dm: add tag support

With dm-tag feature, any U-Boot subsystem is allowed to associate
arbitrary number of data with a particular udevice. This can been
see as expanding "struct udevice" without modifying the definition.

As a first user, UEFI subsystem makes use of tags to associate
an efi_disk object with a block device.

Signed-off-by: AKASHI Takahiro <[email protected]>
Reviewed-by: Simon Glass <[email protected]>

2 files changed, 114 insertions, 0 deletions

diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
index beb8bb90a64..805a6fd6797 100644
--- a/include/asm-generic/global_data.h
+++ b/include/asm-generic/global_data.h
@@ -474,6 +474,10 @@ struct global_data {
 	 */
 	struct event_state event_state;
 #endif
+	/**
+	 * @dmtag_list: List of DM tags
+	 */
+	struct list_head dmtag_list;
 };
 #ifndef DO_DEPS_ONLY
 static_assert(sizeof(struct global_data) == GD_SIZE);
diff --git a/include/dm/tag.h b/include/dm/tag.h
new file mode 100644
index 00000000000..54fc31eb153
--- /dev/null
+++ b/include/dm/tag.h
@@ -0,0 +1,110 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (c) 2021 Linaro Limited
+ *			Author: AKASHI Takahiro
+ */
+
+#ifndef _DM_TAG_H
+#define _DM_TAG_H
+
+#include <linux/list.h>
+#include <linux/types.h>
+
+struct udevice;
+
+enum dm_tag_t {
+	/* EFI_LOADER */
+	DM_TAG_EFI = 0,
+
+	DM_TAG_COUNT,
+};
+
+/**
+ * dmtag_node
+ *
+ * @sibling: List of dm-tag nodes
+ * @dev:     Associated udevice
+ * @tag:     Tag type
+ * @ptr:     Pointer as a value
+ * @val:     Value
+ */
+struct dmtag_node {
+	struct list_head sibling;
+	struct  udevice *dev;
+	enum dm_tag_t tag;
+	union {
+		void *ptr;
+		ulong val;
+	};
+};
+
+/**
+ * dev_tag_set_ptr() - set a tag's value as a pointer
+ * @dev: Device to operate
+ * @tag: Tag type
+ * @ptr: Pointer to set
+ *
+ * Set the value, @ptr, as of @tag associated with the device, @dev
+ *
+ * Return: 0 on success, -ve on error
+ */
+int dev_tag_set_ptr(struct udevice *dev, enum dm_tag_t tag, void *ptr);
+
+/**
+ * dev_tag_set_val() set a tag's value as an integer
+ * @dev: Device to operate
+ * @tag: Tag type
+ * @val: Value to set
+ *
+ * Set the value, @val, as of @tag associated with the device, @dev
+ *
+ * Return: on success, -ve on error
+ */
+int dev_tag_set_val(struct udevice *dev, enum dm_tag_t tag, ulong val);
+
+/**
+ * dev_tag_get_ptr() - get a tag's value as a pointer
+ * @dev: Device to operate
+ * @tag: Tag type
+ * @ptrp: Pointer to tag's value (pointer)
+ *
+ * Get a tag's value as a pointer
+ *
+ * Return: on success, -ve on error
+ */
+int dev_tag_get_ptr(struct udevice *dev, enum dm_tag_t tag, void **ptrp);
+
+/**
+ * dev_tag_get_val() - get a tag's value as an integer
+ * @dev: Device to operate
+ * @tag: Tag type
+ * @valp: Pointer to tag's value (ulong)
+ *
+ * Get a tag's value as an integer
+ *
+ * Return: 0 on success, -ve on error
+ */
+int dev_tag_get_val(struct udevice *dev, enum dm_tag_t tag, ulong *valp);
+
+/**
+ * dev_tag_del() - delete a tag
+ * @dev: Device to operate
+ * @tag: Tag type
+ *
+ * Delete a tag of @tag associated with the device, @dev
+ *
+ * Return: 0 on success, -ve on error
+ */
+int dev_tag_del(struct udevice *dev, enum dm_tag_t tag);
+
+/**
+ * dev_tag_del_all() - delete all tags
+ * @dev: Device to operate
+ *
+ * Delete all the tags associated with the device, @dev
+ *
+ * Return: 0 on success, -ve on error
+ */
+int dev_tag_del_all(struct udevice *dev);
+
+#endif /* _DM_TAG_H */