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author | Thierry Reding <treding@nvidia.com> | 2019-03-20 16:10:03 +0100 |
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committer | Sebastian Huber <sebastian.huber@embedded-brains.de> | 2020-03-02 07:52:19 +0100 |
commit | a0dea6447c061896fdf468b5d492060e7108d5cb (patch) | |
tree | b320618fe25321f227683283fe1e6880829874d5 /cpukit/dtc/libfdt/fdt_ro.c | |
parent | libfdt: Fix FDT_ERR_NOTFOUND typos in documentation (diff) | |
download | rtems-a0dea6447c061896fdf468b5d492060e7108d5cb.tar.bz2 |
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>
Message-Id: <20190320151003.28941-1-thierry.reding@gmail.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Diffstat (limited to 'cpukit/dtc/libfdt/fdt_ro.c')
-rw-r--r-- | cpukit/dtc/libfdt/fdt_ro.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/cpukit/dtc/libfdt/fdt_ro.c b/cpukit/dtc/libfdt/fdt_ro.c index eafc142828..97cdcda0db 100644 --- a/cpukit/dtc/libfdt/fdt_ro.c +++ b/cpukit/dtc/libfdt/fdt_ro.c @@ -170,6 +170,37 @@ uint32_t fdt_get_max_phandle(const void *fdt) return 0; } +int fdt_generate_phandle(const void *fdt, uint32_t *phandle) +{ + uint32_t max = 0; + int offset = -1; + + while (true) { + uint32_t value; + + offset = fdt_next_node(fdt, offset, NULL); + if (offset < 0) { + if (offset == -FDT_ERR_NOTFOUND) + break; + + return offset; + } + + value = fdt_get_phandle(fdt, offset); + + if (value > max) + max = value; + } + + if (max == FDT_MAX_PHANDLE) + return -FDT_ERR_NOPHANDLES; + + if (phandle) + *phandle = max + 1; + + return 0; +} + static const struct fdt_reserve_entry *fdt_mem_rsv(const void *fdt, int n) { int offset = n * sizeof(struct fdt_reserve_entry); |