drm/tegra: sor: Support for audio over HDMI

This code is very similar to the audio over HDMI support on older chips.
Interoperation with the audio codec is done via a pair of codec scratch
registers and an interrupt that is raised at the SOR when the codec has
written those registers.
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/sor.c

@@ -19,6 +19,8 @@
 
 #include <soc/tegra/pmc.h>
 
+#include <sound/hda_verbs.h>
+
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_dp_helper.h>
 #include <drm/drm_panel.h>
@@ -407,6 +409,7 @@ struct tegra_sor {
 	const struct tegra_sor_soc *soc;
 	void __iomem *regs;
 	unsigned int index;
+	unsigned int irq;
 
 	struct reset_control *rst;
 	struct clk *clk_parent;
@@ -433,6 +436,11 @@ struct tegra_sor {
 
 	struct delayed_work scdc;
 	bool scdc_enabled;
+
+	struct {
+		unsigned int sample_rate;
+		unsigned int channels;
+	} audio;
 };
 
 struct tegra_sor_state {
@@ -2139,6 +2147,144 @@ tegra_sor_hdmi_setup_avi_infoframe(struct tegra_sor *sor,
 	return 0;
 }
 
+static void tegra_sor_write_eld(struct tegra_sor *sor)
+{
+	size_t length = drm_eld_size(sor->output.connector.eld), i;
+
+	for (i = 0; i < length; i++)
+		tegra_sor_writel(sor, i << 8 | sor->output.connector.eld[i],
+				 SOR_AUDIO_HDA_ELD_BUFWR);
+
+	/*
+	 * The HDA codec will always report an ELD buffer size of 96 bytes and
+	 * the HDA codec driver will check that each byte read from the buffer
+	 * is valid. Therefore every byte must be written, even if no 96 bytes
+	 * were parsed from EDID.
+	 */
+	for (i = length; i < 96; i++)
+		tegra_sor_writel(sor, i << 8 | 0, SOR_AUDIO_HDA_ELD_BUFWR);
+}
+
+static void tegra_sor_audio_prepare(struct tegra_sor *sor)
+{
+	u32 value;
+
+	tegra_sor_write_eld(sor);
+
+	value = SOR_AUDIO_HDA_PRESENSE_ELDV | SOR_AUDIO_HDA_PRESENSE_PD;
+	tegra_sor_writel(sor, value, SOR_AUDIO_HDA_PRESENSE);
+}
+
+static void tegra_sor_audio_unprepare(struct tegra_sor *sor)
+{
+	tegra_sor_writel(sor, 0, SOR_AUDIO_HDA_PRESENSE);
+}
+
+static int tegra_sor_hdmi_enable_audio_infoframe(struct tegra_sor *sor)
+{
+	u8 buffer[HDMI_INFOFRAME_SIZE(AUDIO)];
+	struct hdmi_audio_infoframe frame;
+	u32 value;
+	int err;
+
+	err = hdmi_audio_infoframe_init(&frame);
+	if (err < 0) {
+		dev_err(sor->dev, "failed to setup audio infoframe: %d\n", err);
+		return err;
+	}
+
+	frame.channels = sor->audio.channels;
+
+	err = hdmi_audio_infoframe_pack(&frame, buffer, sizeof(buffer));
+	if (err < 0) {
+		dev_err(sor->dev, "failed to pack audio infoframe: %d\n", err);
+		return err;
+	}
+
+	tegra_sor_hdmi_write_infopack(sor, buffer, err);
+
+	value = tegra_sor_readl(sor, SOR_HDMI_AUDIO_INFOFRAME_CTRL);
+	value |= INFOFRAME_CTRL_CHECKSUM_ENABLE;
+	value |= INFOFRAME_CTRL_ENABLE;
+	tegra_sor_writel(sor, value, SOR_HDMI_AUDIO_INFOFRAME_CTRL);
+
+	return 0;
+}
+
+static void tegra_sor_hdmi_audio_enable(struct tegra_sor *sor)
+{
+	u32 value;
+
+	value = tegra_sor_readl(sor, SOR_AUDIO_CNTRL);
+
+	/* select HDA audio input */
+	value &= ~SOR_AUDIO_CNTRL_SOURCE_SELECT(SOURCE_SELECT_MASK);
+	value |= SOR_AUDIO_CNTRL_SOURCE_SELECT(SOURCE_SELECT_HDA);
+
+	/* inject null samples */
+	if (sor->audio.channels != 2)
+		value &= ~SOR_AUDIO_CNTRL_INJECT_NULLSMPL;
+	else
+		value |= SOR_AUDIO_CNTRL_INJECT_NULLSMPL;
+
+	value |= SOR_AUDIO_CNTRL_AFIFO_FLUSH;
+
+	tegra_sor_writel(sor, value, SOR_AUDIO_CNTRL);
+
+	/* enable advertising HBR capability */
+	tegra_sor_writel(sor, SOR_AUDIO_SPARE_HBR_ENABLE, SOR_AUDIO_SPARE);
+
+	tegra_sor_writel(sor, 0, SOR_HDMI_ACR_CTRL);
+
+	value = SOR_HDMI_SPARE_ACR_PRIORITY_HIGH |
+		SOR_HDMI_SPARE_CTS_RESET(1) |
+		SOR_HDMI_SPARE_HW_CTS_ENABLE;
+	tegra_sor_writel(sor, value, SOR_HDMI_SPARE);
+
+	/* enable HW CTS */
+	value = SOR_HDMI_ACR_SUBPACK_LOW_SB1(0);
+	tegra_sor_writel(sor, value, SOR_HDMI_ACR_0441_SUBPACK_LOW);
+
+	/* allow packet to be sent */
+	value = SOR_HDMI_ACR_SUBPACK_HIGH_ENABLE;
+	tegra_sor_writel(sor, value, SOR_HDMI_ACR_0441_SUBPACK_HIGH);
+
+	/* reset N counter and enable lookup */
+	value = SOR_HDMI_AUDIO_N_RESET | SOR_HDMI_AUDIO_N_LOOKUP;
+	tegra_sor_writel(sor, value, SOR_HDMI_AUDIO_N);
+
+	value = (24000 * 4096) / (128 * sor->audio.sample_rate / 1000);
+	tegra_sor_writel(sor, value, SOR_AUDIO_AVAL_0320);
+	tegra_sor_writel(sor, 4096, SOR_AUDIO_NVAL_0320);
+
+	tegra_sor_writel(sor, 20000, SOR_AUDIO_AVAL_0441);
+	tegra_sor_writel(sor, 4704, SOR_AUDIO_NVAL_0441);
+
+	tegra_sor_writel(sor, 20000, SOR_AUDIO_AVAL_0882);
+	tegra_sor_writel(sor, 9408, SOR_AUDIO_NVAL_0882);
+
+	tegra_sor_writel(sor, 20000, SOR_AUDIO_AVAL_1764);
+	tegra_sor_writel(sor, 18816, SOR_AUDIO_NVAL_1764);
+
+	value = (24000 * 6144) / (128 * sor->audio.sample_rate / 1000);
+	tegra_sor_writel(sor, value, SOR_AUDIO_AVAL_0480);
+	tegra_sor_writel(sor, 6144, SOR_AUDIO_NVAL_0480);
+
+	value = (24000 * 12288) / (128 * sor->audio.sample_rate / 1000);
+	tegra_sor_writel(sor, value, SOR_AUDIO_AVAL_0960);
+	tegra_sor_writel(sor, 12288, SOR_AUDIO_NVAL_0960);
+
+	value = (24000 * 24576) / (128 * sor->audio.sample_rate / 1000);
+	tegra_sor_writel(sor, value, SOR_AUDIO_AVAL_1920);
+	tegra_sor_writel(sor, 24576, SOR_AUDIO_NVAL_1920);
+
+	value = tegra_sor_readl(sor, SOR_HDMI_AUDIO_N);
+	value &= ~SOR_HDMI_AUDIO_N_RESET;
+	tegra_sor_writel(sor, value, SOR_HDMI_AUDIO_N);
+
+	tegra_sor_hdmi_enable_audio_infoframe(sor);
+}
+
 static void tegra_sor_hdmi_disable_audio_infoframe(struct tegra_sor *sor)
 {
 	u32 value;
@@ -2148,6 +2294,11 @@ static void tegra_sor_hdmi_disable_audio_infoframe(struct tegra_sor *sor)
 	tegra_sor_writel(sor, value, SOR_HDMI_AUDIO_INFOFRAME_CTRL);
 }
 
+static void tegra_sor_hdmi_audio_disable(struct tegra_sor *sor)
+{
+	tegra_sor_hdmi_disable_audio_infoframe(sor);
+}
+
 static struct tegra_sor_hdmi_settings *
 tegra_sor_hdmi_find_settings(struct tegra_sor *sor, unsigned long frequency)
 {
@@ -2243,6 +2394,7 @@ static void tegra_sor_hdmi_disable(struct drm_encoder *encoder)
 	u32 value;
 	int err;
 
+	tegra_sor_audio_unprepare(sor);
 	tegra_sor_hdmi_scdc_stop(sor);
 
 	err = tegra_sor_detach(sor);
@@ -2651,6 +2803,7 @@ static void tegra_sor_hdmi_enable(struct drm_encoder *encoder)
 		dev_err(sor->dev, "failed to wakeup SOR: %d\n", err);
 
 	tegra_sor_hdmi_scdc_start(sor);
+	tegra_sor_audio_prepare(sor);
 }
 
 static const struct drm_encoder_helper_funcs tegra_sor_hdmi_helpers = {
@@ -2666,6 +2819,7 @@ static int tegra_sor_init(struct host1x_client *client)
 	struct tegra_sor *sor = host1x_client_to_sor(client);
 	int connector = DRM_MODE_CONNECTOR_Unknown;
 	int encoder = DRM_MODE_ENCODER_NONE;
+	u32 value;
 	int err;
 
 	if (!sor->aux) {
@@ -2759,6 +2913,15 @@ static int tegra_sor_init(struct host1x_client *client)
 	if (err < 0)
 		return err;
 
+	/*
+	 * Enable and unmask the HDA codec SCRATCH0 register interrupt. This
+	 * is used for interoperability between the HDA codec driver and the
+	 * HDMI/DP driver.
+	 */
+	value = SOR_INT_CODEC_SCRATCH1 | SOR_INT_CODEC_SCRATCH0;
+	tegra_sor_writel(sor, value, SOR_INT_ENABLE);
+	tegra_sor_writel(sor, value, SOR_INT_MASK);
+
 	return 0;
 }
 
@@ -2767,6 +2930,9 @@ static int tegra_sor_exit(struct host1x_client *client)
 	struct tegra_sor *sor = host1x_client_to_sor(client);
 	int err;
 
+	tegra_sor_writel(sor, 0, SOR_INT_MASK);
+	tegra_sor_writel(sor, 0, SOR_INT_ENABLE);
+
 	tegra_output_exit(&sor->output);
 
 	if (sor->aux) {
@@ -3037,6 +3203,54 @@ static int tegra_sor_parse_dt(struct tegra_sor *sor)
 	return 0;
 }
 
+static void tegra_hda_parse_format(unsigned int format, unsigned int *rate,
+				   unsigned int *channels)
+{
+	unsigned int mul, div;
+
+	if (format & AC_FMT_BASE_44K)
+		*rate = 44100;
+	else
+		*rate = 48000;
+
+	mul = (format & AC_FMT_MULT_MASK) >> AC_FMT_MULT_SHIFT;
+	div = (format & AC_FMT_DIV_MASK) >> AC_FMT_DIV_SHIFT;
+
+	*rate = *rate * (mul + 1) / (div + 1);
+
+	*channels = (format & AC_FMT_CHAN_MASK) >> AC_FMT_CHAN_SHIFT;
+}
+
+static irqreturn_t tegra_sor_irq(int irq, void *data)
+{
+	struct tegra_sor *sor = data;
+	u32 value;
+
+	value = tegra_sor_readl(sor, SOR_INT_STATUS);
+	tegra_sor_writel(sor, value, SOR_INT_STATUS);
+
+	if (value & SOR_INT_CODEC_SCRATCH0) {
+		value = tegra_sor_readl(sor, SOR_AUDIO_HDA_CODEC_SCRATCH0);
+
+		if (value & SOR_AUDIO_HDA_CODEC_SCRATCH0_VALID) {
+			unsigned int format, sample_rate, channels;
+
+			format = value & SOR_AUDIO_HDA_CODEC_SCRATCH0_FMT_MASK;
+
+			tegra_hda_parse_format(format, &sample_rate, &channels);
+
+			sor->audio.sample_rate = sample_rate;
+			sor->audio.channels = channels;
+
+			tegra_sor_hdmi_audio_enable(sor);
+		} else {
+			tegra_sor_hdmi_audio_disable(sor);
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
 static int tegra_sor_probe(struct platform_device *pdev)
 {
 	struct device_node *np;
@@ -3119,6 +3333,21 @@ static int tegra_sor_probe(struct platform_device *pdev)
 		goto remove;
 	}
 
+	err = platform_get_irq(pdev, 0);
+	if (err < 0) {
+		dev_err(&pdev->dev, "failed to get IRQ: %d\n", err);
+		goto remove;
+	}
+
+	sor->irq = err;
+
+	err = devm_request_irq(sor->dev, sor->irq, tegra_sor_irq, 0,
+			       dev_name(sor->dev), sor);
+	if (err < 0) {
+		dev_err(&pdev->dev, "failed to request IRQ: %d\n", err);
+		goto remove;
+	}
+
 	if (!pdev->dev.pm_domain) {
 		sor->rst = devm_reset_control_get(&pdev->dev, "sor");
 		if (IS_ERR(sor->rst)) {

drivers/gpu/drm/tegra/sor.h

@@ -364,12 +364,28 @@
 #define  INFOFRAME_HEADER_VERSION(x) (((x) & 0xff) << 8)
 #define  INFOFRAME_HEADER_TYPE(x) (((x) & 0xff) << 0)
 
+#define SOR_HDMI_ACR_CTRL 0xb1
+
+#define SOR_HDMI_ACR_0320_SUBPACK_LOW 0xb2
+#define  SOR_HDMI_ACR_SUBPACK_LOW_SB1(x) (((x) & 0xff) << 24)
+
+#define SOR_HDMI_ACR_0320_SUBPACK_HIGH 0xb3
+#define  SOR_HDMI_ACR_SUBPACK_HIGH_ENABLE (1 << 31)
+
+#define SOR_HDMI_ACR_0441_SUBPACK_LOW 0xb4
+#define SOR_HDMI_ACR_0441_SUBPACK_HIGH 0xb5
+
 #define SOR_HDMI_CTRL 0xc0
 #define  SOR_HDMI_CTRL_ENABLE (1 << 30)
 #define  SOR_HDMI_CTRL_MAX_AC_PACKET(x) (((x) & 0x1f) << 16)
 #define  SOR_HDMI_CTRL_AUDIO_LAYOUT (1 << 10)
 #define  SOR_HDMI_CTRL_REKEY(x) (((x) & 0x7f) << 0)
 
+#define SOR_HDMI_SPARE 0xcb
+#define  SOR_HDMI_SPARE_ACR_PRIORITY_HIGH (1 << 31)
+#define  SOR_HDMI_SPARE_CTS_RESET(x) (((x) & 0x7) << 16)
+#define  SOR_HDMI_SPARE_HW_CTS_ENABLE (1 << 0)
+
 #define SOR_REFCLK 0xe6
 #define  SOR_REFCLK_DIV_INT(x) ((((x) >> 2) & 0xff) << 8)
 #define  SOR_REFCLK_DIV_FRAC(x) (((x) & 0x3) << 6)
@@ -378,10 +394,62 @@
 #define  SOR_INPUT_CONTROL_ARM_VIDEO_RANGE_LIMITED (1 << 1)
 #define  SOR_INPUT_CONTROL_HDMI_SRC_SELECT(x) (((x) & 0x1) << 0)
 
+#define SOR_AUDIO_CNTRL 0xfc
+#define  SOR_AUDIO_CNTRL_INJECT_NULLSMPL (1 << 29)
+#define  SOR_AUDIO_CNTRL_SOURCE_SELECT(x) (((x) & 0x3) << 20)
+#define   SOURCE_SELECT_MASK 0x3
+#define   SOURCE_SELECT_HDA 0x2
+#define   SOURCE_SELECT_SPDIF 0x1
+#define   SOURCE_SELECT_AUTO 0x0
+#define  SOR_AUDIO_CNTRL_AFIFO_FLUSH (1 << 12)
+
+#define SOR_AUDIO_SPARE 0xfe
+#define  SOR_AUDIO_SPARE_HBR_ENABLE (1 << 27)
+
+#define SOR_AUDIO_NVAL_0320 0xff
+#define SOR_AUDIO_NVAL_0441 0x100
+#define SOR_AUDIO_NVAL_0882 0x101
+#define SOR_AUDIO_NVAL_1764 0x102
+#define SOR_AUDIO_NVAL_0480 0x103
+#define SOR_AUDIO_NVAL_0960 0x104
+#define SOR_AUDIO_NVAL_1920 0x105
+
+#define SOR_AUDIO_HDA_CODEC_SCRATCH0 0x10a
+#define  SOR_AUDIO_HDA_CODEC_SCRATCH0_VALID (1 << 30)
+#define  SOR_AUDIO_HDA_CODEC_SCRATCH0_FMT_MASK 0xffff
+
+#define SOR_AUDIO_HDA_ELD_BUFWR 0x10c
+#define  SOR_AUDIO_HDA_ELD_BUFWR_INDEX(x) (((x) & 0xff) << 8)
+#define  SOR_AUDIO_HDA_ELD_BUFWR_DATA(x) (((x) & 0xff) << 0)
+
+#define SOR_AUDIO_HDA_PRESENSE 0x10d
+#define  SOR_AUDIO_HDA_PRESENSE_ELDV (1 << 1)
+#define  SOR_AUDIO_HDA_PRESENSE_PD (1 << 0)
+
+#define SOR_AUDIO_AVAL_0320 0x10f
+#define SOR_AUDIO_AVAL_0441 0x110
+#define SOR_AUDIO_AVAL_0882 0x111
+#define SOR_AUDIO_AVAL_1764 0x112
+#define SOR_AUDIO_AVAL_0480 0x113
+#define SOR_AUDIO_AVAL_0960 0x114
+#define SOR_AUDIO_AVAL_1920 0x115
+
+#define SOR_INT_STATUS 0x11c
+#define  SOR_INT_CODEC_CP_REQUEST (1 << 2)
+#define  SOR_INT_CODEC_SCRATCH1 (1 << 1)
+#define  SOR_INT_CODEC_SCRATCH0 (1 << 0)
+
+#define SOR_INT_MASK 0x11d
+#define SOR_INT_ENABLE 0x11e
+
 #define SOR_HDMI_VSI_INFOFRAME_CTRL 0x123
 #define SOR_HDMI_VSI_INFOFRAME_STATUS 0x124
 #define SOR_HDMI_VSI_INFOFRAME_HEADER 0x125
 
+#define SOR_HDMI_AUDIO_N 0x13c
+#define SOR_HDMI_AUDIO_N_LOOKUP (1 << 28)
+#define SOR_HDMI_AUDIO_N_RESET (1 << 20)
+
 #define SOR_HDMI2_CTRL 0x13e
 #define  SOR_HDMI2_CTRL_CLOCK_MODE_DIV_BY_4 (1 << 1)
 #define  SOR_HDMI2_CTRL_SCRAMBLE (1 << 0)