Messages in this thread | | | Subject | Re: [PATCH v2 11/29] iommu/mediatek: Always pm_runtime_get while tlb flush | From | Dafna Hirschfeld <> | Date | Thu, 30 Sep 2021 13:26:07 +0200 |
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On 13.08.21 08:53, Yong Wu wrote: > Prepare for 2 HWs that sharing pgtable in different power-domains. > > The previous SoC don't have PM. Only mt8192 has power-domain, > and it is display's power-domain which nearly always is enabled.
hi, I see that in mt1873.dtsi, many devices that uses the iommu have the 'power-domains' property.
> > When there are 2 M4U HWs, it may has problem. > In this function, we get the pm_status via the m4u dev, but it don't > reflect the real power-domain status of the HW since there may be other > HW also use that power-domain. > > Currently we could not get the real power-domain status, thus always > pm_runtime_get here. > > Prepare for mt8195, thus, no need fix tags here. > > This patch may drop the performance, we expect the user could > pm_runtime_get_sync before dma_alloc_attrs which need tlb ops. >
Could you explain this sentence a bit? should the user call pm_runtime_get_sync before calling dma_alloc_attrs?
Thanks, Dafna
> Signed-off-by: Yong Wu <yong.wu@mediatek.com> > --- > drivers/iommu/mtk_iommu.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c > index add23a36a5e2..abc721a1da21 100644 > --- a/drivers/iommu/mtk_iommu.c > +++ b/drivers/iommu/mtk_iommu.c > @@ -238,8 +238,11 @@ static void mtk_iommu_tlb_flush_range_sync(unsigned long iova, size_t size, > > for_each_m4u(data, head) { > if (has_pm) { > - if (pm_runtime_get_if_in_use(data->dev) <= 0) > + ret = pm_runtime_resume_and_get(data->dev); > + if (ret < 0) { > + dev_err(data->dev, "tlb flush: pm get fail %d.\n", ret); > continue; > + } > } > > spin_lock_irqsave(&data->tlb_lock, flags); >
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