diff mbox

[v2,1/2] video/hdmi: Introduce helpers for the HDMI audio infoframe payload

Message ID 1500376842-6739-1-git-send-email-zyw@rock-chips.com
State New, archived
Headers show

Commit Message

Chris Zhong July 18, 2017, 11:20 a.m. UTC
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 <zyw@rock-chips.com>
---

Changes in v2: None

 drivers/video/hdmi.c | 66 ++++++++++++++++++++++++++++++++++++++--------------
 include/linux/hdmi.h |  3 ++-
 2 files changed, 50 insertions(+), 19 deletions(-)

Comments

Doug Anderson July 18, 2017, 3:16 p.m. UTC | #1
Hi,

On Tue, Jul 18, 2017 at 4:20 AM, Chris Zhong <zyw@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 <zyw@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.


> +               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?


> @@ -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 July 19, 2017, 12:49 a.m. UTC | #2
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 <zyw@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 <zyw@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
>>
>
>
Doug Anderson July 19, 2017, 5:27 p.m. UTC | #3
Hi

On Tue, Jul 18, 2017 at 5:49 PM, Chris Zhong <zyw@rock-chips.com> wrote:
> 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 <zyw@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 <zyw@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)"

Ah, OK.  My main point was that this function needed to make sense on
its own.  ...and the function in your patch writes to [0] through [4]
without actually confirming that there are at least 5 elements.  I'd
be OK with:

  if ((size < frame->length || 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.

OK, memset() here makes sense with what you say about the frame
needing to be 10 bytes big.

-Doug
diff mbox

Patch

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)
+		return -ENOSPC;
+
+	memset(buffer, 0, size);
+
+	if (frame->channels >= 2)
+		channels = frame->channels - 1;
+	else
+		channels = 0;
+
+	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);
+
+	return 0;
+}
+EXPORT_SYMBOL(hdmi_audio_infoframe_pack_payload);
+
+/**
  * hdmi_audio_infoframe_pack() - write HDMI audio infoframe to binary buffer
  * @frame: HDMI audio infoframe
  * @buffer: destination buffer
@@ -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);
-
-	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);
 enum hdmi_3d_structure {
 	HDMI_3D_STRUCTURE_INVALID = -1,
 	HDMI_3D_STRUCTURE_FRAME_PACKING = 0,