video/hdmi: Introduce a generic hdmi_infoframe union

And a way to pack hdmi_infoframe generically.

Cc: Thierry Reding <thierry.reding@avionic-design.de>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Acked-by: NDave Airlie <airlied@gmail.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/video/hdmi.c

@@ -22,6 +22,7 @@
  */
 
 #include <linux/bitops.h>
+#include <linux/bug.h>
 #include <linux/errno.h>
 #include <linux/export.h>
 #include <linux/hdmi.h>
@@ -321,3 +322,45 @@ ssize_t hdmi_vendor_infoframe_pack(struct hdmi_vendor_infoframe *frame,
 	return length;
 }
 EXPORT_SYMBOL(hdmi_vendor_infoframe_pack);
+
+/**
+ * hdmi_infoframe_pack() - write a HDMI infoframe to binary buffer
+ * @frame: HDMI infoframe
+ * @buffer: destination buffer
+ * @size: size of buffer
+ *
+ * Packs the information contained in the @frame structure into a binary
+ * representation that can be written into the corresponding controller
+ * registers. Also computes the checksum as required by section 5.3.5 of
+ * the HDMI 1.4 specification.
+ *
+ * Returns the number of bytes packed into the binary buffer or a negative
+ * error code on failure.
+ */
+ssize_t
+hdmi_infoframe_pack(union hdmi_infoframe *frame, void *buffer, size_t size)
+{
+	ssize_t length;
+
+	switch (frame->any.type) {
+	case HDMI_INFOFRAME_TYPE_AVI:
+		length = hdmi_avi_infoframe_pack(&frame->avi, buffer, size);
+		break;
+	case HDMI_INFOFRAME_TYPE_SPD:
+		length = hdmi_spd_infoframe_pack(&frame->spd, buffer, size);
+		break;
+	case HDMI_INFOFRAME_TYPE_AUDIO:
+		length = hdmi_audio_infoframe_pack(&frame->audio, buffer, size);
+		break;
+	case HDMI_INFOFRAME_TYPE_VENDOR:
+		length = hdmi_vendor_infoframe_pack(&frame->vendor,
+						    buffer, size);
+		break;
+	default:
+		WARN(1, "Bad infoframe type %d\n", frame->any.type);
+		length = -EINVAL;
+	}
+
+	return length;
+}
+EXPORT_SYMBOL(hdmi_infoframe_pack);

include/linux/hdmi.h

@@ -23,6 +23,12 @@ enum hdmi_infoframe_type {
 #define HDMI_SPD_INFOFRAME_SIZE    25
 #define HDMI_AUDIO_INFOFRAME_SIZE  10
 
+struct hdmi_any_infoframe {
+	enum hdmi_infoframe_type type;
+	unsigned char version;
+	unsigned char length;
+};
+
 enum hdmi_colorspace {
 	HDMI_COLORSPACE_RGB,
 	HDMI_COLORSPACE_YUV422,
@@ -228,4 +234,15 @@ struct hdmi_vendor_infoframe {
 ssize_t hdmi_vendor_infoframe_pack(struct hdmi_vendor_infoframe *frame,
 				   void *buffer, size_t size);
 
+union hdmi_infoframe {
+	struct hdmi_any_infoframe any;
+	struct hdmi_avi_infoframe avi;
+	struct hdmi_spd_infoframe spd;
+	struct hdmi_vendor_infoframe vendor;
+	struct hdmi_audio_infoframe audio;
+};
+
+ssize_t
+hdmi_infoframe_pack(union hdmi_infoframe *frame, void *buffer, size_t size);
+
 #endif /* _DRM_HDMI_H */