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    SubjectRe: [PATCH v16 2/5] iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device
    On Fri, Sep 7, 2018 at 6:38 PM Vivek Gautam <vivek.gautam@codeaurora.org> wrote:
    >
    > Hi Tomasz,
    >
    >
    > On 9/7/2018 2:46 PM, Tomasz Figa wrote:
    > > Hi Vivek,
    > >
    > > On Thu, Aug 30, 2018 at 11:46 PM Vivek Gautam
    > > <vivek.gautam@codeaurora.org> wrote:
    > >> From: Sricharan R <sricharan@codeaurora.org>
    > >>
    > >> The smmu device probe/remove and add/remove master device callbacks
    > >> gets called when the smmu is not linked to its master, that is without
    > >> the context of the master device. So calling runtime apis in those places
    > >> separately.
    > >> Global locks are also initialized before enabling runtime pm as the
    > >> runtime_resume() calls device_reset() which does tlb_sync_global()
    > >> that ultimately requires locks to be initialized.
    > >>
    > >> Signed-off-by: Sricharan R <sricharan@codeaurora.org>
    > >> [vivek: Cleanup pm runtime calls]
    > >> Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
    > >> Reviewed-by: Tomasz Figa <tfiga@chromium.org>
    > >> Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
    > >> ---
    > >> drivers/iommu/arm-smmu.c | 89 +++++++++++++++++++++++++++++++++++++++++++-----
    > >> 1 file changed, 81 insertions(+), 8 deletions(-)
    > > [snip]
    > >> @@ -2215,10 +2281,17 @@ static int arm_smmu_device_remove(struct platform_device *pdev)
    > >> if (!bitmap_empty(smmu->context_map, ARM_SMMU_MAX_CBS))
    > >> dev_err(&pdev->dev, "removing device with active domains!\n");
    > >>
    > >> + arm_smmu_rpm_get(smmu);
    > >> /* Turn the thing off */
    > >> writel(sCR0_CLIENTPD, ARM_SMMU_GR0_NS(smmu) + ARM_SMMU_GR0_sCR0);
    > >> + arm_smmu_rpm_put(smmu);
    > >> +
    > >> + if (pm_runtime_enabled(smmu->dev))
    > >> + pm_runtime_force_suspend(smmu->dev);
    > >> + else
    > >> + clk_bulk_disable(smmu->num_clks, smmu->clks);
    > >>
    > >> - clk_bulk_disable_unprepare(smmu->num_clks, smmu->clks);
    > >> + clk_bulk_unprepare(smmu->num_clks, smmu->clks);
    > > Aren't we missing pm_runtime_disable() here? We'll have the enable
    > > count unbalanced if the driver is removed and probed again.
    >
    > pm_runtime_force_suspend() does a pm_runtime_disable() also if i am not
    > wrong.
    > And, as mentioned in a previous thread [1], we were seeing a warning
    > which we avoided
    > by keeping force_suspend().
    >
    > [1] https://lkml.org/lkml/2018/7/8/124

    I see, thanks. I didn't realize that pm_runtime_force_suspend()
    already disables runtime PM indeed. Sorry for the noise.

    Best regards,
    Tomasz

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