6340b391e1
Currently, most of the Qualcomm SoCs specify both "iommus" and "iommu-map" properties for the PCIe nodes. First one passes the SMR mask to the iommu driver and the latter specifies the SID for each PCIe device. But with "iommus" property, the PCIe controller will be added to the iommu group along with the devices. This makes no sense because the controller will not initiate any DMA transaction on its own. And moreover, it is not strictly required to pass the SMR mask to the iommu driver. If the "iommus" property is not present, then the default mask of "0" would be used which should work for all PCIe devices. On the other side, if the SMR mask specified doesn't match the one expected by the hypervisor, then all the PCIe transactions will end up triggering "Unidentified Stream Fault" by the SMMU. So to get rid of these hassles and also prohibit PCIe controllers from adding to the iommu group, let's remove the "iommus" property from PCIe nodes. Reported-by: Rob Herring <robh@kernel.org> Link: https://lore.kernel.org/linux-arm-msm/20230227195535.GA749409-robh@kernel.org Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> Reviewed-by: Bjorn Andersson <andersson@kernel.org> Signed-off-by: Bjorn Andersson <andersson@kernel.org> Link: https://lore.kernel.org/r/20230308075648.134119-1-manivannan.sadhasivam@linaro.org
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.