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Groups > linux.kernel > #1315498 > unrolled thread
| Started by | Shannon Zhao <zhaoshenglong@huawei.com> |
|---|---|
| First post | 2016-01-23 04:30 +0100 |
| Last post | 2016-01-26 13:30 +0100 |
| Articles | 3 — 2 participants |
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[PATCH v3 16/17] FDT: Add a helper to get specified name subnode Shannon Zhao <zhaoshenglong@huawei.com> - 2016-01-23 04:30 +0100
Re: [PATCH v3 16/17] FDT: Add a helper to get specified name subnode Stefano Stabellini <stefano.stabellini@eu.citrix.com> - 2016-01-26 13:20 +0100
Re: [PATCH v3 16/17] FDT: Add a helper to get specified name subnode Shannon Zhao <zhaoshenglong@huawei.com> - 2016-01-26 13:30 +0100
| From | Shannon Zhao <zhaoshenglong@huawei.com> |
|---|---|
| Date | 2016-01-23 04:30 +0100 |
| Subject | [PATCH v3 16/17] FDT: Add a helper to get specified name subnode |
| Message-ID | <qTX3I-5bz-17@gated-at.bofh.it> |
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;
+
+ /* 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);
--
2.0.4
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| From | Stefano Stabellini <stefano.stabellini@eu.citrix.com> |
|---|---|
| Date | 2016-01-26 13:20 +0100 |
| Subject | Re: [PATCH v3 16/17] FDT: Add a helper to get specified name subnode |
| Message-ID | <qVaLh-3XS-41@gated-at.bofh.it> |
| In reply to | #1315498 |
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
>
>
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| From | Shannon Zhao <zhaoshenglong@huawei.com> |
|---|---|
| Date | 2016-01-26 13:30 +0100 |
| Message-ID | <qVaUZ-42e-55@gated-at.bofh.it> |
| In reply to | #1317822 |
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.
--
Shannon
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