Hi Sam,
On Mon, Sep 06, 2021 at 10:30:26PM +0200, Sam Ravnborg wrote:
Hi Markus,
On Mon, Sep 06, 2021 at 09:35:27PM +0200, Markus Schneider-Pargmann wrote:
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
Any constant we could use or define and use here? Hard coding 0x1b is the less desireable option.
I couldn't find a constant for this, but I will add one.
Also thanks to looking for these defines, I found a struct dp_sdp that could be used instead of the header and data pointers which I would prefer, so I will fix that for the next version.
Thanks for your feedback.
Best, Markus
Sam
- 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); -- 2.33.0