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For devices attached to an IOMMU, translation between IOVA and physical addresses is no longer 1:1 and dma-ranges should be specified to describe the available IOVA address space. On SDM845 the busses are implemented with 36 address bits, so dma-ranges must be defined to reduce the size of the IOVA address space from the 48 bits supported by the SMMU. Without this DMA allocations may end up with IOVAs outside the valid range, that gets truncated by the bus between the device and its translation unit. Also extend ranges to describe the available address space. Tested-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Stephen Boyd <swboyd@chromium.org> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> Signed-off-by: Andy Gross <andy.gross@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.