drm/i915: pass ELD to HDMI/DP audio driver

Add ELD support for Intel Eaglelake, IbexPeak/Ironlake,
SandyBridge/CougarPoint and IvyBridge/PantherPoint chips.

ELD (EDID-Like Data) describes to the HDMI/DP audio driver the audio
capabilities of the plugged monitor. It's built and passed to audio
driver in 2 steps:

(1) at get_modes time, parse EDID and save ELD to drm_connector.eld[]

(2) at mode_set time, write drm_connector.eld[] to the Transcoder's hw
    ELD buffer and set the ELD_valid bit to inform HDMI/DP audio driver

This patch is tested OK on G45/HDMI, IbexPeak/HDMI and IvyBridge/HDMI+DP.
Test scheme: plug in the HDMI/DP monitor, and run

        cat /proc/asound/card0/eld*

to check if the monitor name, HDMI/DP type, etc. show up correctly.

Minor imperfection: the GEN5_AUD_CNTL_ST/DIP_Port_Select field always
reads 0 (reserved). Without knowing the port number, I worked it around
by setting the ELD_valid bit for ALL the three ports. It's tested to not
be a problem, because the audio driver will find invalid ELD data and
hence rightfully abort, even when it sees the ELD_valid indicator.

Thanks to Zhenyu and Pierre-Louis for a lot of valuable help and testing.

CC: Zhao Yakui <yakui.zhao@intel.com>
CC: Wang Zhenyu <zhenyu.z.wang@intel.com>
CC: Jeremy Bush <contractfrombelow@gmail.com>
CC: Christopher White <c.white@pulseforce.com>
CC: Pierre-Louis Bossart <pierre-louis.bossart@intel.com>
CC: Paul Menzel <paulepanter@users.sourceforge.net>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 130 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index a685957566c9..f0e5f9f32aa8 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -31,6 +31,7 @@
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/vgaarb.h>
+#include <drm/drm_edid.h>
 #include "drmP.h"
 #include "intel_drv.h"
 #include "i915_drm.h"
@@ -5669,6 +5670,131 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc,
 	return ret;
 }
 
+static void g4x_write_eld(struct drm_connector *connector,
+			  struct drm_crtc *crtc)
+{
+	struct drm_i915_private *dev_priv = connector->dev->dev_private;
+	uint8_t *eld = connector->eld;
+	uint32_t eldv;
+	uint32_t len;
+	uint32_t i;
+
+	i = I915_READ(G4X_AUD_VID_DID);
+
+	if (i == INTEL_AUDIO_DEVBLC || i == INTEL_AUDIO_DEVCL)
+		eldv = G4X_ELDV_DEVCL_DEVBLC;
+	else
+		eldv = G4X_ELDV_DEVCTG;
+
+	i = I915_READ(G4X_AUD_CNTL_ST);
+	i &= ~(eldv | G4X_ELD_ADDR);
+	len = (i >> 9) & 0x1f;		/* ELD buffer size */
+	I915_WRITE(G4X_AUD_CNTL_ST, i);
+
+	if (!eld[0])
+		return;
+
+	len = min_t(uint8_t, eld[2], len);
+	DRM_DEBUG_DRIVER("ELD size %d\n", len);
+	for (i = 0; i < len; i++)
+		I915_WRITE(G4X_HDMIW_HDMIEDID, *((uint32_t *)eld + i));
+
+	i = I915_READ(G4X_AUD_CNTL_ST);
+	i |= eldv;
+	I915_WRITE(G4X_AUD_CNTL_ST, i);
+}
+
+static void ironlake_write_eld(struct drm_connector *connector,
+				     struct drm_crtc *crtc)
+{
+	struct drm_i915_private *dev_priv = connector->dev->dev_private;
+	uint8_t *eld = connector->eld;
+	uint32_t eldv;
+	uint32_t i;
+	int len;
+	int hdmiw_hdmiedid;
+	int aud_cntl_st;
+	int aud_cntrl_st2;
+
+	if (IS_IVYBRIDGE(connector->dev)) {
+		hdmiw_hdmiedid = GEN7_HDMIW_HDMIEDID_A;
+		aud_cntl_st = GEN7_AUD_CNTRL_ST_A;
+		aud_cntrl_st2 = GEN7_AUD_CNTRL_ST2;
+	} else {
+		hdmiw_hdmiedid = GEN5_HDMIW_HDMIEDID_A;
+		aud_cntl_st = GEN5_AUD_CNTL_ST_A;
+		aud_cntrl_st2 = GEN5_AUD_CNTL_ST2;
+	}
+
+	i = to_intel_crtc(crtc)->pipe;
+	hdmiw_hdmiedid += i * 0x100;
+	aud_cntl_st += i * 0x100;
+
+	DRM_DEBUG_DRIVER("ELD on pipe %c\n", pipe_name(i));
+
+	i = I915_READ(aud_cntl_st);
+	i = (i >> 29) & 0x3;		/* DIP_Port_Select, 0x1 = PortB */
+	if (!i) {
+		DRM_DEBUG_DRIVER("Audio directed to unknown port\n");
+		/* operate blindly on all ports */
+		eldv = GEN5_ELD_VALIDB;
+		eldv |= GEN5_ELD_VALIDB << 4;
+		eldv |= GEN5_ELD_VALIDB << 8;
+	} else {
+		DRM_DEBUG_DRIVER("ELD on port %c\n", 'A' + i);
+		eldv = GEN5_ELD_VALIDB << ((i - 1) * 4);
+	}
+
+	i = I915_READ(aud_cntrl_st2);
+	i &= ~eldv;
+	I915_WRITE(aud_cntrl_st2, i);
+
+	if (!eld[0])
+		return;
+
+	if (intel_pipe_has_type(crtc, INTEL_OUTPUT_DISPLAYPORT)) {
+		DRM_DEBUG_DRIVER("ELD: DisplayPort detected\n");
+		eld[5] |= (1 << 2);	/* Conn_Type, 0x1 = DisplayPort */
+	}
+
+	i = I915_READ(aud_cntl_st);
+	i &= ~GEN5_ELD_ADDRESS;
+	I915_WRITE(aud_cntl_st, i);
+
+	len = min_t(uint8_t, eld[2], 21);	/* 84 bytes of hw ELD buffer */
+	DRM_DEBUG_DRIVER("ELD size %d\n", len);
+	for (i = 0; i < len; i++)
+		I915_WRITE(hdmiw_hdmiedid, *((uint32_t *)eld + i));
+
+	i = I915_READ(aud_cntrl_st2);
+	i |= eldv;
+	I915_WRITE(aud_cntrl_st2, i);
+}
+
+void intel_write_eld(struct drm_encoder *encoder,
+		     struct drm_display_mode *mode)
+{
+	struct drm_crtc *crtc = encoder->crtc;
+	struct drm_connector *connector;
+	struct drm_device *dev = encoder->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	connector = drm_select_eld(encoder, mode);
+	if (!connector)
+		return;
+
+	DRM_DEBUG_DRIVER("ELD on [CONNECTOR:%d:%s], [ENCODER:%d:%s]\n",
+			 connector->base.id,
+			 drm_get_connector_name(connector),
+			 connector->encoder->base.id,
+			 drm_get_encoder_name(connector->encoder));
+
+	connector->eld[6] = drm_av_sync_delay(connector, mode) / 2;
+
+	if (dev_priv->display.write_eld)
+		dev_priv->display.write_eld(connector, crtc);
+}
+
 /** Loads the palette/gamma unit for the CRTC with the prepared values */
 void intel_crtc_load_lut(struct drm_crtc *crtc)
 {
@@ -8185,6 +8311,7 @@ static void intel_init_display(struct drm_device *dev)
 			}
 			dev_priv->display.fdi_link_train = ironlake_fdi_link_train;
 			dev_priv->display.init_clock_gating = ironlake_init_clock_gating;
+			dev_priv->display.write_eld = ironlake_write_eld;
 		} else if (IS_GEN6(dev)) {
 			if (SNB_READ_WM0_LATENCY()) {
 				dev_priv->display.update_wm = sandybridge_update_wm;
@@ -8195,6 +8322,7 @@ static void intel_init_display(struct drm_device *dev)
 			}
 			dev_priv->display.fdi_link_train = gen6_fdi_link_train;
 			dev_priv->display.init_clock_gating = gen6_init_clock_gating;
+			dev_priv->display.write_eld = ironlake_write_eld;
 		} else if (IS_IVYBRIDGE(dev)) {
 			/* FIXME: detect B0+ stepping and use auto training */
 			dev_priv->display.fdi_link_train = ivb_manual_fdi_link_train;
@@ -8206,7 +8334,7 @@ static void intel_init_display(struct drm_device *dev)
 				dev_priv->display.update_wm = NULL;
 			}
 			dev_priv->display.init_clock_gating = ivybridge_init_clock_gating;
-
+			dev_priv->display.write_eld = ironlake_write_eld;
 		} else
 			dev_priv->display.update_wm = NULL;
 	} else if (IS_PINEVIEW(dev)) {
@@ -8226,6 +8354,7 @@ static void intel_init_display(struct drm_device *dev)
 			dev_priv->display.update_wm = pineview_update_wm;
 		dev_priv->display.init_clock_gating = gen3_init_clock_gating;
 	} else if (IS_G4X(dev)) {
+		dev_priv->display.write_eld = g4x_write_eld;
 		dev_priv->display.update_wm = g4x_update_wm;
 		dev_priv->display.init_clock_gating = g4x_init_clock_gating;
 	} else if (IS_GEN4(dev)) {