[PATCH 4/4] ACPI: NHLT: Add query functions

[Cezary Rojewski <cezary.rojewski@intel.com>]

With iteration helpers added there is a room for more complex query
tasks which are commonly performed by sound drivers. Implement them in
common API so that a unified mechanism is available for all of them.

While the acpi_nhlt_endpoint_dmic_count() stands out a bit, it is a
critical component for any AudioDSP driver to know how many digital
microphones it is dealing with. There is no one perfect method, but the
best one available is provided.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
---
 drivers/acpi/nhlt.c | 183 ++++++++++++++++++++++++++++++++++++++++++++
 include/acpi/nhlt.h |  54 +++++++++++++
 2 files changed, 237 insertions(+)

diff --git a/drivers/acpi/nhlt.c b/drivers/acpi/nhlt.c
index 90d74d0d803e..c61cdfd78b74 100644
--- a/drivers/acpi/nhlt.c
+++ b/drivers/acpi/nhlt.c
@@ -6,8 +6,191 @@
 //          Amadeusz Slawinski <amadeuszx.slawinski@linux.intel.com>
 //
 
+#define pr_fmt(fmt) "ACPI: NHLT: " fmt
+
 #include <linux/export.h>
 #include <acpi/nhlt.h>
 
 struct acpi_table_nhlt *acpi_gbl_NHLT;
 EXPORT_SYMBOL_GPL(acpi_gbl_NHLT);
+
+/**
+ * acpi_nhlt_endpoint_match - Verify if an endpoint matches criteria.
+ * @ep:			the endpoint to check.
+ * @link_type:		the hardware link type, e.g.: PDM or SSP.
+ * @dev_type:		the device type.
+ * @dir:		stream direction.
+ * @bus_id:		the ID of virtual bus hosting the endpoint.
+ *
+ * Either of @link_type, @dev_type, @dir or @bus_id may be set to a negative
+ * value to ignore the parameter when matching.
+ *
+ * Return: %true if endpoint matches specified criteria or %false otherwise.
+ */
+bool acpi_nhlt_endpoint_match(const struct acpi_nhlt_endpoint *ep,
+			      int link_type, int dev_type, int dir, int bus_id)
+{
+	return ep &&
+	       (link_type < 0 || ep->link_type == link_type) &&
+	       (dev_type < 0 || ep->device_type == dev_type) &&
+	       (dir < 0 || ep->direction == dir) &&
+	       (bus_id < 0 || ep->virtual_bus_id == bus_id);
+}
+EXPORT_SYMBOL_GPL(acpi_nhlt_endpoint_match);
+
+/**
+ * acpi_nhlt_find_endpoint - Search a NHLT table for an endpoint.
+ * @tb:			the table to search.
+ * @link_type:		the hardware link type, e.g.: PDM or SSP.
+ * @dev_type:		the device type.
+ * @dir:		stream direction.
+ * @bus_id:		the ID of virtual bus hosting the endpoint.
+ *
+ * Either of @link_type, @dev_type, @dir or @bus_id may be set to a negative
+ * value to ignore the parameter during the search.
+ *
+ * Return: A pointer to endpoint matching the criteria, %NULL if not found or
+ * an ERR_PTR() otherwise.
+ */
+struct acpi_nhlt_endpoint *
+acpi_nhlt_find_endpoint(const struct acpi_table_nhlt *tb,
+			int link_type, int dev_type, int dir, int bus_id)
+{
+	struct acpi_nhlt_endpoint *ep;
+
+	if (!tb)
+		return ERR_PTR(-EINVAL);
+
+	for_each_nhlt_endpoint(tb, ep)
+		if (acpi_nhlt_endpoint_match(ep, link_type, dev_type, dir, bus_id))
+			return ep;
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(acpi_nhlt_find_endpoint);
+
+/**
+ * acpi_nhlt_endpoint_find_fmtcfg - Search endpoint's formats configuration space
+ *                                  for a specific format.
+ * @ep:			the endpoint to search.
+ * @ch:			number of channels.
+ * @rate:		samples per second.
+ * @vbps:		valid bits per sample.
+ * @bps:		bits per sample.
+ *
+ * Return: A pointer to format matching the criteria, %NULL if not found or
+ * an ERR_PTR() otherwise.
+ */
+struct acpi_nhlt_format_config *
+acpi_nhlt_endpoint_find_fmtcfg(const struct acpi_nhlt_endpoint *ep,
+			       u16 ch, u32 rate, u16 vbps, u16 bps)
+{
+	struct acpi_nhlt_wave_extensible *wav;
+	struct acpi_nhlt_format_config *fmt;
+
+	if (!ep)
+		return ERR_PTR(-EINVAL);
+
+	for_each_nhlt_endpoint_fmtcfg(ep, fmt) {
+		wav = &fmt->format;
+
+		if (wav->channel_count == ch &&
+		    wav->valid_bits_per_sample == vbps &&
+		    wav->bits_per_sample == bps &&
+		    wav->samples_per_sec == rate)
+			return fmt;
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(acpi_nhlt_endpoint_find_fmtcfg);
+
+/**
+ * acpi_nhlt_find_fmtcfg - Search a NHLT table for a specific format.
+ * @tb:			the table to search.
+ * @link_type:		the hardware link type, e.g.: PDM or SSP.
+ * @dev_type:		the device type.
+ * @dir:		stream direction.
+ * @bus_id:		the ID of virtual bus hosting the endpoint.
+ *
+ * @ch:			number of channels.
+ * @rate:		samples per second.
+ * @vbps:		valid bits per sample.
+ * @bps:		bits per sample.
+ *
+ * Either of @link_type, @dev_type, @dir or @bus_id may be set to a negative
+ * value to ignore the parameter during the search.
+ *
+ * Return: A pointer to format matching the criteria, %NULL if not found or
+ * an ERR_PTR() otherwise.
+ */
+struct acpi_nhlt_format_config *
+acpi_nhlt_find_fmtcfg(const struct acpi_table_nhlt *tb,
+		      int link_type, int dev_type, int dir, int bus_id,
+		      u16 ch, u32 rate, u16 vbps, u16 bps)
+{
+	struct acpi_nhlt_format_config *fmt;
+	struct acpi_nhlt_endpoint *ep;
+
+	if (!tb)
+		return ERR_PTR(-EINVAL);
+
+	for_each_nhlt_endpoint(tb, ep) {
+		if (!acpi_nhlt_endpoint_match(ep, link_type, dev_type, dir, bus_id))
+			continue;
+
+		fmt = acpi_nhlt_endpoint_find_fmtcfg(ep, ch, rate, vbps, bps);
+		if (fmt)
+			return fmt;
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(acpi_nhlt_find_fmtcfg);
+
+/**
+ * acpi_nhlt_endpoint_dmic_count - Retrieve number of digital microphones for a PDM endpoint.
+ * @ep:			the endpoint to return microphones count for.
+ *
+ * Return: A number of microphones or an error code if an invalid endpoint is provided.
+ */
+int acpi_nhlt_endpoint_dmic_count(const struct acpi_nhlt_endpoint *ep)
+{
+	struct acpi_nhlt_vendor_mic_devcfg *vendor_cfg;
+	struct acpi_nhlt_format_config *fmt;
+	struct acpi_nhlt_mic_devcfg *devcfg;
+	u16 max_ch = 0;
+
+	if (!ep || ep->link_type != ACPI_NHLT_PDM)
+		return -EINVAL;
+
+	/* Find max number of channels based on formats configuration. */
+	for_each_nhlt_endpoint_fmtcfg(ep, fmt)
+		max_ch = max(fmt->format.channel_count, max_ch);
+
+	/* If @ep not a mic array, fallback to channels count. */
+	devcfg = acpi_nhlt_endpoint_mic_devcfg(ep);
+	if (!devcfg || devcfg->config_type != ACPI_NHLT_CONFIG_TYPE_MIC_ARRAY)
+		return max_ch;
+
+	switch (devcfg->array_type) {
+	case ACPI_NHLT_SMALL_LINEAR_2ELEMENT:
+	case ACPI_NHLT_BIG_LINEAR_2ELEMENT:
+		return 2;
+
+	case ACPI_NHLT_FIRST_GEOMETRY_LINEAR_4ELEMENT:
+	case ACPI_NHLT_PLANAR_LSHAPED_4ELEMENT:
+	case ACPI_NHLT_SECOND_GEOMETRY_LINEAR_4ELEMENT:
+		return 4;
+
+	case ACPI_NHLT_VENDOR_DEFINED:
+		vendor_cfg = acpi_nhlt_endpoint_vendor_mic_devcfg(ep);
+		if (!vendor_cfg)
+			return -EINVAL;
+		return vendor_cfg->num_mics;
+
+	default:
+		pr_warn("undefined mic array type: %#x\n", devcfg->array_type);
+		return max_ch;
+	}
+}
+EXPORT_SYMBOL_GPL(acpi_nhlt_endpoint_dmic_count);
diff --git a/include/acpi/nhlt.h b/include/acpi/nhlt.h
index 076aac41a74e..ba093fe871d5 100644
--- a/include/acpi/nhlt.h
+++ b/include/acpi/nhlt.h
@@ -149,4 +149,58 @@ acpi_nhlt_endpoint_fmtscfg(const struct acpi_nhlt_endpoint *ep)
 #define for_each_nhlt_endpoint_fmtcfg(ep, fmt) \
 	for_each_nhlt_fmtcfg(acpi_nhlt_endpoint_fmtscfg(ep), fmt)
 
+#if IS_ENABLED(CONFIG_ACPI_NHLT)
+
+bool acpi_nhlt_endpoint_match(const struct acpi_nhlt_endpoint *ep,
+			      int link_type, int dev_type, int dir, int bus_id);
+struct acpi_nhlt_endpoint *
+acpi_nhlt_find_endpoint(const struct acpi_table_nhlt *tb,
+			int link_type, int dev_type, int dir, int bus_id);
+struct acpi_nhlt_format_config *
+acpi_nhlt_endpoint_find_fmtcfg(const struct acpi_nhlt_endpoint *ep,
+			       u16 ch, u32 rate, u16 vbps, u16 bps);
+struct acpi_nhlt_format_config *
+acpi_nhlt_find_fmtcfg(const struct acpi_table_nhlt *tb,
+		      int link_type, int dev_type, int dir, int bus_id,
+		      u16 ch, u32 rate, u16 vpbs, u16 bps);
+int acpi_nhlt_endpoint_dmic_count(const struct acpi_nhlt_endpoint *ep);
+
+#else /* !CONFIG_ACPI_NHLT */
+
+static bool
+acpi_nhlt_endpoint_match(const struct acpi_nhlt_endpoint *ep,
+			 int link_type, int dev_type, int dir, int bus_id)
+{
+	return false;
+}
+
+static inline struct acpi_nhlt_endpoint *
+acpi_nhlt_find_endpoint(const struct acpi_table_nhlt *tb,
+			int link_type, int dev_type, int dir, int bus_id)
+{
+	return NULL;
+}
+
+static inline struct acpi_nhlt_format_config *
+acpi_nhlt_endpoint_find_fmtcfg(const struct acpi_nhlt_endpoint *ep,
+			       u16 ch, u32 rate, u16 vbps, u16 bps)
+{
+	return NULL;
+}
+
+static inline struct acpi_nhlt_format_config *
+acpi_nhlt_find_fmtcfg(const struct acpi_table_nhlt *tb,
+		      int link_type, int dev_type, int dir, int bus_id,
+		      u16 ch, u32 rate, u16 vpbs, u16 bps);
+{
+	return NULL;
+}
+
+static inline int acpi_nhlt_endpoint_dmic_count(const struct acpi_nhlt_endpoint *ep)
+{
+	return 0;
+}
+
+#endif /* !CONFIG_ACPI_NHLT */
+
 #endif /* __ACPI_NHLT_H__ */
-- 
2.25.1