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| author | Rob Herring <robh@kernel.org> | 2021-10-06 11:43:21 -0500 |
|---|---|---|
| committer | Rob Herring <robh@kernel.org> | 2021-10-20 13:36:16 -0500 |
| commit | 795e92ec5fd79027648bd7f779d34bad5b6f2f55 (patch) | |
| tree | 7ed34ab33981d96f3527ec4b5a49fbc7c08d544c /drivers/of/base.c | |
| parent | 378be0cca602cbee8aa441a14f836e9e41e25314 (diff) | |
| download | lwn-795e92ec5fd79027648bd7f779d34bad5b6f2f55.tar.gz lwn-795e92ec5fd79027648bd7f779d34bad5b6f2f55.zip | |
of: Add of_get_cpu_hwid() to read hardware ID from CPU nodes
There are various open coded implementions parsing the CPU node 'reg'
property which contains the CPU's hardware ID. Introduce a new function,
of_get_cpu_hwid(), to read the hardware ID.
All the callers should be DT only code, so no need for an empty
function.
Cc: Frank Rowand <frowand.list@gmail.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20211006164332.1981454-2-robh@kernel.org
Diffstat (limited to 'drivers/of/base.c')
| -rw-r--r-- | drivers/of/base.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/of/base.c b/drivers/of/base.c index f720c0d246f2..e587ab44be22 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -286,6 +286,28 @@ const void *of_get_property(const struct device_node *np, const char *name, } EXPORT_SYMBOL(of_get_property); +/** + * of_get_cpu_hwid - Get the hardware ID from a CPU device node + * + * @cpun: CPU number(logical index) for which device node is required + * @thread: The local thread number to get the hardware ID for. + * + * Return: The hardware ID for the CPU node or ~0ULL if not found. + */ +u64 of_get_cpu_hwid(struct device_node *cpun, unsigned int thread) +{ + const __be32 *cell; + int ac, len; + + ac = of_n_addr_cells(cpun); + cell = of_get_property(cpun, "reg", &len); + if (!cell || !ac || ((sizeof(*cell) * ac * (thread + 1)) > len)) + return ~0ULL; + + cell += ac * thread; + return of_read_number(cell, ac); +} + /* * arch_match_cpu_phys_id - Match the given logical CPU and physical id * |