[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3 16/17] FDT: Add a helper to get specified name subnode
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 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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