sound/hda/codecs/generic.c

Source file repositories/reference/linux-study-clean/sound/hda/codecs/generic.c

File Facts

System
Linux kernel
Corpus path
sound/hda/codecs/generic.c
Extension
.c
Size
168226 bytes
Lines
6146
Domain
Driver Families
Bucket
sound/hda
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (conn[i] != from_nid) {
			/* special case: when from_nid is 0,
			 * try to find an empty DAC
			 */
			if (from_nid ||
			    get_wcaps_type(get_wcaps(codec, conn[i])) != AC_WID_AUD_OUT ||
			    is_dac_already_used(codec, conn[i]))
				continue;
		}
		/* anchor is not requested or already passed? */
		if (anchor_nid <= 0)
			goto found;
	}
	if (depth >= MAX_NID_PATH_DEPTH)
		return false;
	for (i = 0; i < nums; i++) {
		unsigned int type;
		type = get_wcaps_type(get_wcaps(codec, conn[i]));
		if (type == AC_WID_AUD_OUT || type == AC_WID_AUD_IN ||
		    type == AC_WID_PIN)
			continue;
		if (__parse_nid_path(codec, from_nid, conn[i],
				     anchor_nid, path, depth + 1))
			goto found;
	}
	return false;

 found:
	path->path[path->depth] = conn[i];
	path->idx[path->depth + 1] = i;
	if (nums > 1 && get_wcaps_type(get_wcaps(codec, to_nid)) != AC_WID_AUD_MIX)
		path->multi[path->depth + 1] = 1;
	path->depth++;
	return true;
}

/*
 * snd_hda_parse_nid_path - parse the widget path from the given nid to
 * the target nid
 * @codec: the HDA codec
 * @from_nid: the NID where the path start from
 * @to_nid: the NID where the path ends at
 * @anchor_nid: the anchor indication
 * @path: the path object to store the result
 *
 * Returns true if a matching path is found.
 *
 * The parsing behavior depends on parameters:
 * when @from_nid is 0, try to find an empty DAC;
 * when @anchor_nid is set to a positive value, only paths through the widget
 * with the given value are evaluated.
 * when @anchor_nid is set to a negative value, paths through the widget
 * with the negative of given value are excluded, only other paths are chosen.
 * when @anchor_nid is zero, no special handling about path selection.
 */
static bool snd_hda_parse_nid_path(struct hda_codec *codec, hda_nid_t from_nid,
			    hda_nid_t to_nid, int anchor_nid,
			    struct nid_path *path)
{
	if (__parse_nid_path(codec, from_nid, to_nid, anchor_nid, path, 1)) {
		path->path[path->depth] = to_nid;
		path->depth++;
		return true;
	}
	return false;
}

/**
 * snd_hda_add_new_path - parse the path between the given NIDs and
 * add to the path list
 * @codec: the HDA codec
 * @from_nid: the NID where the path start from
 * @to_nid: the NID where the path ends at
 * @anchor_nid: the anchor indication, see snd_hda_parse_nid_path()
 *
 * If no valid path is found, returns NULL.
 */
struct nid_path *
snd_hda_add_new_path(struct hda_codec *codec, hda_nid_t from_nid,
		     hda_nid_t to_nid, int anchor_nid)
{
	struct hda_gen_spec *spec = codec->spec;
	struct nid_path *path;

	if (from_nid && to_nid && !is_reachable_path(codec, from_nid, to_nid))
		return NULL;

	/* check whether the path has been already added */
	path = get_nid_path(codec, from_nid, to_nid, anchor_nid);
	if (path)

Annotation

Implementation Notes