[PATCH v3 16/17] FDT: Add a helper to get specified name subnode
From: Stefano Stabellini <hidden>
Date: 2016-01-26 12:12:37
Also in:
linux-devicetree, linux-efi, lkml
On Sat, 23 Jan 2016, Shannon Zhao wrote:
quoted hunk ↗ jump to hunk
From: Shannon Zhao <redacted> 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 <redacted> --- CC: Rob Herring <robh@kernel.org> --- 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.
+ /* 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 */
quoted hunk ↗ jump to hunk
+ return -FDT_ERR_NOTFOUND; +} + +/** * of_get_flat_dt_root - find the root node in the flat blob */ unsigned long __init of_get_flat_dt_root(void)diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h index df9ef38..fc28162 100644 --- a/include/linux/of_fdt.h +++ b/include/linux/of_fdt.h@@ -52,6 +52,8 @@ extern char __dtb_end[]; extern int of_scan_flat_dt(int (*it)(unsigned long node, const char *uname, int depth, void *data), void *data); +extern int of_get_flat_dt_subnode_by_name(unsigned long node, + const char *uname); extern const void *of_get_flat_dt_prop(unsigned long node, const char *name, int *size); extern int of_flat_dt_is_compatible(unsigned long node, const char *name);-- 2.0.4