[PATCH 01/12] of: Add of_get_cpu_hwid() to read hardware ID from CPU nodes
From: Rob Herring <robh@kernel.org>
Date: 2021-10-06 16:43:43
Also in:
linux-arm-kernel, linux-devicetree, linux-sh, linuxppc-dev, lkml
Subsystem:
open firmware and flattened device tree, the rest · Maintainers:
Rob Herring, Saravana Kannan, Linus Torvalds
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 <redacted> Signed-off-by: Rob Herring <robh@kernel.org> --- drivers/of/base.c | 22 ++++++++++++++++++++++ include/linux/of.h | 1 + 2 files changed, 23 insertions(+)
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 *
diff --git a/include/linux/of.h b/include/linux/of.h
index 6f1c41f109bb..807f8168dad9 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h@@ -353,6 +353,7 @@ extern struct device_node *of_get_cpu_node(int cpu, unsigned int *thread); extern struct device_node *of_get_next_cpu_node(struct device_node *prev); extern struct device_node *of_get_cpu_state_node(struct device_node *cpu_node, int index); +extern u64 of_get_cpu_hwid(struct device_node *cpun, unsigned int thread); #define for_each_property_of_node(dn, pp) \ for (pp = dn->properties; pp != NULL; pp = pp->next)
--
2.30.2
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