f38338cf06
The host1x bus implemented on Tegra SoCs is primarily an abstraction to create logical device from multiple platform devices. Since the devices in such a setup are typically hierarchical, DMA setup still needs to be done so that DMA masks can be properly inherited, but we don't actually want to attach the host1x logical devices to any IOMMU. The platform devices that make up the logical device are responsible for memory bus transactions, so it is them that will need to be attached to the IOMMU. Add a check to __iommu_probe_device() that aborts IOMMU setup early for busses that don't have the IOMMU operations pointer set since they will cause a crash otherwise. Signed-off-by: Thierry Reding <treding@nvidia.com> Link: https://lore.kernel.org/r/20200511161000.3853342-1-thierry.reding@gmail.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.