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>

lib/acpi/Makefile

@@ -3,4 +3,5 @@
 
 obj-y += acpigen.o
 obj-y += acpi_device.o
+obj-y += acpi_dp.o
 obj-y += acpi_table.o

lib/acpi/acpi_dp.c

@@ -0,0 +1,323 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generation of tables for particular device types
+ *
+ * Copyright 2019 Google LLC
+ * Mostly taken from coreboot file acpi_device.c
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <log.h>
+#include <malloc.h>
+#include <uuid.h>
+#include <acpi/acpigen.h>
+#include <acpi/acpi_dp.h>
+#include <dm/acpi.h>
+
+static void acpi_dp_write_array(struct acpi_ctx *ctx,
+				const struct acpi_dp *array);
+
+static void acpi_dp_write_value(struct acpi_ctx *ctx,
+				const struct acpi_dp *prop)
+{
+	switch (prop->type) {
+	case ACPI_DP_TYPE_INTEGER:
+		acpigen_write_integer(ctx, prop->integer);
+		break;
+	case ACPI_DP_TYPE_STRING:
+	case ACPI_DP_TYPE_CHILD:
+		acpigen_write_string(ctx, prop->string);
+		break;
+	case ACPI_DP_TYPE_REFERENCE:
+		acpigen_emit_namestring(ctx, prop->string);
+		break;
+	case ACPI_DP_TYPE_ARRAY:
+		acpi_dp_write_array(ctx, prop->array);
+		break;
+	default:
+		break;
+	}
+}
+
+/* Package (2) { "prop->name", VALUE } */
+static void acpi_dp_write_property(struct acpi_ctx *ctx,
+				   const struct acpi_dp *prop)
+{
+	acpigen_write_package(ctx, 2);
+	acpigen_write_string(ctx, prop->name);
+	acpi_dp_write_value(ctx, prop);
+	acpigen_pop_len(ctx);
+}
+
+/* Write array of Device Properties */
+static void acpi_dp_write_array(struct acpi_ctx *ctx,
+				const struct acpi_dp *array)
+{
+	const struct acpi_dp *dp;
+	char *pkg_count;
+
+	/* Package element count determined as it is populated */
+	pkg_count = acpigen_write_package(ctx, 0);
+
+	/*
+	 * Only acpi_dp of type DP_TYPE_TABLE is allowed to be an array.
+	 * DP_TYPE_TABLE does not have a value to be written. Thus, start
+	 * the loop from next type in the array.
+	 */
+	for (dp = array->next; dp; dp = dp->next) {
+		acpi_dp_write_value(ctx, dp);
+		(*pkg_count)++;
+	}
+
+	acpigen_pop_len(ctx);
+}
+
+static void acpi_dp_free(struct acpi_dp *dp)
+{
+	assert(dp);
+	while (dp) {
+		struct acpi_dp *p = dp->next;
+
+		switch (dp->type) {
+		case ACPI_DP_TYPE_CHILD:
+			acpi_dp_free(dp->child);
+			break;
+		case ACPI_DP_TYPE_ARRAY:
+			acpi_dp_free(dp->array);
+			break;
+		default:
+			break;
+		}
+
+		free(dp);
+		dp = p;
+	}
+}
+
+static int acpi_dp_write_internal(struct acpi_ctx *ctx, struct acpi_dp *table)
+{
+	struct acpi_dp *dp, *prop;
+	char *dp_count, *prop_count = NULL;
+	int child_count = 0;
+	int ret;
+
+	assert(table);
+	if (table->type != ACPI_DP_TYPE_TABLE)
+		return 0;
+
+	/* Name (name) */
+	acpigen_write_name(ctx, table->name);
+
+	/* Device Property list starts with the next entry */
+	prop = table->next;
+
+	/* Package (DP), default to assuming no properties or children */
+	dp_count = acpigen_write_package(ctx, 0);
+
+	/* Print base properties */
+	for (dp = prop; dp; dp = dp->next) {
+		if (dp->type == ACPI_DP_TYPE_CHILD) {
+			child_count++;
+		} else {
+			/*
+			 * The UUID and package is only added when
+			 * we come across the first property.  This
+			 * is to avoid creating a zero-length package
+			 * in situations where there are only children.
+			 */
+			if (!prop_count) {
+				*dp_count += 2;
+				/* ToUUID (ACPI_DP_UUID) */
+				ret = acpigen_write_uuid(ctx, ACPI_DP_UUID);
+				if (ret)
+					return log_msg_ret("touuid", ret);
+				/*
+				 * Package (PROP), element count determined as
+				 * it is populated
+				 */
+				prop_count = acpigen_write_package(ctx, 0);
+			}
+			(*prop_count)++;
+			acpi_dp_write_property(ctx, dp);
+		}
+	}
+
+	if (prop_count) {
+		/* Package (PROP) length, if a package was written */
+		acpigen_pop_len(ctx);
+	}
+
+	if (child_count) {
+		/* Update DP package count to 2 or 4 */
+		*dp_count += 2;
+		/* ToUUID (ACPI_DP_CHILD_UUID) */
+		ret = acpigen_write_uuid(ctx, ACPI_DP_CHILD_UUID);
+		if (ret)
+			return log_msg_ret("child uuid", ret);
+
+		/* Print child pointer properties */
+		acpigen_write_package(ctx, child_count);
+
+		for (dp = prop; dp; dp = dp->next)
+			if (dp->type == ACPI_DP_TYPE_CHILD)
+				acpi_dp_write_property(ctx, dp);
+		/* Package (CHILD) length */
+		acpigen_pop_len(ctx);
+	}
+
+	/* Package (DP) length */
+	acpigen_pop_len(ctx);
+
+	/* Recursively parse children into separate tables */
+	for (dp = prop; dp; dp = dp->next) {
+		if (dp->type == ACPI_DP_TYPE_CHILD) {
+			ret = acpi_dp_write_internal(ctx, dp->child);
+			if (ret)
+				return log_msg_ret("dp child", ret);
+		}
+	}
+
+	return 0;
+}
+
+int acpi_dp_write(struct acpi_ctx *ctx, struct acpi_dp *table)
+{
+	int ret;
+
+	ret = acpi_dp_write_internal(ctx, table);
+
+	/* Clean up */
+	acpi_dp_free(table);
+
+	if (ret)
+		return log_msg_ret("write", ret);
+
+	return 0;
+}
+
+static struct acpi_dp *acpi_dp_new(struct acpi_dp *dp, enum acpi_dp_type type,
+				   const char *name)
+{
+	struct acpi_dp *new;
+
+	new = malloc(sizeof(struct acpi_dp));
+	if (!new)
+		return NULL;
+
+	memset(new, '\0', sizeof(*new));
+	new->type = type;
+	new->name = name;
+
+	if (dp) {
+		/* Add to end of property list */
+		while (dp->next)
+			dp = dp->next;
+		dp->next = new;
+	}
+
+	return new;
+}
+
+struct acpi_dp *acpi_dp_new_table(const char *name)
+{
+	return acpi_dp_new(NULL, ACPI_DP_TYPE_TABLE, name);
+}
+
+struct acpi_dp *acpi_dp_add_integer(struct acpi_dp *dp, const char *name,
+				    u64 value)
+{
+	struct acpi_dp *new;
+
+	assert(dp);
+	new = acpi_dp_new(dp, ACPI_DP_TYPE_INTEGER, name);
+
+	if (new)
+		new->integer = value;
+
+	return new;
+}
+
+struct acpi_dp *acpi_dp_add_string(struct acpi_dp *dp, const char *name,
+				   const char *string)
+{
+	struct acpi_dp *new;
+
+	assert(dp);
+	new = acpi_dp_new(dp, ACPI_DP_TYPE_STRING, name);
+	if (new)
+		new->string = string;
+
+	return new;
+}
+
+struct acpi_dp *acpi_dp_add_reference(struct acpi_dp *dp, const char *name,
+				      const char *reference)
+{
+	struct acpi_dp *new;
+
+	assert(dp);
+	new = acpi_dp_new(dp, ACPI_DP_TYPE_REFERENCE, name);
+	if (new)
+		new->string = reference;
+
+	return new;
+}
+
+struct acpi_dp *acpi_dp_add_child(struct acpi_dp *dp, const char *name,
+				  struct acpi_dp *child)
+{
+	struct acpi_dp *new;
+
+	assert(dp);
+	if (child->type != ACPI_DP_TYPE_TABLE)
+		return NULL;
+
+	new = acpi_dp_new(dp, ACPI_DP_TYPE_CHILD, name);
+	if (new) {
+		new->child = child;
+		new->string = child->name;
+	}
+
+	return new;
+}
+
+struct acpi_dp *acpi_dp_add_array(struct acpi_dp *dp, struct acpi_dp *array)
+{
+	struct acpi_dp *new;
+
+	assert(dp);
+	assert(array);
+	if (array->type != ACPI_DP_TYPE_TABLE)
+		return NULL;
+
+	new = acpi_dp_new(dp, ACPI_DP_TYPE_ARRAY, array->name);
+	if (new)
+		new->array = array;
+
+	return new;
+}
+
+struct acpi_dp *acpi_dp_add_integer_array(struct acpi_dp *dp, const char *name,
+					  u64 *array, int len)
+{
+	struct acpi_dp *dp_array;
+	int i;
+
+	assert(dp);
+	if (len <= 0)
+		return NULL;
+
+	dp_array = acpi_dp_new_table(name);
+	if (!dp_array)
+		return NULL;
+
+	for (i = 0; i < len; i++)
+		if (!acpi_dp_add_integer(dp_array, NULL, array[i]))
+			break;
+
+	if (!acpi_dp_add_array(dp, dp_array))
+		return NULL;
+
+	return dp_array;
+}