From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vivek Gautam Subject: Re: [PATCH v16 2/5] iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device Date: Fri, 7 Sep 2018 15:08:02 +0530 Message-ID: <3ccc3690-dc9d-56e7-e2d1-62e73a189bff@codeaurora.org> References: <20180830144541.17740-1-vivek.gautam@codeaurora.org> <20180830144541.17740-3-vivek.gautam@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Tomasz Figa Cc: Mark Rutland , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Alex Williamson , Linux PM , sboyd-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, "Rafael J. Wysocki" , Will Deacon , Linux Kernel Mailing List , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Rob Herring , linux-arm-msm , freedreno , Robin Murphy List-Id: devicetree@vger.kernel.org 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 > wrote: >> From: Sricharan R >> >> 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 >> [vivek: Cleanup pm runtime calls] >> Signed-off-by: Vivek Gautam >> Reviewed-by: Tomasz Figa >> Tested-by: Srinivas Kandagatla >> --- >> 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 Thanks Vivek > > Also, if we add pm_runtime_disable(), we can reorder things a bit and > simplify into: > > arm_smmu_rpm_get(smmu); > > /* Turn the thing off */ > writel(sCR0_CLIENTPD, ARM_SMMU_GR0_NS(smmu) + ARM_SMMU_GR0_sCR0); > > if (pm_runtime_enabled()) > pm_runtime_disable(); > arm_smmu_rpm_put(smmu); > > clk_bulk_disable_unprepare(smmu->num_clks, smmu->clks); > > Best regards, > Tomasz