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_dma.h>
20 #include <linux/platform_device.h>
21 #include <linux/pm_runtime.h>
22 #include <linux/slab.h>
23 #include <linux/spinlock.h>
24 
25 #include "../virt-dma.h"
26 
27 /* The default number of virtual channel */
28 #define MTK_UART_APDMA_NR_VCHANS	8
29 
30 #define VFF_EN_B		BIT(0)
31 #define VFF_STOP_B		BIT(0)
32 #define VFF_FLUSH_B		BIT(0)
33 #define VFF_4G_EN_B		BIT(0)
34 /* rx valid size >=  vff thre */
35 #define VFF_RX_INT_EN_B		(BIT(0) | BIT(1))
36 /* tx left size >= vff thre */
37 #define VFF_TX_INT_EN_B		BIT(0)
38 #define VFF_WARM_RST_B		BIT(0)
39 #define VFF_RX_INT_CLR_B	(BIT(0) | BIT(1))
40 #define VFF_TX_INT_CLR_B	0
41 #define VFF_STOP_CLR_B		0
42 #define VFF_EN_CLR_B		0
43 #define VFF_INT_EN_CLR_B	0
44 #define VFF_4G_SUPPORT_CLR_B	0
45 
46 /*
47  * interrupt trigger level for tx
48  * if threshold is n, no polling is required to start tx.
49  * otherwise need polling VFF_FLUSH.
50  */
51 #define VFF_TX_THRE(n)		(n)
52 /* interrupt trigger level for rx */
53 #define VFF_RX_THRE(n)		((n) * 3 / 4)
54 
55 #define VFF_RING_SIZE	0xffff
56 /* invert this bit when wrap ring head again */
57 #define VFF_RING_WRAP	0x10000
58 
59 #define VFF_INT_FLAG		0x00
60 #define VFF_INT_EN		0x04
61 #define VFF_EN			0x08
62 #define VFF_RST			0x0c
63 #define VFF_STOP		0x10
64 #define VFF_FLUSH		0x14
65 #define VFF_ADDR		0x1c
66 #define VFF_LEN			0x24
67 #define VFF_THRE		0x28
68 #define VFF_WPT			0x2c
69 #define VFF_RPT			0x30
70 /* TX: the buffer size HW can read. RX: the buffer size SW can read. */
71 #define VFF_VALID_SIZE		0x3c
72 /* TX: the buffer size SW can write. RX: the buffer size HW can write. */
73 #define VFF_LEFT_SIZE		0x40
74 #define VFF_DEBUG_STATUS	0x50
75 #define VFF_4G_SUPPORT		0x54
76 
77 struct mtk_uart_apdmadev {
78 	struct dma_device ddev;
79 	struct clk *clk;
80 	bool support_33bits;
81 	unsigned int dma_requests;
82 };
83 
84 struct mtk_uart_apdma_desc {
85 	struct virt_dma_desc vd;
86 
87 	dma_addr_t addr;
88 	unsigned int avail_len;
89 };
90 
91 struct mtk_chan {
92 	struct virt_dma_chan vc;
93 	struct dma_slave_config	cfg;
94 	struct mtk_uart_apdma_desc *desc;
95 	enum dma_transfer_direction dir;
96 
97 	void __iomem *base;
98 	unsigned int irq;
99 
100 	unsigned int rx_status;
101 };
102 
103 static inline struct mtk_uart_apdmadev *
104 to_mtk_uart_apdma_dev(struct dma_device *d)
105 {
106 	return container_of(d, struct mtk_uart_apdmadev, ddev);
107 }
108 
109 static inline struct mtk_chan *to_mtk_uart_apdma_chan(struct dma_chan *c)
110 {
111 	return container_of(c, struct mtk_chan, vc.chan);
112 }
113 
114 static inline struct mtk_uart_apdma_desc *to_mtk_uart_apdma_desc
115 	(struct dma_async_tx_descriptor *t)
116 {
117 	return container_of(t, struct mtk_uart_apdma_desc, vd.tx);
118 }
119 
120 static void mtk_uart_apdma_write(struct mtk_chan *c,
121 			       unsigned int reg, unsigned int val)
122 {
123 	writel(val, c->base + reg);
124 }
125 
126 static unsigned int mtk_uart_apdma_read(struct mtk_chan *c, unsigned int reg)
127 {
128 	return readl(c->base + reg);
129 }
130 
131 static void mtk_uart_apdma_desc_free(struct virt_dma_desc *vd)
132 {
133 	kfree(container_of(vd, struct mtk_uart_apdma_desc, vd));
134 }
135 
136 static void mtk_uart_apdma_start_tx(struct mtk_chan *c)
137 {
138 	struct mtk_uart_apdmadev *mtkd =
139 				to_mtk_uart_apdma_dev(c->vc.chan.device);
140 	struct mtk_uart_apdma_desc *d = c->desc;
141 	unsigned int wpt, vff_sz;
142 
143 	vff_sz = c->cfg.dst_port_window_size;
144 	if (!mtk_uart_apdma_read(c, VFF_LEN)) {
145 		mtk_uart_apdma_write(c, VFF_ADDR, d->addr);
146 		mtk_uart_apdma_write(c, VFF_LEN, vff_sz);
147 		mtk_uart_apdma_write(c, VFF_THRE, VFF_TX_THRE(vff_sz));
148 		mtk_uart_apdma_write(c, VFF_WPT, 0);
149 		mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);
150 
151 		if (mtkd->support_33bits)
152 			mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_EN_B);
153 	}
154 
155 	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_B);
156 	if (mtk_uart_apdma_read(c, VFF_EN) != VFF_EN_B)
157 		dev_err(c->vc.chan.device->dev, "Enable TX fail\n");
158 
159 	if (!mtk_uart_apdma_read(c, VFF_LEFT_SIZE)) {
160 		mtk_uart_apdma_write(c, VFF_INT_EN, VFF_TX_INT_EN_B);
161 		return;
162 	}
163 
164 	wpt = mtk_uart_apdma_read(c, VFF_WPT);
165 
166 	wpt += c->desc->avail_len;
167 	if ((wpt & VFF_RING_SIZE) == vff_sz)
168 		wpt = (wpt & VFF_RING_WRAP) ^ VFF_RING_WRAP;
169 
170 	/* Let DMA start moving data */
171 	mtk_uart_apdma_write(c, VFF_WPT, wpt);
172 
173 	/* HW auto set to 0 when left size >= threshold */
174 	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_TX_INT_EN_B);
175 	if (!mtk_uart_apdma_read(c, VFF_FLUSH))
176 		mtk_uart_apdma_write(c, VFF_FLUSH, VFF_FLUSH_B);
177 }
178 
179 static void mtk_uart_apdma_start_rx(struct mtk_chan *c)
180 {
181 	struct mtk_uart_apdmadev *mtkd =
182 				to_mtk_uart_apdma_dev(c->vc.chan.device);
183 	struct mtk_uart_apdma_desc *d = c->desc;
184 	unsigned int vff_sz;
185 
186 	vff_sz = c->cfg.src_port_window_size;
187 	if (!mtk_uart_apdma_read(c, VFF_LEN)) {
188 		mtk_uart_apdma_write(c, VFF_ADDR, d->addr);
189 		mtk_uart_apdma_write(c, VFF_LEN, vff_sz);
190 		mtk_uart_apdma_write(c, VFF_THRE, VFF_RX_THRE(vff_sz));
191 		mtk_uart_apdma_write(c, VFF_RPT, 0);
192 		mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);
193 
194 		if (mtkd->support_33bits)
195 			mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_EN_B);
196 	}
197 
198 	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_RX_INT_EN_B);
199 	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_B);
200 	if (mtk_uart_apdma_read(c, VFF_EN) != VFF_EN_B)
201 		dev_err(c->vc.chan.device->dev, "Enable RX fail\n");
202 }
203 
204 static void mtk_uart_apdma_tx_handler(struct mtk_chan *c)
205 {
206 	mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);
207 	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
208 	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);
209 }
210 
211 static void mtk_uart_apdma_rx_handler(struct mtk_chan *c)
212 {
213 	struct mtk_uart_apdma_desc *d = c->desc;
214 	unsigned int len, wg, rg;
215 	int cnt;
216 
217 	mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);
218 
219 	if (!mtk_uart_apdma_read(c, VFF_VALID_SIZE))
220 		return;
221 
222 	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);
223 	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
224 
225 	len = c->cfg.src_port_window_size;
226 	rg = mtk_uart_apdma_read(c, VFF_RPT);
227 	wg = mtk_uart_apdma_read(c, VFF_WPT);
228 	cnt = (wg & VFF_RING_SIZE) - (rg & VFF_RING_SIZE);
229 
230 	/*
231 	 * The buffer is ring buffer. If wrap bit different,
232 	 * represents the start of the next cycle for WPT
233 	 */
234 	if ((rg ^ wg) & VFF_RING_WRAP)
235 		cnt += len;
236 
237 	c->rx_status = d->avail_len - cnt;
238 	mtk_uart_apdma_write(c, VFF_RPT, wg);
239 }
240 
241 static void mtk_uart_apdma_chan_complete_handler(struct mtk_chan *c)
242 {
243 	struct mtk_uart_apdma_desc *d = c->desc;
244 
245 	if (d) {
246 		list_del(&d->vd.node);
247 		vchan_cookie_complete(&d->vd);
248 		c->desc = NULL;
249 	}
250 }
251 
252 static irqreturn_t mtk_uart_apdma_irq_handler(int irq, void *dev_id)
253 {
254 	struct dma_chan *chan = (struct dma_chan *)dev_id;
255 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
256 	unsigned long flags;
257 
258 	spin_lock_irqsave(&c->vc.lock, flags);
259 	if (c->dir == DMA_DEV_TO_MEM)
260 		mtk_uart_apdma_rx_handler(c);
261 	else if (c->dir == DMA_MEM_TO_DEV)
262 		mtk_uart_apdma_tx_handler(c);
263 	mtk_uart_apdma_chan_complete_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_resume_and_get(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 		goto err_pm;
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 		ret = -EINVAL;
297 		goto err_pm;
298 	}
299 
300 	if (mtkd->support_33bits)
301 		mtk_uart_apdma_write(c, VFF_4G_SUPPORT, VFF_4G_SUPPORT_CLR_B);
302 
303 err_pm:
304 	pm_runtime_put_noidle(mtkd->ddev.dev);
305 	return ret;
306 }
307 
308 static void mtk_uart_apdma_free_chan_resources(struct dma_chan *chan)
309 {
310 	struct mtk_uart_apdmadev *mtkd = to_mtk_uart_apdma_dev(chan->device);
311 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
312 
313 	free_irq(c->irq, chan);
314 
315 	tasklet_kill(&c->vc.task);
316 
317 	vchan_free_chan_resources(&c->vc);
318 
319 	pm_runtime_put_sync(mtkd->ddev.dev);
320 }
321 
322 static enum dma_status mtk_uart_apdma_tx_status(struct dma_chan *chan,
323 					 dma_cookie_t cookie,
324 					 struct dma_tx_state *txstate)
325 {
326 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
327 	enum dma_status ret;
328 
329 	ret = dma_cookie_status(chan, cookie, txstate);
330 	if (!txstate)
331 		return ret;
332 
333 	dma_set_residue(txstate, c->rx_status);
334 
335 	return ret;
336 }
337 
338 /*
339  * dmaengine_prep_slave_single will call the function. and sglen is 1.
340  * 8250 uart using one ring buffer, and deal with one sg.
341  */
342 static struct dma_async_tx_descriptor *mtk_uart_apdma_prep_slave_sg
343 	(struct dma_chan *chan, struct scatterlist *sgl,
344 	unsigned int sglen, enum dma_transfer_direction dir,
345 	unsigned long tx_flags, void *context)
346 {
347 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
348 	struct mtk_uart_apdma_desc *d;
349 
350 	if (!is_slave_direction(dir) || sglen != 1)
351 		return NULL;
352 
353 	/* Now allocate and setup the descriptor */
354 	d = kzalloc(sizeof(*d), GFP_NOWAIT);
355 	if (!d)
356 		return NULL;
357 
358 	d->avail_len = sg_dma_len(sgl);
359 	d->addr = sg_dma_address(sgl);
360 	c->dir = dir;
361 
362 	return vchan_tx_prep(&c->vc, &d->vd, tx_flags);
363 }
364 
365 static void mtk_uart_apdma_issue_pending(struct dma_chan *chan)
366 {
367 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
368 	struct virt_dma_desc *vd;
369 	unsigned long flags;
370 
371 	spin_lock_irqsave(&c->vc.lock, flags);
372 	if (vchan_issue_pending(&c->vc) && !c->desc) {
373 		vd = vchan_next_desc(&c->vc);
374 		c->desc = to_mtk_uart_apdma_desc(&vd->tx);
375 
376 		if (c->dir == DMA_DEV_TO_MEM)
377 			mtk_uart_apdma_start_rx(c);
378 		else if (c->dir == DMA_MEM_TO_DEV)
379 			mtk_uart_apdma_start_tx(c);
380 	}
381 
382 	spin_unlock_irqrestore(&c->vc.lock, flags);
383 }
384 
385 static int mtk_uart_apdma_slave_config(struct dma_chan *chan,
386 				   struct dma_slave_config *config)
387 {
388 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
389 
390 	memcpy(&c->cfg, config, sizeof(*config));
391 
392 	return 0;
393 }
394 
395 static int mtk_uart_apdma_terminate_all(struct dma_chan *chan)
396 {
397 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
398 	unsigned long flags;
399 	unsigned int status;
400 	LIST_HEAD(head);
401 	int ret;
402 
403 	mtk_uart_apdma_write(c, VFF_FLUSH, VFF_FLUSH_B);
404 
405 	ret = readx_poll_timeout(readl, c->base + VFF_FLUSH,
406 			  status, status != VFF_FLUSH_B, 10, 100);
407 	if (ret)
408 		dev_err(c->vc.chan.device->dev, "flush: fail, status=0x%x\n",
409 			mtk_uart_apdma_read(c, VFF_DEBUG_STATUS));
410 
411 	/*
412 	 * Stop need 3 steps.
413 	 * 1. set stop to 1
414 	 * 2. wait en to 0
415 	 * 3. set stop as 0
416 	 */
417 	mtk_uart_apdma_write(c, VFF_STOP, VFF_STOP_B);
418 	ret = readx_poll_timeout(readl, c->base + VFF_EN,
419 			  status, !status, 10, 100);
420 	if (ret)
421 		dev_err(c->vc.chan.device->dev, "stop: fail, status=0x%x\n",
422 			mtk_uart_apdma_read(c, VFF_DEBUG_STATUS));
423 
424 	mtk_uart_apdma_write(c, VFF_STOP, VFF_STOP_CLR_B);
425 	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
426 
427 	if (c->dir == DMA_DEV_TO_MEM)
428 		mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_RX_INT_CLR_B);
429 	else if (c->dir == DMA_MEM_TO_DEV)
430 		mtk_uart_apdma_write(c, VFF_INT_FLAG, VFF_TX_INT_CLR_B);
431 
432 	synchronize_irq(c->irq);
433 
434 	spin_lock_irqsave(&c->vc.lock, flags);
435 	vchan_get_all_descriptors(&c->vc, &head);
436 	spin_unlock_irqrestore(&c->vc.lock, flags);
437 
438 	vchan_dma_desc_free_list(&c->vc, &head);
439 
440 	return 0;
441 }
442 
443 static int mtk_uart_apdma_device_pause(struct dma_chan *chan)
444 {
445 	struct mtk_chan *c = to_mtk_uart_apdma_chan(chan);
446 	unsigned long flags;
447 
448 	spin_lock_irqsave(&c->vc.lock, flags);
449 
450 	mtk_uart_apdma_write(c, VFF_EN, VFF_EN_CLR_B);
451 	mtk_uart_apdma_write(c, VFF_INT_EN, VFF_INT_EN_CLR_B);
452 
453 	spin_unlock_irqrestore(&c->vc.lock, flags);
454 	synchronize_irq(c->irq);
455 
456 	return 0;
457 }
458 
459 static void mtk_uart_apdma_free(struct mtk_uart_apdmadev *mtkd)
460 {
461 	while (!list_empty(&mtkd->ddev.channels)) {
462 		struct mtk_chan *c = list_first_entry(&mtkd->ddev.channels,
463 			struct mtk_chan, vc.chan.device_node);
464 
465 		list_del(&c->vc.chan.device_node);
466 		tasklet_kill(&c->vc.task);
467 	}
468 }
469 
470 static const struct of_device_id mtk_uart_apdma_match[] = {
471 	{ .compatible = "mediatek,mt6577-uart-dma", },
472 	{ /* sentinel */ },
473 };
474 MODULE_DEVICE_TABLE(of, mtk_uart_apdma_match);
475 
476 static int mtk_uart_apdma_probe(struct platform_device *pdev)
477 {
478 	struct device_node *np = pdev->dev.of_node;
479 	struct mtk_uart_apdmadev *mtkd;
480 	int bit_mask = 32, rc;
481 	struct mtk_chan *c;
482 	unsigned int i;
483 
484 	mtkd = devm_kzalloc(&pdev->dev, sizeof(*mtkd), GFP_KERNEL);
485 	if (!mtkd)
486 		return -ENOMEM;
487 
488 	mtkd->clk = devm_clk_get(&pdev->dev, NULL);
489 	if (IS_ERR(mtkd->clk)) {
490 		dev_err(&pdev->dev, "No clock specified\n");
491 		rc = PTR_ERR(mtkd->clk);
492 		return rc;
493 	}
494 
495 	if (of_property_read_bool(np, "mediatek,dma-33bits"))
496 		mtkd->support_33bits = true;
497 
498 	if (mtkd->support_33bits)
499 		bit_mask = 33;
500 
501 	rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(bit_mask));
502 	if (rc)
503 		return rc;
504 
505 	dma_cap_set(DMA_SLAVE, mtkd->ddev.cap_mask);
506 	mtkd->ddev.device_alloc_chan_resources =
507 				mtk_uart_apdma_alloc_chan_resources;
508 	mtkd->ddev.device_free_chan_resources =
509 				mtk_uart_apdma_free_chan_resources;
510 	mtkd->ddev.device_tx_status = mtk_uart_apdma_tx_status;
511 	mtkd->ddev.device_issue_pending = mtk_uart_apdma_issue_pending;
512 	mtkd->ddev.device_prep_slave_sg = mtk_uart_apdma_prep_slave_sg;
513 	mtkd->ddev.device_config = mtk_uart_apdma_slave_config;
514 	mtkd->ddev.device_pause = mtk_uart_apdma_device_pause;
515 	mtkd->ddev.device_terminate_all = mtk_uart_apdma_terminate_all;
516 	mtkd->ddev.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
517 	mtkd->ddev.dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
518 	mtkd->ddev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
519 	mtkd->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
520 	mtkd->ddev.dev = &pdev->dev;
521 	INIT_LIST_HEAD(&mtkd->ddev.channels);
522 
523 	mtkd->dma_requests = MTK_UART_APDMA_NR_VCHANS;
524 	if (of_property_read_u32(np, "dma-requests", &mtkd->dma_requests)) {
525 		dev_info(&pdev->dev,
526 			 "Using %u as missing dma-requests property\n",
527 			 MTK_UART_APDMA_NR_VCHANS);
528 	}
529 
530 	for (i = 0; i < mtkd->dma_requests; i++) {
531 		c = devm_kzalloc(mtkd->ddev.dev, sizeof(*c), GFP_KERNEL);
532 		if (!c) {
533 			rc = -ENODEV;
534 			goto err_no_dma;
535 		}
536 
537 		c->base = devm_platform_ioremap_resource(pdev, i);
538 		if (IS_ERR(c->base)) {
539 			rc = PTR_ERR(c->base);
540 			goto err_no_dma;
541 		}
542 		c->vc.desc_free = mtk_uart_apdma_desc_free;
543 		vchan_init(&c->vc, &mtkd->ddev);
544 
545 		rc = platform_get_irq(pdev, i);
546 		if (rc < 0)
547 			goto err_no_dma;
548 		c->irq = rc;
549 	}
550 
551 	pm_runtime_enable(&pdev->dev);
552 
553 	rc = dma_async_device_register(&mtkd->ddev);
554 	if (rc)
555 		goto rpm_disable;
556 
557 	platform_set_drvdata(pdev, mtkd);
558 
559 	/* Device-tree DMA controller registration */
560 	rc = of_dma_controller_register(np, of_dma_xlate_by_chan_id, mtkd);
561 	if (rc)
562 		goto dma_remove;
563 
564 	return rc;
565 
566 dma_remove:
567 	dma_async_device_unregister(&mtkd->ddev);
568 rpm_disable:
569 	pm_runtime_disable(&pdev->dev);
570 err_no_dma:
571 	mtk_uart_apdma_free(mtkd);
572 	return rc;
573 }
574 
575 static int mtk_uart_apdma_remove(struct platform_device *pdev)
576 {
577 	struct mtk_uart_apdmadev *mtkd = platform_get_drvdata(pdev);
578 
579 	of_dma_controller_free(pdev->dev.of_node);
580 
581 	mtk_uart_apdma_free(mtkd);
582 
583 	dma_async_device_unregister(&mtkd->ddev);
584 
585 	pm_runtime_disable(&pdev->dev);
586 
587 	return 0;
588 }
589 
590 #ifdef CONFIG_PM_SLEEP
591 static int mtk_uart_apdma_suspend(struct device *dev)
592 {
593 	struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
594 
595 	if (!pm_runtime_suspended(dev))
596 		clk_disable_unprepare(mtkd->clk);
597 
598 	return 0;
599 }
600 
601 static int mtk_uart_apdma_resume(struct device *dev)
602 {
603 	int ret;
604 	struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
605 
606 	if (!pm_runtime_suspended(dev)) {
607 		ret = clk_prepare_enable(mtkd->clk);
608 		if (ret)
609 			return ret;
610 	}
611 
612 	return 0;
613 }
614 #endif /* CONFIG_PM_SLEEP */
615 
616 #ifdef CONFIG_PM
617 static int mtk_uart_apdma_runtime_suspend(struct device *dev)
618 {
619 	struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
620 
621 	clk_disable_unprepare(mtkd->clk);
622 
623 	return 0;
624 }
625 
626 static int mtk_uart_apdma_runtime_resume(struct device *dev)
627 {
628 	struct mtk_uart_apdmadev *mtkd = dev_get_drvdata(dev);
629 
630 	return clk_prepare_enable(mtkd->clk);
631 }
632 #endif /* CONFIG_PM */
633 
634 static const struct dev_pm_ops mtk_uart_apdma_pm_ops = {
635 	SET_SYSTEM_SLEEP_PM_OPS(mtk_uart_apdma_suspend, mtk_uart_apdma_resume)
636 	SET_RUNTIME_PM_OPS(mtk_uart_apdma_runtime_suspend,
637 			   mtk_uart_apdma_runtime_resume, NULL)
638 };
639 
640 static struct platform_driver mtk_uart_apdma_driver = {
641 	.probe	= mtk_uart_apdma_probe,
642 	.remove	= mtk_uart_apdma_remove,
643 	.driver = {
644 		.name		= KBUILD_MODNAME,
645 		.pm		= &mtk_uart_apdma_pm_ops,
646 		.of_match_table = of_match_ptr(mtk_uart_apdma_match),
647 	},
648 };
649 
650 module_platform_driver(mtk_uart_apdma_driver);
651 
652 MODULE_DESCRIPTION("MediaTek UART APDMA Controller Driver");
653 MODULE_AUTHOR("Long Cheng <long.cheng@mediatek.com>");
654 MODULE_LICENSE("GPL v2");
655