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06e931e0fc
Mali GPU Arch spec forbids the GPU PTEs to indicate Inner or Outer shareability when no_coherency protocol is selected. Doing so results in unexpected or undesired snooping of the CPU caches on some platforms, such as Juno FPGA, causing functional issues. For example the boot of MCU firmware fails as GPU ends up reading stale data for the FW memory pages from the CPU's cache. The FW memory pages are initialized with uncached mapping when the device is not reported to be dma-coherent. The shareability bits are set to inner-shareable when IOMMU_CACHE flag is passed to map_pages() callback and IOMMU_CACHE flag is passed by Panthor driver when memory needs to be mapped as cached on the GPU side. IOMMU_CACHE seems to imply cache coherent and is probably not fit for purpose for the memory that is mapped as cached on GPU side but doesn't need to remain coherent with the CPU. This commit updates the programming of MEMATTR register to use MIDGARD_INNER instead of CPU_INNER when coherency is disabled. That way the inner-shareability specified in the GPU PTEs would map to Mali's internal-shareable mode, which is always supported by the GPU regardless of the coherency protocal and is required by the Userspace driver to ensure coherency between the shader cores. v2: - Added R-b tags Signed-off-by: Akash Goel <akash.goel@arm.com> Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com> Reviewed-by: Liviu Dudau <liviu.dudau@arm.com> Reviewed-by: Steven Price <steven.price@arm.com> Link: https://lore.kernel.org/r/20241030225407.4077513-2-akash.goel@arm.com Signed-off-by: Liviu Dudau <liviu.dudau@arm.com> |
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| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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 reStructuredText 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.