Messages in this thread | | | Subject | Re: [PATCH v5 1/2] PM / Domains: Add support for 'required-opps' to set default perf state | From | Rajendra Nayak <> | Date | Wed, 4 Aug 2021 16:38:09 +0530 |
| |
On 8/3/2021 10:08 AM, Rajendra Nayak wrote: > > On 8/2/2021 6:29 PM, Ulf Hansson wrote: >> On Tue, 20 Jul 2021 at 09:12, Rajendra Nayak <rnayak@codeaurora.org> wrote: >>> >>> Some devices within power domains with performance states do not >>> support DVFS, but still need to vote on a default/static state >>> while they are active. They can express this using the 'required-opps' >>> property in device tree, which points to the phandle of the OPP >>> supported by the corresponding power-domains. >>> >>> Add support to parse this information from DT and then set the >>> specified performance state during attach and drop it on detach. >>> runtime suspend/resume callbacks already have logic to drop/set >>> the vote as needed and should take care of dropping the default >>> perf state vote on runtime suspend and restore it back on runtime >>> resume. >>> >>> Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org> >>> --- >>> drivers/base/power/domain.c | 28 +++++++++++++++++++++++++--- >>> include/linux/pm_domain.h | 1 + >>> 2 files changed, 26 insertions(+), 3 deletions(-) >>> >>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c >>> index a934c67..f454031 100644 >>> --- a/drivers/base/power/domain.c >>> +++ b/drivers/base/power/domain.c >>> @@ -2598,6 +2598,12 @@ static void genpd_dev_pm_detach(struct device *dev, bool power_off) >>> >>> dev_dbg(dev, "removing from PM domain %s\n", pd->name); >>> >>> + /* Drop the default performance state */ >>> + if (dev_gpd_data(dev)->default_pstate) { >>> + dev_pm_genpd_set_performance_state(dev, 0); >>> + dev_gpd_data(dev)->default_pstate = 0; >>> + } >>> + >>> for (i = 1; i < GENPD_RETRY_MAX_MS; i <<= 1) { >>> ret = genpd_remove_device(pd, dev); >>> if (ret != -EAGAIN) >>> @@ -2635,9 +2641,10 @@ static void genpd_dev_pm_sync(struct device *dev) >>> static int __genpd_dev_pm_attach(struct device *dev, struct device *base_dev, >>> unsigned int index, bool power_on) >>> { >>> + struct device_node *np; >>> struct of_phandle_args pd_args; >>> struct generic_pm_domain *pd; >>> - int ret; >>> + int ret, pstate; >>> >>> ret = of_parse_phandle_with_args(dev->of_node, "power-domains", >>> "#power-domain-cells", index, &pd_args); >>> @@ -2675,10 +2682,25 @@ static int __genpd_dev_pm_attach(struct device *dev, struct device *base_dev, >>> genpd_unlock(pd); >>> } >>> >>> - if (ret) >>> + if (ret) { >>> genpd_remove_device(pd, dev); >>> + return -EPROBE_DEFER; >>> + } >>> + >>> + /* Set the default performance state */ >>> + np = base_dev->of_node; >> >> Please use dev->of_node instead (it is set to the same of_node as >> base_dev by the callers of __genpd_dev_pm_attach) as it's more >> consistent with existing code. >> >>> + if (of_parse_phandle(np, "required-opps", index)) { >>> + pstate = of_get_required_opp_performance_state(np, index); >>> + if (pstate < 0) { >>> + ret = pstate; >>> + dev_err(dev, "failed to set required performance state for power-domain %s: %d\n", >>> + pd->name, ret); >>> + } >>> + dev_pm_genpd_set_performance_state(dev, pstate); >>> + dev_gpd_data(dev)->default_pstate = pstate; >> >> This doesn't look entirely correct to me. If we fail to translate a >> required opp to a performance state, we shouldn't try to set it. > > yeah, that does not seem right at all :( > >> Perhaps it's also easier to call >> of_get_required_opp_performance_state() unconditionally of whether a >> "required-opps" specifier exists. If it fails with the translation, >> then we just skip setting a default state and continue with returning >> 1. >> >> Would that work?
Looks like calling of_get_required_opp_performance_state() unconditionally makes it spit out a pr_err() in case the node is missing "required-opps" property, so I posted a v6 [1] with the check in place and adding the missing else condition.
[1] https://lore.kernel.org/patchwork/project/lkml/list/?series=510727
-- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
| |