acpi: Support writing Device Properties objects via _DSD

More complex device properties can be provided to drivers via a
device-specific data (_DSD) object.

To create this we need to build it up in a separate data structure and
then generate the ACPI code, due to its recursive nature.

Add an implementation of this.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

2 files changed, 218 insertions, 0 deletions

diff --git a/include/acpi/acpi_dp.h b/include/acpi/acpi_dp.h
new file mode 100644
index 0000000000..a82330856a
--- /dev/null
+++ b/include/acpi/acpi_dp.h
@@ -0,0 +1,217 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Device properties, a temporary data structure for adding to ACPI code
+ *
+ * Copyright 2019 Google LLC
+ * Mostly taken from coreboot file acpi_device.h
+ */
+
+#ifndef __ACPI_DP_H
+#define __ACPI_DP_H
+
+struct acpi_ctx;
+
+/*
+ * Writing Device Properties objects via _DSD
+ *
+ * This is described in ACPI 6.3 section 6.2.5
+ *
+ * This provides a structure to handle nested device-specific data which ends
+ * up in a _DSD table.
+ *
+ * https://www.kernel.org/doc/html/latest/firmware-guide/acpi/DSD-properties-rules.html
+ * https://uefi.org/sites/default/files/resources/_DSD-device-properties-UUID.pdf
+ * https://uefi.org/sites/default/files/resources/_DSD-hierarchical-data-extension-UUID-v1.1.pdf
+ *
+ * The Device Property Hierarchy can be multiple levels deep with multiple
+ * children possible in each level.  In order to support this flexibility
+ * the device property hierarchy must be built up before being written out.
+ *
+ * For example:
+ *
+ * Child table with string and integer:
+ * struct acpi_dp *child = acpi_dp_new_table("CHLD");
+ * acpi_dp_add_string(child, "childstring", "CHILD");
+ * acpi_dp_add_integer(child, "childint", 100);
+ *
+ * _DSD table with integer and gpio and child pointer:
+ * struct acpi_dp *dsd = acpi_dp_new_table("_DSD");
+ * acpi_dp_add_integer(dsd, "number1", 1);
+ * acpi_dp_add_gpio(dsd, "gpio", "\_SB.PCI0.GPIO", 0, 0, 1);
+ * acpi_dp_add_child(dsd, "child", child);
+ *
+ * Write entries into SSDT and clean up resources:
+ * acpi_dp_write(dsd);
+ *
+ * Name(_DSD, Package() {
+ *   ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301")
+ *   Package() {
+ *     Package() { "gpio", Package() { \_SB.PCI0.GPIO, 0, 0, 0 } }
+ *     Package() { "number1", 1 }
+ *   }
+ *   ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b")
+ *   Package() {
+ *     Package() { "child", CHLD }
+ *   }
+ * }
+ * Name(CHLD, Package() {
+ *   ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301")
+ *   Package() {
+ *     Package() { "childstring", "CHILD" }
+ *     Package() { "childint", 100 }
+ *   }
+ * }
+ */
+
+#define ACPI_DP_UUID		"daffd814-6eba-4d8c-8a91-bc9bbf4aa301"
+#define ACPI_DP_CHILD_UUID	"dbb8e3e6-5886-4ba6-8795-1319f52a966b"
+
+/**
+ * enum acpi_dp_type - types of device property objects
+ *
+ * These refer to the types defined by struct acpi_dp below
+ *
+ * @ACPI_DP_TYPE_UNKNOWN: Unknown / do not use
+ * @ACPI_DP_TYPE_INTEGER: Integer value (u64) in @integer
+ * @ACPI_DP_TYPE_STRING: String value in @string
+ * @ACPI_DP_TYPE_REFERENCE: Reference to another object, with value in @string
+ * @ACPI_DP_TYPE_TABLE: Type for a top-level table which may have children
+ * @ACPI_DP_TYPE_ARRAY: Array of items with first item in @array and following
+ *	items linked from that item's @next
+ * @ACPI_DP_TYPE_CHILD: Child object, with siblings in that child's @next
+ */
+enum acpi_dp_type {
+	ACPI_DP_TYPE_UNKNOWN,
+	ACPI_DP_TYPE_INTEGER,
+	ACPI_DP_TYPE_STRING,
+	ACPI_DP_TYPE_REFERENCE,
+	ACPI_DP_TYPE_TABLE,
+	ACPI_DP_TYPE_ARRAY,
+	ACPI_DP_TYPE_CHILD,
+};
+
+/**
+ * struct acpi_dp - ACPI device properties
+ *
+ * @type: Table type
+ * @name: Name of object, typically _DSD but could be CHLD for a child object.
+ *	This can be NULL if there is no name
+ * @next: Next object in list (next array element or next sibling)
+ * @child: Pointer to first child, if @type == ACPI_DP_TYPE_CHILD, else NULL
+ * @array: First array element, if @type == ACPI_DP_TYPE_ARRAY, else NULL
+ * @integer: Integer value of the property, if @type == ACPI_DP_TYPE_INTEGER
+ * @string: String value of the property, if @type == ACPI_DP_TYPE_STRING;
+ *	child name if @type == ACPI_DP_TYPE_CHILD;
+ *	reference name if @type == ACPI_DP_TYPE_REFERENCE;
+ */
+struct acpi_dp {
+	enum acpi_dp_type type;
+	const char *name;
+	struct acpi_dp *next;
+	union {
+		struct acpi_dp *child;
+		struct acpi_dp *array;
+	};
+	union {
+		u64 integer;
+		const char *string;
+	};
+};
+
+/**
+ * acpi_dp_new_table() - Start a new Device Property table
+ *
+ * @ref: ACPI reference (e.g. "_DSD")
+ * @return pointer to table, or NULL if out of memory
+ */
+struct acpi_dp *acpi_dp_new_table(const char *ref);
+
+/**
+ * acpi_dp_add_integer() - Add integer Device Property
+ *
+ * A new node is added to the end of the property list of @dp
+ *
+ * @dp: Table to add this property to
+ * @name: Name of property, or NULL for none
+ * @value: Integer value
+ * @return pointer to new node, or NULL if out of memory
+ */
+struct acpi_dp *acpi_dp_add_integer(struct acpi_dp *dp, const char *name,
+				    u64 value);
+
+/**
+ * acpi_dp_add_string() - Add string Device Property
+ *
+ * A new node is added to the end of the property list of @dp
+ *
+ * @dp: Table to add this property to
+ * @name: Name of property, or NULL for none
+ * @string: String value
+ * @return pointer to new node, or NULL if out of memory
+ */
+struct acpi_dp *acpi_dp_add_string(struct acpi_dp *dp, const char *name,
+				   const char *string);
+
+/**
+ * acpi_dp_add_reference() - Add reference Device Property
+ *
+ * A new node is added to the end of the property list of @dp
+ *
+ * @dp: Table to add this property to
+ * @name: Name of property, or NULL for none
+ * @reference: Reference value
+ * @return pointer to new node, or NULL if out of memory
+ */
+struct acpi_dp *acpi_dp_add_reference(struct acpi_dp *dp, const char *name,
+				      const char *reference);
+
+/**
+ * acpi_dp_add_array() - Add array Device Property
+ *
+ * A new node is added to the end of the property list of @dp, with the array
+ * attached to that.
+ *
+ * @dp: Table to add this property to
+ * @name: Name of property, or NULL for none
+ * @return pointer to new node, or NULL if out of memory
+ */
+struct acpi_dp *acpi_dp_add_array(struct acpi_dp *dp, struct acpi_dp *array);
+
+/**
+ * acpi_dp_add_integer_array() - Add an array of integers
+ *
+ * A new node is added to the end of the property list of @dp, with the array
+ * attached to that. Each element of the array becomes a new node.
+ *
+ * @dp: Table to add this property to
+ * @name: Name of property, or NULL for none
+ * @return pointer to new array node, or NULL if out of memory
+ */
+struct acpi_dp *acpi_dp_add_integer_array(struct acpi_dp *dp, const char *name,
+					  u64 *array, int len);
+
+/**
+ * acpi_dp_add_child() - Add a child table of Device Properties
+ *
+ * A new node is added as a child of @dp
+ *
+ * @dp: Table to add this child to
+ * @name: Name of child, or NULL for none
+ * @child: Child node to add
+ * @return pointer to new child node, or NULL if out of memory
+ */
+struct acpi_dp *acpi_dp_add_child(struct acpi_dp *dp, const char *name,
+				  struct acpi_dp *child);
+
+/**
+ * acpi_dp_write() - Write Device Property hierarchy and clean up resources
+ *
+ * This writes the table using acpigen and then frees it
+ *
+ * @ctx: ACPI context
+ * @table: Table to write
+ * @return 0 if OK, -ve on error
+ */
+int acpi_dp_write(struct acpi_ctx *ctx, struct acpi_dp *table);
+
+#endif
diff --git a/include/acpi/acpigen.h b/include/acpi/acpigen.h
index 31fa20a806..b10226f8f8 100644
--- a/include/acpi/acpigen.h
+++ b/include/acpi/acpigen.h
@@ -31,6 +31,7 @@ enum {
 	PACKAGE_OP		= 0x12,
 	DUAL_NAME_PREFIX	= 0x2e,
 	MULTI_NAME_PREFIX	= 0x2f,
+	ROOT_PREFIX		= 0x5c,
 };
 
 /**