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
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