Hi Doug
On Tuesday, July 18, 2017 11:16 PM, Doug Anderson wrote:
Hi,
On Tue, Jul 18, 2017 at 4:20 AM, Chris Zhong <z...@rock-chips.com> wrote:
The DP is using the same audio infoframe payload as hdmi, per DP 1.3
spec, but it has a different header. Provide a new interface here,
it just packs the payload.
Signed-off-by: Chris Zhong <z...@rock-chips.com>
---
Changes in v2: None
drivers/video/hdmi.c | 66 ++++++++++++++++++++++++++++++++++++++--------------
include/linux/hdmi.h | 3 ++-
2 files changed, 50 insertions(+), 19 deletions(-)
diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c
index 1cf907e..e0b041e 100644
--- a/drivers/video/hdmi.c
+++ b/drivers/video/hdmi.c
@@ -240,6 +240,49 @@ int hdmi_audio_infoframe_init(struct hdmi_audio_infoframe
*frame)
EXPORT_SYMBOL(hdmi_audio_infoframe_init);
/**
+ * hdmi_audio_infoframe_pack_payload() - write HDMI audio infoframe payload to
+ * binary buffer
+ * @frame: HDMI audio infoframe
+ * @buffer: destination buffer
+ * @size: size of buffer
+ *
+ * Packs the information contained in the @frame structure into a binary
+ * representation that can be written into the corresponding controller
+ * registers.
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+ssize_t hdmi_audio_infoframe_pack_payload(struct hdmi_audio_infoframe *frame,
+ void *buffer, size_t size)
+{
+ unsigned char channels;
+ u8 *ptr = buffer;
+
+ if (size < frame->length)
You also need to return -ENOSPC if (size < 5). That's because below
you always write 5 elements into this array. I'll leave it to someone
with actual DRM experience to say whether they want a #define of some
sort here. Probably they do since someone made a #define for
"HDMI_INFOFRAME_HEADER_SIZE".
Also: you don't use frame->length anywhere in this function and it
doesn't seem to be related with packing the payload. Seems like you
shouldn't check it here.
Actually, I think it should be "if (size < HDMI_AUDIO_INFOFRAME_SIZE)"
+ return -ENOSPC;
+
+ memset(buffer, 0, size);
I don't think the memset belongs here. It seems like all this
function is doing is setting up ptr[0] through ptr[4] and the memset()
doesn't belong with that, does it?
I think the length of payload is 10 Bytes(DB1~DB10), per audio infoframe
Format,
but we only use the front 5 Bytes, the back 5 bytes must be 0. If we
take the 10
bytes as a whole, it make sense.
@@ -256,22 +299,15 @@ EXPORT_SYMBOL(hdmi_audio_infoframe_init);
ssize_t hdmi_audio_infoframe_pack(struct hdmi_audio_infoframe *frame,
void *buffer, size_t size)
{
- unsigned char channels;
u8 *ptr = buffer;
size_t length;
+ int ret;
length = HDMI_INFOFRAME_HEADER_SIZE + frame->length;
if (size < length)
return -ENOSPC;
- memset(buffer, 0, size);
It seems like the memset() belongs here, logically. This function
deals with the whole buffer so it should be clearing it.
-
- if (frame->channels >= 2)
- channels = frame->channels - 1;
- else
- channels = 0;
-
ptr[0] = frame->type;
ptr[1] = frame->version;
ptr[2] = frame->length;
@@ -279,16 +315,10 @@ ssize_t hdmi_audio_infoframe_pack(struct
hdmi_audio_infoframe *frame,
/* 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);
+ ret = hdmi_audio_infoframe_pack_payload(frame, ptr,
+ size - HDMI_INFOFRAME_HEADER_SIZE);
+ if (ret)
+ return ret;
hdmi_infoframe_set_checksum(buffer, length);
diff --git a/include/linux/hdmi.h b/include/linux/hdmi.h
index d271ff2..d93c709 100644
--- a/include/linux/hdmi.h
+++ b/include/linux/hdmi.h
@@ -272,7 +272,8 @@ 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_payload(struct hdmi_audio_infoframe *frame,
+ void *buffer, size_t size);
nit: seems like you're changing whitespace here (there used to be a
blank line before the enum).
enum hdmi_3d_structure {
HDMI_3D_STRUCTURE_INVALID = -1,
HDMI_3D_STRUCTURE_FRAME_PACKING = 0,
--
2.7.4
--
Chris Zhong
