On Wed, 27 Mar 2019 at 15:35, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: > > Changes in v13: > - Use WRITE|READ_ONCE when reading/writing the "next_hrtimer" variable in the > struct cpuidle_device. Also reset the same variable after resumed from idle to > avoid it from containing a stale value. > - Added acks from Daniel Lezcano. > - The entire v13 series, including the PSCI/ARM changes are available in a > git branch [3]. Rafael, I have address the received comments on this version $subject series, is there anything that is holding you back from queuing it? If you like I can send a pull-request, to simplify for you. Moreover, there is another series which I have pinged you about earlier, which I would appreciate to queue via your tree. It's acked by PSCI maintainers and is ready to go. "[PATCH v2 0/5] drivers: firmware: psci: Some cleanup and refactoring". Kind regards Uffe > > Changes in v12: > - Drop the patches for restructuring tick_nohz_get_sleep_length(). Instead > replace them all with a new timer/cpuidle patch, according to suggestions by > Rafael. > - The entire v12 series, including the PSCI/ARM changes are available in a > git branch [2]. > > Changes in v11: > - This version contains only the infrastructure changes that is needed for > deployment. The PSCI/ARM changes have also been updated and tested, but I will > post them separately. Still, to provide completeness, I have published a branch > containing everything to a git tree [1], feel free to have a look and test. > - The v10 series contained a patch, "timer: Export next wakeup time of a CPU", > which has been replaced by a couple of new patches, whom reworks the existing > tick_nohz_get_sleep_length() function, to provide the next timer expiration > instead of the duration. > - More changelogs are available per patch. > > Changes in v10: > - Quite significant changes have been to the PSCI driver deployment. According > to an agreement with Lorenzo, the hierarchical CPU layout for PSCI should be > orthogonal to whether the PSCI FW supports OSI or not. This has been taken > care of in this version. > - Drop the generic attach/detach helpers of CPUs to genpd, instead make that > related code internal to PSCI, for now. > - Fix "BUG: sleeping for invalid context" for hotplug, as reported by Raju. > - Addressed various comments from version 8 and 9. > - Clarified changelogs and re-wrote the cover-letter to better explain the > motivations behind these changes. > > Background: > > For ARM64/ARM based platforms CPUs are often arranged in a hierarchical manner. > From a CPU idle state perspective, this means some states may be shared among a > group of CPUs (aka CPU cluster). > > To deal with idle management of a group of CPUs, sometimes the kernel needs to > be involved to manage the last-man standing algorithm, simply because it can't > rely solely on power management FWs to deal with this. Depending on the > platform, of course. > > There are a couple of typical scenarios for when the kernel needs to be in > control, dealing with synchronization of when the last CPU in a cluster is about > to enter a deep idle state. > > 1) > The kernel needs to carry out so called last-man activities before the > CPU cluster can enter a deep idle state. This may for example involve to > configure external logics for wakeups, as the GIC may no longer be functional > once a deep cluster idle state have been entered. Likewise, these operations > may need to be restored, when the first CPU wakes up. > > 2) > Other more generic I/O devices, such as an MMC controller for example, may be a > part of the same power domain as the CPU cluster, due to a shared power-rail. > For these scenarios, when the MMC controller is in use dealing with an MMC > request, a deeper idle state of the CPU cluster may needs to be temporarily > disabled. This is needed to retain the MMC controller in a functional state, > else it may loose its register-context in the middle of serving a request. > > In this series, we are extending the generic PM domain (aka genpd) to be used > for also CPU devices. Hence the goal is to re-use much of its current code to > help us manage the last-man standing synchronization. Moreover, as we already > use genpd to model power domains for generic I/O devices, both 1) and 2) can be > address with its help. > > Moreover, to address these problems for ARM64 DT based platforms, we are > deploying support for genpd and runtime PM to the PSCI FW driver - and finally > we make some updates to two ARM64 DTBs, as to deploy the new PSCI CPU topology > layout. > > The series has been tested on a Qcom 410c dragonboard and on a Hisilicon Hikey > board. The first one uses PSCI OS-initiated mode, while the second uses the PSCI > Platform-Coordinated mode. > > Kind regards > Ulf Hansson > > [1] > git.linaro.org/people/ulf.hansson/linux-pm.git next_v11 > [2] > git.linaro.org/people/ulf.hansson/linux-pm.git next_v12 > [2] > git.linaro.org/people/ulf.hansson/linux-pm.git next_v13 > > > Ulf Hansson (4): > PM / Domains: Add a generic data pointer to the genpd_power_state > struct > PM / Domains: Add support for CPU devices to genpd > cpuidle: Export the next timer/tick expiration for a CPU > PM / Domains: Add genpd governor for CPUs > > drivers/base/power/domain.c | 77 ++++++++++++++++++++++++++-- > drivers/base/power/domain_governor.c | 65 ++++++++++++++++++++++- > drivers/cpuidle/cpuidle.c | 19 ++++++- > include/linux/cpuidle.h | 1 + > include/linux/pm_domain.h | 20 +++++++- > include/linux/tick.h | 7 ++- > kernel/time/tick-sched.c | 12 +++++ > 7 files changed, 193 insertions(+), 8 deletions(-) > > -- > 2.17.1 >
