Some architectures have some cpus which does not support idle states.

Let the underlying low level code to return -ENXIO when it is not
possible to set an idle state.

Signed-off-by: Daniel Lezcano <[email protected]>
---
 drivers/cpuidle/cpuidle-arm.c | 42 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 40 insertions(+), 2 deletions(-)

diff --git a/drivers/cpuidle/cpuidle-arm.c b/drivers/cpuidle/cpuidle-arm.c
index 1c94b88..e4a6eba 100644
--- a/drivers/cpuidle/cpuidle-arm.c
+++ b/drivers/cpuidle/cpuidle-arm.c
@@ -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 +107,54 @@ 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);
+
+               /* This cpu does not support any idle states */
+               if (ret == -ENXIO)
+                       continue;
+
                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",
+                              cpu);
+                       kfree(dev);
+                       goto out_fail;
                }
        }
 
-       return cpuidle_register(drv, NULL);
+       return 0;
+out_fail:
+       while (--cpu >= 0) {
+               dev = per_cpu(cpuidle_devices, cpu);
+               cpuidle_unregister_device(dev);
+               kfree(dev);
+       }
+
+       cpuidle_unregister_driver(drv);
+
+       return ret;
 }
 device_initcall(arm_idle_init);
-- 
1.9.1

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