[PATCH v3 1/4] ACPI: NHLT: Device configuration access interface

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

Device configuration structures are plenty so declare a struct for each
known variant. As neither of them shall be accessed without verifying
the memory block first, introduce macros to make it easy to do so.

Link: https://github.com/acpica/acpica/pull/881
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
---
 include/acpi/actbl2.h | 28 ++++++++++++++++++
 include/acpi/nhlt.h   | 66 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 94 insertions(+)
 create mode 100644 include/acpi/nhlt.h

diff --git a/include/acpi/actbl2.h b/include/acpi/actbl2.h
index 0029336775a9..c4c9a3a89ba6 100644
--- a/include/acpi/actbl2.h
+++ b/include/acpi/actbl2.h
@@ -2014,6 +2014,25 @@ struct acpi_nhlt_vendor_mic_count {
 	u8 microphone_count;
 };
 
+/* The only guaranteed configuration space header. Any other requires validation. */
+struct acpi_nhlt_cfg {
+	u32 capabilities_size;
+	u8 capabilities[];
+};
+
+struct acpi_nhlt_devcfg {
+	u32 capabilities_size;
+	u8 virtual_slot;
+	u8 config_type;
+};
+
+struct acpi_nhlt_mic_devcfg {
+	u32 capabilities_size;
+	u8 virtual_slot;
+	u8 config_type;
+	u8 array_type;
+};
+
 struct acpi_nhlt_vendor_mic_config {
 	u8 type;
 	u8 panel;
@@ -2030,6 +2049,15 @@ struct acpi_nhlt_vendor_mic_config {
 	u16 work_horizontal_angle_end;	/* -180 - + 180 with 2 deg step */
 };
 
+struct acpi_nhlt_vendor_mic_devcfg {
+	u32 capabilities_size;
+	u8 virtual_slot;
+	u8 config_type;
+	u8 array_type;
+	u8 num_mics;
+	struct acpi_nhlt_vendor_mic_config mics[];
+};
+
 /* Values for Type field above */
 
 #define ACPI_NHLT_MIC_OMNIDIRECTIONAL       0
diff --git a/include/acpi/nhlt.h b/include/acpi/nhlt.h
new file mode 100644
index 000000000000..af3ec45ba4f9
--- /dev/null
+++ b/include/acpi/nhlt.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright(c) 2023 Intel Corporation. All rights reserved.
+ *
+ * Authors: Cezary Rojewski <cezary.rojewski@intel.com>
+ *          Amadeusz Slawinski <amadeuszx.slawinski@linux.intel.com>
+ */
+
+#ifndef __ACPI_NHLT_H__
+#define __ACPI_NHLT_H__
+
+#include <linux/acpi.h>
+#include <linux/overflow.h>
+#include <linux/types.h>
+
+#define __acpi_nhlt_endpoint_cfg(ep)	((void *)((ep) + 1))
+
+/*
+ * As device configuration spaces present in NHLT tables around the world are
+ * not following single pattern, first check if 'capabilities_size' is correct
+ * in respect to size of the specified space type before returning the pointer.
+ */
+#define __acpi_nhlt_endpoint_devcfg(ep, type) ({				\
+	struct acpi_nhlt_cfg *__cfg = __acpi_nhlt_endpoint_cfg(ep);		\
+	__cfg->capabilities_size >= sizeof(type) ?				\
+		((type *)__cfg) : NULL; })
+
+/*
+ * acpi_nhlt_endpoint_devcfg - Test and access device configuration.
+ * @ep:		endpoint for which to retrieve device configuration.
+ *
+ * Return: A pointer to device configuration space or NULL if the space's
+ * 'capabilities_size' is insufficient to cover the nested structure.
+ */
+#define acpi_nhlt_endpoint_devcfg(ep) \
+	__acpi_nhlt_endpoint_devcfg(ep, struct acpi_nhlt_devcfg)
+
+/*
+ * acpi_nhlt_endpoint_mic_devcfg - Test and access device configuration.
+ * @ep:		endpoint for which to retrieve device configuration.
+ *
+ * Return: A pointer to device configuration space or NULL if the space's
+ * 'capabilities_size' is insufficient to cover the nested structure.
+ */
+#define acpi_nhlt_endpoint_mic_devcfg(ep) \
+	__acpi_nhlt_endpoint_devcfg(ep, struct acpi_nhlt_mic_devcfg)
+
+/*
+ * acpi_nhlt_endpoint_vendor_mic_devcfg - Test and access device configuration.
+ * @ep:		endpoint for which to retrieve device configuration.
+ * @ptr:	pointer to a device configuration structure.
+ *
+ * This is the same as acpi_nhlt_endpoint_devcfg(), except that it verifies
+ * if size of the flexible array following the structure header is also
+ * reflected in 'capabilities_size'.
+ *
+ * Return: A pointer to device configuration space or NULL if the space's
+ * 'capabilities_size' is insufficient to cover the nested structure.
+ */
+#define acpi_nhlt_endpoint_vendor_mic_devcfg(ep) ({					\
+	struct acpi_nhlt_vendor_mic_devcfg *__cfg = __acpi_nhlt_endpoint_cfg(ep);	\
+	__cfg->capabilities_size >= sizeof(*__cfg) &&					\
+	__cfg->capabilities_size == struct_size(__cfg, mics, __cfg->num_mics) ?		\
+		__cfg : NULL; })
+
+#endif /* __ACPI_NHLT_H__ */
-- 
2.25.1