On 2016/1/26 20:11, Stefano Stabellini wrote:
> On Sat, 23 Jan 2016, Shannon Zhao wrote:
>> > From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
>> >
>> > Sometimes it needs to check if there is a node in FDT by full path.
>> > Introduce this helper to get the specified name subnode if it exists.
>> >
>> > Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
>> > ---
>> > CC: Rob Herring <robh@xxxxxxxxxx>
>> > ---
>> > drivers/of/fdt.c | 35 +++++++++++++++++++++++++++++++++++
>> > include/linux/of_fdt.h | 2 ++
>> > 2 files changed, 37 insertions(+)
>> >
>> > diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
>> > index 655f79d..112ec16 100644
>> > --- a/drivers/of/fdt.c
>> > +++ b/drivers/of/fdt.c
>> > @@ -645,6 +645,41 @@ int __init of_scan_flat_dt(int (*it)(unsigned long node,
>> > }
>> >
>> > /**
>> > + * of_get_flat_dt_subnode_by_name - get subnode of specified node by name
>> > + *
>> > + * @node: the parent node
>> > + * @uname: the name of subnode
>> > + * @return offset of the subnode, or -FDT_ERR_NOTFOUND if there is none
>> > + */
>> > +
>> > +int of_get_flat_dt_subnode_by_name(unsigned long node, const char *uname)
>> > +{
>> > + const void *blob = initial_boot_params;
>> > + int offset;
>> > + const char *pathp;
>> > +
>> > + /* Find first subnode if it exists */
>> > + offset = fdt_first_subnode(blob, node);
>> > + if (offset < 0)
>> > + return -FDT_ERR_NOTFOUND;
>> > + pathp = fdt_get_name(blob, offset, NULL);
>> > + if (strncmp(pathp, uname, strlen(uname)) == 0)
>> > + return offset;
> Wouldn't this check succeed even if uname is "uefi" and the node
> name is actually "uefiiiii"? You might have to use strcmp.
>
Ah, yes. Will fix this.
>
>> > + /* Find other subnodes */
>> > + do {
>> > + offset = fdt_next_subnode(blob, offset);
>> > + if (offset < 0)
>> > + return -FDT_ERR_NOTFOUND;
>> > + pathp = fdt_get_name(blob, offset, NULL);
>> > + if (strncmp(pathp, uname, strlen(uname)) == 0)
>> > + return offset;
>> > + } while (offset >= 0);
> Rather than writing the name check twice, I think it would be best to
> code this loop as:
>
> for (offset = fdt_first_subnode(blob, offset);
> offset >= 0;
> offset = fdt_next_subnode(blob, offset)) {
>
> /* do name check */
>
>
>
Thanks for your suggestion. Will change this.
--
Shannon
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