Introduce function fdt_get_max_phandle(), which returns the largest value of all phandles in a device tree. This is useful for allocating a new phandle property, since all phandles must be unique.

Signed-off-by: Timur Tabi timur@freescale.com --- include/libfdt.h | 20 ++++++++++++++++++++ lib/libfdt/fdt_ro.c | 17 +++++++++++++++++ 2 files changed, 37 insertions(+), 0 deletions(-)

diff --git a/include/libfdt.h b/include/libfdt.h index d23d40e..62c4e5b 100644 --- a/include/libfdt.h +++ b/include/libfdt.h @@ -833,6 +833,26 @@ int fdt_nop_property(void *fdt, int nodeoffset, const char *name); */ int fdt_nop_node(void *fdt, int nodeoffset);

+/** + * fdt_get_max_phandle - return the largest value of all phandles in the fdt + * @fdt: pointer to the device tree blob + * + * fdt_get_max_phandle() returns the largest value of all phandles. + * + * phandles are generally numbered sequentially from 1. To allow U-Boot to + * create a new phandle property, the value of that phandle must be unique. + * The safest way to do that is to determine the largest value among all + * phandles, and set the new phandle to that value plus one. + * + * returns: + * 0, there are no phandles in the fdt + * >0, the largest value of the phandles + * -FDT_ERR_BADMAGIC, + * -FDT_ERR_BADVERSION, + * -FDT_ERR_BADSTATE, standard meanings + */ +int fdt_get_max_phandle(const void *fdt); + /**********************************************************************/ /* Sequential write functions */ /**********************************************************************/ diff --git a/lib/libfdt/fdt_ro.c b/lib/libfdt/fdt_ro.c index 1e1e322..4a4a84b 100644 --- a/lib/libfdt/fdt_ro.c +++ b/lib/libfdt/fdt_ro.c @@ -504,3 +504,20 @@ int fdt_node_offset_by_compatible(const void *fdt, int startoffset,

return offset; /* error from fdt_next_node() */ } + +int fdt_get_max_phandle(const void *fdt) +{ + int offset; + uint32_t temp, phandle = 0; + + FDT_CHECK_HEADER(fdt); + + for (offset = fdt_next_node(fdt, -1, NULL); offset >= 0; + offset = fdt_next_node(fdt, offset, NULL)) { + temp = fdt_get_phandle(fdt, offset); + if (temp > phandle) + phandle = temp; + } + + return phandle; +}