1 files changed, 350 insertions, 0 deletions
diff --git a/sound/soc/loongson/loongson_dma.c b/sound/soc/loongson/loongson_dma.c
new file mode 100644
index 000000000000..8090662e8ff2
--- /dev/null
+++ b/sound/soc/loongson/loongson_dma.c
@@ -0,0 +1,350 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Loongson ALSA SoC Platform (DMA) driver
+//
+// Copyright (C) 2023 Loongson Technology Corporation Limited
+// Author: Yingkun Meng <mengyingkun@loongson.cn>
+//
+
+#include <linux/module.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/delay.h>
+#include <linux/pm_runtime.h>
+#include <linux/dma-mapping.h>
+#include <sound/soc.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include "loongson_i2s.h"
+
+/* DMA dma_order Register */
+#define DMA_ORDER_STOP          (1 << 4) /* DMA stop */
+#define DMA_ORDER_START         (1 << 3) /* DMA start */
+#define DMA_ORDER_ASK_VALID     (1 << 2) /* DMA ask valid flag */
+#define DMA_ORDER_AXI_UNCO      (1 << 1) /* Uncache access */
+#define DMA_ORDER_ADDR_64       (1 << 0) /* 64bits address support */
+
+#define DMA_ORDER_ASK_MASK      (~0x1fUL) /* Ask addr mask */
+#define DMA_ORDER_CTRL_MASK     (0x0fUL)  /* Control mask  */
+
+/*
+ * DMA registers descriptor.
+ */
+struct loongson_dma_desc {
+	u32 order;		/* Next descriptor address register */
+	u32 saddr;		/* Source address register */
+	u32 daddr;		/* Device address register */
+	u32 length;		/* Total length register */
+	u32 step_length;	/* Memory stride register */
+	u32 step_times;		/* Repeat time register */
+	u32 cmd;		/* Command register */
+	u32 stats;		/* Status register */
+	u32 order_hi;		/* Next descriptor high address register */
+	u32 saddr_hi;		/* High source address register */
+	u32 res[6];		/* Reserved */
+} __packed;
+
+struct loongson_runtime_data {
+	struct loongson_dma_data *dma_data;
+
+	struct loongson_dma_desc *dma_desc_arr;
+	dma_addr_t dma_desc_arr_phy;
+	int dma_desc_arr_size;
+
+	struct loongson_dma_desc *dma_pos_desc;
+	dma_addr_t dma_pos_desc_phy;
+};
+
+static const struct snd_pcm_hardware ls_pcm_hardware = {
+	.info = SNDRV_PCM_INFO_MMAP |
+		SNDRV_PCM_INFO_INTERLEAVED |
+		SNDRV_PCM_INFO_MMAP_VALID |
+		SNDRV_PCM_INFO_RESUME |
+		SNDRV_PCM_INFO_PAUSE,
+	.formats = (SNDRV_PCM_FMTBIT_S8 |
+		SNDRV_PCM_FMTBIT_S16_LE |
+		SNDRV_PCM_FMTBIT_S20_3LE |
+		SNDRV_PCM_FMTBIT_S24_LE),
+	.period_bytes_min = 128,
+	.period_bytes_max = 128 * 1024,
+	.periods_min = 1,
+	.periods_max = PAGE_SIZE / sizeof(struct loongson_dma_desc),
+	.buffer_bytes_max = 1024 * 1024,
+};
+
+static struct
+loongson_dma_desc *dma_desc_save(struct loongson_runtime_data *prtd)
+{
+	void __iomem *order_reg = prtd->dma_data->order_addr;
+	u64 val;
+
+	val = (u64)prtd->dma_pos_desc_phy & DMA_ORDER_ASK_MASK;
+	val |= (readq(order_reg) & DMA_ORDER_CTRL_MASK);
+	val |= DMA_ORDER_ASK_VALID;
+	writeq(val, order_reg);
+
+	while (readl(order_reg) & DMA_ORDER_ASK_VALID)
+		udelay(2);
+
+	return prtd->dma_pos_desc;
+}
+
+static int loongson_pcm_trigger(struct snd_soc_component *component,
+				struct snd_pcm_substream *substream, int cmd)
+{
+	struct loongson_runtime_data *prtd = substream->runtime->private_data;
+	struct device *dev = substream->pcm->card->dev;
+	void __iomem *order_reg = prtd->dma_data->order_addr;
+	u64 val;
+	int ret = 0;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		val = prtd->dma_pos_desc_phy & DMA_ORDER_ASK_MASK;
+		if (dev->coherent_dma_mask == DMA_BIT_MASK(64))
+			val |= DMA_ORDER_ADDR_64;
+		else
+			val &= ~DMA_ORDER_ADDR_64;
+		val |= (readq(order_reg) & DMA_ORDER_CTRL_MASK);
+		val |= DMA_ORDER_START;
+		writeq(val, order_reg);
+
+		while ((readl(order_reg) & DMA_ORDER_START))
+			udelay(2);
+		break;
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		dma_desc_save(prtd);
+
+		/* dma stop */
+		val = readq(order_reg) | DMA_ORDER_STOP;
+		writeq(val, order_reg);
+		udelay(1000);
+
+		break;
+	default:
+		dev_err(dev, "Invalid pcm trigger operation\n");
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static int loongson_pcm_hw_params(struct snd_soc_component *component,
+				  struct snd_pcm_substream *substream,
+				  struct snd_pcm_hw_params *params)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct device *dev = substream->pcm->card->dev;
+	struct loongson_runtime_data *prtd = runtime->private_data;
+	size_t buf_len = params_buffer_bytes(params);
+	size_t period_len = params_period_bytes(params);
+	dma_addr_t order_addr, mem_addr;
+	struct loongson_dma_desc *desc;
+	u32 num_periods;
+	int i;
+
+	if (buf_len % period_len) {
+		dev_err(dev, "buf len not multiply of period len\n");
+		return -EINVAL;
+	}
+
+	num_periods = buf_len / period_len;
+	if (!num_periods || num_periods > prtd->dma_desc_arr_size) {
+		dev_err(dev, "dma data too small or too big\n");
+		return -EINVAL;
+	}
+
+	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
+	runtime->dma_bytes = buf_len;
+
+	/* initialize dma descriptor array */
+	mem_addr = runtime->dma_addr;
+	order_addr = prtd->dma_desc_arr_phy;
+	for (i = 0; i < num_periods; i++) {
+		desc = &prtd->dma_desc_arr[i];
+
+		/* next descriptor physical address */
+		order_addr += sizeof(*desc);
+		desc->order = lower_32_bits(order_addr | BIT(0));
+		desc->order_hi = upper_32_bits(order_addr);
+
+		desc->saddr = lower_32_bits(mem_addr);
+		desc->saddr_hi = upper_32_bits(mem_addr);
+		desc->daddr = prtd->dma_data->dev_addr;
+
+		desc->cmd = BIT(0);
+		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+			desc->cmd |= BIT(12);
+
+		desc->length = period_len >> 2;
+		desc->step_length = 0;
+		desc->step_times = 1;
+
+		mem_addr += period_len;
+	}
+	desc = &prtd->dma_desc_arr[num_periods - 1];
+	desc->order = lower_32_bits(prtd->dma_desc_arr_phy | BIT(0));
+	desc->order_hi = upper_32_bits(prtd->dma_desc_arr_phy);
+
+	/* init position descriptor */
+	*prtd->dma_pos_desc = *prtd->dma_desc_arr;
+
+	return 0;
+}
+
+static snd_pcm_uframes_t
+loongson_pcm_pointer(struct snd_soc_component *component,
+		     struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct loongson_runtime_data *prtd = runtime->private_data;
+	struct loongson_dma_desc *desc;
+	snd_pcm_uframes_t x;
+	u64 addr;
+
+	desc = dma_desc_save(prtd);
+	addr = ((u64)desc->saddr_hi << 32) | desc->saddr;
+
+	x = bytes_to_frames(runtime, addr - runtime->dma_addr);
+	if (x == runtime->buffer_size)
+		x = 0;
+	return x;
+}
+
+static irqreturn_t loongson_pcm_dma_irq(int irq, void *devid)
+{
+	struct snd_pcm_substream *substream = devid;
+
+	snd_pcm_period_elapsed(substream);
+	return IRQ_HANDLED;
+}
+
+static int loongson_pcm_open(struct snd_soc_component *component,
+			     struct snd_pcm_substream *substream)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct snd_card *card = substream->pcm->card;
+	struct loongson_runtime_data *prtd;
+	struct loongson_dma_data *dma_data;
+	int ret;
+
+	/*
+	 * For mysterious reasons (and despite what the manual says)
+	 * playback samples are lost if the DMA count is not a multiple
+	 * of the DMA burst size.  Let's add a rule to enforce that.
+	 */
+	snd_pcm_hw_constraint_step(runtime, 0,
+				   SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 128);
+	snd_pcm_hw_constraint_step(runtime, 0,
+				   SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 128);
+	snd_pcm_hw_constraint_integer(substream->runtime,
+				      SNDRV_PCM_HW_PARAM_PERIODS);
+	snd_soc_set_runtime_hwparams(substream, &ls_pcm_hardware);
+
+	prtd = kzalloc(sizeof(*prtd), GFP_KERNEL);
+	if (!prtd)
+		return -ENOMEM;
+
+	prtd->dma_desc_arr = dma_alloc_coherent(card->dev, PAGE_SIZE,
+						&prtd->dma_desc_arr_phy,
+						GFP_KERNEL);
+	if (!prtd->dma_desc_arr) {
+		ret = -ENOMEM;
+		goto desc_err;
+	}
+	prtd->dma_desc_arr_size = PAGE_SIZE / sizeof(*prtd->dma_desc_arr);
+
+	prtd->dma_pos_desc = dma_alloc_coherent(card->dev,
+						sizeof(*prtd->dma_pos_desc),
+						&prtd->dma_pos_desc_phy,
+						GFP_KERNEL);
+	if (!prtd->dma_pos_desc) {
+		ret = -ENOMEM;
+		goto pos_err;
+	}
+
+	dma_data = snd_soc_dai_get_dma_data(snd_soc_rtd_to_cpu(rtd, 0), substream);
+	prtd->dma_data = dma_data;
+
+	substream->runtime->private_data = prtd;
+
+	return 0;
+pos_err:
+	dma_free_coherent(card->dev, PAGE_SIZE, prtd->dma_desc_arr,
+			  prtd->dma_desc_arr_phy);
+desc_err:
+	kfree(prtd);
+
+	return ret;
+}
+
+static int loongson_pcm_close(struct snd_soc_component *component,
+			      struct snd_pcm_substream *substream)
+{
+	struct snd_card *card = substream->pcm->card;
+	struct loongson_runtime_data *prtd = substream->runtime->private_data;
+
+	dma_free_coherent(card->dev, PAGE_SIZE, prtd->dma_desc_arr,
+			  prtd->dma_desc_arr_phy);
+
+	dma_free_coherent(card->dev, sizeof(*prtd->dma_pos_desc),
+			  prtd->dma_pos_desc, prtd->dma_pos_desc_phy);
+
+	kfree(prtd);
+	return 0;
+}
+
+static int loongson_pcm_mmap(struct snd_soc_component *component,
+			     struct snd_pcm_substream *substream,
+			     struct vm_area_struct *vma)
+{
+	return remap_pfn_range(vma, vma->vm_start,
+			substream->dma_buffer.addr >> PAGE_SHIFT,
+			vma->vm_end - vma->vm_start, vma->vm_page_prot);
+}
+
+static int loongson_pcm_new(struct snd_soc_component *component,
+			    struct snd_soc_pcm_runtime *rtd)
+{
+	struct snd_card *card = rtd->card->snd_card;
+	struct snd_pcm_substream *substream;
+	struct loongson_dma_data *dma_data;
+	unsigned int i;
+	int ret;
+
+	for_each_pcm_streams(i) {
+		substream = rtd->pcm->streams[i].substream;
+		if (!substream)
+			continue;
+
+		dma_data = snd_soc_dai_get_dma_data(snd_soc_rtd_to_cpu(rtd, 0),
+						    substream);
+		ret = devm_request_irq(card->dev, dma_data->irq,
+				       loongson_pcm_dma_irq,
+				       IRQF_TRIGGER_HIGH, LS_I2S_DRVNAME,
+				       substream);
+		if (ret < 0) {
+			dev_err(card->dev, "request irq for DMA failed\n");
+			return ret;
+		}
+	}
+
+	return snd_pcm_set_fixed_buffer_all(rtd->pcm, SNDRV_DMA_TYPE_DEV,
+					    card->dev,
+					    ls_pcm_hardware.buffer_bytes_max);
+}
+
+const struct snd_soc_component_driver loongson_i2s_component = {
+	.name		= LS_I2S_DRVNAME,
+	.open		= loongson_pcm_open,
+	.close		= loongson_pcm_close,
+	.hw_params	= loongson_pcm_hw_params,
+	.trigger	= loongson_pcm_trigger,
+	.pointer	= loongson_pcm_pointer,
+	.mmap		= loongson_pcm_mmap,
+	.pcm_construct	= loongson_pcm_new,
+};