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.
Signed-off-by: Markus Schneider-Pargmann msp@baylibre.com --- drivers/video/hdmi.c | 87 +++++++++++++++++++++++++++++++++++--------- include/linux/hdmi.h | 4 ++ 2 files changed, 73 insertions(+), 18 deletions(-)
diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c index 947be761dfa4..59c4341549e4 100644 --- a/drivers/video/hdmi.c +++ b/drivers/video/hdmi.c @@ -387,6 +387,28 @@ int hdmi_audio_infoframe_check(struct hdmi_audio_infoframe *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 +426,6 @@ 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 +441,13 @@ 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 +485,51 @@ 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 + * @header Header buffer to be used + * @header_size Size of header buffer + * @data Data buffer to be used + * @data_size Size of data buffer + * @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 both header and data buffer with the required data. + * + * Return: Number of total written bytes or a negative errno on failure. + */ +ssize_t hdmi_audio_infoframe_pack_for_dp(struct hdmi_audio_infoframe *frame, + void *header, size_t header_size, + void *data, size_t data_size, + u8 dp_version) +{ + int ret; + u8 *hdr_ptr = header; + + ret = hdmi_audio_infoframe_check(frame); + if (ret) + return ret; + + if (header_size < 4 || data_size < frame->length) + return -ENOSPC; + + memset(header, 0, header_size); + memset(data, 0, data_size); + + // Secondary-data packet header + hdr_ptr[1] = frame->type; + hdr_ptr[2] = 0x1B; // As documented by DP spec for Secondary-data Packets + hdr_ptr[3] = (dp_version & 0x3f) << 2; + + hdmi_audio_infoframe_pack_payload(frame, data); + + 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/linux/hdmi.h b/include/linux/hdmi.h index c8ec982ff498..f576a0b08c85 100644 --- a/include/linux/hdmi.h +++ b/include/linux/hdmi.h @@ -334,6 +334,10 @@ struct hdmi_audio_infoframe { int hdmi_audio_infoframe_init(struct hdmi_audio_infoframe *frame); ssize_t hdmi_audio_infoframe_pack(struct hdmi_audio_infoframe *frame, void *buffer, size_t size); +ssize_t hdmi_audio_infoframe_pack_for_dp(struct hdmi_audio_infoframe *frame, + void *header, size_t header_size, + void *data, size_t data_size, + u8 dp_version); 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);