[alsa-devel] [PATCH 03/13] ASoC: topology: ABI - Define DPCM trigger ordering for PCM

[Mengdong Lin]

On 08/24/2016 01:41 AM, Mark Brown wrote:
> On Fri, Aug 19, 2016 at 06:12:55PM +0800, mengdong.lin at linux.intel.com wrote:
>
>> Definition of dynamic PCM trigger ordering is exposed to uapi asoc.h,
>> and topology allows user space to define the trigger ordering for PCM
>> (FE links).
>
> This seems *incredibly* implementation specific.  Why wouldn't the
> driver for the thing implementing the topology be able to figure out the
> ordering here?  What's the use case?  What happens when we change away
> from DPCM?
>

There is another patch (04/13) to add generic flags and flag mask to PCM 
objects. So we'll allow users to set DPCM trigger ordering as flags as 
below, to avoid using trigger[] in ABI. The topology kernel driver will 
check the flag bits and set the proper trigger ordering to FE DAI links. 
If we change away from DPCM in the future, user can stop using these 
flags. And the 32-bit flags seems enough for future extension.

diff --git a/include/uapi/sound/asoc.h b/include/uapi/sound/asoc.h
index f734bea..30da32f 100644
--- a/include/uapi/sound/asoc.h
+++ b/include/uapi/sound/asoc.h
@@ -130,6 +130,16 @@
  #define SND_SOC_TPLG_DAI_FLGBIT_SYMMETRIC_CHANNELS      (1 << 1)
  #define SND_SOC_TPLG_DAI_FLGBIT_SYMMETRIC_SAMPLEBITS    (1 << 2)

+/* DAI link flags */
+#define SND_SOC_TPLG_LNK_FLGBIT_IGNORE_SUSPEND          (1 << 0)
+#define SND_SOC_TPLG_LNK_FLGBIT_IGNORE_POWERDOWN_TIME   (1 << 1)
+#define SND_SOC_TPLG_LNK_FLGBIT_PLAYBACK_DPCM_TRIGGER_PRE       (1<<2)
+#define SND_SOC_TPLG_LNK_FLGBIT_PLAYBACK_DPCM_TRIGGER_POST      (1<<3)
+#define SND_SOC_TPLG_LNK_FLGBIT_PLAYBACK_DPCM_TRIGGER_BESPOKE   (1<<4)
+#define SND_SOC_TPLG_LNK_FLGBIT_CAPTURE_DPCM_TRIGGER_PRE        (1<<2)
+#define SND_SOC_TPLG_LNK_FLGBIT_CAPTURE_DPCM_TRIGGER_POST       (1<<3)
+#define SND_SOC_TPLG_LNK_FLGBIT_CAPTURE_DPCM_TRIGGER_BESPOKE    (1<<4)
+
  /*
   * Block Header.
   * This header precedes all object and object arrays below.
@@ -439,6 +449,8 @@ struct snd_soc_tplg_pcm {
         struct snd_soc_tplg_stream 
stream[SND_SOC_TPLG_STREAM_CONFIG_MAX]; /* for DAI link */
         __le32 num_streams;     /* number of streams */
         struct snd_soc_tplg_stream_caps caps[2]; /* playback and 
capture for DAI */
+       __le32 flag_mask;       /* bitmask of flags to configure */
+       __le32 flags;           /* SND_SOC_TPLG_LNK_FLGBIT_* flag value */
  } __attribute__((packed));


Thanks
Mengdong