On Wed, 2015-10-14 at 14:53 +0200, Joerg Roedel wrote:
> On Fri, Oct 09, 2015 at 10:23:07AM +0800, Yong Wu wrote:
> > + /*
> > + * There is a domain for each a iommu device in normal case.
> > + * But MTK only has one iommu domain called the m4u domain which all
> > + * the multimedia HW share. Here we reserve one as the m4u domain and
> > + * free the others.
> > + *
> > + * And the attach_device that from __iommu_setup_dma_ops
> > + * will be called earlier than probe.
> > + */
>
> Okay, with this being the case, you need to put all devices behind one
> IOMMU into the same iommu-group, because the IOMMU can't really isolate
> the devices from each other.
>
> > +static int mtk_iommu_add_device(struct device *dev)
> > +{
> > + struct iommu_group *group;
> > + struct mtk_iommu_client_priv *priv;
> > + struct mtk_iommu_domain *m4udom;
> > + struct iommu_domain *domain;
> > + int ret;
> > +
> > + if (!dev->archdata.iommu) /* Not a iommu client device */
> > + return -ENODEV;
> > +
> > + group = iommu_group_get(dev);
> > + if (!group) {
> > + group = iommu_group_alloc();
> > + if (IS_ERR(group)) {
> > + dev_err(dev, "Failed to allocate IOMMU group\n");
> > + return PTR_ERR(group);
> > + }
> > + }
> > +
> > + ret = iommu_group_add_device(group, dev);
> > + if (ret) {
> > + dev_err(dev, "Failed to add IOMMU group\n");
> > + goto err_group_put;
> > + }
> > +
> > + domain = iommu_get_domain_for_dev(dev);
> > + if (!domain) {
> > + /*
> > + * Get the m4u iommu domain from the m4u device.
> > + * Attach all the client devices into the m4u domain.
> > + */
> > + priv = dev->archdata.iommu;
> > + m4udom = dev_get_drvdata(priv->m4udev);
> > + ret = iommu_attach_group(&m4udom->domain, group);
> > + if (ret)
> > + dev_err(dev, "Failed to attach IOMMU group\n");
> > + }
> > +
> > +err_group_put:
> > + iommu_group_put(group);
> > + return ret;
> > +}
>
> Here it looks like you are allocating one group for each device. As I
> said, all devices need to be in one group.
>
> Joerg
>
Thanks for this suggestion. I have put all the iommu client devices into
the same iommu group, the code looks like below.
And I will send this in the next version after the Short descriptor is
reviewed.
static int mtk_iommu_add_device(struct device *dev)
{
struct iommu_group *group;
struct mtk_iommu_client_priv *priv;
struct mtk_iommu_domain *m4udom;
struct iommu_domain *domain;
int ret;
priv = dev->archdata.iommu;
if (!priv) /* Not a iommu client device */
return -ENODEV;
m4udom = dev_get_drvdata(priv->m4udev);
group = iommu_group_get(dev);
if (!group) {
/*
* All the iommu client devices are in the m4u domain,
* they all are in the same m4u iommu-group too here.
*/
if (!m4udom->m4u_group) {
group = iommu_group_alloc();
if (IS_ERR(group)) {
dev_err(dev, "Failed to allocate IOMMU group\n");
return PTR_ERR(group);
}
m4udom->m4u_group = group;
} else {
group = m4udom->m4u_group;
}
}
ret = iommu_group_add_device(group, dev);
if (ret) {
dev_err(dev, "Failed to add IOMMU group\n");
goto err_group_put;
}
domain = iommu_get_domain_for_dev(dev);
if (!domain)
ret = iommu_attach_group(&m4udom->domain, group);
err_group_put:
iommu_group_put(group);
return ret;
}
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