On Tue, Mar 24, 2015 at 09:54:01AM +0000, Daniel Lezcano wrote:
> 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: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> ---
> 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..545069d 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 +107,57 @@ 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)
> + 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
>
>
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
