Re: [U-Boot] [PATCH - resend due to bounce] libfdt: Add fdt functionality for more intuitive

[Jerry Van Baren]

Hi Peter,

On 05/07/2012 09:52 AM, Peter Feuerer wrote:
> libfdt: Add fdt functionality for more intuitive fdt handling
> 
> New functions:
> fdt_read - retrieve the value of a property by full path
> fdt_write - create or change a property with full path and create subnodes if 
> needed
> fdt_create_path - create subnode path with parents
> 
> Signed-off-by: Peter Feuerer 
> CC: David Gibson 
> CC: Gerald Van Baren 

As David pointed out, this needs to go through the upstream libfdt (dtc)
library so that we stay in sync.



Thanks,
gvb

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[U-Boot] [PATCH - resend due to bounce] libfdt: Add fdt functionality for more intuitive

[Peter Feuerer]

libfdt: Add fdt functionality for more intuitive fdt handling

New functions:
fdt_read - retrieve the value of a property by full path
fdt_write - create or change a property with full path and create subnodes if 
needed
fdt_create_path - create subnode path with parents

Signed-off-by: Peter Feuerer 
CC: David Gibson 
CC: Gerald Van Baren 

---
 include/libfdt.h |   93 
 lib/libfdt/fdt_ro.c  |   30 +
 lib/libfdt/fdt_rw.c  |   97 ++
 lib/libfdt/libfdt_internal.h |4 ++
 4 files changed, 224 insertions(+), 0 deletions(-)

diff --git a/include/libfdt.h b/include/libfdt.h
index de82ed5..822ab18 100644
--- a/include/libfdt.h
+++ b/include/libfdt.h
@@ -548,6 +548,37 @@ static inline void *fdt_getprop_w(void *fdt, int 
nodeoffset,
 }
 
 /**
+ * fdt_read - retrieve the value of a property by full path
+ * @fdt: pointer to the device tree blob
+ * @path: string containing the absolute path of the property
+ * @name: name of the property
+ * @lenp: pointer to an integer variable (will be overwritten) or NULL
+ *
+ * fdt_getprop() retrieves a pointer to the value of the property
+ * named 'name' of the node at offset nodeoffset (this will be a
+ * pointer to within the device blob itself, not a copy of the value).
+ * If lenp is non-NULL, the length of the property value is also
+ * returned, in the integer pointed to by lenp.
+ *
+ * returns:
+ * pointer to the property's value
+ * if lenp is non-NULL, *lenp contains the length of the property
+ * value (>=0)
+ * NULL, on error
+ * if lenp is non-NULL, *lenp contains an error code (<0):
+ * -FDT_ERR_NOTFOUND, node does not have named property
+ * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE 
tag
+ * -FDT_ERR_BADPATH,
+ * -FDT_ERR_BADMAGIC,
+ * -FDT_ERR_BADVERSION,
+ * -FDT_ERR_BADSTATE,
+ * -FDT_ERR_BADSTRUCTURE,
+ * -FDT_ERR_TRUNCATED, standard meanings
+ */
+const void *fdt_read(const void *fdt, const char *path,
+   const char *name, int *lenp);
+
+/**
  * fdt_get_phandle - retrieve the phandle of a given node
  * @fdt: pointer to the device tree blob
  * @nodeoffset: structure block offset of the node
@@ -1066,6 +1097,38 @@ int fdt_set_name(void *fdt, int nodeoffset, const char 
*name);
  */
 int fdt_setprop(void *fdt, int nodeoffset, const char *name,
const void *val, int len);
+/**
+ * fdt_write - create or change a property with full path and create
+ * all subnodes to the property if needed
+ * @fdt: pointer to the device tree blob
+ * @path: string containing the absolute path of the property
+ * @name: name of the property to change
+ * @val: pointer to data to set the property value to
+ * @len: length of the property value
+ *
+ * fdt_write() sets the value of the named property in the given
+ * node to the given value and length, creating the property if it
+ * does not already exist. Additionally it creates all parent nodes if
+ * not yet existing.
+ *
+ * This function may insert or delete data from the blob, and will
+ * therefore change the offsets of some existing nodes.
+ *
+ * returns:
+ * 0, on success
+ * -FDT_ERR_NOSPACE, there is insufficient free space in the blob to
+ * contain the new property value
+ * -FDT_ERR_BADOFFSET, nodeoffset did not point to FDT_BEGIN_NODE tag
+ * -FDT_ERR_BADLAYOUT,
+ * -FDT_ERR_BADMAGIC,
+ * -FDT_ERR_BADVERSION,
+ * -FDT_ERR_BADSTATE,
+ * -FDT_ERR_BADSTRUCTURE,
+ * -FDT_ERR_BADLAYOUT,
+ * -FDT_ERR_TRUNCATED, standard meanings
+ */
+int fdt_write(void *fdt, const char *path, const char *name,
+   const void *val, int len);
 
 /**
  * fdt_setprop_cell - set a property to a single cell value
@@ -1204,6 +1267,36 @@ int fdt_add_subnode_namelen(void *fdt, int parentoffset,
 int fdt_add_subnode(void *fdt, int parentoffset, const char *name);
 
 /**
+ * fdt_create_path - create subnode path with parents
+ * @fdt: pointer to the device tree blob
+ * @path: absolute path of subnodes to create
+ *
+ * fdt_create_path() creates absolute subnode path with all needed
+ * parents, if they don't exist.
+ *
+ * This function will insert data into the blob, and will therefore
+ * change the offsets of some existing nodes.
+ *
+ * returns:
+ * structure block offset of the created nodeequested subnode (>=0), on 
success
+ * -FDT_ERR_NOTFOUND, if the requested subnode does not exist
+ * -FDT_ERR_BADOFFSET, if parentoffset did not point to an FDT_BEGIN_NODE 
tag
+ * -FDT_ERR_EXISTS, if the node at parentoffset already has a subnode of
+ * the given name
+ * -FDT_ERR_NOSPACE, if there is insufficient free space in the
+ * blob to contain the new node
+ * -FDT_ERR_NOSPACE,
+ * -FDT_ERR_BADPATH,
+