Peter,
On 01/25/2016 03:26 PM, Peter Maydell wrote:
> On 18 January 2016 at 15:16, Eric Auger <eric.au...@linaro.org> wrote:
>> This new helper routine returns a NULL terminated array of
>> node paths matching a node name and a compat string.
>>
>> Signed-off-by: Eric Auger <eric.au...@linaro.org>
>>
>> ---
>>
>> v4 -> v5:
>> - support the case where several nodes exist, ie.
>> return an array of node paths. Also add Error **
>> parameter
>>
>> v1 -> v2:
>> - move doc comment in header file
>> - do not use a fixed size buffer
>> - break on errors in while loop
>> - use strcmp instead of strncmp
>>
>> RFC -> v1:
>> - improve error handling according to Alex' comments
>> ---
>> device_tree.c | 49
>> ++++++++++++++++++++++++++++++++++++++++++++
>> include/sysemu/device_tree.h | 14 +++++++++++++
>> 2 files changed, 63 insertions(+)
>>
>> diff --git a/device_tree.c b/device_tree.c
>> index b262c2d..3c88a37 100644
>> --- a/device_tree.c
>> +++ b/device_tree.c
>> @@ -231,6 +231,55 @@ static int findnode_nofail(void *fdt, const char
>> *node_path)
>> return offset;
>> }
>>
>> +char **qemu_fdt_node_path(void *fdt, const char *name, char *compat,
>> + Error **errp)
>> +{
>> + int offset, len, ret;
>> + const char *iter_name;
>> + unsigned int path_len = 16, n = 0;
>> + GSList *path_list = NULL, *iter;
>> + char **path_array;
>> +
>> + offset = fdt_node_offset_by_compatible(fdt, -1, compat);
>> +
>> + while (offset >= 0) {
>> + iter_name = fdt_get_name(fdt, offset, &len);
>> + if (!iter_name) {
>> + offset = len;
>> + break;
>> + }
>> + if (!strcmp(iter_name, name)) {
>> + char *path;
>> +
>> + path = g_malloc(path_len);
>> + while ((ret = fdt_get_path(fdt, offset, path, path_len))
>> + == -FDT_ERR_NOSPACE) {
>> + path_len += 16;
>> + path = g_realloc(path, path_len);
>> + }
>> + path_list = g_slist_prepend(path_list, path);
>> + n++;
>> + }
>> + offset = fdt_node_offset_by_compatible(fdt, offset, compat);
>> + }
>> +
>> + if (offset < 0 && offset != -FDT_ERR_NOTFOUND) {
>> + error_setg(errp, "%s: abort parsing dt for %s/%s: %s",
>> + __func__, name, compat, fdt_strerror(offset));
>
> Needs to bail out (freeing memory).
effectively in case I get an error, it's better to free everything and
return a vector with with a single NULL element, see comment below. I
will correct this.
>
>> + }
>> +
>> + path_array = g_new(char *, n + 1);
>> + path_array[n--] = NULL;
>
> 0, or '\0'. NULL is a pointer, not the NUL character. (This is a
> style issue, not a correctness one.)
actually I want to put NULL as the last element of my array and not a
NUL char. The function returns a NULL terminated vector as
g_strsplit_set does, for instance.
Thanks
Eric
>
>> +
>> + for (iter = path_list; iter; iter = iter->next) {
>> + path_array[n--] = iter->data;
>> + }
>> +
>> + g_slist_free(path_list);
>> +
>> + return path_array;
>> +}
>> +
>> int qemu_fdt_setprop(void *fdt, const char *node_path,
>> const char *property, const void *val, int size)
>> {
>> diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h
>> index fdf25a4..436b5dd 100644
>> --- a/include/sysemu/device_tree.h
>> +++ b/include/sysemu/device_tree.h
>> @@ -20,6 +20,20 @@ void *load_device_tree(const char *filename_path, int
>> *sizep);
>> void *load_device_tree_from_sysfs(void);
>> #endif
>>
>> +/**
>> + * qemu_fdt_node_path: return the paths of nodes matching a given
>> + * name and compat string
>> + * @fdt: pointer to the dt blob
>> + * @name: node name
>> + * @compat: compatibility string
>> + * @errp: handle to an error object
>> + *
>> + * returns a newly allocated NULL-terminated array of node paths.
>
> Should say what we return on error (NULL ?)
>
>> + * Use g_strfreev() to free it.
>> + */
>> +char **qemu_fdt_node_path(void *fdt, const char *name, char *compat,
>> + Error **errp);
>> +
>> int qemu_fdt_setprop(void *fdt, const char *node_path,
>> const char *property, const void *val, int size);
>> int qemu_fdt_setprop_cell(void *fdt, const char *node_path,
>> --
>> 1.9.1
>>
>
> thanks
> -- PMM
>
