topology: Revise document and comments for ABI v5

Revise the obsolete content in document and comments.

Here are the major changes in implementation from early phase design:
- PCM object is used to configure front end DAI & DAI links, not used by
  physical DAI or DAI links.
- No longer use separate object for backend or codec<->codec links, but
  use physical links to cover them.

Signed-off-by: Mengdong Lin <mengdong.lin@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/topology.h

@@ -40,9 +40,10 @@ extern "C" {
  * currently recognises the following object types :-
  *
  *  * Controls (mixer, enumerated and byte) including TLV data.
- *  * PCMs (FE and BE configurations and capabilities)
+ *  * PCMs (Front End DAI & DAI link)
  *  * DAPM widgets
  *  * DAPM graph elements.
+ *  * Physical DAI & DAI links
  *  * Private data for each object type.
  *  * Manifest (containing count of each object type)
  *
@@ -511,8 +512,8 @@ extern "C" {
  * refer to section Control Private Data.
  *
  * <h4>PCM Capabilities</h4>
- * Topology can also define the capabilities of FE and BE PCMs. Capabilities
+ * Topology can also define the PCM capabilities of front end or physical DAIs.
- * can be defined with the following section :-
+ * Capabilities can be defined with the following section :-
  *
  * <pre>
  * SectionPCMCapabilities."name" {
@@ -525,8 +526,8 @@ extern "C" {
  * }
  * </pre>
  * The supported formats use the same naming convention as the driver macros.
- * The PCM capabilities name can be referred to and included by BE, PCM and
+ * The PCM capabilities name can be referred to and included by PCM and
- * Codec <-> codec topology sections.
+ * physical DAI sections.
  *
  * <h4>PCM Configurations</h4>
  * PCM runtime configurations can be defined for playback and capture stream
@@ -552,31 +553,14 @@ extern "C" {
  * </pre>
  *
  * The supported formats use the same naming convention as the driver macros.
- * The PCM configuration name can be referred to and included by BE, PCM and
+ * The PCM configuration name can be referred to and included by PCM and
- * Codec <-> codec topology sections.
+ * physical link sections.
  *
- * <h4>PCM Configurations</h4>
+ * <h4>PCM (Front-end DAI & DAI link) </h4>
- * PCM, BE and Codec to Codec link sections define the supported capabilities
+ * PCM sections define the supported capabilities and configurations for
- * and configurations for supported playback and capture streams. The
+ * supported playback and capture streams, names and flags for front end
- * definitions and content for PCMs, BE and Codec links are the same with the
+ * DAI & DAI links. Topology kernel driver will use a PCM object to create
- * exception of the section type :-
+ * a pair of FE DAI & DAI links.
- *
- * <pre>
- * SectionPCM."name" {
- *	....
- * }
- * SectionBE."name" {
- *	....
- * }
- * SectionCC."name" {
- *	....
- * }
- * </pre>
- *
- * The section types above should be used for PCMs, Back Ends and Codec to Codec
- * links respectively.<br>
- *
- * The data for each section is defined as follows :-
  *
  * <pre>
  * SectionPCM."name" {
@@ -1031,7 +1015,7 @@ struct snd_tplg_dai_template {
 };
 
 /** \struct snd_tplg_link_template
- * \brief Template type for BE and CC DAI Links.
+ * \brief Template type for physical DAI Links.
  */
 struct snd_tplg_link_template {
 	const char *name;	/*!< link name, used to match */
@@ -1065,7 +1049,7 @@ typedef struct snd_tplg_obj_template {
 		struct snd_tplg_enum_template *enum_ctl;	/*!< Enum control */
 		struct snd_tplg_graph_template *graph;		/*!< Graph elements */
 		struct snd_tplg_pcm_template *pcm;		/*!< PCM elements */
-		struct snd_tplg_link_template *link;		/*!< BE and CC Links */
+		struct snd_tplg_link_template *link;		/*!< physical DAI Links */
 		struct snd_tplg_dai_template *dai;		/*!< Physical DAI */
 	};
 } snd_tplg_obj_template_t;

src/topology/pcm.c

@@ -1198,7 +1198,6 @@ int tplg_add_link_object(snd_tplg_t *tplg, snd_tplg_obj_template_t *t)
 	    && t->type != SND_TPLG_TYPE_CC)
 		return -EINVAL;
 
-	/* here type can be either BE or CC. */
 	elem = tplg_elem_new_common(tplg, NULL, link_tpl->name, t->type);
 	if (!elem)
 		return -ENOMEM;