ALSA: hda: intel-nhlt: verify config type

Multiple bug reports report issues with the SOF and SST drivers when
dealing with single microphone cases.

We currently read the DMIC array information unconditionally but we
don't check that the configuration type is actually a mic array.

When the DMIC link does not rely on a mic array configuration, the
recommendation is to check the format information to infer the maximum
number of channels, and map this to the number of microphones.

This leaves a potential for a mismatch between actual microphones
available in hardware and what the ACPI table contains, but we have no
other source of information.

Note that single microphone configurations can alternatively be
handled with a 'mic array' configuration along with a 'vendor-defined'
geometry.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=201251
BugLink: https://github.com/thesofproject/linux/issues/2725
Fixes: 7a33ea70e1 ('ALSA: hda: intel-nhlt: handle NHLT VENDOR_DEFINED DMIC geometry')
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20210302000146.1177770-1-pierre-louis.bossart@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/intel-nhlt.h

@@ -112,6 +112,11 @@ struct nhlt_vendor_dmic_array_config {
 	/* TODO add vendor mic config */
 } __packed;
 
+enum {
+	NHLT_CONFIG_TYPE_GENERIC = 0,
+	NHLT_CONFIG_TYPE_MIC_ARRAY = 1
+};
+
 enum {
 	NHLT_MIC_ARRAY_2CH_SMALL = 0xa,
 	NHLT_MIC_ARRAY_2CH_BIG = 0xb,

sound/hda/intel-nhlt.c

@@ -31,18 +31,44 @@ int intel_nhlt_get_dmic_geo(struct device *dev, struct nhlt_acpi_table *nhlt)
 	struct nhlt_endpoint *epnt;
 	struct nhlt_dmic_array_config *cfg;
 	struct nhlt_vendor_dmic_array_config *cfg_vendor;
+	struct nhlt_fmt *fmt_configs;
 	unsigned int dmic_geo = 0;
-	u8 j;
+	u16 max_ch = 0;
+	u8 i, j;
 
 	if (!nhlt)
 		return 0;
 
-	epnt = (struct nhlt_endpoint *)nhlt->desc;
+	for (j = 0, epnt = nhlt->desc; j < nhlt->endpoint_count; j++,
+	     epnt = (struct nhlt_endpoint *)((u8 *)epnt + epnt->length)) {
 
-	for (j = 0; j < nhlt->endpoint_count; j++) {
-		if (epnt->linktype == NHLT_LINK_DMIC) {
-			cfg = (struct nhlt_dmic_array_config  *)
-					(epnt->config.caps);
+		if (epnt->linktype != NHLT_LINK_DMIC)
+			continue;
+
+		cfg = (struct nhlt_dmic_array_config  *)(epnt->config.caps);
+		fmt_configs = (struct nhlt_fmt *)(epnt->config.caps + epnt->config.size);
+
+		/* find max number of channels based on format_configuration */
+		if (fmt_configs->fmt_count) {
+			dev_dbg(dev, "%s: found %d format definitions\n",
+				__func__, fmt_configs->fmt_count);
+
+			for (i = 0; i < fmt_configs->fmt_count; i++) {
+				struct wav_fmt_ext *fmt_ext;
+
+				fmt_ext = &fmt_configs->fmt_config[i].fmt_ext;
+
+				if (fmt_ext->fmt.channels > max_ch)
+					max_ch = fmt_ext->fmt.channels;
+			}
+			dev_dbg(dev, "%s: max channels found %d\n", __func__, max_ch);
+		} else {
+			dev_dbg(dev, "%s: No format information found\n", __func__);
+		}
+
+		if (cfg->device_config.config_type != NHLT_CONFIG_TYPE_MIC_ARRAY) {
+			dmic_geo = max_ch;
+		} else {
 			switch (cfg->array_type) {
 			case NHLT_MIC_ARRAY_2CH_SMALL:
 			case NHLT_MIC_ARRAY_2CH_BIG:
@@ -59,13 +85,23 @@ int intel_nhlt_get_dmic_geo(struct device *dev, struct nhlt_acpi_table *nhlt)
 				dmic_geo = cfg_vendor->nb_mics;
 				break;
 			default:
-				dev_warn(dev, "undefined DMIC array_type 0x%0x\n",
-					 cfg->array_type);
+				dev_warn(dev, "%s: undefined DMIC array_type 0x%0x\n",
+					 __func__, cfg->array_type);
+			}
+
+			if (dmic_geo > 0) {
+				dev_dbg(dev, "%s: Array with %d dmics\n", __func__, dmic_geo);
+			}
+			if (max_ch > dmic_geo) {
+				dev_dbg(dev, "%s: max channels %d exceed dmic number %d\n",
+					__func__, max_ch, dmic_geo);
 			}
 		}
-		epnt = (struct nhlt_endpoint *)((u8 *)epnt + epnt->length);
 	}
 
+	dev_dbg(dev, "%s: dmic number %d max_ch %d\n",
+		__func__, dmic_geo, max_ch);
+
 	return dmic_geo;
 }
 EXPORT_SYMBOL_GPL(intel_nhlt_get_dmic_geo);