Hi David,
On 28 January 2016 at 22:29, David Gibson <david@xxxxxxxxxxxxxxxxxxxxx> wrote:
> On Thu, Jan 28, 2016 at 09:39:27AM -0700, Simon Glass wrote:
>> The existing function to add a new property to a tree being built requires
>> that the entire contents of the new property be passed in. For some
>> applications it is more convenient to be able to add the property contents
>> later, perhaps by reading from a file. This avoids double-buffering of the
>> contents.
>>
>> Add a new function to support this and adust the existing fdt_property() to
>> use it.
>>
>> Signed-off-by: Simon Glass <sjg@xxxxxxxxxxxx>
>
> So, obviously such a patch should really go towards upstream libfdt.
>
> I'm happy enough with the concept, but I don't like the name.
>
> I'd prefer fdt_property_reserve() - the idea being that it reserves
> space for the property but doesn't fill it in.
Sounds good. I'll work up a patch. I tend to sync with upstream one a
quarter or so.
>
>> ---
>>
>> include/libfdt.h | 16 ++++++++++++++++
>> lib/libfdt/fdt_sw.c | 16 ++++++++++++++--
>> 2 files changed, 30 insertions(+), 2 deletions(-)
>>
>> diff --git a/include/libfdt.h b/include/libfdt.h
>> index e48c21a..c3f37ee 100644
>> --- a/include/libfdt.h
>> +++ b/include/libfdt.h
>> @@ -1181,6 +1181,22 @@ static inline int fdt_property_cell(void *fdt, const char *name, uint32_t val)
>> {
>> return fdt_property_u32(fdt, name, val);
>> }
>> +
>> +/**
>> + * fdt_property_val - add a new property and return a pointer to its value
>> + *
>> + * @fdt: pointer to the device tree blob
>> + * @name: name of property to add
>> + * @len: length of property value in bytes
>> + * @valp: returns a pointer to where where the value should be placed
>> + *
>> + * returns:
>> + * 0, on success
>> + * -FDT_ERR_BADMAGIC,
>> + * -FDT_ERR_NOSPACE, standard meanings
>> + */
>> +int fdt_property_val(void *fdt, const char *name, int len, void **valp);
>> +
>> #define fdt_property_string(fdt, name, str) \
>> fdt_property(fdt, name, str, strlen(str)+1)
>> int fdt_end_node(void *fdt);
>> diff --git a/lib/libfdt/fdt_sw.c b/lib/libfdt/fdt_sw.c
>> index 320a914..9c1df3d 100644
>> --- a/lib/libfdt/fdt_sw.c
>> +++ b/lib/libfdt/fdt_sw.c
>> @@ -175,7 +175,7 @@ static int _fdt_find_add_string(void *fdt, const char *s)
>> return offset;
>> }
>>
>> -int fdt_property(void *fdt, const char *name, const void *val, int len)
>> +int fdt_property_val(void *fdt, const char *name, int len, void **valp)
>> {
>> struct fdt_property *prop;
>> int nameoff;
>> @@ -193,7 +193,19 @@ int fdt_property(void *fdt, const char *name, const void *val, int len)
>> prop->tag = cpu_to_fdt32(FDT_PROP);
>> prop->nameoff = cpu_to_fdt32(nameoff);
>> prop->len = cpu_to_fdt32(len);
>> - memcpy(prop->data, val, len);
>> + *valp = prop->data;
>> + return 0;
>> +}
>> +
>> +int fdt_property(void *fdt, const char *name, const void *val, int len)
>> +{
>> + void *ptr;
>> + int ret;
>> +
>> + ret = fdt_property_val(fdt, name, len, &ptr);
>> + if (ret)
>> + return ret;
>> + memcpy(ptr, val, len);
>> return 0;
>> }
>>
Regards,
Simon
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