drm: bridge: dw_hdmi: Audio: Add General Parallel Audio (GPA) driver

General Parallel Audio (GPA) interface is one of the supported
audio interface for synopsys HDMI module, which has verified for
i.MX8MPlus platform.
This is initial version for GPA.

Signed-off-by: Shengjiu Wang <[e-mail]>
Signed-off-by: Sandor Yu <[e-mail]>
Reviewed-by: Neil Armstrong <[e-mail]>
Signed-off-by: Robert Foss <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/f[e-mail]

drivers/gpu/drm/bridge/synopsys/Kconfig

···
 	  Support the I2S Audio interface which is part of the Synopsys
 	  Designware HDMI block.
 
+config DRM_DW_HDMI_GP_AUDIO
+	tristate "Synopsys Designware GP Audio interface"
+	depends on DRM_DW_HDMI && SND
+	select SND_PCM
+	select SND_PCM_ELD
+	select SND_PCM_IEC958
+	help
+	  Support the GP Audio interface which is part of the Synopsys
+	  Designware HDMI block.
+
 config DRM_DW_HDMI_CEC
 	tristate "Synopsis Designware CEC interface"
 	depends on DRM_DW_HDMI

drivers/gpu/drm/bridge/synopsys/Makefile

···
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
 obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
+obj-$(CONFIG_DRM_DW_HDMI_GP_AUDIO) += dw-hdmi-gp-audio.o
 obj-$(CONFIG_DRM_DW_HDMI_I2S_AUDIO) += dw-hdmi-i2s-audio.o
 obj-$(CONFIG_DRM_DW_HDMI_CEC) += dw-hdmi-cec.o
 

drivers/gpu/drm/bridge/synopsys/dw-hdmi-gp-audio.c

···
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * dw-hdmi-gp-audio.c
+ *
+ * Copyright 2020-2022 NXP
+ */
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <drm/bridge/dw_hdmi.h>
+#include <drm/drm_edid.h>
+#include <drm/drm_connector.h>
+
+#include <sound/hdmi-codec.h>
+#include <sound/asoundef.h>
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/pcm.h>
+#include <sound/pcm_drm_eld.h>
+#include <sound/pcm_iec958.h>
+#include <sound/dmaengine_pcm.h>
+
+#include "dw-hdmi-audio.h"
+
+#define DRIVER_NAME "dw-hdmi-gp-audio"
+#define DRV_NAME    "hdmi-gp-audio"
+
+struct snd_dw_hdmi {
+	struct dw_hdmi_audio_data data;
+	struct platform_device  *audio_pdev;
+	unsigned int pos;
+};
+
+struct dw_hdmi_channel_conf {
+	u8 conf1;
+	u8 ca;
+};
+
+/*
+ * The default mapping of ALSA channels to HDMI channels and speaker
+ * allocation bits.  Note that we can't do channel remapping here -
+ * channels must be in the same order.
+ *
+ * Mappings for alsa-lib pcm/surround*.conf files:
+ *
+ *		Front	Sur4.0	Sur4.1	Sur5.0	Sur5.1	Sur7.1
+ * Channels	2	4	6	6	6	8
+ *
+ * Our mapping from ALSA channel to CEA686D speaker name and HDMI channel:
+ *
+ *				Number of ALSA channels
+ * ALSA Channel	2	3	4	5	6	7	8
+ * 0		FL:0	=	=	=	=	=	=
+ * 1		FR:1	=	=	=	=	=	=
+ * 2			FC:3	RL:4	LFE:2	=	=	=
+ * 3				RR:5	RL:4	FC:3	=	=
+ * 4					RR:5	RL:4	=	=
+ * 5						RR:5	=	=
+ * 6							RC:6	=
+ * 7							RLC/FRC	RLC/FRC
+ */
+static struct dw_hdmi_channel_conf default_hdmi_channel_config[7] = {
+	{ 0x03, 0x00 },	/* FL,FR */
+	{ 0x0b, 0x02 },	/* FL,FR,FC */
+	{ 0x33, 0x08 },	/* FL,FR,RL,RR */
+	{ 0x37, 0x09 },	/* FL,FR,LFE,RL,RR */
+	{ 0x3f, 0x0b },	/* FL,FR,LFE,FC,RL,RR */
+	{ 0x7f, 0x0f },	/* FL,FR,LFE,FC,RL,RR,RC */
+	{ 0xff, 0x13 },	/* FL,FR,LFE,FC,RL,RR,[FR]RC,[FR]LC */
+};
+
+static int audio_hw_params(struct device *dev,  void *data,
+			   struct hdmi_codec_daifmt *daifmt,
+			   struct hdmi_codec_params *params)
+{
+	struct snd_dw_hdmi *dw = dev_get_drvdata(dev);
+	int ret = 0;
+	u8 ca;
+
+	dw_hdmi_set_sample_rate(dw->data.hdmi, params->sample_rate);
+
+	ca = default_hdmi_channel_config[params->channels - 2].ca;
+
+	dw_hdmi_set_channel_count(dw->data.hdmi, params->channels);
+	dw_hdmi_set_channel_allocation(dw->data.hdmi, ca);
+
+	dw_hdmi_set_sample_non_pcm(dw->data.hdmi,
+				   params->iec.status[0] & IEC958_AES0_NONAUDIO);
+	dw_hdmi_set_sample_width(dw->data.hdmi, params->sample_width);
+
+	return ret;
+}
+
+static void audio_shutdown(struct device *dev, void *data)
+{
+}
+
+static int audio_mute_stream(struct device *dev, void *data,
+			     bool enable, int direction)
+{
+	struct snd_dw_hdmi *dw = dev_get_drvdata(dev);
+	int ret = 0;
+
+	if (!enable)
+		dw_hdmi_audio_enable(dw->data.hdmi);
+	else
+		dw_hdmi_audio_disable(dw->data.hdmi);
+
+	return ret;
+}
+
+static int audio_get_eld(struct device *dev, void *data,
+			 u8 *buf, size_t len)
+{
+	struct dw_hdmi_audio_data *audio = data;
+	u8 *eld;
+
+	eld = audio->get_eld(audio->hdmi);
+	if (eld)
+		memcpy(buf, eld, min_t(size_t, MAX_ELD_BYTES, len));
+	else
+		/* Pass en empty ELD if connector not available */
+		memset(buf, 0, len);
+
+	return 0;
+}
+
+static int audio_hook_plugged_cb(struct device *dev, void *data,
+				 hdmi_codec_plugged_cb fn,
+				 struct device *codec_dev)
+{
+	struct snd_dw_hdmi *dw = dev_get_drvdata(dev);
+
+	return dw_hdmi_set_plugged_cb(dw->data.hdmi, fn, codec_dev);
+}
+
+static const struct hdmi_codec_ops audio_codec_ops = {
+	.hw_params = audio_hw_params,
+	.audio_shutdown = audio_shutdown,
+	.mute_stream = audio_mute_stream,
+	.get_eld = audio_get_eld,
+	.hook_plugged_cb = audio_hook_plugged_cb,
+};
+
+static int snd_dw_hdmi_probe(struct platform_device *pdev)
+{
+	struct dw_hdmi_audio_data *data = pdev->dev.platform_data;
+	struct snd_dw_hdmi *dw;
+
+	const struct hdmi_codec_pdata codec_data = {
+		.i2s = 1,
+		.spdif = 0,
+		.ops = &audio_codec_ops,
+		.max_i2s_channels = 8,
+		.data = data,
+	};
+
+	dw = devm_kzalloc(&pdev->dev, sizeof(*dw), GFP_KERNEL);
+	if (!dw)
+		return -ENOMEM;
+
+	dw->data = *data;
+
+	platform_set_drvdata(pdev, dw);
+
+	dw->audio_pdev = platform_device_register_data(&pdev->dev,
+						       HDMI_CODEC_DRV_NAME, 1,
+						       &codec_data,
+						       sizeof(codec_data));
+
+	return PTR_ERR_OR_ZERO(dw->audio_pdev);
+}
+
+static int snd_dw_hdmi_remove(struct platform_device *pdev)
+{
+	struct snd_dw_hdmi *dw = platform_get_drvdata(pdev);
+
+	platform_device_unregister(dw->audio_pdev);
+
+	return 0;
+}
+
+static struct platform_driver snd_dw_hdmi_driver = {
+	.probe	= snd_dw_hdmi_probe,
+	.remove	= snd_dw_hdmi_remove,
+	.driver	= {
+		.name = DRIVER_NAME,
+	},
+};
+
+module_platform_driver(snd_dw_hdmi_driver);
+
+MODULE_AUTHOR("Shengjiu Wang <[e-mail]>");
+MODULE_DESCRIPTION("Synopsys Designware HDMI GPA ALSA interface");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:" DRIVER_NAME);

drivers/gpu/drm/bridge/synopsys/dw-hdmi.c

···
 
 	spinlock_t audio_lock;
 	struct mutex audio_mutex;
+	unsigned int sample_non_pcm;
+	unsigned int sample_width;
 	unsigned int sample_rate;
+	unsigned int channels;
 	unsigned int audio_cts;
 	unsigned int audio_n;
 	bool audio_enable;
···
 			n = 4096;
 		else if (pixel_clk == 74176000 || pixel_clk == 148352000)
 			n = 11648;
+		else if (pixel_clk == 297000000)
+			n = 3072;
 		else
 			n = 4096;
 		n *= mult;
···
 			n = 17836;
 		else if (pixel_clk == 148352000)
 			n = 8918;
+		else if (pixel_clk == 297000000)
+			n = 4704;
 		else
 			n = 6272;
 		n *= mult;
···
 			n = 11648;
 		else if (pixel_clk == 148352000)
 			n = 5824;
+		else if (pixel_clk == 297000000)
+			n = 5120;
 		else
 			n = 6144;
 		n *= mult;
···
 
 	config3 = hdmi_readb(hdmi, HDMI_CONFIG3_ID);
 
-	/* Only compute CTS when using internal AHB audio */
-	if (config3 & HDMI_CONFIG3_AHBAUDDMA) {
+	/* Compute CTS when using internal AHB audio or General Parallel audio*/
+	if ((config3 & HDMI_CONFIG3_AHBAUDDMA) || (config3 & HDMI_CONFIG3_GPAUD)) {
 		/*
 		 * Compute the CTS value from the N value.  Note that CTS and N
 		 * can be up to 20 bits in total, so we need 64-bit math.  Also
···
 	mutex_unlock(&hdmi->audio_mutex);
 }
 
+void dw_hdmi_set_sample_width(struct dw_hdmi *hdmi, unsigned int width)
+{
+	mutex_lock(&hdmi->audio_mutex);
+	hdmi->sample_width = width;
+	mutex_unlock(&hdmi->audio_mutex);
+}
+EXPORT_SYMBOL_GPL(dw_hdmi_set_sample_width);
+
+void dw_hdmi_set_sample_non_pcm(struct dw_hdmi *hdmi, unsigned int non_pcm)
+{
+	mutex_lock(&hdmi->audio_mutex);
+	hdmi->sample_non_pcm = non_pcm;
+	mutex_unlock(&hdmi->audio_mutex);
+}
+EXPORT_SYMBOL_GPL(dw_hdmi_set_sample_non_pcm);
+
 void dw_hdmi_set_sample_rate(struct dw_hdmi *hdmi, unsigned int rate)
 {
 	mutex_lock(&hdmi->audio_mutex);
···
 	u8 layout;
 
 	mutex_lock(&hdmi->audio_mutex);
+	hdmi->channels = cnt;
 
 	/*
 	 * For >2 channel PCM audio, we need to select layout 1
···
 		return NULL;
 
 	return hdmi->curr_conn->eld;
+}
+
+static void dw_hdmi_gp_audio_enable(struct dw_hdmi *hdmi)
+{
+	const struct dw_hdmi_plat_data *pdata = hdmi->plat_data;
+	int sample_freq = 0x2, org_sample_freq = 0xD;
+	int ch_mask = BIT(hdmi->channels) - 1;
+
+	switch (hdmi->sample_rate) {
+	case 32000:
+		sample_freq = 0x03;
+		org_sample_freq = 0x0C;
+		break;
+	case 44100:
+		sample_freq = 0x00;
+		org_sample_freq = 0x0F;
+		break;
+	case 48000:
+		sample_freq = 0x02;
+		org_sample_freq = 0x0D;
+		break;
+	case 88200:
+		sample_freq = 0x08;
+		org_sample_freq = 0x07;
+		break;
+	case 96000:
+		sample_freq = 0x0A;
+		org_sample_freq = 0x05;
+		break;
+	case 176400:
+		sample_freq = 0x0C;
+		org_sample_freq = 0x03;
+		break;
+	case 192000:
+		sample_freq = 0x0E;
+		org_sample_freq = 0x01;
+		break;
+	default:
+		break;
+	}
+
+	hdmi_set_cts_n(hdmi, hdmi->audio_cts, hdmi->audio_n);
+	hdmi_enable_audio_clk(hdmi, true);
+
+	hdmi_writeb(hdmi, 0x1, HDMI_FC_AUDSCHNLS0);
+	hdmi_writeb(hdmi, hdmi->channels, HDMI_FC_AUDSCHNLS2);
+	hdmi_writeb(hdmi, 0x22, HDMI_FC_AUDSCHNLS3);
+	hdmi_writeb(hdmi, 0x22, HDMI_FC_AUDSCHNLS4);
+	hdmi_writeb(hdmi, 0x11, HDMI_FC_AUDSCHNLS5);
+	hdmi_writeb(hdmi, 0x11, HDMI_FC_AUDSCHNLS6);
+	hdmi_writeb(hdmi, (0x3 << 4) | sample_freq, HDMI_FC_AUDSCHNLS7);
+	hdmi_writeb(hdmi, (org_sample_freq << 4) | 0xb, HDMI_FC_AUDSCHNLS8);
+
+	hdmi_writeb(hdmi, ch_mask, HDMI_GP_CONF1);
+	hdmi_writeb(hdmi, 0x02, HDMI_GP_CONF2);
+	hdmi_writeb(hdmi, 0x01, HDMI_GP_CONF0);
+
+	hdmi_modb(hdmi,  0x3, 0x3, HDMI_FC_DATAUTO3);
+
+	/* hbr */
+	if (hdmi->sample_rate == 192000 && hdmi->channels == 8 &&
+	    hdmi->sample_width == 32 && hdmi->sample_non_pcm)
+		hdmi_modb(hdmi, 0x01, 0x01, HDMI_GP_CONF2);
+
+	if (pdata->enable_audio)
+		pdata->enable_audio(hdmi,
+					    hdmi->channels,
+					    hdmi->sample_width,
+					    hdmi->sample_rate,
+					    hdmi->sample_non_pcm);
+}
+
+static void dw_hdmi_gp_audio_disable(struct dw_hdmi *hdmi)
+{
+	const struct dw_hdmi_plat_data *pdata = hdmi->plat_data;
+
+	hdmi_set_cts_n(hdmi, hdmi->audio_cts, 0);
+
+	hdmi_modb(hdmi,  0, 0x3, HDMI_FC_DATAUTO3);
+	if (pdata->disable_audio)
+		pdata->disable_audio(hdmi);
+
+	hdmi_enable_audio_clk(hdmi, false);
 }
 
 static void dw_hdmi_ahb_audio_enable(struct dw_hdmi *hdmi)
···
 	hdmi->plat_data = plat_data;
 	hdmi->dev = dev;
 	hdmi->sample_rate = 48000;
+	hdmi->channels = 2;
 	hdmi->disabled = true;
 	hdmi->rxsense = true;
 	hdmi->phy_mask = (u8)~(HDMI_PHY_HPD | HDMI_PHY_RX_SENSE);
···
 		hdmi->disable_audio = dw_hdmi_i2s_audio_disable;
 
 		pdevinfo.name = "dw-hdmi-i2s-audio";
+		pdevinfo.data = &audio;
+		pdevinfo.size_data = sizeof(audio);
+		pdevinfo.dma_mask = DMA_BIT_MASK(32);
+		hdmi->audio = platform_device_register_full(&pdevinfo);
+	} else if (iores && config3 & HDMI_CONFIG3_GPAUD) {
+		struct dw_hdmi_audio_data audio;
+
+		audio.phys = iores->start;
+		audio.base = hdmi->regs;
+		audio.irq = irq;
+		audio.hdmi = hdmi;
+		audio.get_eld = hdmi_audio_get_eld;
+
+		hdmi->enable_audio = dw_hdmi_gp_audio_enable;
+		hdmi->disable_audio = dw_hdmi_gp_audio_disable;
+
+		pdevinfo.name = "dw-hdmi-gp-audio";
+		pdevinfo.id = PLATFORM_DEVID_NONE;
 		pdevinfo.data = &audio;
 		pdevinfo.size_data = sizeof(audio);
 		pdevinfo.dma_mask = DMA_BIT_MASK(32);

drivers/gpu/drm/bridge/synopsys/dw-hdmi.h

···
 #define HDMI_FC_SPDDEVICEINF                    0x1062
 #define HDMI_FC_AUDSCONF                        0x1063
 #define HDMI_FC_AUDSSTAT                        0x1064
-#define HDMI_FC_AUDSCHNLS7                      0x106e
-#define HDMI_FC_AUDSCHNLS8                      0x106f
+#define HDMI_FC_AUDSV                           0x1065
+#define HDMI_FC_AUDSU                           0x1066
+#define HDMI_FC_AUDSCHNLS0                       0x1067
+#define HDMI_FC_AUDSCHNLS1                       0x1068
+#define HDMI_FC_AUDSCHNLS2                       0x1069
+#define HDMI_FC_AUDSCHNLS3                       0x106A
+#define HDMI_FC_AUDSCHNLS4                       0x106B
+#define HDMI_FC_AUDSCHNLS5                       0x106C
+#define HDMI_FC_AUDSCHNLS6                       0x106D
+#define HDMI_FC_AUDSCHNLS7                       0x106E
+#define HDMI_FC_AUDSCHNLS8                       0x106F
 #define HDMI_FC_DATACH0FILL                     0x1070
 #define HDMI_FC_DATACH1FILL                     0x1071
 #define HDMI_FC_DATACH2FILL                     0x1072

include/drm/bridge/dw_hdmi.h

···
 					   const struct drm_display_info *info,
 					   const struct drm_display_mode *mode);
 
+	/* Platform-specific audio enable/disable (optional) */
+	void (*enable_audio)(struct dw_hdmi *hdmi, int channel,
+			     int width, int rate, int non_pcm);
+	void (*disable_audio)(struct dw_hdmi *hdmi);
+
 	/* Vendor PHY support */
 	const struct dw_hdmi_phy_ops *phy_ops;
 	const char *phy_name;
···
 
 int dw_hdmi_set_plugged_cb(struct dw_hdmi *hdmi, hdmi_codec_plugged_cb fn,
 			   struct device *codec_dev);
+void dw_hdmi_set_sample_non_pcm(struct dw_hdmi *hdmi, unsigned int non_pcm);
+void dw_hdmi_set_sample_width(struct dw_hdmi *hdmi, unsigned int width);
 void dw_hdmi_set_sample_rate(struct dw_hdmi *hdmi, unsigned int rate);
 void dw_hdmi_set_channel_count(struct dw_hdmi *hdmi, unsigned int cnt);
 void dw_hdmi_set_channel_status(struct dw_hdmi *hdmi, u8 *channel_status);