[U-Boot] [PATCH v2 8/9] dm: core: Add ofnode to represent device tree nodes

[Masahiro Yamada]

2017-05-02 0:18 GMT+09:00 Simon Glass <sjg at chromium.org>:

> diff --git a/include/dm/ofnode.h b/include/dm/ofnode.h
> new file mode 100644
> index 0000000000..f952c989d2
> --- /dev/null
> +++ b/include/dm/ofnode.h
> @@ -0,0 +1,100 @@
> +/*
> + * Copyright (c) 2017 Google, Inc
> + * Written by Simon Glass <sjg at chromium.org>
> + *
> + * SPDX-License-Identifier:    GPL-2.0+
> + */
> +
> +#ifndef _DM_OFNODE_H
> +#define _DM_OFNODE_H
> +
> +DECLARE_GLOBAL_DATA_PTR;

Which line in this header references gd?



> +
> +struct fdtdec_phandle_args;
> +
> +/**
> + * ofnode - reference to a device tree node
> + *
> + * This union can hold either a straightforward pointer to a struct device_node
> + * in the live device tree, or an offset within the flat device tree. In the
> + * latter case, the pointer value is just the integer offset within the flat DT.
> + *
> + * Thus we can reference nodes in both the live tree (once available) and the
> + * flat tree (until then). Functions are available to translate between an
> + * ofnode and either an offset or a struct device_node *.
> + *
> + * The reference can also hold a null offset, in which case the pointer value
> + * here is (void *)-1. This corresponds to a struct device_node * value of
> + * NULL, or an offset of -1.
> + *
> + * There is no ambiguity as to whether ofnode holds an offset or a node
> + * pointer: when the live tree is active it holds a node pointer, otherwise it
> + * holds an offset. The value itself does not need to be unique and in theory
> + * the same value could point to a valid device node or a valid offset. We
> + * could arrange for a unique value to be used (e.g. by making the pointer
> + * point to an offset within the flat device tree in the case of an offset) but
> + * this increases code size slightly due to the subtraction. Since it offers no
> + * real benefit, the approach described here seems best.
> + *
> + * For now these points use constant types, since we don't allow writing
> + * the DT.
> + *
> + * @np: Pointer to device node, used for live tree
> + * @flat_ptr: Pointer into flat device tree, used for flat tree. Note that this
> + *     is not a really a pointer to a node: it is an offset value. See above.
> + */
> +typedef union ofnode_union {
> +       const struct device_node *np;   /* will be used for future live tree */
> +       long of_offset;
> +} ofnode;
> +
> +/**
> + * ofnode_to_offset() - convert an ofnode to a flat DT offset
> + *
> + * This cannot be called if the reference contains a node pointer.
> + *
> + * @node: Reference containing offset (possibly invalid)
> + * @return DT offset (can be -1)
> + */
> +static inline int ofnode_to_offset(ofnode node)
> +{
> +       return node.of_offset;
> +}
> +
> +/**
> + * ofnode_valid() - check if an ofnode is valid
> + *
> + * @return true if the reference contains a valid ofnode, false if it is NULL
> + */
> +static inline bool ofnode_valid(ofnode node)
> +{
> +       return node.of_offset != -1;
> +}
> +
> +/**
> + * offset_to_ofnode() - convert a DT offset to an ofnode
> + *
> + * @of_offset: DT offset (either valid, or -1)
> + * @return reference to the associated DT offset
> + */
> +static inline ofnode offset_to_ofnode(int of_offset)
> +{
> +       ofnode node;
> +
> +       node.of_offset = of_offset;
> +
> +       return node;
> +}
> +
> +/**
> + * ofnode_equal() - check if two references are equal
> + *
> + * @return true if equal, else false
> + */
> +static inline bool ofnode_equal(ofnode ref1, ofnode ref2)
> +{
> +       /* We only need to compare the contents */
> +       return ref1.of_offset == ref2.of_offset;
> +}
> +
> +#endif




-- 
Best Regards
Masahiro Yamada