993cc87534
The Falcon microcontroller that runs the XUSB firmware and which is responsible for exposing the XHCI interface can address only 40 bits of memory. Typically that's not a problem because Tegra devices don't have enough system memory to exceed those 40 bits. However, if the ARM SMMU is enable on Tegra186 and later, the addresses passed to the XUSB controller can be anywhere in the 48-bit IOV address space of the ARM SMMU. Since the DMA/IOMMU API starts allocating from the top of the IOVA space, the Falcon microcontroller is not able to load the firmware successfully. Fix this by setting the DMA mask to 40 bits, which will force the DMA API to map the buffer for the firmware to an IOVA that is addressable by the Falcon. Signed-off-by: Nagarjuna Kristam <nkristam@nvidia.com> Signed-off-by: Thierry Reding <treding@nvidia.com> Link: https://lore.kernel.org/r/1566989697-13049-1-git-send-email-nkristam@nvidia.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.