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From:   =?UTF-8?q?Martin=20Povi=C5=A1er?= <povik+lin@cutebit.org>
To:     Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzk+dt@kernel.org>,
        Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>
Cc:     =?UTF-8?q?Martin=20Povi=C5=A1er?= <povik+lin@cutebit.org>,
        alsa-devel@alsa-project.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, Mark Kettenis <kettenis@openbsd.org>,
        Hector Martin <marcan@marcan.st>,
        Sven Peter <sven@svenpeter.dev>, asahi@lists.linux.dev
Subject: [RFC PATCH v2 3/5] ASoC: apple: Add MCA platform driver for Apple SoCs
Date:   Mon,  6 Jun 2022 21:19:08 +0200
Message-Id: <20220606191910.16580-4-povik+lin@cutebit.org>
In-Reply-To: <20220606191910.16580-1-povik+lin@cutebit.org>
References: <20220606191910.16580-1-povik+lin@cutebit.org>
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Precedence: bulk

Add ASoC platform driver for the MCA peripheral found on Apple M1 and
other chips.

Signed-off-by: Martin Povišer <povik+lin@cutebit.org>
---
 sound/soc/Kconfig        |    1 +
 sound/soc/Makefile       |    1 +
 sound/soc/apple/Kconfig  |    9 +
 sound/soc/apple/Makefile |    3 +
 sound/soc/apple/mca.c    | 1122 ++++++++++++++++++++++++++++++++++++++
 5 files changed, 1136 insertions(+)
 create mode 100644 sound/soc/apple/Kconfig
 create mode 100644 sound/soc/apple/Makefile
 create mode 100644 sound/soc/apple/mca.c

diff --git a/sound/soc/Kconfig b/sound/soc/Kconfig
index 5dcf77af07af..aec82db3114b 100644
--- a/sound/soc/Kconfig
+++ b/sound/soc/Kconfig
@@ -61,6 +61,7 @@ config SND_SOC_ACPI
 # All the supported SoCs
 source "sound/soc/adi/Kconfig"
 source "sound/soc/amd/Kconfig"
+source "sound/soc/apple/Kconfig"
 source "sound/soc/atmel/Kconfig"
 source "sound/soc/au1x/Kconfig"
 source "sound/soc/bcm/Kconfig"
diff --git a/sound/soc/Makefile b/sound/soc/Makefile
index a7b37c06dc43..706dfbc28a6d 100644
--- a/sound/soc/Makefile
+++ b/sound/soc/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_SND_SOC_ACPI) += snd-soc-acpi.o
 obj-$(CONFIG_SND_SOC)	+= snd-soc-core.o
 obj-$(CONFIG_SND_SOC)	+= codecs/
 obj-$(CONFIG_SND_SOC)	+= generic/
+obj-$(CONFIG_SND_SOC)	+= apple/
 obj-$(CONFIG_SND_SOC)	+= adi/
 obj-$(CONFIG_SND_SOC)	+= amd/
 obj-$(CONFIG_SND_SOC)	+= atmel/
diff --git a/sound/soc/apple/Kconfig b/sound/soc/apple/Kconfig
new file mode 100644
index 000000000000..0ba955657e98
--- /dev/null
+++ b/sound/soc/apple/Kconfig
@@ -0,0 +1,9 @@
+config SND_SOC_APPLE_MCA
+	tristate "Apple Silicon MCA driver"
+	depends on ARCH_APPLE || COMPILE_TEST
+	select SND_DMAENGINE_PCM
+	select COMMON_CLK
+	default ARCH_APPLE
+	help
+	  This option enables an ASoC platform driver for MCA peripherals found
+	  on Apple Silicon SoCs.
diff --git a/sound/soc/apple/Makefile b/sound/soc/apple/Makefile
new file mode 100644
index 000000000000..7a30bf452817
--- /dev/null
+++ b/sound/soc/apple/Makefile
@@ -0,0 +1,3 @@
+snd-soc-apple-mca-objs	:= mca.o
+
+obj-$(CONFIG_SND_SOC_APPLE_MCA)	+= snd-soc-apple-mca.o
diff --git a/sound/soc/apple/mca.c b/sound/soc/apple/mca.c
new file mode 100644
index 000000000000..c53c9367efa5
--- /dev/null
+++ b/sound/soc/apple/mca.c
@@ -0,0 +1,1122 @@
+/*
+ * Apple SoCs MCA driver
+ *
+ * Copyright (C) The Asahi Linux Contributors
+ *
+ * The MCA peripheral is made up of a number of identical units called clusters.
+ * Each cluster has its separate clock parent, SYNC signal generator, carries
+ * four SERDES units and has a dedicated I2S port on the SoC's periphery.
+ *
+ * The clusters can operate independently, or can be combined together in a
+ * configurable manner. We mostly treat them as self-contained independent
+ * units and don't configure any cross-cluster connections except for the I2S
+ * ports. The I2S ports can be routed to any of the clusters (irrespective
+ * of their native cluster). We map this onto ASoC's (DPCM) notion of backend
+ * and frontend DAIs. The 'cluster guts' are frontends which are dynamically
+ * routed to backend I2S ports.
+ *
+ * DAI references in devicetree are resolved as backends. The machine driver
+ * makes up some routing to the frontends in the DAPM paths it supplies, which
+ * can mostly be arbitrary.
+ */
+
+#include <linux/clk.h>
+#include <linux/dma-mapping.h>
+#include <linux/init.h>
+#include <linux/bitfield.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_clk.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+#include <sound/dmaengine_pcm.h>
+
+#define USE_RXB_FOR_CAPTURE
+
+/* relative to cluster base */
+#define REG_STATUS		0x0
+#define STATUS_MCLK_EN		BIT(0)
+#define REG_MCLK_CONF		0x4
+#define MCLK_CONF_DIV		GENMASK(11, 8)
+
+#define REG_SYNCGEN_STATUS	0x100
+#define SYNCGEN_STATUS_EN	BIT(0)
+#define REG_SYNCGEN_MCLK_SEL	0x104
+#define SYNCGEN_MCLK_SEL	GENMASK(3, 0)
+#define REG_SYNCGEN_HI_PERIOD	0x108
+#define REG_SYNCGEN_LO_PERIOD	0x10c
+
+#define REG_PORT_ENABLES	0x600
+#define PORT_ENABLES_CLOCKS	GENMASK(2, 1)
+#define PORT_ENABLES_TX_DATA	BIT(3)
+#define REG_PORT_CLOCK_SEL	0x604
+#define PORT_CLOCK_SEL		GENMASK(11, 8)
+#define REG_PORT_DATA_SEL	0x608
+#define PORT_DATA_SEL_TXA(cl)	(1 << ((cl)*2))
+#define PORT_DATA_SEL_TXB(cl)	(2 << ((cl)*2))
+
+#define REG_INTSTATE		0x700
+#define REG_INTMASK		0x704
+
+/* bases of serdes units (relative to cluster) */
+#define CLUSTER_RXA_OFF	0x200
+#define CLUSTER_TXA_OFF	0x300
+#define CLUSTER_RXB_OFF	0x400
+#define CLUSTER_TXB_OFF	0x500
+
+#define CLUSTER_TX_OFF	CLUSTER_TXA_OFF
+
+#ifndef USE_RXB_FOR_CAPTURE
+#define CLUSTER_RX_OFF	CLUSTER_RXA_OFF
+#else
+#define CLUSTER_RX_OFF	CLUSTER_RXB_OFF
+#endif
+
+/* relative to serdes unit base */
+#define REG_SERDES_STATUS	0x00
+#define SERDES_STATUS_EN	BIT(0)
+#define SERDES_STATUS_RST	BIT(1)
+#define REG_TX_SERDES_CONF	0x04
+#define REG_RX_SERDES_CONF	0x08
+#define SERDES_CONF_NCHANS	GENMASK(3, 0)
+#define SERDES_CONF_WIDTH_MASK	GENMASK(8, 4)
+#define SERDES_CONF_WIDTH_16BIT 0x40
+#define SERDES_CONF_WIDTH_20BIT 0x80
+#define SERDES_CONF_WIDTH_24BIT 0xc0
+#define SERDES_CONF_WIDTH_32BIT 0x100
+#define SERDES_CONF_BCLK_POL	0x400
+#define SERDES_CONF_LSB_FIRST	0x800
+#define SERDES_CONF_UNK1	BIT(12)
+#define SERDES_CONF_UNK2	BIT(13)
+#define SERDES_CONF_UNK3	BIT(14)
+#define SERDES_CONF_NO_DATA_FEEDBACK	BIT(14)
+#define SERDES_CONF_SYNC_SEL	GENMASK(18, 16)
+#define SERDES_CONF_SOME_RST	BIT(19)
+#define REG_TX_SERDES_BITSTART	0x08
+#define REG_RX_SERDES_BITSTART	0x0c
+#define REG_TX_SERDES_SLOTMASK	0x0c
+#define REG_RX_SERDES_SLOTMASK	0x10
+#define REG_RX_SERDES_PORT	0x04
+
+/* relative to switch base */
+#define REG_DMA_ADAPTER_A(cl)	(0x8000 * (cl))
+#define REG_DMA_ADAPTER_B(cl)	(0x8000 * (cl) + 0x4000)
+#define DMA_ADAPTER_TX_LSB_PAD	GENMASK(4, 0)
+#define DMA_ADAPTER_TX_NCHANS	GENMASK(6, 5)
+#define DMA_ADAPTER_RX_MSB_PAD	GENMASK(12, 8)
+#define DMA_ADAPTER_RX_NCHANS	GENMASK(14, 13)
+#define DMA_ADAPTER_NCHANS	GENMASK(22, 20)
+
+#define SWITCH_STRIDE	0x8000
+#define CLUSTER_STRIDE	0x4000
+
+#define MAX_NCLUSTERS	6
+
+#define APPLE_MCA_FMTBITS (SNDRV_PCM_FMTBIT_S16_LE | \
+			   SNDRV_PCM_FMTBIT_S24_LE | \
+			   SNDRV_PCM_FMTBIT_S32_LE)
+
+struct mca_cluster {
+	int no;
+	__iomem void *base;
+	struct mca_data *host;
+	struct device *pd_dev;
+	struct clk *clk_parent;
+	struct dma_chan *dma_chans[SNDRV_PCM_STREAM_LAST + 1];
+
+	bool port_started[SNDRV_PCM_STREAM_LAST + 1];
+	int port_driver;
+	bool clocks_in_use[SNDRV_PCM_STREAM_LAST + 1];
+	struct device_link *pd_link;
+
+	unsigned int set_sysclk;
+
+	int tdm_slots;
+	int tdm_slot_width;
+	unsigned int tdm_tx_mask;
+	unsigned int tdm_rx_mask;
+};
+
+struct mca_data {
+	struct device *dev;
+
+	__iomem void *switch_base;
+
+	struct device *pd_dev;
+	struct device_link *pd_link;
+
+	int nclusters;
+	struct mca_cluster clusters[];
+};
+
+static void mca_modify(struct mca_cluster *cl, int regoffset,
+		       u32 mask, u32 val)
+{
+	__iomem void *ptr = cl->base + regoffset;
+	u32 newval;
+
+	newval = (val & mask) | (readl_relaxed(ptr) & ~mask);
+	writel_relaxed(newval, ptr);
+}
+
+/*
+ * Get the cluster of FE or BE DAI
+ */
+static struct mca_cluster *mca_dai_to_cluster(struct snd_soc_dai *dai)
+{
+	struct mca_data *mca = snd_soc_dai_get_drvdata(dai);
+	/*
+	 * FE DAIs are         0 ... nclusters - 1
+	 * BE DAIs are nclusters ... 2*nclusters - 1
+	 */
+	int cluster_no = dai->id % mca->nclusters;
+
+	return &mca->clusters[cluster_no];
+}
+
+/* called before PCM trigger */
+static void mca_fe_early_trigger(struct snd_pcm_substream *substream,
+				 int cmd, struct snd_soc_dai *dai)
+{
+	struct mca_cluster *cl = mca_dai_to_cluster(dai);
+	bool is_tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
+	int serdes_unit = is_tx ? CLUSTER_TX_OFF : CLUSTER_RX_OFF;
+	int serdes_conf = serdes_unit + (is_tx ? REG_TX_SERDES_CONF : REG_RX_SERDES_CONF);
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		mca_modify(cl, serdes_unit + REG_SERDES_STATUS,
+			SERDES_STATUS_EN | SERDES_STATUS_RST,
+			SERDES_STATUS_RST);
+		mca_modify(cl, serdes_conf,
+			SERDES_CONF_SOME_RST, SERDES_CONF_SOME_RST);
+		(void) readl_relaxed(cl->base + serdes_conf);
+		mca_modify(cl, serdes_conf,
+			SERDES_STATUS_RST, 0);
+		WARN_ON(readl_relaxed(cl->base + REG_SERDES_STATUS)
+				& SERDES_STATUS_RST);
+		break;
+	default:
+		break;
+	}
+}
+
+static int mca_fe_trigger(struct snd_pcm_substream *substream,
+			  int cmd, struct snd_soc_dai *dai)
+{
+	struct mca_cluster *cl = mca_dai_to_cluster(dai);
+	bool is_tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
+	int serdes_unit = is_tx ? CLUSTER_TX_OFF : CLUSTER_RX_OFF;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		mca_modify(cl, serdes_unit + REG_SERDES_STATUS,
+			SERDES_STATUS_EN | SERDES_STATUS_RST,
+			SERDES_STATUS_EN);
+		break;
+
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		mca_modify(cl, serdes_unit + REG_SERDES_STATUS,
+			SERDES_STATUS_EN, 0);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int mca_fe_enable_clocks(struct mca_cluster *cl)
+{
+	struct mca_data *mca = cl->host;
+	int ret;
+
+	ret = clk_prepare_enable(cl->clk_parent);
+	if (ret) {
+		dev_err(mca->dev, "cluster %d: unable to enable clock parent: %d\n",
+			cl->no, ret);
+		return ret;
+	}
+
+	cl->pd_link = device_link_add(mca->dev, cl->pd_dev,
+				DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME |
+				DL_FLAG_RPM_ACTIVE);
+	if (!cl->pd_link) {
+		dev_err(mca->dev, "cluster %d: unable to prop-up power domain\n",
+			cl->no);
+		clk_disable_unprepare(cl->clk_parent);
+		return -EINVAL;
+	}
+
+	writel_relaxed(cl->no + 1,
+		cl->base + REG_SYNCGEN_MCLK_SEL);
+	mca_modify(cl, REG_SYNCGEN_STATUS,
+		SYNCGEN_STATUS_EN, SYNCGEN_STATUS_EN);
+	mca_modify(cl, REG_STATUS,
+		STATUS_MCLK_EN, STATUS_MCLK_EN);
+
+	return 0;
+}
+
+static void mca_fe_disable_clocks(struct mca_cluster *cl)
+{
+	mca_modify(cl, REG_SYNCGEN_STATUS,
+		SYNCGEN_STATUS_EN, 0);
+	mca_modify(cl, REG_STATUS,
+		STATUS_MCLK_EN, 0);
+
+	device_link_del(cl->pd_link);
+	clk_disable_unprepare(cl->clk_parent);
+}
+
+static bool mca_fe_clocks_in_use(struct mca_cluster *cl)
+{
+	struct mca_data *mca = cl->host;
+	struct mca_cluster *be_cl;
+	int stream, i;
+
+	for (i = 0; i < mca->nclusters; i++) {
+		be_cl = &mca->clusters[i];
+
+		if (be_cl->port_driver != cl->no)
+			continue;
+
+		for_each_pcm_streams(stream)
+			if (be_cl->clocks_in_use[stream])
+				return true;
+	}
+	return false;
+}
+
+static int mca_be_prepare(struct snd_pcm_substream *substream,
+			struct snd_soc_dai *dai)
+{
+	struct mca_cluster *cl = mca_dai_to_cluster(dai);
+	struct mca_data *mca = cl->host;
+	struct mca_cluster *fe_cl;
+	int ret;
+
+	if (cl->port_driver < 0)
+		return -EINVAL;
+
+	fe_cl = &mca->clusters[cl->port_driver];
+
+	/*
+	 * Codecs require clocks at time of umute with the 'mute_stream' op.
+	 * We need to enable them here at the latest (frontend prepare would
+	 * be too late).
+	 */
+	if (!mca_fe_clocks_in_use(fe_cl)) {
+		ret = mca_fe_enable_clocks(fe_cl);
+		if (ret < 0)
+			return ret;
+	}
+
+	cl->clocks_in_use[substream->stream] = true;
+
+	return 0;
+}
+
+static int mca_be_hw_free(struct snd_pcm_substream *substream,
+			struct snd_soc_dai *dai)
+{
+	struct mca_cluster *cl = mca_dai_to_cluster(dai);
+	struct mca_data *mca = cl->host;
+	struct mca_cluster *fe_cl;
+
+	if (cl->port_driver < 0)
+		return -EINVAL;
+
+	fe_cl = &mca->clusters[cl->port_driver];
+	if (!mca_fe_clocks_in_use(fe_cl))
+		return 0; /* Nothing to do */
+
+	cl->clocks_in_use[substream->stream] = false;
+
+	if (!mca_fe_clocks_in_use(fe_cl))
+		mca_fe_disable_clocks(fe_cl);
+
+	return 0;
+}
+
+static unsigned int mca_crop_mask(unsigned int mask, int nchans)
+{
+	while (hweight32(mask) > nchans)
+		mask &= ~(1 << __fls(mask));
+
+	return mask;
+}
+
+static int mca_configure_serdes(struct mca_cluster *cl, int serdes_unit,
+				unsigned int mask, int slots, int nchans, int slot_width,
+				bool is_tx, int port)
+{
+	u32 serdes_conf, serdes_conf_mask;
+
+	serdes_conf_mask = SERDES_CONF_WIDTH_MASK | SERDES_CONF_NCHANS;
+	serdes_conf = FIELD_PREP(SERDES_CONF_NCHANS, max(slots, 1) - 1);
+	switch (slot_width) {
+	case 16:
+		serdes_conf |= SERDES_CONF_WIDTH_16BIT;
+		break;
+	case 20:
+		serdes_conf |= SERDES_CONF_WIDTH_20BIT;
+		break;
+	case 24:
+		serdes_conf |= SERDES_CONF_WIDTH_24BIT;
+		break;
+	case 32:
+		serdes_conf |= SERDES_CONF_WIDTH_32BIT;
+		break;
+	default:
+		goto err;
+	}
+
+	serdes_conf_mask |= SERDES_CONF_SYNC_SEL;
+	serdes_conf |= FIELD_PREP(SERDES_CONF_SYNC_SEL, cl->no + 1);
+
+	if (is_tx) {
+		serdes_conf_mask |= SERDES_CONF_UNK1 | SERDES_CONF_UNK2 | SERDES_CONF_UNK3;
+		serdes_conf |= SERDES_CONF_UNK1 | SERDES_CONF_UNK2 | SERDES_CONF_UNK3;
+	} else {
+
+		serdes_conf_mask |= SERDES_CONF_UNK1 | SERDES_CONF_UNK2 | SERDES_CONF_UNK3
+				| SERDES_CONF_NO_DATA_FEEDBACK;
+		serdes_conf |= SERDES_CONF_UNK1 | SERDES_CONF_UNK2
+				| SERDES_CONF_NO_DATA_FEEDBACK;
+	}
+
+	mca_modify(cl, serdes_unit + (is_tx ? REG_TX_SERDES_CONF : REG_RX_SERDES_CONF),
+		serdes_conf_mask, serdes_conf);
+
+	if (is_tx) {
+		writel_relaxed(0xffffffff,
+			cl->base + serdes_unit + REG_TX_SERDES_SLOTMASK);
+		writel_relaxed(~((u32) mca_crop_mask(mask, nchans)),
+			cl->base + serdes_unit + REG_TX_SERDES_SLOTMASK + 0x4);
+		writel_relaxed(0xffffffff,
+			cl->base + serdes_unit + REG_TX_SERDES_SLOTMASK + 0x8);
+		writel_relaxed(~((u32) mask),
+			cl->base + serdes_unit + REG_TX_SERDES_SLOTMASK + 0xc);
+	} else {
+		writel_relaxed(0xffffffff,
+			cl->base + serdes_unit + REG_RX_SERDES_SLOTMASK);
+		writel_relaxed(~((u32) mask),
+			cl->base + serdes_unit + REG_RX_SERDES_SLOTMASK + 0x4);
+		writel_relaxed(1 << port,
+			cl->base + serdes_unit + REG_RX_SERDES_PORT);
+	}
+
+	return 0;
+
+err:
+	dev_err(cl->host->dev, "unsupported SERDES configuration requested (mask=0x%x slots=%d slot_width=%d)\n",
+			mask, slots, slot_width);
+	return -EINVAL;
+}
+
+static int mca_fe_set_tdm_slot(struct snd_soc_dai *dai, unsigned int tx_mask,
+				unsigned int rx_mask, int slots, int slot_width)
+{
+	struct mca_cluster *cl = mca_dai_to_cluster(dai);
+
+	cl->tdm_slots = slots;
+	cl->tdm_slot_width = slot_width;
+	cl->tdm_tx_mask = tx_mask;
+	cl->tdm_rx_mask = rx_mask;
+
+	return 0;
+}
+
+static int mca_fe_set_fmt(struct snd_soc_dai *dai,
+				unsigned int fmt)
+{
+	struct mca_cluster *cl = mca_dai_to_cluster(dai);
+	struct mca_data *mca = cl->host;
+	bool fpol_inv = false;
+	u32 serdes_conf = 0;
+	u32 bitstart;
+
+	if ((fmt & SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK) !=
+			SND_SOC_DAIFMT_CBC_CFC)
+		goto err;
+
+	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
+	case SND_SOC_DAIFMT_I2S:
+		fpol_inv = 0;
+		bitstart = 1;
+		break;
+	case SND_SOC_DAIFMT_LEFT_J:
+		fpol_inv = 1;
+		bitstart = 0;
+		break;
+	default:
+		goto err;
+	}
+
+	switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
+	case SND_SOC_DAIFMT_NB_IF:
+	case SND_SOC_DAIFMT_IB_IF:
+		fpol_inv ^= 1;
+		break;
+	}
+
+	switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
+	case SND_SOC_DAIFMT_NB_NF:
+	case SND_SOC_DAIFMT_NB_IF:
+		serdes_conf |= SERDES_CONF_BCLK_POL;
+		break;
+	}
+
+	if (!fpol_inv)
+		goto err;
+
+	mca_modify(cl, CLUSTER_TX_OFF + REG_TX_SERDES_CONF,
+			SERDES_CONF_BCLK_POL,
+			serdes_conf);
+	writel_relaxed(bitstart,
+		cl->base + CLUSTER_TX_OFF + REG_TX_SERDES_BITSTART);
+	mca_modify(cl, CLUSTER_RX_OFF + REG_RX_SERDES_CONF,
+			SERDES_CONF_BCLK_POL,
+			serdes_conf);
+	writel_relaxed(bitstart,
+		cl->base + CLUSTER_RX_OFF + REG_RX_SERDES_BITSTART);
+
+	return 0;
+
+err:
+	dev_err(mca->dev, "unsupported DAI format (0x%x) requested\n", fmt);
+	return -EINVAL;
+}
+
+static int mca_fe_set_sysclk(struct snd_soc_dai *dai, int clk_id,
+				unsigned int freq, int dir)
+{
+	struct mca_cluster *cl = mca_dai_to_cluster(dai);
+	int ret;
+
+	if (freq == cl->set_sysclk)
+		return 0;
+
+	if (mca_fe_clocks_in_use(cl))
+		return -EBUSY;
+
+	ret = clk_set_rate(cl->clk_parent, freq);
+	if (!ret)
+		cl->set_sysclk = freq;
+	return ret;
+}
+
+static int mca_fe_hw_params(struct snd_pcm_substream *substream,
+			struct snd_pcm_hw_params *params,
+			struct snd_soc_dai *dai)
+{
+	struct mca_cluster *cl = mca_dai_to_cluster(dai);
+	struct mca_data *mca = cl->host;
+	struct device *dev = mca->dev;
+	unsigned int samp_rate = params_rate(params);
+	bool is_tx = substream->stream == SNDRV_PCM_STREAM_PLAYBACK;
+	bool refine_tdm = false;
+	unsigned long bclk_ratio;
+	unsigned int tdm_slots, tdm_slot_width, tdm_mask;
+	u32 regval, pad;
+	int ret, nchans_ceiled;
+
+	if (!cl->tdm_slot_width) {
+		/*
+		 * We were not given TDM settings from above, set initial
+		 * guesses which will later be refined.
+		 */
+		tdm_slot_width = params_width(params);
+		tdm_slots = params_channels(params);
+		refine_tdm = true;
+	} else {
+		tdm_slot_width = cl->tdm_slot_width;
+		tdm_slots = cl->tdm_slots;
+		tdm_mask = is_tx ? cl->tdm_tx_mask : cl->tdm_rx_mask;
+	}
+
+	if (cl->set_sysclk)
+		bclk_ratio = cl->set_sysclk / samp_rate;
+	else
+		bclk_ratio = tdm_slot_width * tdm_slots;
+
+	if (refine_tdm) {
+		int nchannels = params_channels(params);
+
+		if (nchannels > 2) {
+			dev_err(dev, "missing TDM for stream with over two channels\n");
+			return -EINVAL;
+		}
+
+		if ((bclk_ratio % nchannels) != 0) {
+			dev_err(dev, "BCLK ratio (%ld) not divisible by no of channels (%d)\n",
+					bclk_ratio, nchannels);
+			return -EINVAL;
+		}
+
+		tdm_slot_width = bclk_ratio / nchannels;
+
+		if (tdm_slot_width > 32 && nchannels == 1)
+			tdm_slot_width = 32;
+
+		if (tdm_slot_width < params_width(params)) {
+			dev_err(dev, "TDM slots too narrow (tdm=%d params=%d)\n",
+					tdm_slot_width, params_width(params));
+			return -EINVAL;
+		}
+
+		tdm_mask = (1 << tdm_slots) - 1;
+	}
+
+	ret = mca_configure_serdes(cl, is_tx ? CLUSTER_TX_OFF : CLUSTER_RX_OFF,
+				tdm_mask, tdm_slots, params_channels(params),
+				tdm_slot_width, is_tx, cl->no);
+	if (ret)
+		return ret;
+
+	pad = 32 - params_width(params);
+
+	/*
+	 * TODO: Here the register semantics aren't clear.
+	 */
+	nchans_ceiled = min_t(int, params_channels(params), 4);
+	regval = FIELD_PREP(DMA_ADAPTER_NCHANS, nchans_ceiled)
+			| FIELD_PREP(DMA_ADAPTER_TX_NCHANS, 0x2)
+			| FIELD_PREP(DMA_ADAPTER_RX_NCHANS, 0x2)
+			| FIELD_PREP(DMA_ADAPTER_TX_LSB_PAD, pad)
+			| FIELD_PREP(DMA_ADAPTER_RX_MSB_PAD, pad);
+
+#ifndef USE_RXB_FOR_CAPTURE
+	writel_relaxed(regval, mca->switch_base + REG_DMA_ADAPTER_A(cl->no));
+#else
+	if (is_tx)
+		writel_relaxed(regval, mca->switch_base + REG_DMA_ADAPTER_A(cl->no));
+	else
+		writel_relaxed(regval, mca->switch_base + REG_DMA_ADAPTER_B(cl->no));
+#endif
+
+	if (!mca_fe_clocks_in_use(cl)) {
+		/*
+		 * Set up FSYNC duty cycle as even as possible.
+		 */
+		writel_relaxed((bclk_ratio / 2) - 1, cl->base + REG_SYNCGEN_HI_PERIOD);
+		writel_relaxed(((bclk_ratio + 1) / 2) - 1, cl->base + REG_SYNCGEN_LO_PERIOD);
+		writel_relaxed(FIELD_PREP(MCLK_CONF_DIV, 0x1), cl->base + REG_MCLK_CONF);
+
+		ret = clk_set_rate(cl->clk_parent, bclk_ratio * samp_rate);
+		if (ret) {
+			dev_err(mca->dev, "cluster %d: unable to set clock parent: %d\n",
+				cl->no, ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+
+static const struct snd_soc_dai_ops mca_fe_ops = {
+	.set_fmt      = mca_fe_set_fmt,
+	.set_sysclk   = mca_fe_set_sysclk,
+	.set_tdm_slot = mca_fe_set_tdm_slot,
+	.hw_params    = mca_fe_hw_params,
+	.trigger      = mca_fe_trigger,
+};
+
+static bool mca_be_started(struct mca_cluster *cl)
+{
+	int stream;
+
+	for_each_pcm_streams(stream)
+		if (cl->port_started[stream])
+			return true;
+	return false;
+}
+
+static int mca_be_startup(struct snd_pcm_substream *substream,
+			  struct snd_soc_dai *dai)
+{
+	struct snd_soc_pcm_runtime *be = asoc_substream_to_rtd(substream);
+	struct snd_soc_pcm_runtime *fe;
+	struct mca_cluster *cl = mca_dai_to_cluster(dai);
+	struct mca_cluster *fe_cl;
+	struct mca_data *mca = cl->host;
+	struct snd_soc_dpcm *dpcm;
+
+	fe = NULL;
+
+	for_each_dpcm_fe(be, substream->stream, dpcm) {
+		if (fe && dpcm->fe != fe) {
+			dev_err(mca->dev, "many FE per one BE unsupported\n");
+			return -EINVAL;
+		}
+
+		fe = dpcm->fe;
+	}
+
+	if (!fe)
+		return -EINVAL;
+
+	fe_cl = mca_dai_to_cluster(asoc_rtd_to_cpu(fe, 0));
+
+	if (mca_be_started(cl)) {
+		/*
+		 * Port is already started in the other direction.
+		 * Check it isn't driven from different cluster.
+		 */
+		if (fe_cl->no != cl->port_driver)
+			return -EINVAL;
+
+		cl->port_started[substream->stream] = true;
+		return 0;
+	}
+
+	writel_relaxed(PORT_ENABLES_CLOCKS | PORT_ENABLES_TX_DATA,
+			cl->base + REG_PORT_ENABLES);
+	writel_relaxed(FIELD_PREP(PORT_CLOCK_SEL, fe_cl->no + 1),
+			cl->base + REG_PORT_CLOCK_SEL);
+	writel_relaxed(PORT_DATA_SEL_TXA(fe_cl->no),
+			cl->base + REG_PORT_DATA_SEL);
+	cl->port_driver = fe_cl->no;
+	cl->port_started[substream->stream] = true;
+
+	return 0;
+}
+
+static void mca_be_shutdown(struct snd_pcm_substream *substream,
+				struct snd_soc_dai *dai)
+{
+	struct mca_cluster *cl = mca_dai_to_cluster(dai);
+
+	cl->port_started[substream->stream] = false;
+
+	if (!mca_be_started(cl)) {
+		/*
+		 * Were we the last direction to shutdown?
+		 * Turn off the lights.
+		 */
+		writel_relaxed(0, cl->base + REG_PORT_ENABLES);
+		writel_relaxed(0, cl->base + REG_PORT_DATA_SEL);
+		cl->port_driver = -1;
+	}
+}
+
+static const struct snd_soc_dai_ops mca_be_ops = {
+	.prepare  = mca_be_prepare,
+	.hw_free  = mca_be_hw_free,
+	.startup  = mca_be_startup,
+	.shutdown = mca_be_shutdown,
+};
+
+static int mca_set_runtime_hwparams(struct snd_soc_component *component,
+				struct snd_pcm_substream *substream, struct dma_chan *chan)
+{
+	struct device *dma_dev = chan->device->dev;
+	struct snd_dmaengine_dai_dma_data dma_data = {};
+	int ret;
+
+	struct snd_pcm_hardware hw;
+
+	memset(&hw, 0, sizeof(hw));
+
+	hw.info = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
+			SNDRV_PCM_INFO_INTERLEAVED;
+	hw.periods_min = 2;
+	hw.periods_max = UINT_MAX;
+	hw.period_bytes_min = 256;
+	hw.period_bytes_max = dma_get_max_seg_size(dma_dev);
+	hw.buffer_bytes_max = SIZE_MAX;
+	hw.fifo_size = 16;
+
+	ret = snd_dmaengine_pcm_refine_runtime_hwparams(substream,
+						&dma_data, &hw, chan);
+
+	if (ret)
+		return ret;
+
+	return snd_soc_set_runtime_hwparams(substream, &hw);
+}
+
+static int mca_pcm_open(struct snd_soc_component *component,
+			struct snd_pcm_substream *substream)
+{
+	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+	struct mca_cluster *cl = mca_dai_to_cluster(asoc_rtd_to_cpu(rtd, 0));
+	struct dma_chan *chan = cl->dma_chans[substream->stream];
+	int ret;
+
+	if (rtd->dai_link->no_pcm)
+		return 0;
+
+	ret = mca_set_runtime_hwparams(component, substream, chan);
+	if (ret)
+		return ret;
+
+	return snd_dmaengine_pcm_open(substream, chan);
+}
+
+static int mca_hw_params(struct snd_soc_component *component,
+			struct snd_pcm_substream *substream,
+			struct snd_pcm_hw_params *params)
+{
+	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+	struct dma_chan *chan = snd_dmaengine_pcm_get_chan(substream);
+	struct dma_slave_config slave_config;
+	int ret;
+
+	if (rtd->dai_link->no_pcm)
+		return 0;
+
+	memset(&slave_config, 0, sizeof(slave_config));
+	ret = snd_hwparams_to_dma_slave_config(substream, params, &slave_config);
+	if (ret < 0)
+		return ret;
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		slave_config.dst_port_window_size = min_t(u32, params_channels(params), 4);
+	else
+		slave_config.src_port_window_size = min_t(u32, params_channels(params), 4);
+
+	return dmaengine_slave_config(chan, &slave_config);
+}
+
+static int mca_close(struct snd_soc_component *component,
+		struct snd_pcm_substream *substream)
+{
+	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+
+	if (rtd->dai_link->no_pcm)
+		return 0;
+
+	return snd_dmaengine_pcm_close(substream);
+}
+
+static int mca_trigger(struct snd_soc_component *component,
+		struct snd_pcm_substream *substream, int cmd)
+{
+	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+
+	if (rtd->dai_link->no_pcm)
+		return 0;
+
+	/*
+	 * Before we do the PCM trigger proper, insert an opportunity
+	 * to reset the frontend's SERDES.
+	 */
+	mca_fe_early_trigger(substream, cmd, asoc_rtd_to_cpu(rtd, 0));
+
+	return snd_dmaengine_pcm_trigger(substream, cmd);
+}
+
+static snd_pcm_uframes_t mca_pointer(struct snd_soc_component *component,
+				struct snd_pcm_substream *substream)
+{
+	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+
+	if (rtd->dai_link->no_pcm)
+		return -ENOTSUPP;
+
+	return snd_dmaengine_pcm_pointer(substream);
+}
+
+static int mca_pcm_new(struct snd_soc_component *component,
+			struct snd_soc_pcm_runtime *rtd)
+{
+	struct mca_cluster *cl = mca_dai_to_cluster(asoc_rtd_to_cpu(rtd, 0));
+	unsigned int i;
+
+	if (rtd->dai_link->no_pcm)
+		return 0;
+
+	for_each_pcm_streams(i) {
+		struct snd_pcm_substream *substream = rtd->pcm->streams[i].substream;
+		struct dma_chan *chan = cl->dma_chans[i];
+
+		if (!substream)
+			continue;
+
+		if (!chan) {
+			dev_err(component->dev, "missing DMA channel for stream %d on SERDES %d\n",
+				i, cl->no);
+			return -EINVAL;
+		}
+
+		snd_pcm_set_managed_buffer(substream, SNDRV_DMA_TYPE_DEV_IRAM,
+					chan->device->dev, 512*1024*6,
+					SIZE_MAX);
+	}
+
+	return 0;
+}
+
+static const struct snd_soc_component_driver mca_component = {
+	.name 		= "apple-mca",
+	.open		= mca_pcm_open,
+	.close		= mca_close,
+	.hw_params	= mca_hw_params,
+	.trigger	= mca_trigger,
+	.pointer	= mca_pointer,
+	.pcm_construct	= mca_pcm_new,
+};
+
+static void apple_mca_release(struct mca_data *mca)
+{
+	int i, stream;
+
+	for (i = 0; i < mca->nclusters; i++) {
+		struct mca_cluster *cl = &mca->clusters[i];
+
+		for_each_pcm_streams(stream) {
+			if (IS_ERR_OR_NULL(cl->dma_chans[stream]))
+				continue;
+
+			dma_release_channel(cl->dma_chans[stream]);
+		}
+
+		if (!IS_ERR_OR_NULL(cl->clk_parent))
+			clk_put(cl->clk_parent);
+
+		if (!IS_ERR_OR_NULL(cl->pd_dev))
+			dev_pm_domain_detach(cl->pd_dev, true);
+	}
+
+	if (mca->pd_link)
+		device_link_del(mca->pd_link);
+
+	if (!IS_ERR_OR_NULL(mca->pd_dev))
+		dev_pm_domain_detach(mca->pd_dev, true);
+}
+
+static int apple_mca_probe(struct platform_device *pdev)
+{
+	struct mca_data *mca;
+	struct mca_cluster *clusters;
+	struct snd_soc_dai_driver *dai_drivers;
+	struct resource *res;
+	void __iomem *base;
+	int nclusters;
+	int ret, i;
+
+	base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	if (resource_size(res) < CLUSTER_STRIDE)
+		return -EINVAL;
+	nclusters = (resource_size(res) - CLUSTER_STRIDE) / CLUSTER_STRIDE + 1;
+
+	mca = devm_kzalloc(&pdev->dev, struct_size(mca, clusters, nclusters),
+				GFP_KERNEL);
+	if (!mca)
+		return -ENOMEM;
+	mca->dev = &pdev->dev;
+	mca->nclusters = nclusters;
+	platform_set_drvdata(pdev, mca);
+	clusters = mca->clusters;
+
+	mca->switch_base = devm_platform_ioremap_resource_byname(pdev, "switch");
+	if (IS_ERR(mca->switch_base))
+		return PTR_ERR(mca->switch_base);
+
+	{
+		/*
+		 * TODO: The only reset domain which seems to have an effect is
+		 * AUDIO_P, which is shared with ADMAC (at minimum) and so can only
+		 * be triggered non-exclusively.
+		 */
+		struct reset_control *rst;
+
+		rst = of_reset_control_array_get(pdev->dev.of_node, true, true, false);
+		if (IS_ERR(rst)) {
+			dev_err(&pdev->dev, "unable to obtain reset control: %ld\n",
+					PTR_ERR(rst));
+		} else if (rst) {
+			reset_control_reset(rst);
+			reset_control_put(rst);
+		}
+	}
+
+	dai_drivers = devm_kzalloc(&pdev->dev, sizeof(*dai_drivers) * 2 * nclusters,
+					GFP_KERNEL);
+	if (!dai_drivers)
+		return -ENOMEM;
+
+	mca->pd_dev = dev_pm_domain_attach_by_id(&pdev->dev, 0);
+	if (IS_ERR(mca->pd_dev))
+		return -EINVAL;
+
+	/*
+	 * TODO: need cleanup?
+	 */
+	mca->pd_link = device_link_add(&pdev->dev, mca->pd_dev,
+				       DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME |
+				       DL_FLAG_RPM_ACTIVE);
+	if (!mca->pd_link) {
+		ret = -EINVAL;
+		goto err_release;
+	}
+
+	for (i = 0; i < nclusters; i++) {
+		struct mca_cluster *cl = &clusters[i];
+		struct snd_soc_dai_driver *fe = &dai_drivers[mca->nclusters + i];
+		struct snd_soc_dai_driver *be = &dai_drivers[i];
+		int stream;
+
+		cl->host = mca;
+		cl->no = i;
+		cl->base = base + CLUSTER_STRIDE * i;
+		cl->port_driver = -1;
+		cl->clk_parent = of_clk_get(pdev->dev.of_node, i);
+		if (IS_ERR(cl->clk_parent)) {
+			dev_err(&pdev->dev, "unable to obtain clock %d: %ld\n",
+				i, PTR_ERR(cl->clk_parent));
+			ret = PTR_ERR(cl->clk_parent);
+			goto err_release;
+		}
+		cl->pd_dev = dev_pm_domain_attach_by_id(&pdev->dev, i + 1);
+		if (IS_ERR(cl->pd_dev)) {
+			dev_err(&pdev->dev, "unable to obtain cluster %d PD: %ld\n",
+				i, PTR_ERR(cl->pd_dev));
+			ret = PTR_ERR(cl->pd_dev);
+			goto err_release;
+		}
+
+		for_each_pcm_streams(stream) {
+			struct dma_chan *chan;
+			bool is_tx = (stream == SNDRV_PCM_STREAM_PLAYBACK);
+#ifndef USE_RXB_FOR_CAPTURE
+			char *name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+					is_tx ? "tx%da" : "rx%da", i);
+#else
+			char *name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+					is_tx ? "tx%da" : "rx%db", i);
+#endif
+
+			chan = of_dma_request_slave_channel(pdev->dev.of_node, name);
+			if (IS_ERR(chan)) {
+				if (PTR_ERR(chan) != -EPROBE_DEFER)
+					dev_err(&pdev->dev, "no %s DMA channel: %ld\n",
+						name, PTR_ERR(chan));
+
+				ret = PTR_ERR(chan);
+				goto err_release;
+			}
+
+			cl->dma_chans[stream] = chan;
+		}
+
+		fe->id = i;
+		fe->name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+						"mca-pcm-%d", i);
+		if (!fe->name) {
+			ret = -ENOMEM;
+			goto err_release;
+		}
+		fe->ops = &mca_fe_ops;
+		fe->playback.channels_min = 1;
+		fe->playback.channels_max = 32;
+		fe->playback.rates = SNDRV_PCM_RATE_8000_192000;
+		fe->playback.formats = APPLE_MCA_FMTBITS;
+		fe->capture.channels_min = 1;
+		fe->capture.channels_max = 32;
+		fe->capture.rates = SNDRV_PCM_RATE_8000_192000;
+		fe->capture.formats = APPLE_MCA_FMTBITS;
+		fe->symmetric_rate = 1;
+
+		fe->playback.stream_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+							   "PCM%d TX", i);
+		fe->capture.stream_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+							   "PCM%d RX", i);
+
+		if (!fe->playback.stream_name || !fe->capture.stream_name) {
+			ret = -ENOMEM;
+			goto err_release;
+		}
+
+		be->id = i + nclusters;
+		be->name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+						"mca-i2s-%d", i);
+		if (!be->name) {
+			ret = -ENOMEM;
+			goto err_release;
+		}
+		be->ops = &mca_be_ops;
+		be->playback.channels_min = 1;
+		be->playback.channels_max = 32;
+		be->playback.rates = SNDRV_PCM_RATE_8000_192000;
+		be->playback.formats = APPLE_MCA_FMTBITS;
+		be->capture.channels_min = 1;
+		be->capture.channels_max = 32;
+		be->capture.rates = SNDRV_PCM_RATE_8000_192000;
+		be->capture.formats = APPLE_MCA_FMTBITS;
+
+		be->playback.stream_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+							   "I2S%d TX", i);
+		be->capture.stream_name = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+							   "I2S%d RX", i);
+		if (!be->playback.stream_name || !be->capture.stream_name) {
+			ret = -ENOMEM;
+			goto err_release;
+		}
+	}
+
+	ret = devm_snd_soc_register_component(&pdev->dev, &mca_component,
+						dai_drivers, nclusters * 2);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to register ASoC component: %d\n", ret);
+		goto err_release;
+	}
+
+	return 0;
+
+err_release:
+	apple_mca_release(mca);
+	return ret;
+}
+
+static int apple_mca_remove(struct platform_device *pdev)
+{
+	struct mca_data *mca = platform_get_drvdata(pdev);
+
+	apple_mca_release(mca);
+	return 0;
+}
+
+static const struct of_device_id apple_mca_of_match[] = {
+	{ .compatible = "apple,mca", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, apple_mca_of_match);
+
+static struct platform_driver apple_mca_driver = {
+	.driver = {
+		.name = "apple-mca",
+		.owner = THIS_MODULE,
+		.of_match_table = apple_mca_of_match,
+	},
+	.probe = apple_mca_probe,
+	.remove = apple_mca_remove,
+};
+module_platform_driver(apple_mca_driver);
+
+MODULE_AUTHOR("Martin Povišer <povik+lin@cutebit.org>");
+MODULE_DESCRIPTION("ASoC platform driver for Apple Silicon SoCs");
+MODULE_LICENSE("GPL");
-- 
2.33.0