[PATCH v9 06/22] video/hdmi: Add audio_infoframe packing for DP

Guillaume Ranquet
2022-03-27T22:42:34Z

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.

Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
Signed-off-by: Guillaume Ranquet <granquet@baylibre.com>
---
drivers/video/hdmi.c | 82 ++++++++++++++++++++++++++--------
include/drm/dp/drm_dp_helper.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..5f50237554ed 100644
--- a/drivers/video/hdmi.c
+++ b/drivers/video/hdmi.c
@@ -21,6 +21,7 @@
* DEALINGS IN THE SOFTWARE.
*/

+#include <drm/dp/drm_dp_helper.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/dp/drm_dp_helper.h b/include/drm/dp/drm_dp_helper.h
index 51e02cf75277..d4adb479263e 100644
--- a/include/drm/dp/drm_dp_helper.h
+++ b/include/drm/dp/drm_dp_helper.h
@@ -1576,6 +1576,8 @@ int drm_dp_bw_code_to_link_rate(u8 link_bw);
#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,
--
2.34.1