[v2,9/9] drm/i915: set proper N/M in modeset

Submitted by Jani Nikula on Sept. 23, 2016, 12:02 p.m.

Details

Message ID 84b780032952f3e77f11cab3121fcac7000671ce.1474632005.git.jani.nikula@intel.com
State New
Headers show
Series "drm/i915/audio: audio cleanups, 4k fixes" ( rev: 2 ) in Intel GFX

Not browsing as part of any series.

Commit Message

Jani Nikula Sept. 23, 2016, 12:02 p.m.
When modeset occurs and the LS_CLK is set to some
special values in DP mode, the N/M need to be set
manually if audio is playing. Otherwise the first
several seconds may be silent in audio playback.

The relationship of Maud and Naud is expressed in
the following equation:
Maud/Naud = 512 * fs / f_LS_Clk

Please refer VESA DisplayPort Standard spec for details.

Signed-off-by: Libin Yang <libin.yang@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h    |   7 +++
 drivers/gpu/drm/i915/intel_audio.c | 100 ++++++++++++++++++++++++++++++++++++-
 2 files changed, 105 insertions(+), 2 deletions(-)

Patch hide | download patch | download mbox

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index dc04ce68f8b6..2ceeeede9513 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -7358,6 +7358,13 @@  enum {
 #define _HSW_AUD_MISC_CTRL_B		0x65110
 #define HSW_AUD_MISC_CTRL(pipe)		_MMIO_PIPE(pipe, _HSW_AUD_MISC_CTRL_A, _HSW_AUD_MISC_CTRL_B)
 
+#define _HSW_AUD_M_CTS_ENABLE_A		0x65028
+#define _HSW_AUD_M_CTS_ENABLE_B		0x65128
+#define HSW_AUD_M_CTS_ENABLE(pipe)	_MMIO_PIPE(pipe, _HSW_AUD_M_CTS_ENABLE_A, _HSW_AUD_M_CTS_ENABLE_B)
+#define   AUD_M_CTS_M_VALUE_INDEX	(1 << 21)
+#define   AUD_M_CTS_M_PROG_ENABLE	(1 << 20)
+#define   AUD_CONFIG_M_MASK		0xfffff
+
 #define _HSW_AUD_DIP_ELD_CTRL_ST_A	0x650b4
 #define _HSW_AUD_DIP_ELD_CTRL_ST_B	0x651b4
 #define HSW_AUD_DIP_ELD_CTRL(pipe)	_MMIO_PIPE(pipe, _HSW_AUD_DIP_ELD_CTRL_ST_A, _HSW_AUD_DIP_ELD_CTRL_ST_B)
diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
index 81df29ca4947..0bc2701b6c9c 100644
--- a/drivers/gpu/drm/i915/intel_audio.c
+++ b/drivers/gpu/drm/i915/intel_audio.c
@@ -57,6 +57,70 @@ 
  * struct &i915_audio_component_audio_ops @audio_ops is called from i915 driver.
  */
 
+/* DP N/M table */
+#define LC_540M 540000
+#define LC_270M 270000
+#define LC_162M 162000
+
+struct dp_aud_n_m {
+	int sample_rate;
+	int clock;
+	u16 n;
+	u16 m;
+};
+
+static const struct dp_aud_n_m dp_aud_n_m[] = {
+	{ 192000, LC_540M, 5625, 1024 },
+	{ 176400, LC_540M, 9375, 1568 },
+	{ 96000, LC_540M, 5625, 512 },
+	{ 88200, LC_540M, 9375, 784 },
+	{ 48000, LC_540M, 5625, 256 },
+	{ 44100, LC_540M, 9375, 392 },
+	{ 32000, LC_540M, 16875, 512 },
+	{ 192000, LC_270M, 5625, 2048 },
+	{ 176400, LC_270M, 9375, 3136 },
+	{ 96000, LC_270M, 5625, 1024 },
+	{ 88200, LC_270M, 9375, 1568 },
+	{ 48000, LC_270M, 5625, 512 },
+	{ 44100, LC_270M, 9375, 784 },
+	{ 32000, LC_270M, 16875, 1024 },
+	{ 192000, LC_162M, 3375, 2048 },
+	{ 176400, LC_162M, 5625, 3136 },
+	{ 96000, LC_162M, 3375, 1024 },
+	{ 88200, LC_162M, 5625, 1568 },
+	{ 48000, LC_162M, 3375, 512 },
+	{ 44100, LC_162M, 5625, 784 },
+	{ 32000, LC_162M, 10125, 1024 },
+};
+
+static const struct dp_aud_n_m *
+audio_config_dp_get_n_m(struct intel_crtc *intel_crtc, int rate)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(dp_aud_n_m); i++) {
+		if (rate == dp_aud_n_m[i].sample_rate &&
+		    intel_crtc->config->port_clock == dp_aud_n_m[i].clock)
+			return &dp_aud_n_m[i];
+	}
+
+	return NULL;
+}
+
+static int audio_config_dp_get_m(struct intel_crtc *intel_crtc, int rate)
+{
+	const struct dp_aud_n_m *nm = audio_config_dp_get_n_m(intel_crtc, rate);
+
+	return nm ? nm->m : 0;
+}
+
+static int audio_config_dp_get_n(struct intel_crtc *intel_crtc, int rate)
+{
+	const struct dp_aud_n_m *nm = audio_config_dp_get_n_m(intel_crtc, rate);
+
+	return nm ? nm->n : 0;
+}
+
 static const struct {
 	int clock;
 	u32 config;
@@ -225,8 +289,10 @@  hsw_dp_audio_config_update(struct intel_crtc *intel_crtc, enum port port,
 			   const struct drm_display_mode *adjusted_mode)
 {
 	struct drm_i915_private *dev_priv = to_i915(intel_crtc->base.dev);
+	struct i915_audio_component *acomp = dev_priv->audio_component;
+	int rate = acomp ? acomp->aud_sample_rate[port] : 0;
 	enum pipe pipe = intel_crtc->pipe;
-	u32 tmp;
+	u32 tmp, n, m;
 
 	tmp = I915_READ(HSW_AUD_CFG(pipe));
 	tmp &= ~AUD_CONFIG_N_VALUE_INDEX;
@@ -234,7 +300,30 @@  hsw_dp_audio_config_update(struct intel_crtc *intel_crtc, enum port port,
 	tmp &= ~AUD_CONFIG_N_PROG_ENABLE;
 	tmp |= AUD_CONFIG_N_VALUE_INDEX;
 
+	if (intel_crtc->config->port_clock == LC_540M ||
+	    intel_crtc->config->port_clock == LC_270M ||
+	    intel_crtc->config->port_clock == LC_162M) {
+		n = audio_config_dp_get_n(intel_crtc, rate);
+		if (n != 0) {
+			tmp &= ~AUD_CONFIG_N_MASK;
+			tmp |= AUD_CONFIG_N(n);
+			tmp |= AUD_CONFIG_N_PROG_ENABLE;
+		} else {
+			DRM_DEBUG_KMS("no suitable N value is found\n");
+		}
+	}
+
 	I915_WRITE(HSW_AUD_CFG(pipe), tmp);
+
+	m = audio_config_dp_get_m(intel_crtc, rate);
+	if (m) {
+		tmp = I915_READ(HSW_AUD_M_CTS_ENABLE(pipe));
+		tmp &= ~AUD_CONFIG_M_MASK;
+		tmp |= m;
+		tmp |= AUD_M_CTS_M_VALUE_INDEX;
+		tmp |= AUD_M_CTS_M_PROG_ENABLE;
+		I915_WRITE(HSW_AUD_M_CTS_ENABLE(pipe), tmp);
+	}
 }
 
 static void
@@ -267,6 +356,12 @@  hsw_hdmi_audio_config_update(struct intel_crtc *intel_crtc, enum port port,
 	}
 
 	I915_WRITE(HSW_AUD_CFG(pipe), tmp);
+
+	tmp = I915_READ(HSW_AUD_M_CTS_ENABLE(pipe));
+	tmp &= ~AUD_CONFIG_M_MASK;
+	tmp &= ~AUD_M_CTS_M_VALUE_INDEX;
+	tmp |= AUD_M_CTS_M_PROG_ENABLE;
+	I915_WRITE(HSW_AUD_M_CTS_ENABLE(pipe), tmp);
 }
 
 static void
@@ -687,7 +782,8 @@  static int i915_audio_component_sync_audio_rate(struct device *kdev, int port,
 	/* 1. get the pipe */
 	intel_encoder = get_saved_enc(dev_priv, port, pipe);
 	if (!intel_encoder || !intel_encoder->base.crtc ||
-	    intel_encoder->type != INTEL_OUTPUT_HDMI) {
+	    (intel_encoder->type != INTEL_OUTPUT_HDMI &&
+	     intel_encoder->type != INTEL_OUTPUT_DP)) {
 		DRM_DEBUG_KMS("Not valid for port %c\n", port_name(port));
 		err = -ENODEV;
 		goto unlock;