video/hdmi: Add Unpack only function for DRM infoframe
authorGwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Thu, 14 May 2020 06:07:19 +0000 (09:07 +0300)
committerJani Nikula <jani.nikula@intel.com>
Thu, 14 May 2020 10:50:43 +0000 (13:50 +0300)
It adds an unpack only function for DRM infoframe for dynamic range and
mastering infoframe readout.
It unpacks the information data block contained in the binary buffer into
a structured frame of the HDMI Dynamic Range and Mastering (DRM)
information frame.

In contrast to hdmi_drm_infoframe_unpack() function, it does not verify
a checksum.

It can be used for unpacking a DP HDR Metadata Infoframe SDP case.
DP HDR Metadata Infoframe SDP uses the same Dynamic Range and Mastering
(DRM) information (CTA-861-G spec.) such as HDMI DRM infoframe.
But DP SDP header and payload structure are different from HDMI DRM
Infoframe. Therefore unpacking DRM infoframe for DP requires skipping of
a verifying checksum.

v9: Add clear comments to hdmi_drm_infoframe_unpack_only() and
    hdmi_drm_infoframe_unpack() (Laurent Pinchart)

Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200514060732.3378396-2-gwan-gyeong.mun@intel.com
drivers/video/hdmi.c
include/linux/hdmi.h

index 856a8c4e84a25a895d355ace01da87dbe201edfb..e70792b3e367488667df008803bdf66d8c358ead 100644 (file)
@@ -1768,20 +1768,21 @@ hdmi_vendor_any_infoframe_unpack(union hdmi_vendor_any_infoframe *frame,
 }
 
 /**
- * hdmi_drm_infoframe_unpack() - unpack binary buffer to a HDMI DRM infoframe
+ * hdmi_drm_infoframe_unpack_only() - unpack binary buffer of CTA-861-G DRM
+ *                                    infoframe DataBytes to a HDMI DRM
+ *                                    infoframe
  * @frame: HDMI DRM infoframe
  * @buffer: source buffer
  * @size: size of buffer
  *
- * Unpacks the information contained in binary @buffer into a structured
- * @frame of the HDMI Dynamic Range and Mastering (DRM) information frame.
- * Also verifies the checksum as required by section 5.3.5 of the HDMI 1.4
- * specification.
+ * Unpacks CTA-861-G DRM infoframe DataBytes contained in the binary @buffer
+ * into a structured @frame of the HDMI Dynamic Range and Mastering (DRM)
+ * infoframe.
  *
  * Returns 0 on success or a negative error code on failure.
  */
-static int hdmi_drm_infoframe_unpack(struct hdmi_drm_infoframe *frame,
-                                    const void *buffer, size_t size)
+int hdmi_drm_infoframe_unpack_only(struct hdmi_drm_infoframe *frame,
+                                  const void *buffer, size_t size)
 {
        const u8 *ptr = buffer;
        const u8 *temp;
@@ -1790,23 +1791,13 @@ static int hdmi_drm_infoframe_unpack(struct hdmi_drm_infoframe *frame,
        int ret;
        int i;
 
-       if (size < HDMI_INFOFRAME_SIZE(DRM))
-               return -EINVAL;
-
-       if (ptr[0] != HDMI_INFOFRAME_TYPE_DRM ||
-           ptr[1] != 1 ||
-           ptr[2] != HDMI_DRM_INFOFRAME_SIZE)
-               return -EINVAL;
-
-       if (hdmi_infoframe_checksum(buffer, HDMI_INFOFRAME_SIZE(DRM)) != 0)
+       if (size < HDMI_DRM_INFOFRAME_SIZE)
                return -EINVAL;
 
        ret = hdmi_drm_infoframe_init(frame);
        if (ret)
                return ret;
 
-       ptr += HDMI_INFOFRAME_HEADER_SIZE;
-
        frame->eotf = ptr[0] & 0x7;
        frame->metadata_type = ptr[1] & 0x7;
 
@@ -1814,7 +1805,7 @@ static int hdmi_drm_infoframe_unpack(struct hdmi_drm_infoframe *frame,
        for (i = 0; i < 3; i++) {
                x_lsb = *temp++;
                x_msb = *temp++;
-               frame->display_primaries[i].x =  (x_msb << 8) | x_lsb;
+               frame->display_primaries[i].x = (x_msb << 8) | x_lsb;
                y_lsb = *temp++;
                y_msb = *temp++;
                frame->display_primaries[i].y = (y_msb << 8) | y_lsb;
@@ -1830,6 +1821,42 @@ static int hdmi_drm_infoframe_unpack(struct hdmi_drm_infoframe *frame,
 
        return 0;
 }
+EXPORT_SYMBOL(hdmi_drm_infoframe_unpack_only);
+
+/**
+ * hdmi_drm_infoframe_unpack() - unpack binary buffer to a HDMI DRM infoframe
+ * @frame: HDMI DRM infoframe
+ * @buffer: source buffer
+ * @size: size of buffer
+ *
+ * Unpacks the CTA-861-G DRM infoframe contained in the binary @buffer into
+ * a structured @frame of the HDMI Dynamic Range and Mastering (DRM)
+ * infoframe. It also verifies the checksum as required by section 5.3.5 of
+ * the HDMI 1.4 specification.
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+static int hdmi_drm_infoframe_unpack(struct hdmi_drm_infoframe *frame,
+                                    const void *buffer, size_t size)
+{
+       const u8 *ptr = buffer;
+       int ret;
+
+       if (size < HDMI_INFOFRAME_SIZE(DRM))
+               return -EINVAL;
+
+       if (ptr[0] != HDMI_INFOFRAME_TYPE_DRM ||
+           ptr[1] != 1 ||
+           ptr[2] != HDMI_DRM_INFOFRAME_SIZE)
+               return -EINVAL;
+
+       if (hdmi_infoframe_checksum(buffer, HDMI_INFOFRAME_SIZE(DRM)) != 0)
+               return -EINVAL;
+
+       ret = hdmi_drm_infoframe_unpack_only(frame, ptr + HDMI_INFOFRAME_HEADER_SIZE,
+                                            size - HDMI_INFOFRAME_HEADER_SIZE);
+       return ret;
+}
 
 /**
  * hdmi_infoframe_unpack() - unpack binary buffer to a HDMI infoframe
index 9613d796cfb1772a97f225e79936fe21a68e224b..50c31f1a0a2d097a57b9ceac6adb3d54cbd53747 100644 (file)
@@ -219,6 +219,8 @@ ssize_t hdmi_drm_infoframe_pack(struct hdmi_drm_infoframe *frame, void *buffer,
 ssize_t hdmi_drm_infoframe_pack_only(const struct hdmi_drm_infoframe *frame,
                                     void *buffer, size_t size);
 int hdmi_drm_infoframe_check(struct hdmi_drm_infoframe *frame);
+int hdmi_drm_infoframe_unpack_only(struct hdmi_drm_infoframe *frame,
+                                  const void *buffer, size_t size);
 
 enum hdmi_spd_sdi {
        HDMI_SPD_SDI_UNKNOWN,