Re: [PATCH v4 13/24] iommu/mediatek: Add device link for smi-common and m4u

[Yong Wu <yong.wu@mediatek.com>]

On Thu, 2020-11-12 at 09:10 +0800, Nicolas Boichat wrote:
> On Wed, Nov 11, 2020 at 8:40 PM Yong Wu <yong.wu@mediatek.com> wrote:
> >
> > In the lastest SoC, M4U has its special power domain. thus, If the engine
> > begin to work, it should help enable the power for M4U firstly.
> > Currently if the engine work, it always enable the power/clocks for
> > smi-larbs/smi-common. This patch adds device_link for smi-common and M4U.
> > then, if smi-common power is enabled, the M4U power also is powered on
> > automatically.
> >
> > Normally M4U connect with several smi-larbs and their smi-common always
> > are the same, In this patch it get smi-common dev from the first smi-larb
> > device(i==0), then add the device_link only while m4u has power-domain.
> >
> > Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> > ---
> >  drivers/iommu/mtk_iommu.c | 36 +++++++++++++++++++++++++++++++++---
> >  drivers/iommu/mtk_iommu.h |  1 +
> >  2 files changed, 34 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index cfdf5ce696fd..4ce7e0883e4d 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -20,6 +20,7 @@
> >  #include <linux/of_irq.h>
> >  #include <linux/of_platform.h>
> >  #include <linux/platform_device.h>
> > +#include <linux/pm_runtime.h>
> >  #include <linux/regmap.h>
> >  #include <linux/slab.h>
> >  #include <linux/spinlock.h>
> > @@ -705,7 +706,7 @@ static int mtk_iommu_probe(struct platform_device *pdev)
> >                 return larb_nr;
> >
> >         for (i = 0; i < larb_nr; i++) {
> > -               struct device_node *larbnode;
> > +               struct device_node *larbnode, *smicomm_node;
> >                 struct platform_device *plarbdev;
> >                 u32 id;
> >
> > @@ -731,6 +732,26 @@ static int mtk_iommu_probe(struct platform_device *pdev)
> >
> >                 component_match_add_release(dev, &match, release_of,
> >                                             compare_of, larbnode);
> > +               if (!i) {
> 
> Maybe more of a style preference, but since you are actually comparing
> an integer, I prefer seeing i == 0.
> 
> Also, might be nicer to do
> 
> if (i != 0)
>    continue;
> 
> And de-indent the rest.

Thanks. will fix.

> 
> > +                       smicomm_node = of_parse_phandle(larbnode, "mediatek,smi", 0);
> > +                       if (!smicomm_node)
> > +                               return -EINVAL;
> > +
> > +                       plarbdev = of_find_device_by_node(smicomm_node);
> > +                       of_node_put(smicomm_node);
> > +                       data->smicomm_dev = &plarbdev->dev;
> > +               }
> > +       }
> > +
> > +       if (dev->pm_domain) {
> > +               struct device_link *link;
> > +
> > +               link = device_link_add(data->smicomm_dev, dev,
> > +                                      DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME);
> > +               if (!link) {
> > +                       dev_err(dev, "Unable link %s.\n", dev_name(data->smicomm_dev));
> > +                       return -EINVAL;
> > +               }
> >         }
> >
> >         platform_set_drvdata(pdev, data);
> > @@ -738,14 +759,14 @@ static int mtk_iommu_probe(struct platform_device *pdev)
> >         ret = iommu_device_sysfs_add(&data->iommu, dev, NULL,
> >                                      "mtk-iommu.%pa", &ioaddr);
> >         if (ret)
> > -               return ret;
> > +               goto out_link_remove;
> >
> >         iommu_device_set_ops(&data->iommu, &mtk_iommu_ops);
> >         iommu_device_set_fwnode(&data->iommu, &pdev->dev.of_node->fwnode);
> >
> >         ret = iommu_device_register(&data->iommu);
> >         if (ret)
> > -               return ret;
> > +               goto out_sysfs_remove;
> 
> Technically, this change is unrelated.

Sharp eye. Right. I thought it was small enough to squash here.

I will use a new patch to fix this(add fixes tag, and no need add
cc-stable I think.).

> 
> >
> >         spin_lock_init(&data->tlb_lock);
> >         list_add_tail(&data->list, &m4ulist);
> > @@ -754,6 +775,13 @@ static int mtk_iommu_probe(struct platform_device *pdev)
> >                 bus_set_iommu(&platform_bus_type, &mtk_iommu_ops);
> >
> >         return component_master_add_with_match(dev, &mtk_iommu_com_ops, match);
> > +
> > +out_sysfs_remove:
> > +       iommu_device_sysfs_remove(&data->iommu);
> > +out_link_remove:
> > +       if (dev->pm_domain)
> > +               device_link_remove(data->smicomm_dev, dev);
> > +       return ret;
> >  }
> >
> >  static int mtk_iommu_remove(struct platform_device *pdev)
> > @@ -767,6 +795,8 @@ static int mtk_iommu_remove(struct platform_device *pdev)
> >                 bus_set_iommu(&platform_bus_type, NULL);
> >
> >         clk_disable_unprepare(data->bclk);
> > +       if (pdev->dev.pm_domain)
> > +               device_link_remove(data->smicomm_dev, &pdev->dev);
> >         devm_free_irq(&pdev->dev, data->irq, data);
> >         component_master_del(&pdev->dev, &mtk_iommu_com_ops);
> >         return 0;
> > diff --git a/drivers/iommu/mtk_iommu.h b/drivers/iommu/mtk_iommu.h
> > index d0c93652bdbe..5e03a029c4dc 100644
> > --- a/drivers/iommu/mtk_iommu.h
> > +++ b/drivers/iommu/mtk_iommu.h
> > @@ -68,6 +68,7 @@ struct mtk_iommu_data {
> >
> >         struct iommu_device             iommu;
> >         const struct mtk_iommu_plat_data *plat_data;
> > +       struct device                   *smicomm_dev;
> >
> >         struct dma_iommu_mapping        *mapping; /* For mtk_iommu_v1.c */
> >
> > --
> > 2.18.0
> >
> 
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