Commit a0d46a3d authored by Daniel Lezcano's avatar Daniel Lezcano

ARM: cpuidle: Register per cpuidle device

If the cpuidle init cpu operation returns -ENXIO, therefore reporting HW
failure or misconfiguration, the CPUidle driver skips the respective
cpuidle device initialization because the associated platform back-end HW
is not operational.

That prevents the system to crash and allows to handle the error gracefully.

For example, on Qcom's platform, each core has a SPM. The device associated
with this SPM is initialized before the cpuidle framework. If there is an error
in the initialization (eg. error in the DT), the system continues to boot but
in degraded mode as some SPM may not be correctly initialized.
Signed-off-by: default avatarDaniel Lezcano <>
Acked-by: default avatarLorenzo Pieralisi <>
parent 0e087044
......@@ -17,6 +17,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <asm/cpuidle.h>
......@@ -94,6 +95,7 @@ static int __init arm_idle_init(void)
int cpu, ret;
struct cpuidle_driver *drv = &arm_idle_driver;
struct cpuidle_device *dev;
* Initialize idle states data, starting at index 1.
......@@ -105,18 +107,57 @@ static int __init arm_idle_init(void)
if (ret <= 0)
return ret ? : -ENODEV;
ret = cpuidle_register_driver(drv);
if (ret) {
pr_err("Failed to register cpuidle driver\n");
return ret;
* Call arch CPU operations in order to initialize
* idle states suspend back-end specific data
for_each_possible_cpu(cpu) {
ret = arm_cpuidle_init(cpu);
* Skip the cpuidle device initialization if the reported
* failure is a HW misconfiguration/breakage (-ENXIO).
if (ret == -ENXIO)
if (ret) {
pr_err("CPU %d failed to init idle CPU ops\n", cpu);
return ret;
goto out_fail;
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev) {
pr_err("Failed to allocate cpuidle device\n");
goto out_fail;
dev->cpu = cpu;
ret = cpuidle_register_device(dev);
if (ret) {
pr_err("Failed to register cpuidle device for CPU %d\n",
goto out_fail;
return cpuidle_register(drv, NULL);
return 0;
while (--cpu >= 0) {
dev = per_cpu(cpuidle_devices, cpu);
return ret;
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment