From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lorenzo Pieralisi Subject: Re: [PATCH V5 1/2] ARM: cpuidle: Register per cpuidle device Date: Tue, 24 Mar 2015 18:10:44 +0000 Message-ID: <20150324181044.GA27311@red-moon> References: <20150323225828.GC15435@e102568-lin.cambridge.arm.com> <1427190842-30675-1-git-send-email-daniel.lezcano@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1427190842-30675-1-git-send-email-daniel.lezcano@linaro.org> Sender: linux-kernel-owner@vger.kernel.org To: Daniel Lezcano Cc: "rjw@rjwysocki.net" , "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Catalin Marinas , "robherring2@gmail.com" , "arnd@arndb.de" , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "lina.iyer@linaro.org" , "sboyd@codeaurora.org" List-Id: devicetree@vger.kernel.org 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 Acked-by: Lorenzo Pieralisi > --- > 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 > #include > #include > +#include > > #include > > @@ -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 > >