| Message ID | 1453519184-11908-17-git-send-email-zhaoshenglong@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Sat, 23 Jan 2016, Shannon Zhao wrote: > From: Shannon Zhao <shannon.zhao@linaro.org> > > 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@linaro.org> > --- > 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 */ > + 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 > >
On 2016/1/26 20:11, Stefano Stabellini wrote: > On Sat, 23 Jan 2016, Shannon Zhao wrote: >> > From: Shannon Zhao <shannon.zhao@linaro.org> >> > >> > 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@linaro.org> >> > --- >> > 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. > 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.
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; + + /* 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); + + 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);