) {
164 		mtk_uart_apdma_write(c, VFF_INT_EN, VFF_TX_INT_EN_B);
165 		return;
166 	}
167 
168 	wpt = mtk_uart_apdma_read(c, VFF_WPT);
169 
170 	wpt += c->desc->avail_len;
171 	if ((wpt & VFF_RING_SIZE) == vff_sz)
172 		wpt = (wpt & VFF_RING_WRAP) ^ VFF_RING_WRAP;
173 
174 	/* Let DMA start moving data */
175 	mtk_uart_apdma_write(c, VFF_WPT, wpt);
176 
177 	/* HW auto set to 0 when left size >= threshold */
178 	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_TX_INT_EN_B);
179 	if (!mtk_uart_apdma_read(c, VFF_FLUSH))
180 		mtk_uart_apdma_write(c, VFF_FLUSH, VFF_FLUSH_B);
181 }
182 
183 static void mtk_uart_apdma_start_rx(struct mtk_chan *c)
184 {
185 	struct mtk_uart_apdmadev *mtkd =
186 				to_mtk_uart_apdma_dev(c->vc.chan.device);
187 	struct mtk_uart_apdma_desc *d = c->desc;
188 	unsigned int vff_sz;
189 
190 	vff_sz = c->cfg.src_port_window_size;
191 	if (!mtk_uart_apdma_read(c, VFF_LEN)) {
192 		mtk_uart_apdma_write(c, VFF_ADDR, d->addr);
193 		mtk_uart_apdma_write(c, VFF_LEN, vff_sz);
194 		mtk_uart_apdma_write(c, VFF_THRE, VFF_RX_THRE(vff_sz));
195 		mtk_uart_apdma_write(c, VFF_RPT, 0);
196 		mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);
197 
198 		if (mtkd->support_33bits)
199 			mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_EN_B);
200 	}
201 
202 	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_RX_INT_EN_B);
203 	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_B);
204 	if (mtk_uart_apdma_read(c, VFF_EN) != VFF_EN_B)
205 		dev_err(c->vc.chan.device->dev, "Enable RX fail\n");
206 }
207 
208 static void mtk_uart_apdma_tx_handler(struct mtk_chan *c)
209 {
210 	struct mtk_uart_apdma_desc *d = c->desc;
211 
212 	mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);
213 	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
214 	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);
215 
216 	list_del(&d->vd.node);
217 	vchan_cookie_complete(&d->vd);
218 }
219 
220 static void mtk_uart_apdma_rx_handler(struct mtk_chan *c)
221 {
222 	struct mtk_uart_apdma_desc *d = c->desc;
223 	unsigned int len, wg, rg;
224 	int cnt;
225 
226 	mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);
227 
228 	if (!mtk_uart_apdma_read(c, VFF_VALID_SIZE))
229 		return;
230 
231 	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);
232 	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
233 
234 	len = c->cfg.src_port_window_size;
235 	rg = mtk_uart_apdma_read(c, VFF_RPT);
236 	wg = mtk_uart_apdma_read(c, VFF_WPT);
237 	cnt = (wg & VFF_RING_SIZE) - (rg & VFF_RING_SIZE);
238 
239 	/*
240 	 * The buffer is ring buffer. If wrap bit different,
241 	 * represents the start of the next cycle for WPT
242 	 */
243 	if ((rg ^ wg) & VFF_RING_WRAP)
244 		cnt += len;
245 
246 	c->rx_status = d->avail_len - cnt;
247 	mtk_uart_apdma_write(c, VFF_RPT, wg);
248 
249 	list_del(&d->vd.node);
250 	vchan_cookie_complete(&d->vd);
251 }
252 
253 static irqreturn_t mtk_uart_apdma_irq_handler(int irq, void *dev_id)
254 {
255 	struct dma_chan *chan = (struct dma_chan *)dev_id;
256 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
257 	unsigned long flags;
258 
259 	spin_lock_irqsave(&c->vc.lock, flags);
260 	if (c->dir == DMA_DEV_TO_MEM)
261 		mtk_uart_apdma_rx_handler(c);
262 	else if (c->dir == DMA_MEM_TO_DEV)
263 		mtk_uart_apdma_tx_handler(c);
264 	spin_unlock_irqrestore(&c->vc.lock, flags);
265 
266 	return IRQ_HANDLED;
267 }
268 
269 static int mtk_uart_apdma_alloc_chan_resources(struct dma_chan *chan)
270 {
271 	struct mtk_uart_apdmadev *mtkd = to_mtk_uart_apdma_dev(chan->device);
272 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
273 	unsigned int status;
274 	int ret;
275 
276 	ret = pm_runtime_get_sync(mtkd->ddev.dev);
277 	if (ret < 0) {
278 		pm_runtime_put_noidle(chan->device->dev);
279 		return ret;
280 	}
281 
282 	mtk_uart_apdma_write(c, VFF_ADDR, 0);
283 	mtk_uart_apdma_write(c, VFF_THRE, 0);
284 	mtk_uart_apdma_write(c, VFF_LEN, 0);
285 	mtk_uart_apdma_write(c, VFF_RST, VFF_WARM_RST_B);
286 
287 	ret = readx_poll_timeout(readl, c->base + VFF_EN,
288 			  status, !status, 10, 100);
289 	if (ret)
290 		return ret;
291 
292 	ret = request_irq(c->irq, mtk_uart_apdma_irq_handler,
293 			  IRQF_TRIGGER_NONE, KBUILD_MODNAME, chan);
294 	if (ret < 0) {
295 		dev_err(chan->device->dev, "Can't request dma IRQ\n");
296 		return -EINVAL;
297 	}
298 
299 	if (mtkd->support_33bits)
300 		mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_SUPPORT_CLR_B);
301 
302 	return ret;
303 }
304 
305 static void mtk_uart_apdma_free_chan_resources(struct dma_chan *chan)
306 {
307 	struct mtk_uart_apdmadev *mtkd = to_mtk_uart_apdma_dev(chan->device);
308 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
309 
310 	free_irq(c->irq, chan);
311 
312 	tasklet_kill(&c->vc.task);
313 
314 	vchan_free_chan_resources(&c->vc);
315 
316 	pm_runtime_put_sync(mtkd->ddev.dev);
317 }
318 
319 static enum dma_status mtk_uart_apdma_tx_status(struct dma_chan *chan,
320 					 dma_cookie_t cookie,
321 					 struct dma_tx_state *txstate)
322 {
323 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
324 	enum dma_status ret;
325 
326 	ret = dma_cookie_status(chan, cookie, txstate);
327 	if (!txstate)
328 		return ret;
329 
330 	dma_set_residue(txstate, c->rx_status);
331 
332 	return ret;
333 }
334 
335 /*
336  * dmaengine_prep_slave_single will call the function. and sglen is 1.
337  * 8250 uart using one ring buffer, and deal with one sg.
338  */
339 static struct dma_async_tx_descriptor *mtk_uart_apdma_prep_slave_sg
340 	(struct dma_chan *chan, struct scatterlist *sgl,
341 	unsigned int sglen, enum dma_transfer_direction dir,
342 	unsigned long tx_flags, void *context)
343 {
344 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
345 	struct mtk_uart_apdma_desc *d;
346 
347 	if (!is_slave_direction(dir) || sglen != 1)
348 		return NULL;
349 
350 	/* Now allocate and setup the descriptor */
351 	d = kzalloc(sizeof(*d), GFP_ATOMIC);
352 	if (!d)
353 		return NULL;
354 
355 	d->avail_len = sg_dma_len(sgl);
356 	d->addr = sg_dma_address(sgl);
357 	c->dir = dir;
358 
359 	return vchan_tx_prep(&c->vc, &d->vd, tx_flags);
360 }
361 
362 static void mtk_uart_apdma_issue_pending(struct dma_chan *chan)
363 {
364 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
365 	struct virt_dma_desc *vd;
366 	unsigned long flags;
367 
368 	spin_lock_irqsave(&c->vc.lock, flags);
369 	if (vchan_issue_pending(&c->vc)) {
370 		vd = vchan_next_desc(&c->vc);
371 		c->desc = to_mtk_uart_apdma_desc(&vd->tx);
372 
373 		if (c->dir == DMA_DEV_TO_MEM)
374 			mtk_uart_apdma_start_rx(c);
375 		else if (c->dir == DMA_MEM_TO_DEV)
376 			mtk_uart_apdma_start_tx(c);
377 	}
378 
379 	spin_unlock_irqrestore(&c->vc.lock, flags);
380 }
381 
382 static int mtk_uart_apdma_slave_config(struct dma_chan *chan,
383 				   struct dma_slave_config *config)
384 {
385 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
386 
387 	memcpy(&c->cfg, config, sizeof(*config));
388 
389 	return 0;
390 }
391 
392 static int mtk_uart_apdma_terminate_all(struct dma_chan *chan)
393 {
394 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
395 	unsigned long flags;
396 	unsigned int status;
397 	LIST_HEAD(head);
398 	int ret;
399 
400 	mtk_uart_apdma_write(c, VFF_FLUSH, VFF_FLUSH_B);
401 
402 	ret = readx_poll_timeout(readl, c->base + VFF_FLUSH,
403 			  status, status != VFF_FLUSH_B, 10, 100);
404 	if (ret)
405 		dev_err(c->vc.chan.device->dev, "flush: fail, status=0x%x\n",
406 			mtk_uart_apdma_read(c, VFF_DEBUG_STATUS));
407 
408 	/*
409 	 * Stop need 3 steps.
410 	 * 1. set stop to 1
411 	 * 2. wait en to 0
412 	 * 3. set stop as 0
413 	 */
414 	mtk_uart_apdma_write(c, VFF_STOP, VFF_STOP_B);
415 	ret = readx_poll_timeout(readl, c->base + VFF_EN,
416 			  status, !status, 10, 100);
417 	if (ret)
418 		dev_err(c->vc.chan.device->dev, "stop: fail, status=0x%x\n",
419 			mtk_uart_apdma_read(c, VFF_DEBUG_STATUS));
420 
421 	mtk_uart_apdma_write(c, VFF_STOP, VFF_STOP_CLR_B);
422 	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
423 
424 	if (c->dir == DMA_DEV_TO_MEM)
425 		mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);
426 	else if (c->dir == DMA_MEM_TO_DEV)
427 		mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);
428 
429 	synchronize_irq(c->irq);
430 
431 	spin_lock_irqsave(&c->vc.lock, flags);
432 	vchan_get_all_descriptors(&c->vc, &head);
433 	spin_unlock_irqrestore(&c->vc.lock, flags);
434 
435 	vchan_dma_desc_free_list(&c->vc, &head);
436 
437 	return 0;
438 }
439 
440 static int mtk_uart_apdma_device_pause(struct dma_chan *chan)
441 {
442 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
443 	unsigned long flags;
444 
445 	spin_lock_irqsave(&c->vc.lock, flags);
446 
447 	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);
448 	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
449 
450 	synchronize_irq(c->irq);
451 
452 	spin_unlock_irqrestore(&c->vc.lock, flags);
453 
454 	return 0;
455 }
456 
457 static void mtk_uart_apdma_free(struct mtk_uart_apdmadev *mtkd)
458 {
459 	while (!list_empty(&mtkd->ddev.channels)) {
460 		struct mtk_chan *c = list_first_entry(&mtkd->ddev.channels,
461 			struct mtk_chan, vc.chan.device_node);
462 
463 		list_del(&c->vc.chan.device_node);
464 		tasklet_kill(&c->vc.task);
465 	}
466 }
467 
468 static const struct of_device_id mtk_uart_apdma_match[] = {
469 	{ .compatible = "mediatek,mt6577-uart-dma", },
470 	{ /* sentinel */ },
471 };
472 MODULE_DEVICE_TABLE(of, mtk_uart_apdma_match);
473 
474 static int mtk_uart_apdma_probe(struct platform_device *pdev)
475 {
476 	struct device_node *np = pdev->dev.of_node;
477 	struct mtk_uart_apdmadev *mtkd;
478 	int bit_mask = 32, rc;
479 	struct mtk_chan *c;
480 	unsigned int i;
481 
482 	mtkd = devm_kzalloc(&pdev->dev, sizeof(*mtkd), GFP_KERNEL);
483 	if (!mtkd)
484 		return -ENOMEM;
485 
486 	mtkd->clk = devm_clk_get(&pdev->dev, NULL);
487 	if (IS_ERR(mtkd->clk)) {
488 		dev_err(&pdev->dev, "No clock specified\n");
489 		rc = PTR_ERR(mtkd->clk);
490 		return rc;
491 	}
492 
493 	if (of_property_read_bool(np, "mediatek,dma-33bits"))
494 		mtkd->support_33bits = true;
495 
496 	if (mtkd->support_33bits)
497 		bit_mask = 33;
498 
499 	rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(bit_mask));
500 	if (rc)
501 		return rc;
502 
503 	dma_cap_set(DMA_SLAVE, mtkd->ddev.cap_mask);
504 	mtkd->ddev.device_alloc_chan_resources =
505 				mtk_uart_apdma_alloc_chan_resources;
506 	mtkd->ddev.device_free_chan_resources =
507 				mtk_uart_apdma_free_chan_resources;
508 	mtkd->ddev.device_tx_status = mtk_uart_apdma_tx_status;
509 	mtkd->ddev.device_issue_pending = mtk_uart_apdma_issue_pending;
510 	mtkd->ddev.device_prep_slave_sg = mtk_uart_apdma_prep_slave_sg;
511 	mtkd->ddev.device_config = mtk_uart_apdma_slave_config;
512 	mtkd->ddev.device_pause = mtk_uart_apdma_device_pause;
513 	mtkd->ddev.device_terminate_all = mtk_uart_apdma_terminate_all;
514 	mtkd->ddev.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
515 	mtkd->ddev.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
516 	mtkd->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
517 	mtkd->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
518 	mtkd->ddev.dev = &pdev->dev;
519 	INIT_LIST_HEAD(&mtkd->ddev.channels);
520 
521 	mtkd->dma_requests = MTK_UART_APDMA_NR_VCHANS;
522 	if (of_property_read_u32(np, "dma-requests", &mtkd->dma_requests)) {
523 		dev_info(&pdev->dev,
524 			 "Using %u as missing dma-requests property\n",
525 			 MTK_UART_APDMA_NR_VCHANS);
526 	}
527 
528 	for (i = 0; i < mtkd->dma_requests; i++) {
529 		c = devm_kzalloc(mtkd->ddev.dev, sizeof(*c), GFP_KERNEL);
530 		if (!c) {
531 			rc = -ENODEV;
532 			goto err_no_dma;
533 		}
534 
535 		c->base = devm_platform_ioremap_resource(pdev, i);
536 		if (IS_ERR(c->base)) {
537 			rc = PTR_ERR(c->base);
538 			goto err_no_dma;
539 		}
540 		c->vc.desc_free = mtk_uart_apdma_desc_free;
541 		vchan_init(&c->vc, &mtkd->ddev);
542 
543 		rc = platform_get_irq(pdev, i);
544 		if (rc < 0)
545 			goto err_no_dma;
546 		c->irq = rc;
547 	}
548 
549 	pm_runtime_enable(&pdev->dev);
550 	pm_runtime_set_active(&pdev->dev);
551 
552 	rc = dma_async_device_register(&mtkd->ddev);
553 	if (rc)
554 		goto rpm_disable;
555 
556 	platform_set_drvdata(pdev, mtkd);
557 
558 	/* Device-tree DMA controller registration */
559 	rc = of_dma_controller_register(np, of_dma_xlate_by_chan_id, mtkd);
560 	if (rc)
561 		goto dma_remove;
562 
563 	return rc;
564 
565 dma_remove:
566 	dma_async_device_unregister(&mtkd->ddev);
567 rpm_disable:
568 	pm_runtime_disable(&pdev->dev);
569 err_no_dma:
570 	mtk_uart_apdma_free(mtkd);
571 	return rc;
572 }
573 
574 static int mtk_uart_apdma_remove(struct platform_device *pdev)
575 {
576 	struct mtk_uart_apdmadev *mtkd = platform_get_drvdata(pdev);
577 
578 	of_dma_controller_free(pdev->dev.of_node);
579 
580 	mtk_uart_apdma_free(mtkd);
581 
582 	dma_async_device_unregister(&mtkd->ddev);
583 
584 	pm_runtime_disable(&pdev->dev);
585 
586 	return 0;
587 }
588 
589 #ifdef CONFIG_PM_SLEEP
590 static int mtk_uart_apdma_suspend(struct device *dev)
591 {
592 	struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
593 
594 	if (!pm_runtime_suspended(dev))
595 		clk_disable_unprepare(mtkd->clk);
596 
597 	return 0;
598 }
599 
600 static int mtk_uart_apdma_resume(struct device *dev)
601 {
602 	int ret;
603 	struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
604 
605 	if (!pm_runtime_suspended(dev)) {
606 		ret = clk_prepare_enable(mtkd->clk);
607 		if (ret)
608 			return ret;
609 	}
610 
611 	return 0;
612 }
613 #endif /* CONFIG_PM_SLEEP */
614 
615 #ifdef CONFIG_PM
616 static int mtk_uart_apdma_runtime_suspend(struct device *dev)
617 {
618 	struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
619 
620 	clk_disable_unprepare(mtkd->clk);
621 
622 	return 0;
623 }
624 
625 static int mtk_uart_apdma_runtime_resume(struct device *dev)
626 {
627 	struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
628 
629 	return clk_prepare_enable(mtkd->clk);
630 }
631 #endif /* CONFIG_PM */
632 
633 static const struct dev_pm_ops mtk_uart_apdma_pm_ops = {
634 	SET_SYSTEM_SLEEP_PM_OPS(mtk_uart_apdma_suspend, mtk_uart_apdma_resume)
635 	SET_RUNTIME_PM_OPS(mtk_uart_apdma_runtime_suspend,
636 			   mtk_uart_apdma_runtime_resume, NULL)
637 };
638 
639 static struct platform_driver mtk_uart_apdma_driver = {
640 	.probe	= mtk_uart_apdma_probe,
641 	.remove	= mtk_uart_apdma_remove,
642 	.driver = {
643 		.name		= KBUILD_MODNAME,
644 		.pm		= &mtk_uart_apdma_pm_ops,
645 		.of_match_table = of_match_ptr(mtk_uart_apdma_match),
646 	},
647 };
648 
649 module_platform_driver(mtk_uart_apdma_driver);
650 
651 MODULE_DESCRIPTION("MediaTek UART APDMA Controller Driver");
652 MODULE_AUTHOR("Long Cheng <long.cheng@mediatek.com>");
653 MODULE_LICENSE("GPL v2");
654