1// SPDX-License-Identifier: GPL-2.0
2//
3// Loongson ALSA SoC Platform (DMA) driver
4//
5// Copyright (C) 2023 Loongson Technology Corporation Limited
6// Author: Yingkun Meng <mengyingkun@loongson.cn>
7//
8
9#include <linux/module.h>
10#include <linux/io-64-nonatomic-lo-hi.h>
11#include <linux/delay.h>
12#include <linux/pm_runtime.h>
13#include <linux/dma-mapping.h>
14#include <sound/soc.h>
15#include <sound/pcm.h>
16#include <sound/pcm_params.h>
17#include "loongson_i2s.h"
18
19/* DMA dma_order Register */
20#define DMA_ORDER_STOP          (1 << 4) /* DMA stop */
21#define DMA_ORDER_START         (1 << 3) /* DMA start */
22#define DMA_ORDER_ASK_VALID     (1 << 2) /* DMA ask valid flag */
23#define DMA_ORDER_AXI_UNCO      (1 << 1) /* Uncache access */
24#define DMA_ORDER_ADDR_64       (1 << 0) /* 64bits address support */
25
26#define DMA_ORDER_ASK_MASK      (~0x1fUL) /* Ask addr mask */
27#define DMA_ORDER_CTRL_MASK     (0x0fUL)  /* Control mask  */
28
29/*
30 * DMA registers descriptor.
31 */
32struct loongson_dma_desc {
33	u32 order;		/* Next descriptor address register */
34	u32 saddr;		/* Source address register */
35	u32 daddr;		/* Device address register */
36	u32 length;		/* Total length register */
37	u32 step_length;	/* Memory stride register */
38	u32 step_times;		/* Repeat time register */
39	u32 cmd;		/* Command register */
40	u32 stats;		/* Status register */
41	u32 order_hi;		/* Next descriptor high address register */
42	u32 saddr_hi;		/* High source address register */
43	u32 res[6];		/* Reserved */
44} __packed;
45
46struct loongson_runtime_data {
47	struct loongson_dma_data *dma_data;
48
49	struct loongson_dma_desc *dma_desc_arr;
50	dma_addr_t dma_desc_arr_phy;
51	int dma_desc_arr_size;
52
53	struct loongson_dma_desc *dma_pos_desc;
54	dma_addr_t dma_pos_desc_phy;
55};
56
57static const struct snd_pcm_hardware ls_pcm_hardware = {
58	.info = SNDRV_PCM_INFO_MMAP |
59		SNDRV_PCM_INFO_INTERLEAVED |
60		SNDRV_PCM_INFO_MMAP_VALID |
61		SNDRV_PCM_INFO_RESUME |
62		SNDRV_PCM_INFO_PAUSE,
63	.formats = (SNDRV_PCM_FMTBIT_S8 |
64		SNDRV_PCM_FMTBIT_S16_LE |
65		SNDRV_PCM_FMTBIT_S20_3LE |
66		SNDRV_PCM_FMTBIT_S24_LE),
67	.period_bytes_min = 128,
68	.period_bytes_max = 128 * 1024,
69	.periods_min = 1,
70	.periods_max = PAGE_SIZE / sizeof(struct loongson_dma_desc),
71	.buffer_bytes_max = 1024 * 1024,
72};
73
74static struct
75loongson_dma_desc *dma_desc_save(struct loongson_runtime_data *prtd)
76{
77	void __iomem *order_reg = prtd->dma_data->order_addr;
78	u64 val;
79
80	val = (u64)prtd->dma_pos_desc_phy & DMA_ORDER_ASK_MASK;
81	val |= (readq(order_reg) & DMA_ORDER_CTRL_MASK);
82	val |= DMA_ORDER_ASK_VALID;
83	writeq(val, order_reg);
84
85	while (readl(order_reg) & DMA_ORDER_ASK_VALID)
86		udelay(2);
87
88	return prtd->dma_pos_desc;
89}
90
91static int loongson_pcm_trigger(struct snd_soc_component *component,
92				struct snd_pcm_substream *substream, int cmd)
93{
94	struct loongson_runtime_data *prtd = substream->runtime->private_data;
95	struct device *dev = substream->pcm->card->dev;
96	void __iomem *order_reg = prtd->dma_data->order_addr;
97	u64 val;
98	int ret = 0;
99
100	switch (cmd) {
101	case SNDRV_PCM_TRIGGER_START:
102	case SNDRV_PCM_TRIGGER_RESUME:
103	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
104		val = prtd->dma_pos_desc_phy & DMA_ORDER_ASK_MASK;
105		if (dev->coherent_dma_mask == DMA_BIT_MASK(64))
106			val |= DMA_ORDER_ADDR_64;
107		else
108			val &= ~DMA_ORDER_ADDR_64;
109		val |= (readq(order_reg) & DMA_ORDER_CTRL_MASK);
110		val |= DMA_ORDER_START;
111		writeq(val, order_reg);
112
113		while ((readl(order_reg) & DMA_ORDER_START))
114			udelay(2);
115		break;
116	case SNDRV_PCM_TRIGGER_STOP:
117	case SNDRV_PCM_TRIGGER_SUSPEND:
118	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
119		dma_desc_save(prtd);
120
121		/* dma stop */
122		val = readq(order_reg) | DMA_ORDER_STOP;
123		writeq(val, order_reg);
124		udelay(1000);
125
126		break;
127	default:
128		dev_err(dev, "Invalid pcm trigger operation\n");
129		return -EINVAL;
130	}
131
132	return ret;
133}
134
135static int loongson_pcm_hw_params(struct snd_soc_component *component,
136				  struct snd_pcm_substream *substream,
137				  struct snd_pcm_hw_params *params)
138{
139	struct snd_pcm_runtime *runtime = substream->runtime;
140	struct device *dev = substream->pcm->card->dev;
141	struct loongson_runtime_data *prtd = runtime->private_data;
142	size_t buf_len = params_buffer_bytes(params);
143	size_t period_len = params_period_bytes(params);
144	dma_addr_t order_addr, mem_addr;
145	struct loongson_dma_desc *desc;
146	u32 num_periods;
147	int i;
148
149	if (buf_len % period_len) {
150		dev_err(dev, "buf len not multiply of period len\n");
151		return -EINVAL;
152	}
153
154	num_periods = buf_len / period_len;
155	if (!num_periods || num_periods > prtd->dma_desc_arr_size) {
156		dev_err(dev, "dma data too small or too big\n");
157		return -EINVAL;
158	}
159
160	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
161	runtime->dma_bytes = buf_len;
162
163	/* initialize dma descriptor array */
164	mem_addr = runtime->dma_addr;
165	order_addr = prtd->dma_desc_arr_phy;
166	for (i = 0; i < num_periods; i++) {
167		desc = &prtd->dma_desc_arr[i];
168
169		/* next descriptor physical address */
170		order_addr += sizeof(*desc);
171		desc->order = lower_32_bits(order_addr | BIT(0));
172		desc->order_hi = upper_32_bits(order_addr);
173
174		desc->saddr = lower_32_bits(mem_addr);
175		desc->saddr_hi = upper_32_bits(mem_addr);
176		desc->daddr = prtd->dma_data->dev_addr;
177
178		desc->cmd = BIT(0);
179		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
180			desc->cmd |= BIT(12);
181
182		desc->length = period_len >> 2;
183		desc->step_length = 0;
184		desc->step_times = 1;
185
186		mem_addr += period_len;
187	}
188	desc = &prtd->dma_desc_arr[num_periods - 1];
189	desc->order = lower_32_bits(prtd->dma_desc_arr_phy | BIT(0));
190	desc->order_hi = upper_32_bits(prtd->dma_desc_arr_phy);
191
192	/* init position descriptor */
193	*prtd->dma_pos_desc = *prtd->dma_desc_arr;
194
195	return 0;
196}
197
198static snd_pcm_uframes_t
199loongson_pcm_pointer(struct snd_soc_component *component,
200		     struct snd_pcm_substream *substream)
201{
202	struct snd_pcm_runtime *runtime = substream->runtime;
203	struct loongson_runtime_data *prtd = runtime->private_data;
204	struct loongson_dma_desc *desc;
205	snd_pcm_uframes_t x;
206	u64 addr;
207
208	desc = dma_desc_save(prtd);
209	addr = ((u64)desc->saddr_hi << 32) | desc->saddr;
210
211	x = bytes_to_frames(runtime, addr - runtime->dma_addr);
212	if (x == runtime->buffer_size)
213		x = 0;
214	return x;
215}
216
217static irqreturn_t loongson_pcm_dma_irq(int irq, void *devid)
218{
219	struct snd_pcm_substream *substream = devid;
220
221	snd_pcm_period_elapsed(substream);
222	return IRQ_HANDLED;
223}
224
225static int loongson_pcm_open(struct snd_soc_component *component,
226			     struct snd_pcm_substream *substream)
227{
228	struct snd_pcm_runtime *runtime = substream->runtime;
229	struct snd_soc_pcm_runtime *rtd = substream->private_data;
230	struct snd_card *card = substream->pcm->card;
231	struct loongson_runtime_data *prtd;
232	struct loongson_dma_data *dma_data;
233	int ret;
234
235	/*
236	 * For mysterious reasons (and despite what the manual says)
237	 * playback samples are lost if the DMA count is not a multiple
238	 * of the DMA burst size.  Let's add a rule to enforce that.
239	 */
240	snd_pcm_hw_constraint_step(runtime, 0,
241				   SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 128);
242	snd_pcm_hw_constraint_step(runtime, 0,
243				   SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 128);
244	snd_pcm_hw_constraint_integer(substream->runtime,
245				      SNDRV_PCM_HW_PARAM_PERIODS);
246	snd_soc_set_runtime_hwparams(substream, &ls_pcm_hardware);
247
248	prtd = kzalloc(sizeof(*prtd), GFP_KERNEL);
249	if (!prtd)
250		return -ENOMEM;
251
252	prtd->dma_desc_arr = dma_alloc_coherent(card->dev, PAGE_SIZE,
253						&prtd->dma_desc_arr_phy,
254						GFP_KERNEL);
255	if (!prtd->dma_desc_arr) {
256		ret = -ENOMEM;
257		goto desc_err;
258	}
259	prtd->dma_desc_arr_size = PAGE_SIZE / sizeof(*prtd->dma_desc_arr);
260
261	prtd->dma_pos_desc = dma_alloc_coherent(card->dev,
262						sizeof(*prtd->dma_pos_desc),
263						&prtd->dma_pos_desc_phy,
264						GFP_KERNEL);
265	if (!prtd->dma_pos_desc) {
266		ret = -ENOMEM;
267		goto pos_err;
268	}
269
270	dma_data = snd_soc_dai_get_dma_data(asoc_rtd_to_cpu(rtd, 0), substream);
271	prtd->dma_data = dma_data;
272
273	substream->runtime->private_data = prtd;
274
275	return 0;
276pos_err:
277	dma_free_coherent(card->dev, PAGE_SIZE, prtd->dma_desc_arr,
278			  prtd->dma_desc_arr_phy);
279desc_err:
280	kfree(prtd);
281
282	return ret;
283}
284
285static int loongson_pcm_close(struct snd_soc_component *component,
286			      struct snd_pcm_substream *substream)
287{
288	struct snd_card *card = substream->pcm->card;
289	struct loongson_runtime_data *prtd = substream->runtime->private_data;
290
291	dma_free_coherent(card->dev, PAGE_SIZE, prtd->dma_desc_arr,
292			  prtd->dma_desc_arr_phy);
293
294	dma_free_coherent(card->dev, sizeof(*prtd->dma_pos_desc),
295			  prtd->dma_pos_desc, prtd->dma_pos_desc_phy);
296
297	kfree(prtd);
298	return 0;
299}
300
301static int loongson_pcm_mmap(struct snd_soc_component *component,
302			     struct snd_pcm_substream *substream,
303			     struct vm_area_struct *vma)
304{
305	return remap_pfn_range(vma, vma->vm_start,
306			substream->dma_buffer.addr >> PAGE_SHIFT,
307			vma->vm_end - vma->vm_start, vma->vm_page_prot);
308}
309
310static int loongson_pcm_new(struct snd_soc_component *component,
311			    struct snd_soc_pcm_runtime *rtd)
312{
313	struct snd_card *card = rtd->card->snd_card;
314	struct snd_pcm_substream *substream;
315	struct loongson_dma_data *dma_data;
316	unsigned int i;
317	int ret;
318
319	for_each_pcm_streams(i) {
320		substream = rtd->pcm->streams[i].substream;
321		if (!substream)
322			continue;
323
324		dma_data = snd_soc_dai_get_dma_data(asoc_rtd_to_cpu(rtd, 0),
325						    substream);
326		ret = devm_request_irq(card->dev, dma_data->irq,
327				       loongson_pcm_dma_irq,
328				       IRQF_TRIGGER_HIGH, LS_I2S_DRVNAME,
329				       substream);
330		if (ret < 0) {
331			dev_err(card->dev, "request irq for DMA failed\n");
332			return ret;
333		}
334	}
335
336	return snd_pcm_set_fixed_buffer_all(rtd->pcm, SNDRV_DMA_TYPE_DEV,
337					    card->dev,
338					    ls_pcm_hardware.buffer_bytes_max);
339}
340
341const struct snd_soc_component_driver loongson_i2s_component = {
342	.name		= LS_I2S_DRVNAME,
343	.open		= loongson_pcm_open,
344	.close		= loongson_pcm_close,
345	.hw_params	= loongson_pcm_hw_params,
346	.trigger	= loongson_pcm_trigger,
347	.pointer	= loongson_pcm_pointer,
348	.mmap		= loongson_pcm_mmap,
349	.pcm_construct	= loongson_pcm_new,
350};
351