From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yong Wu Subject: Re: [PATCH 04/13] iommu/mediatek: Add device_link between the consumer and the larb devices Date: Wed, 13 Mar 2019 17:11:53 +0800 Message-ID: <1552468313.7433.14.camel@mhfsdcap03> References: <1546318276-18993-1-git-send-email-yong.wu@mediatek.com> <1546318276-18993-5-git-send-email-yong.wu@mediatek.com> <709d7d66-9610-eeb3-128e-e2156bcfb616@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <709d7d66-9610-eeb3-128e-e2156bcfb616@arm.com> Sender: linux-kernel-owner@vger.kernel.org To: Robin Murphy Cc: Joerg Roedel , Greg Kroah-Hartman , Matthias Brugger , Rob Herring , youlin.pei@mediatek.com, devicetree@vger.kernel.org, Nicolas Boichat , arnd@arndb.de, srv_heupstream@mediatek.com, Will Deacon , linux-kernel@vger.kernel.org, Tomasz Figa , iommu@lists.linux-foundation.org, linux-mediatek@lists.infradead.org, yingjoe.chen@mediatek.com, linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org Hi Robin, sorry for reply so late. On Wed, 2019-02-27 at 19:30 +0000, Robin Murphy wrote: > On 01/01/2019 04:51, Yong Wu wrote: > > MediaTek IOMMU don't have its power-domain. all the consumer connect > > with smi-larb, then connect with smi-common. > > > > M4U > > | > > smi-common > > | > > ------------- > > | | ... > > | | > > larb1 larb2 > > | | > > vdec venc > > > > When the consumer works, it should enable the smi-larb's power which > > also need enable the smi-common's power firstly. > > > > Thus, First of all, use the device link connect the consumer and the > > smi-larbs. then add device link between the smi-larb and smi-common. > > > > This patch adds device_link between the consumer and the larbs. > > > > Suggested-by: Tomasz Figa > > Signed-off-by: Yong Wu > > --- > > drivers/iommu/mtk_iommu.c | 15 +++++++++++++-- > > drivers/iommu/mtk_iommu_v1.c | 14 ++++++++++++-- > > 2 files changed, 25 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c > > index 202e41b..735ae8d 100644 > > --- a/drivers/iommu/mtk_iommu.c > > +++ b/drivers/iommu/mtk_iommu.c > > @@ -247,6 +247,7 @@ static void mtk_iommu_config(struct mtk_iommu_data *data, > > struct mtk_smi_larb_iommu *larb_mmu; > > unsigned int larbid, portid; > > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); > > + struct device_link *link; > > int i; > > > > for (i = 0; i < fwspec->num_ids; ++i) { > > @@ -257,10 +258,20 @@ static void mtk_iommu_config(struct mtk_iommu_data *data, > > dev_dbg(dev, "%s iommu port: %d\n", > > enable ? "enable" : "disable", portid); > > > > - if (enable) > > + if (enable) { > > larb_mmu->mmu |= MTK_SMI_MMU_EN(portid); > > - else > > + /* Link the consumer with the larb device(supplier) */ > > + link = device_link_add(dev, larb_mmu->dev, > > + DL_FLAG_PM_RUNTIME | > > + DL_FLAG_AUTOREMOVE_CONSUMER); > > This looks technically wrong, since we get here from > mtk_iommu_attach_device(), and in theory a device could get attached to > any number of domains over its lifetime, so adding a link at this point > when there's no corresponding cleanup on detach is definitely > unbalanced. If you want this layer to manage the link on behalf of the > consumer, it would probably be better to do it at the point of > mtk_iommu_add_device(), and either track it for manual cleanup in > mtk_iommu_remove_device() or rely on AUTOREMOVE_SUPPLIER. Thanks. I will try to move the "device_link_add" in add_device in next version. > > Robin. > > > + if (!link) { > > + dev_err(dev, "Unable to link %s\n", > > + dev_name(larb_mmu->dev)); > > + return; > > + } > > + } else { > > larb_mmu->mmu &= ~MTK_SMI_MMU_EN(portid); > > + } > > } > > } > > > > diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c > > index 9386aee..022bad9 100644 > > --- a/drivers/iommu/mtk_iommu_v1.c > > +++ b/drivers/iommu/mtk_iommu_v1.c > > @@ -201,6 +201,7 @@ static void mtk_iommu_config(struct mtk_iommu_data *data, > > struct mtk_smi_larb_iommu *larb_mmu; > > unsigned int larbid, portid; > > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); > > + struct device_link *link; > > int i; > > > > for (i = 0; i < fwspec->num_ids; ++i) { > > @@ -211,10 +212,19 @@ static void mtk_iommu_config(struct mtk_iommu_data *data, > > dev_dbg(dev, "%s iommu port: %d\n", > > enable ? "enable" : "disable", portid); > > > > - if (enable) > > + if (enable) { > > larb_mmu->mmu |= MTK_SMI_MMU_EN(portid); > > - else > > + link = device_link_add(dev, larb_mmu->dev, > > + DL_FLAG_PM_RUNTIME | > > + DL_FLAG_AUTOREMOVE_CONSUMER); > > + if (!link) { > > + dev_err(dev, "Unable to link %s\n", > > + dev_name(larb_mmu->dev)); > > + return; > > + } > > + } else { > > larb_mmu->mmu &= ~MTK_SMI_MMU_EN(portid); > > + } > > } > > } > > > >