ASoC: fsl_rpmsg: Add CPU DAI driver for audio base on rpmsg

This is a cpu dai driver for rpmsg audio use case,
which is mainly used for getting the user's configuration
from devicetree and configure the clocks which is used by
Cortex-M core.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>

sound/soc/fsl/Kconfig

@@ -115,6 +115,13 @@ config SND_SOC_FSL_AUD2HTX
 config SND_SOC_FSL_UTILS
 	tristate
 
+config SND_SOC_FSL_RPMSG
+	tristate "Audio Base on RPMSG support"
+	help
+	  Say Y if you want to add rpmsg audio support for the Freescale CPUs.
+	  This option is only useful for out-of-tree drivers since
+	  in-tree drivers select it automatically.
+
 config SND_SOC_IMX_PCM_DMA
 	tristate
 	select SND_SOC_GENERIC_DMAENGINE_PCM

sound/soc/fsl/Makefile

@@ -27,6 +27,7 @@ snd-soc-fsl-mqs-objs := fsl_mqs.o
 snd-soc-fsl-easrc-objs := fsl_easrc.o
 snd-soc-fsl-xcvr-objs := fsl_xcvr.o
 snd-soc-fsl-aud2htx-objs := fsl_aud2htx.o
+snd-soc-fsl-rpmsg-objs := fsl_rpmsg.o
 
 obj-$(CONFIG_SND_SOC_FSL_AUDMIX) += snd-soc-fsl-audmix.o
 obj-$(CONFIG_SND_SOC_FSL_ASOC_CARD) += snd-soc-fsl-asoc-card.o
@@ -42,6 +43,7 @@ obj-$(CONFIG_SND_SOC_FSL_EASRC) += snd-soc-fsl-easrc.o
 obj-$(CONFIG_SND_SOC_POWERPC_DMA) += snd-soc-fsl-dma.o
 obj-$(CONFIG_SND_SOC_FSL_XCVR) += snd-soc-fsl-xcvr.o
 obj-$(CONFIG_SND_SOC_FSL_AUD2HTX) += snd-soc-fsl-aud2htx.o
+obj-$(CONFIG_SND_SOC_FSL_RPMSG) += snd-soc-fsl-rpmsg.o
 
 # MPC5200 Platform Support
 obj-$(CONFIG_SND_MPC52xx_DMA) += mpc5200_dma.o

sound/soc/fsl/fsl_rpmsg.c

@@ -0,0 +1,261 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright 2018-2021 NXP
+
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/pm_runtime.h>
+#include <linux/rpmsg.h>
+#include <linux/slab.h>
+#include <sound/core.h>
+#include <sound/dmaengine_pcm.h>
+#include <sound/pcm_params.h>
+
+#include "fsl_rpmsg.h"
+#include "imx-pcm.h"
+
+#define FSL_RPMSG_RATES        (SNDRV_PCM_RATE_8000 | \
+				SNDRV_PCM_RATE_16000 | \
+				SNDRV_PCM_RATE_48000)
+#define FSL_RPMSG_FORMATS	SNDRV_PCM_FMTBIT_S16_LE
+
+static const unsigned int fsl_rpmsg_rates[] = {
+	8000, 11025, 16000, 22050, 44100,
+	32000, 48000, 96000, 88200, 176400, 192000,
+	352800, 384000, 705600, 768000, 1411200, 2822400,
+};
+
+static const struct snd_pcm_hw_constraint_list fsl_rpmsg_rate_constraints = {
+	.count = ARRAY_SIZE(fsl_rpmsg_rates),
+	.list = fsl_rpmsg_rates,
+};
+
+static int fsl_rpmsg_hw_params(struct snd_pcm_substream *substream,
+			       struct snd_pcm_hw_params *params,
+			       struct snd_soc_dai *dai)
+{
+	struct fsl_rpmsg *rpmsg = snd_soc_dai_get_drvdata(dai);
+	struct clk *p = rpmsg->mclk, *pll = 0, *npll = 0;
+	unsigned int rate = params_rate(params);
+	int ret = 0;
+
+	/* Get current pll parent */
+	while (p && rpmsg->pll8k && rpmsg->pll11k) {
+		struct clk *pp = clk_get_parent(p);
+
+		if (clk_is_match(pp, rpmsg->pll8k) ||
+		    clk_is_match(pp, rpmsg->pll11k)) {
+			pll = pp;
+			break;
+		}
+		p = pp;
+	}
+
+	/* Switch to another pll parent if needed. */
+	if (pll) {
+		npll = (do_div(rate, 8000) ? rpmsg->pll11k : rpmsg->pll8k);
+		if (!clk_is_match(pll, npll)) {
+			ret = clk_set_parent(p, npll);
+			if (ret < 0)
+				dev_warn(dai->dev, "failed to set parent %s: %d\n",
+					 __clk_get_name(npll), ret);
+		}
+	}
+
+	if (!(rpmsg->mclk_streams & BIT(substream->stream))) {
+		ret = clk_prepare_enable(rpmsg->mclk);
+		if (ret) {
+			dev_err(dai->dev, "failed to enable mclk: %d\n", ret);
+			return ret;
+		}
+
+		rpmsg->mclk_streams |= BIT(substream->stream);
+	}
+
+	return ret;
+}
+
+static int fsl_rpmsg_hw_free(struct snd_pcm_substream *substream,
+			     struct snd_soc_dai *dai)
+{
+	struct fsl_rpmsg *rpmsg = snd_soc_dai_get_drvdata(dai);
+
+	if (rpmsg->mclk_streams & BIT(substream->stream)) {
+		clk_disable_unprepare(rpmsg->mclk);
+		rpmsg->mclk_streams &= ~BIT(substream->stream);
+	}
+
+	return 0;
+}
+
+static int fsl_rpmsg_startup(struct snd_pcm_substream *substream,
+			     struct snd_soc_dai *cpu_dai)
+{
+	int ret;
+
+	ret = snd_pcm_hw_constraint_list(substream->runtime, 0,
+					 SNDRV_PCM_HW_PARAM_RATE,
+					 &fsl_rpmsg_rate_constraints);
+
+	return ret;
+}
+
+static const struct snd_soc_dai_ops fsl_rpmsg_dai_ops = {
+	.startup	= fsl_rpmsg_startup,
+	.hw_params      = fsl_rpmsg_hw_params,
+	.hw_free        = fsl_rpmsg_hw_free,
+};
+
+static struct snd_soc_dai_driver fsl_rpmsg_dai = {
+	.playback = {
+		.stream_name = "CPU-Playback",
+		.channels_min = 2,
+		.channels_max = 2,
+		.rates = SNDRV_PCM_RATE_KNOT,
+		.formats = FSL_RPMSG_FORMATS,
+	},
+	.capture = {
+		.stream_name = "CPU-Capture",
+		.channels_min = 2,
+		.channels_max = 2,
+		.rates = SNDRV_PCM_RATE_KNOT,
+		.formats = FSL_RPMSG_FORMATS,
+	},
+	.symmetric_rate        = 1,
+	.symmetric_channels    = 1,
+	.symmetric_sample_bits = 1,
+	.ops = &fsl_rpmsg_dai_ops,
+};
+
+static const struct snd_soc_component_driver fsl_component = {
+	.name           = "fsl-rpmsg",
+};
+
+static const struct of_device_id fsl_rpmsg_ids[] = {
+	{ .compatible = "fsl,imx7ulp-rpmsg"},
+	{ .compatible = "fsl,imx8mm-rpmsg"},
+	{ .compatible = "fsl,imx8mn-rpmsg"},
+	{ .compatible = "fsl,imx8mp-rpmsg"},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, fsl_rpmsg_ids);
+
+static int fsl_rpmsg_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct fsl_rpmsg *rpmsg;
+	int ret;
+
+	rpmsg = devm_kzalloc(&pdev->dev, sizeof(struct fsl_rpmsg), GFP_KERNEL);
+	if (!rpmsg)
+		return -ENOMEM;
+
+	ret = of_property_read_u32(np, "fsl,audioindex", &rpmsg->audioindex);
+	if (ret)
+		rpmsg->audioindex = 0;
+
+	if (of_property_read_u32(np, "fsl,buffer-size", &rpmsg->buffer_size))
+		rpmsg->buffer_size = IMX_DEFAULT_DMABUF_SIZE;
+
+	if (of_property_read_bool(pdev->dev.of_node, "fsl,enable-lpa"))
+		rpmsg->enable_lpa = 1;
+
+	ret = of_property_read_u32(np, "fsl,version", &rpmsg->version);
+	if (ret)
+		rpmsg->version = API_VERSION_V2;
+
+	/*Get the optional clocks */
+	rpmsg->ipg = devm_clk_get(&pdev->dev, "ipg");
+	if (IS_ERR(rpmsg->ipg))
+		rpmsg->ipg = NULL;
+
+	rpmsg->mclk = devm_clk_get(&pdev->dev, "mclk");
+	if (IS_ERR(rpmsg->mclk))
+		rpmsg->mclk = NULL;
+
+	rpmsg->dma = devm_clk_get(&pdev->dev, "dma");
+	if (IS_ERR(rpmsg->dma))
+		rpmsg->dma = NULL;
+
+	rpmsg->pll8k = devm_clk_get(&pdev->dev, "pll8k");
+	if (IS_ERR(rpmsg->pll8k))
+		rpmsg->pll8k = NULL;
+
+	rpmsg->pll11k = devm_clk_get(&pdev->dev, "pll11k");
+	if (IS_ERR(rpmsg->pll11k))
+		rpmsg->pll11k = NULL;
+
+	platform_set_drvdata(pdev, rpmsg);
+	pm_runtime_enable(&pdev->dev);
+
+	ret = devm_snd_soc_register_component(&pdev->dev, &fsl_component,
+					      &fsl_rpmsg_dai, 1);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int fsl_rpmsg_runtime_resume(struct device *dev)
+{
+	struct fsl_rpmsg *rpmsg = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_prepare_enable(rpmsg->ipg);
+	if (ret) {
+		dev_err(dev, "failed to enable ipg clock: %d\n", ret);
+		goto ipg_err;
+	}
+
+	ret = clk_prepare_enable(rpmsg->dma);
+	if (ret) {
+		dev_err(dev, "Failed to enable dma clock %d\n", ret);
+		goto dma_err;
+	}
+
+	return 0;
+
+dma_err:
+	clk_disable_unprepare(rpmsg->ipg);
+ipg_err:
+	return ret;
+}
+
+static int fsl_rpmsg_runtime_suspend(struct device *dev)
+{
+	struct fsl_rpmsg *rpmsg = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(rpmsg->dma);
+	clk_disable_unprepare(rpmsg->ipg);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops fsl_rpmsg_pm_ops = {
+	SET_RUNTIME_PM_OPS(fsl_rpmsg_runtime_suspend,
+			   fsl_rpmsg_runtime_resume,
+			   NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
+};
+
+static struct platform_driver fsl_rpmsg_driver = {
+	.probe  = fsl_rpmsg_probe,
+	.driver = {
+		.name = "fsl_rpmsg",
+		.pm = &fsl_rpmsg_pm_ops,
+		.of_match_table = fsl_rpmsg_ids,
+	},
+};
+module_platform_driver(fsl_rpmsg_driver);
+
+MODULE_DESCRIPTION("Freescale SoC Audio PRMSG CPU Interface");
+MODULE_AUTHOR("Shengjiu Wang <shengjiu.wang@nxp.com>");
+MODULE_ALIAS("platform:fsl_rpmsg");
+MODULE_LICENSE("GPL");

sound/soc/fsl/fsl_rpmsg.h

@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2017-2021 NXP
+ */
+
+#ifndef __FSL_RPMSG_H
+#define __FSL_RPMSG_H
+
+#define API_VERSION_V1  1
+#define API_VERSION_V2  2
+
+/*
+ * struct fsl_rpmsg - rpmsg private data
+ *
+ * @ipg: ipg clock for cpu dai (SAI)
+ * @mclk: master clock for cpu dai (SAI)
+ * @dma: clock for dma device
+ * @pll8k: parent clock for multiple of 8kHz frequency
+ * @pll11k: parent clock for multiple of 11kHz frequency
+ * @mclk_streams: Active streams that are using baudclk
+ * @force_lpa: force enable low power audio routine if condition satisfy
+ * @enable_lpa: enable low power audio routine according to dts setting
+ * @buffer_size: pre allocated dma buffer size
+ * @audioindex: audio instance index
+ * @version: rpmsg image version
+ */
+struct fsl_rpmsg {
+	struct clk *ipg;
+	struct clk *mclk;
+	struct clk *dma;
+	struct clk *pll8k;
+	struct clk *pll11k;
+	unsigned int mclk_streams;
+	int force_lpa;
+	int enable_lpa;
+	int buffer_size;
+	int audioindex;
+	int version;
+};
+#endif /* __FSL_RPMSG_H */