Allow fully disabling CPU nodes using status = "fail". Having no status property at all is still interpreted as "okay" as usual. This allows a bootloader to change the number of available CPUs (for example when a common DTS is used for SoC variants with different numbers of cores) without deleting the nodes altogether, which could require additional fixups to avoid dangling phandle references. References: - https://www.lkml.org/lkml/2020/8/26/1237 - https://www.spinics.net/lists/devicetree-spec/msg01007.html - https://github.com/devicetree-org/dt-schema/pull/61 Signed-off-by: Matthias Schiffer <matthias.schiffer@xxxxxxxxxxxxxxx> --- drivers/of/base.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/drivers/of/base.c b/drivers/of/base.c index 61de453b885c..4e9973627c8d 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -650,6 +650,32 @@ bool of_device_is_available(const struct device_node *device) } EXPORT_SYMBOL(of_device_is_available); +/** + * __of_device_is_disabled - check if a device has status "disabled" + * + * @device: Node to check status for, with locks already held + * + * Return: True if the status property is set to "disabled", + * false otherwise + * + * Most callers should use __of_device_is_available() instead, this function + * only exists due to the special interpretation of the "disabled" status for + * CPU nodes. + */ +static bool __of_device_is_disabled(const struct device_node *device) +{ + const char *status; + + if (!device) + return false; + + status = __of_get_property(device, "status", NULL); + if (status == NULL) + return false; + + return !strcmp(status, "disabled"); +} + /** * of_device_is_big_endian - check if a device has BE registers * @@ -817,6 +843,9 @@ struct device_node *of_get_next_cpu_node(struct device_node *prev) of_node_put(node); } for (; next; next = next->sibling) { + if (!__of_device_is_available(next) && + !__of_device_is_disabled(next)) + continue; if (!(of_node_name_eq(next, "cpu") || __of_node_is_type(next, "cpu"))) continue; -- 2.17.1
