From: Thierry Reding treding@nvidia.com
This function allows looking up the highest phandle value stored in a device tree, which is useful to determine the next best phandle value for new nodes.
Signed-off-by: Thierry Reding treding@nvidia.com --- include/fdtdec.h | 12 ++++++++++++ lib/fdtdec.c | 28 ++++++++++++++++++++++++++++ 2 files changed, 40 insertions(+)
diff --git a/include/fdtdec.h b/include/fdtdec.h index a965c33157c9..5eb3c0c237a9 100644 --- a/include/fdtdec.h +++ b/include/fdtdec.h @@ -956,6 +956,18 @@ int fdtdec_setup_mem_size_base(void); */ int fdtdec_setup_memory_banksize(void);
+/** + * fdtdec_get_max_phandle() - return the highest phandle in an FDT blob + * + * Returns the highest phandle in the given FDT blob. The result of this can + * be used to generate a new phandle by incrementing by one. + * + * @param blob FDT blob + * @param maxp return location for the highest phandle in the FDT blob + * @return 0 on success or a negative error code on failure + */ +int fdtdec_get_max_phandle(const void *blob, uint32_t *maxp); + /** * Set up the device tree ready for use */ diff --git a/lib/fdtdec.c b/lib/fdtdec.c index 09a7e133a539..f2af947c106e 100644 --- a/lib/fdtdec.c +++ b/lib/fdtdec.c @@ -1243,6 +1243,34 @@ __weak void *board_fdt_blob_setup(void) } #endif
+int fdtdec_get_max_phandle(const void *blob, uint32_t *maxp) +{ + uint32_t max = 0; + int offset = -1; + + while (true) { + uint32_t phandle; + + offset = fdt_next_node(blob, offset, NULL); + if (offset < 0) { + if (offset == -FDT_ERR_NOTFOUND) + break; + + return offset; + } + + phandle = fdt_get_phandle(blob, offset); + + if (phandle > max) + max = phandle; + } + + if (maxp) + *maxp = max; + + return 0; +} + int fdtdec_setup(void) { #if CONFIG_IS_ENABLED(OF_CONTROL)