drm/i915/audio: constify ELD pointers

The hooks aren't supposed to modify the ELD, so use const pointer. As a
drive-by fix, use drm_eld_size() to log ELD size.

Suggested-by: Ville Syrjala <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180619124437.10982-1-jani.nikula@intel.com

drivers/gpu/drm/i915/intel_audio.c

@@ -213,7 +213,7 @@ static bool intel_eld_uptodate(struct drm_connector *connector,
 			       i915_reg_t reg_edid)
 {
 	struct drm_i915_private *dev_priv = to_i915(connector->dev);
-	u8 *eld = connector->eld;
+	const u8 *eld = connector->eld;
 	u32 tmp;
 	int i;
 
@@ -228,7 +228,7 @@ static bool intel_eld_uptodate(struct drm_connector *connector,
 	I915_WRITE(reg_elda, tmp);
 
 	for (i = 0; i < drm_eld_size(eld) / 4; i++)
-		if (I915_READ(reg_edid) != *((u32 *)eld + i))
+		if (I915_READ(reg_edid) != *((const u32 *)eld + i))
 			return false;
 
 	return true;
@@ -261,12 +261,12 @@ static void g4x_audio_codec_enable(struct intel_encoder *encoder,
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	struct drm_connector *connector = conn_state->connector;
-	u8 *eld = connector->eld;
+	const u8 *eld = connector->eld;
 	u32 eldv;
 	u32 tmp;
 	int len, i;
 
-	DRM_DEBUG_KMS("Enable audio codec, %u bytes ELD\n", eld[2]);
+	DRM_DEBUG_KMS("Enable audio codec, %u bytes ELD\n", drm_eld_size(eld));
 
 	tmp = I915_READ(G4X_AUD_VID_DID);
 	if (tmp == INTEL_AUDIO_DEVBLC || tmp == INTEL_AUDIO_DEVCL)
@@ -288,7 +288,7 @@ static void g4x_audio_codec_enable(struct intel_encoder *encoder,
 	len = min(drm_eld_size(eld) / 4, len);
 	DRM_DEBUG_DRIVER("ELD size %d\n", len);
 	for (i = 0; i < len; i++)
-		I915_WRITE(G4X_HDMIW_HDMIEDID, *((u32 *)eld + i));
+		I915_WRITE(G4X_HDMIW_HDMIEDID, *((const u32 *)eld + i));
 
 	tmp = I915_READ(G4X_AUD_CNTL_ST);
 	tmp |= eldv;
@@ -466,7 +466,7 @@ static void hsw_audio_codec_enable(struct intel_encoder *encoder,
 	/* Up to 84 bytes of hw ELD buffer */
 	len = min(drm_eld_size(eld), 84);
 	for (i = 0; i < len / 4; i++)
-		I915_WRITE(HSW_AUD_EDID_DATA(pipe), *((u32 *)eld + i));
+		I915_WRITE(HSW_AUD_EDID_DATA(pipe), *((const u32 *)eld + i));
 
 	/* ELD valid */
 	tmp = I915_READ(HSW_AUD_PIN_ELD_CP_VLD);
@@ -534,7 +534,7 @@ static void ilk_audio_codec_enable(struct intel_encoder *encoder,
 	struct drm_connector *connector = conn_state->connector;
 	enum pipe pipe = crtc->pipe;
 	enum port port = encoder->port;
-	u8 *eld = connector->eld;
+	const u8 *eld = connector->eld;
 	u32 tmp, eldv;
 	int len, i;
 	i915_reg_t hdmiw_hdmiedid, aud_config, aud_cntl_st, aud_cntrl_st2;
@@ -585,7 +585,7 @@ static void ilk_audio_codec_enable(struct intel_encoder *encoder,
 	/* Up to 84 bytes of hw ELD buffer */
 	len = min(drm_eld_size(eld), 84);
 	for (i = 0; i < len / 4; i++)
-		I915_WRITE(hdmiw_hdmiedid, *((u32 *)eld + i));
+		I915_WRITE(hdmiw_hdmiedid, *((const u32 *)eld + i));
 
 	/* ELD valid */
 	tmp = I915_READ(aud_cntrl_st2);