Messages in this thread | | | Subject | Re: [PATCH v8 04/12] iommu/mediatek: Add device_link between the consumer and the larb devices | From | Dafna Hirschfeld <> | Date | Mon, 11 Oct 2021 14:36:13 +0200 |
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On 29.09.21 03:37, Yong Wu wrote: > MediaTek IOMMU-SMI diagram is like below. 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. > > When device_link_add, I add the flag DL_FLAG_STATELESS to avoid calling > pm_runtime_xx to keep the original status of clocks. It can avoid two > issues: > 1) Display HW show fastlogo abnormally reported in [1]. At the beggining, > all the clocks are enabled before entering kernel, but the clocks for > display HW(always in larb0) will be gated after clk_enable and clk_disable > called from device_link_add(->pm_runtime_resume) and rpm_idle. The clock > operation happened before display driver probe. At that time, the display > HW will be abnormal. > > 2) A deadlock issue reported in [2]. Use DL_FLAG_STATELESS to skip > pm_runtime_xx to avoid the deadlock. > > Corresponding, DL_FLAG_AUTOREMOVE_CONSUMER can't be added, then > device_link_removed should be added explicitly. > > [1] https://lore.kernel.org/linux-mediatek/1564213888.22908.4.camel@mhfsdcap03/ > [2] https://lore.kernel.org/patchwork/patch/1086569/ > > Suggested-by: Tomasz Figa <tfiga@chromium.org> > Signed-off-by: Yong Wu <yong.wu@mediatek.com> > Tested-by: Frank Wunderlich <frank-w@public-files.de> # BPI-R2/MT7623 > --- > drivers/iommu/mtk_iommu.c | 22 ++++++++++++++++++++++ > drivers/iommu/mtk_iommu_v1.c | 20 +++++++++++++++++++- > 2 files changed, 41 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c > index d5848f78a677..a2fa55899434 100644 > --- a/drivers/iommu/mtk_iommu.c > +++ b/drivers/iommu/mtk_iommu.c > @@ -560,22 +560,44 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev) > { > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); > struct mtk_iommu_data *data; > + struct device_link *link; > + struct device *larbdev; > + unsigned int larbid; > > if (!fwspec || fwspec->ops != &mtk_iommu_ops) > return ERR_PTR(-ENODEV); /* Not a iommu client device */ > > data = dev_iommu_priv_get(dev); > > + /* > + * Link the consumer device with the smi-larb device(supplier) > + * The device in each a larb is a independent HW. thus only link > + * one larb here. > + */ > + larbid = MTK_M4U_TO_LARB(fwspec->ids[0]);
so larbid is always the same for all the ids of a device? If so maybe it worth testing it and return error if this is not the case.
Thanks, Dafna
> + larbdev = data->larb_imu[larbid].dev; > + link = device_link_add(dev, larbdev, > + DL_FLAG_PM_RUNTIME | DL_FLAG_STATELESS); > + if (!link) > + dev_err(dev, "Unable to link %s\n", dev_name(larbdev)); > return &data->iommu; > } > > static void mtk_iommu_release_device(struct device *dev) > { > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); > + struct mtk_iommu_data *data; > + struct device *larbdev; > + unsigned int larbid; > > if (!fwspec || fwspec->ops != &mtk_iommu_ops) > return; > > + data = dev_iommu_priv_get(dev); > + larbid = MTK_M4U_TO_LARB(fwspec->ids[0]); > + larbdev = data->larb_imu[larbid].dev; > + device_link_remove(dev, larbdev); > + > iommu_fwspec_free(dev); > } > > diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c > index 4d7809432239..e6f13459470e 100644 > --- a/drivers/iommu/mtk_iommu_v1.c > +++ b/drivers/iommu/mtk_iommu_v1.c > @@ -423,7 +423,9 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev) > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); > struct of_phandle_args iommu_spec; > struct mtk_iommu_data *data; > - int err, idx = 0; > + int err, idx = 0, larbid; > + struct device_link *link; > + struct device *larbdev; > > /* > * In the deferred case, free the existed fwspec. > @@ -453,6 +455,14 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev) > > data = dev_iommu_priv_get(dev); > > + /* Link the consumer device with the smi-larb device(supplier) */ > + larbid = mt2701_m4u_to_larb(fwspec->ids[0]); > + larbdev = data->larb_imu[larbid].dev; > + link = device_link_add(dev, larbdev, > + DL_FLAG_PM_RUNTIME | DL_FLAG_STATELESS); > + if (!link) > + dev_err(dev, "Unable to link %s\n", dev_name(larbdev)); > + > return &data->iommu; > } > > @@ -473,10 +483,18 @@ static void mtk_iommu_probe_finalize(struct device *dev) > static void mtk_iommu_release_device(struct device *dev) > { > struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev); > + struct mtk_iommu_data *data; > + struct device *larbdev; > + unsigned int larbid; > > if (!fwspec || fwspec->ops != &mtk_iommu_ops) > return; > > + data = dev_iommu_priv_get(dev); > + larbid = mt2701_m4u_to_larb(fwspec->ids[0]); > + larbdev = data->larb_imu[larbid].dev; > + device_link_remove(dev, larbdev); > + > iommu_fwspec_free(dev); > } > >
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