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    Subject[PATCH v13 04/10] video/hdmi: Add audio_infoframe packing for DP
    Date
    From: Markus Schneider-Pargmann <msp@baylibre.com>

    Similar to HDMI, DP uses audio infoframes as well which are structured
    very similar to the HDMI ones.

    This patch adds a helper function to pack the HDMI audio infoframe for
    DP, called hdmi_audio_infoframe_pack_for_dp().
    hdmi_audio_infoframe_pack_only() is split into two parts. One of them
    packs the payload only and can be used for HDMI and DP.

    Also constify the frame parameter in hdmi_audio_infoframe_check() as
    it is passed to hdmi_audio_infoframe_check_only() which expects a const.

    Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
    Signed-off-by: Guillaume Ranquet <granquet@baylibre.com>
    Signed-off-by: Bo-Chen Chen <rex-bc.chen@mediatek.com>
    ---
    drivers/video/hdmi.c | 82 +++++++++++++++++++++++++++---------
    include/drm/display/drm_dp.h | 2 +
    include/linux/hdmi.h | 7 ++-
    3 files changed, 71 insertions(+), 20 deletions(-)

    diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c
    index 947be761dfa4..86805d77cc86 100644
    --- a/drivers/video/hdmi.c
    +++ b/drivers/video/hdmi.c
    @@ -21,6 +21,7 @@
    * DEALINGS IN THE SOFTWARE.
    */

    +#include <drm/display/drm_dp.h>
    #include <linux/bitops.h>
    #include <linux/bug.h>
    #include <linux/errno.h>
    @@ -381,12 +382,34 @@ static int hdmi_audio_infoframe_check_only(const struct hdmi_audio_infoframe *fr
    *
    * Returns 0 on success or a negative error code on failure.
    */
    -int hdmi_audio_infoframe_check(struct hdmi_audio_infoframe *frame)
    +int hdmi_audio_infoframe_check(const struct hdmi_audio_infoframe *frame)
    {
    return hdmi_audio_infoframe_check_only(frame);
    }
    EXPORT_SYMBOL(hdmi_audio_infoframe_check);

    +static void
    +hdmi_audio_infoframe_pack_payload(const struct hdmi_audio_infoframe *frame,
    + u8 *buffer)
    +{
    + u8 channels;
    +
    + if (frame->channels >= 2)
    + channels = frame->channels - 1;
    + else
    + channels = 0;
    +
    + buffer[0] = ((frame->coding_type & 0xf) << 4) | (channels & 0x7);
    + buffer[1] = ((frame->sample_frequency & 0x7) << 2) |
    + (frame->sample_size & 0x3);
    + buffer[2] = frame->coding_type_ext & 0x1f;
    + buffer[3] = frame->channel_allocation;
    + buffer[4] = (frame->level_shift_value & 0xf) << 3;
    +
    + if (frame->downmix_inhibit)
    + buffer[4] |= BIT(7);
    +}
    +
    /**
    * hdmi_audio_infoframe_pack_only() - write HDMI audio infoframe to binary buffer
    * @frame: HDMI audio infoframe
    @@ -404,7 +427,6 @@ EXPORT_SYMBOL(hdmi_audio_infoframe_check);
    ssize_t hdmi_audio_infoframe_pack_only(const struct hdmi_audio_infoframe *frame,
    void *buffer, size_t size)
    {
    - unsigned char channels;
    u8 *ptr = buffer;
    size_t length;
    int ret;
    @@ -420,28 +442,13 @@ ssize_t hdmi_audio_infoframe_pack_only(const struct hdmi_audio_infoframe *frame,

    memset(buffer, 0, size);

    - if (frame->channels >= 2)
    - channels = frame->channels - 1;
    - else
    - channels = 0;
    -
    ptr[0] = frame->type;
    ptr[1] = frame->version;
    ptr[2] = frame->length;
    ptr[3] = 0; /* checksum */

    - /* start infoframe payload */
    - ptr += HDMI_INFOFRAME_HEADER_SIZE;
    -
    - ptr[0] = ((frame->coding_type & 0xf) << 4) | (channels & 0x7);
    - ptr[1] = ((frame->sample_frequency & 0x7) << 2) |
    - (frame->sample_size & 0x3);
    - ptr[2] = frame->coding_type_ext & 0x1f;
    - ptr[3] = frame->channel_allocation;
    - ptr[4] = (frame->level_shift_value & 0xf) << 3;
    -
    - if (frame->downmix_inhibit)
    - ptr[4] |= BIT(7);
    + hdmi_audio_infoframe_pack_payload(frame,
    + ptr + HDMI_INFOFRAME_HEADER_SIZE);

    hdmi_infoframe_set_checksum(buffer, length);

    @@ -479,6 +486,43 @@ ssize_t hdmi_audio_infoframe_pack(struct hdmi_audio_infoframe *frame,
    }
    EXPORT_SYMBOL(hdmi_audio_infoframe_pack);

    +/**
    + * hdmi_audio_infoframe_pack_for_dp - Pack a HDMI Audio infoframe for DisplayPort
    + *
    + * @frame: HDMI Audio infoframe
    + * @sdp: secondary data packet for display port. This is filled with the
    + * appropriate: data
    + * @dp_version: Display Port version to be encoded in the header
    + *
    + * Packs a HDMI Audio Infoframe to be sent over Display Port. This function
    + * fills the secondary data packet to be used for Display Port.
    + *
    + * Return: Number of total written bytes or a negative errno on failure.
    + */
    +ssize_t
    +hdmi_audio_infoframe_pack_for_dp(const struct hdmi_audio_infoframe *frame,
    + struct dp_sdp *sdp, u8 dp_version)
    +{
    + int ret;
    +
    + ret = hdmi_audio_infoframe_check(frame);
    + if (ret)
    + return ret;
    +
    + memset(sdp->db, 0, sizeof(sdp->db));
    +
    + /* Secondary-data packet header */
    + sdp->sdp_header.HB0 = 0;
    + sdp->sdp_header.HB1 = frame->type;
    + sdp->sdp_header.HB2 = DP_SDP_AUDIO_INFOFRAME_HB2;
    + sdp->sdp_header.HB3 = (dp_version & 0x3f) << 2;
    +
    + hdmi_audio_infoframe_pack_payload(frame, sdp->db);
    +
    + return frame->length + 4;
    +}
    +EXPORT_SYMBOL(hdmi_audio_infoframe_pack_for_dp);
    +
    /**
    * hdmi_vendor_infoframe_init() - initialize an HDMI vendor infoframe
    * @frame: HDMI vendor infoframe
    diff --git a/include/drm/display/drm_dp.h b/include/drm/display/drm_dp.h
    index 9e3aff7e68bb..6c0871164771 100644
    --- a/include/drm/display/drm_dp.h
    +++ b/include/drm/display/drm_dp.h
    @@ -1536,6 +1536,8 @@ enum drm_dp_phy {
    #define DP_SDP_VSC_EXT_CEA 0x21 /* DP 1.4 */
    /* 0x80+ CEA-861 infoframe types */

    +#define DP_SDP_AUDIO_INFOFRAME_HB2 0x1b
    +
    /**
    * struct dp_sdp_header - DP secondary data packet header
    * @HB0: Secondary Data Packet ID
    diff --git a/include/linux/hdmi.h b/include/linux/hdmi.h
    index c8ec982ff498..2f4dcc8d060e 100644
    --- a/include/linux/hdmi.h
    +++ b/include/linux/hdmi.h
    @@ -336,7 +336,12 @@ ssize_t hdmi_audio_infoframe_pack(struct hdmi_audio_infoframe *frame,
    void *buffer, size_t size);
    ssize_t hdmi_audio_infoframe_pack_only(const struct hdmi_audio_infoframe *frame,
    void *buffer, size_t size);
    -int hdmi_audio_infoframe_check(struct hdmi_audio_infoframe *frame);
    +int hdmi_audio_infoframe_check(const struct hdmi_audio_infoframe *frame);
    +
    +struct dp_sdp;
    +ssize_t
    +hdmi_audio_infoframe_pack_for_dp(const struct hdmi_audio_infoframe *frame,
    + struct dp_sdp *sdp, u8 dp_version);

    enum hdmi_3d_structure {
    HDMI_3D_STRUCTURE_INVALID = -1,
    --
    2.18.0
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