Re: [PATCH v2 5/5] cpuidle: psci: Prevent domain idlestates until consumers are ready
From: Lukasz Luba <lukasz.luba@arm.com>
Date: 2020-07-10 12:18:09
Also in:
linux-pm
On 7/7/20 1:58 PM, Ulf Hansson wrote:
Depending on the SoC/platform, additional devices may be part of the PSCI PM domain topology. This is the case with 'qcom,rpmh-rsc' device, for example, even if this is not yet visible in the corresponding DTS-files.
I was interested by your description and checked related DT to this device. It's probably the best what we can do in such situation and such requirements.
Without going into too much details, a device like the 'qcom,rpmh-rsc' may have HW constraints that needs to be obeyed to, before a domain idlestate can be picked. Therefore, let's implement the ->sync_state() callback to receive a notification when all consumers of the PSCI PM domain providers have been attached/probed to it. In this way, we can make sure all constraints from all relevant devices, are taken into account before allowing a domain idlestate to be picked. Acked-by: Saravana Kannan <redacted> Signed-off-by: Ulf Hansson <redacted>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
quoted hunk ↗ jump to hunk
--- drivers/cpuidle/cpuidle-psci-domain.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)diff --git a/drivers/cpuidle/cpuidle-psci-domain.c b/drivers/cpuidle/cpuidle-psci-domain.c index bf527d2bb4b6..b6e9649ab0da 100644 --- a/drivers/cpuidle/cpuidle-psci-domain.c +++ b/drivers/cpuidle/cpuidle-psci-domain.c@@ -27,6 +27,7 @@ struct psci_pd_provider { }; static LIST_HEAD(psci_pd_providers); +static bool psci_pd_allow_domain_state; static int psci_pd_power_off(struct generic_pm_domain *pd) {@@ -36,6 +37,9 @@ static int psci_pd_power_off(struct generic_pm_domain *pd) if (!state->data) return 0; + if (!psci_pd_allow_domain_state) + return -EBUSY; + /* OSI mode is enabled, set the corresponding domain state. */ pd_state = state->data; psci_set_domain_state(*pd_state);@@ -222,6 +226,15 @@ static void psci_pd_remove_topology(struct device_node *np) psci_pd_init_topology(np, false); } +static void psci_cpuidle_domain_sync_state(struct device *dev) +{ + /* + * All devices have now been attached/probed to the PM domain topology, + * hence it's fine to allow domain states to be picked. + */ + psci_pd_allow_domain_state = true; +} + static const struct of_device_id psci_of_match[] = { { .compatible = "arm,psci-1.0" }, {}@@ -289,6 +302,7 @@ static struct platform_driver psci_cpuidle_domain_driver = { .driver = { .name = "psci-cpuidle-domain", .of_match_table = psci_of_match, + .sync_state = psci_cpuidle_domain_sync_state, }, };
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