| Message ID | 20210813065324.29220-12-yong.wu@mediatek.com |
|---|---|
| State | New |
| Headers | show |
| Series | MT8195 IOMMU SUPPORT | expand |
On Fri, Aug 13, 2021 at 2:57 PM Yong Wu <yong.wu@mediatek.com> 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. > > 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. Can you check if there are existing users that need to add this change? > > Signed-off-by: Yong Wu <yong.wu@mediatek.com> > --- <snip>
On Tue, 2021-08-24 at 15:10 +0800, Hsin-Yi Wang wrote: > On Fri, Aug 13, 2021 at 2:57 PM Yong Wu <yong.wu@mediatek.com> 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. > > > > 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. > > Can you check if there are existing users that need to add this > change? The issue may exist in our most users. Our users mainly are in v4l2. normally their flow like this: a) VIDIOC_REQBUFS: call dma_alloc_attrs or dma_buf_map_attachment. b) VIDIOC_STREAMON. c) VIDIOC_QBUF: device_run: pm_runtime_get_sync. Requesting they call pm_runtime_get before dma_alloc_attrs looks not reasonable. It seems that they should not care about this. This patch mainly make sure the flow is right. Locally I have a TODO to try get the real power-domain status here, the sample code like below: static struct notifier_block mtk_penpd_notifier; /* Register the genpd notifier. */ mtk_penpd_notifier.notifier_call = mtk_iommu_pd_callback; ret = dev_pm_genpd_add_notifier(dev, &mtk_penpd_notifier); /* Then get the real power domain status in the notifier */ static int mtk_iommu_pd_callback(struct notifier_block *nb, unsigned long flags, void *data) { if (flags == GENPD_NOTIFY_ON) /* the real power domain is power on */ else if (flags == GENPD_NOTIFY_PRE_OFF) /* the real power domain are going to power off. Take it as power off. * Skip the tlb ops after receivice this flag. */ } How about this? or any other suggestion to get the real power-domain rather than the iommu device's power domain status. Thanks. > > > > > > Signed-off-by: Yong Wu <yong.wu@mediatek.com> > > --- > > <snip>
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); >
On Thu, 2021-09-30 at 13:26 +0200, Dafna Hirschfeld wrote: > > 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. Sorry, I didn't clarify this clear. I mean the iommu device don't have this property rather than the other device. > > > > > 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? In v3, I have removed this patch. Use [1] instead. [1] https://lore.kernel.org/linux-mediatek/20210923115840.17813-13-yong.wu@mediatek.com/ Thanks. > > 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); > >
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);
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. 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. Signed-off-by: Yong Wu <yong.wu@mediatek.com> --- drivers/iommu/mtk_iommu.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)