diff options
| author | Thierry Reding <treding@nvidia.com> | 2019-03-21 19:09:58 +0100 |
|---|---|---|
| committer | Simon Glass <sjg@chromium.org> | 2019-04-11 20:10:50 -0600 |
| commit | ea1df3e07cc5a4b155e69fcb7f583cb7f4c2cbe3 (patch) | |
| tree | 7ea3d9dec579e6379ea3b9f4270a1edfaee5fb4b /scripts/dtc/libfdt/libfdt.h | |
| parent | c7fbee540e006b4cf6cda9272d0d5c9847b3db11 (diff) | |
libfdt: Add phandle generation helper
The new fdt_generate_phandle() function can be used to generate a new,
unused phandle given a specific device tree blob. The implementation is
somewhat naive in that it simply walks the entire device tree to find
the highest phandle value and then returns a phandle value one higher
than that. A more clever implementation might try to find holes in the
current set of phandle values and fill them. But this implementation is
relatively simple and works reliably.
Also add a test that validates that phandles generated by this new API
are indeed unique.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Diffstat (limited to 'scripts/dtc/libfdt/libfdt.h')
| -rw-r--r-- | scripts/dtc/libfdt/libfdt.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/scripts/dtc/libfdt/libfdt.h b/scripts/dtc/libfdt/libfdt.h index fd73688f9e9..cf86ddba881 100644 --- a/scripts/dtc/libfdt/libfdt.h +++ b/scripts/dtc/libfdt/libfdt.h @@ -139,6 +139,10 @@ #define FDT_ERR_MAX 17 +/* constants */ +#define FDT_MAX_PHANDLE 0xfffffffe + /* Valid values for phandles range from 1 to 2^32-2. */ + /**********************************************************************/ /* Low-level functions (you probably don't need these) */ /**********************************************************************/ @@ -314,6 +318,21 @@ const char *fdt_string(const void *fdt, int stroffset); uint32_t fdt_get_max_phandle(const void *fdt); /** + * fdt_generate_phandle - return a new, unused phandle for a device tree blob + * @fdt: pointer to the device tree blob + * @phandle: return location for the new phandle + * + * Walks the device tree blob and looks for the highest phandle value. On + * success, the new, unused phandle value (one higher than the previously + * highest phandle value in the device tree blob) will be returned in the + * @phandle parameter. + * + * Returns: + * 0 on success or a negative error-code on failure + */ +int fdt_generate_phandle(const void *fdt, uint32_t *phandle); + +/** * fdt_num_mem_rsv - retrieve the number of memory reserve map entries * @fdt: pointer to the device tree blob * |