77a0b09dd9
Loading the firmware requires an allocation of IOVA space to make sure that the VIC's Falcon microcontroller can read the firmware if address translation via the SMMU is enabled. However, the allocation currently happens at a time where the geometry of an IOMMU domain may not have been initialized yet. This happens for example on Tegra186 and later where an ARM SMMU is used. Domains which are created by the ARM SMMU driver postpone the geometry setup until a device is attached to the domain. This is because IOMMU domains aren't attached to a specific IOMMU instance at allocation time and hence the input address space, which defines the geometry, is not known yet. Work around this by postponing the firmware load until it is needed at the time where a channel is opened to the VIC. At this time the shared IOMMU domain's geometry has been properly initialized. As a byproduct this allows the Tegra DRM to be created in the absence of VIC firmware, since the VIC initialization no longer fails if the firmware can't be found. Based on an earlier patch by Dmitry Osipenko <digetx@gmail.com>. Signed-off-by: Thierry Reding <treding@nvidia.com> Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
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.