From: Daniel Lezcano <daniel.lezc...@linaro.org>

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

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

Signed-off-by: Daniel Lezcano <daniel.lezc...@linaro.org>
Signed-off-by: Lina Iyer <lina.i...@linaro.org>
[Minor clean ups and fixes of the per-cpu variable]
---
 drivers/cpuidle/cpuidle-arm.c | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/drivers/cpuidle/cpuidle-arm.c b/drivers/cpuidle/cpuidle-arm.c
index 1c94b88..f7cdb73 100644
--- a/drivers/cpuidle/cpuidle-arm.c
+++ b/drivers/cpuidle/cpuidle-arm.c
@@ -17,11 +17,14 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/slab.h>
 
 #include <asm/cpuidle.h>
 
 #include "dt_idle_states.h"
 
+static DEFINE_PER_CPU(struct cpuidle_device, *cpuidle_arm_dev);
+
 /*
  * arm_enter_idle_state - Programs CPU to enter the specified state
  *
@@ -93,6 +96,7 @@ static const struct of_device_id arm_idle_state_match[] 
__initconst = {
 static int __init arm_idle_init(void)
 {
        int cpu, ret;
+       struct cpuidle_device *dev;
        struct cpuidle_driver *drv = &arm_idle_driver;
 
        /*
@@ -105,18 +109,46 @@ 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 == -ENOSYS)
+                       continue;
+
                if (ret) {
                        pr_err("CPU %d failed to init idle CPU ops\n", cpu);
                        return ret;
                }
+
+               dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+               if (!dev)
+                       return -ENOMEM;
+
+               dev->cpu = cpu;
+               ret = cpuidle_register_device(dev);
+               if (ret) {
+                       pr_err("Failed to register cpuidle device for CPU %d\n",
+                              cpu);
+                       return ret;
+               }
+
+               per_cpu(cpuidle_arm_dev, cpu) = dev;
        }
 
-       return cpuidle_register(drv, NULL);
+       return 0;
 }
 device_initcall(arm_idle_init);
-- 
2.1.0

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