[PATCH v3 1/2] video/hdmi: Introduce helpers for the HDMI audio infoframe payload

[Chris Zhong]

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 
---

Changes in v3:
- add size < HDMI_AUDIO_INFOFRAME_SIZE check according to Doug's advice

Changes in v2: None

 drivers/video/hdmi.c | 66 ++--
 include/linux/hdmi.h |  2 ++
 2 files changed, 50 insertions(+), 18 deletions(-)

diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c
index 1cf907e..9868050 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 || size < HDMI_AUDIO_INFOFRAME_SIZE)
+   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..a4be132 100644
--- a/include/linux/hdmi.h
+++ b/include/linux/hdmi.h
@@ -272,6 +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,
-- 
2.7.4

[PATCH v3 1/2] video/hdmi: Introduce helpers for the HDMI audio infoframe payload

[Chris Zhong]

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 
---

Changes in v3:
- add size < HDMI_AUDIO_INFOFRAME_SIZE check according to Doug's advice

Changes in v2: None

 drivers/video/hdmi.c | 66 ++--
 include/linux/hdmi.h |  2 ++
 2 files changed, 50 insertions(+), 18 deletions(-)

diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c
index 1cf907e..9868050 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 || size < HDMI_AUDIO_INFOFRAME_SIZE)
+   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..a4be132 100644
--- a/include/linux/hdmi.h
+++ b/include/linux/hdmi.h
@@ -272,6 +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,
-- 
2.7.4