[PATCH v4 3/4] ACPI: NHLT: Table manipulation helpers

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

The table is composed of a range of endpoints with each describing
audio formats they support. Thus most of the operations involve
iterating over elements of the table. Simplify the process by
implementing range of getters.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
---
 include/acpi/nhlt.h | 68 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)

diff --git a/include/acpi/nhlt.h b/include/acpi/nhlt.h
index e68e0534412d..9a2e47e49de7 100644
--- a/include/acpi/nhlt.h
+++ b/include/acpi/nhlt.h
@@ -63,6 +63,74 @@
 	__cfg->capabilities_size == struct_size(__cfg, mics, __cfg->num_mics) ?		\
 		__cfg : NULL; })
 
+/**
+ * acpi_nhlt_endpoint_fmtscfg - Get the formats configuration space.
+ * @ep:		the endpoint to retrieve the space for.
+ *
+ * Return: A pointer to the formats configuration space.
+ */
+static inline struct acpi_nhlt_formats_config *
+acpi_nhlt_endpoint_fmtscfg(const struct acpi_nhlt_endpoint *ep)
+{
+	struct acpi_nhlt_cfg *cfg = __acpi_nhlt_endpoint_cfg(ep);
+
+	return (struct acpi_nhlt_formats_config *)((u8 *)(cfg + 1) + cfg->capabilities_size);
+}
+
+#define __acpi_nhlt_first_endpoint(tb) \
+	((void *)(tb + 1))
+
+#define __acpi_nhlt_next_endpoint(ep) \
+	((void *)((u8 *)(ep) + (ep)->descriptor_length))
+
+#define __acpi_nhlt_get_endpoint(tb, ep, i) \
+	((i) ? __acpi_nhlt_next_endpoint(ep) : __acpi_nhlt_first_endpoint(tb))
+
+#define __acpi_nhlt_first_fmtcfg(fmts) \
+	((void *)(fmts + 1))
+
+#define __acpi_nhlt_next_fmtcfg(fmt) \
+	((void *)((u8 *)((fmt) + 1) + (fmt)->capability_size))
+
+#define __acpi_nhlt_get_fmtcfg(fmts, fmt, i) \
+	((i) ? __acpi_nhlt_next_fmtcfg(fmt) : __acpi_nhlt_first_fmtcfg(fmts))
+
+/*
+ * The for_each_nhlt_*() macros rely on an iterator to deal with the
+ * variable length of each endpoint structure and the possible presence
+ * of an OED-Config used by Windows only.
+ */
+
+/**
+ * for_each_nhlt_endpoint - Iterate over endpoints in a NHLT table.
+ * @tb:		the pointer to a NHLT table.
+ * @ep:		the pointer to endpoint to use as loop cursor.
+ */
+#define for_each_nhlt_endpoint(tb, ep)					\
+	for (unsigned int __i = 0;					\
+	     __i < (tb)->endpoint_count &&				\
+		(ep = __acpi_nhlt_get_endpoint(tb, ep, __i));		\
+	     __i++)
+
+/**
+ * for_each_nhlt_fmtcfg - Iterate over format configurations.
+ * @fmts:	the pointer to formats configuration space.
+ * @fmt:	the pointer to format to use as loop cursor.
+ */
+#define for_each_nhlt_fmtcfg(fmts, fmt)					\
+	for (unsigned int __i = 0;					\
+	     __i < (fmts)->formats_count &&				\
+		(fmt = __acpi_nhlt_get_fmtcfg(fmts, fmt, __i));	\
+	     __i++)
+
+/**
+ * for_each_nhlt_endpoint_fmtcfg - Iterate over format configurations in an endpoint.
+ * @ep:		the pointer to an endpoint.
+ * @fmt:	the pointer to format to use as loop cursor.
+ */
+#define for_each_nhlt_endpoint_fmtcfg(ep, fmt) \
+	for_each_nhlt_fmtcfg(acpi_nhlt_endpoint_fmtscfg(ep), fmt)
+
 #if IS_ENABLED(CONFIG_ACPI_NHLT)
 
 /*
-- 
2.25.1