Re: [PATCH V2 7/8] ARM: cpuidle: Register per cpuidle device
From: Lina Iyer
Date: Thu Mar 19 2015 - 11:42:57 EST
On Thu, Mar 19 2015 at 09:33 -0600, Daniel Lezcano wrote:
On 03/19/2015 04:31 PM, Lina Iyer wrote:
On Wed, Mar 18 2015 at 12:46 -0600, Daniel Lezcano wrote:
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.lezcano@xxxxxxxxxx>
---
drivers/cpuidle/cpuidle-arm.c | 45
+++++++++++++++++++++++++++++++++++++++++--
1 file changed, 43 insertions(+), 2 deletions(-)
diff --git a/drivers/cpuidle/cpuidle-arm.c
b/drivers/cpuidle/cpuidle-arm.c
index 1c94b88..0682ed0 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);
Is a per-cpu variable needed? There seems to be no per-cpu access, other
than at init.
:)
Actually it is the cpuidle framework which is using the per cpu variable.
But this is static pointer, I can see that struct cpuidle_device * being
used by cpuidle framework.
It gets stored here?
DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
But we dont need to save it here, for in this file, there is no per-cpu
access, other than when the registration fails.
+
/*
* arm_enter_idle_state - Programs CPU to enter the specified state
*
@@ -94,6 +97,7 @@ 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 +109,55 @@ 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;
+ 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;
+ per_cpu(cpuidle_arm_dev, cpu) = dev;
+
+ ret = cpuidle_register_device(dev);
+ if (ret) {
+ pr_err("Failed to register cpuidle device for CPU %d\n",
+ cpu);
+ kfree(dev);
+ goto out_fail;
}
}
+out:
+ return ret;
- return cpuidle_register(drv, NULL);
+out_fail:
+ for (cpu--; cpu <= 0; cpu--) {
+ dev = per_cpu(cpuidle_arm_dev, cpu);
+ cpuidle_unregister_device(dev);
+ kfree(dev);
+ }
+ cpuidle_unregister_driver(drv);
+ goto out;
}
device_initcall(arm_idle_init);
--
1.9.1
--
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