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[ Upstream commit76ce65464f] In M4U 4GB mode, the physical address is remapped as below: CPU Physical address: ==================== 0 1G 2G 3G 4G 5G |---A---|---B---|---C---|---D---|---E---| +--I/O--+------------Memory-------------+ IOMMU output physical address: ============================= 4G 5G 6G 7G 8G |---E---|---B---|---C---|---D---| +------------Memory-------------+ The Region 'A'(I/O) can not be mapped by M4U; For Region 'B'/'C'/'D', the bit32 of the CPU physical address always is needed to set, and for Region 'E', the CPU physical address keep as is. something looks like this: CPU PA -> M4U OUTPUT PA 0x4000_0000 0x1_4000_0000 (Add bit32) 0x8000_0000 0x1_8000_0000 ... 0xc000_0000 0x1_c000_0000 ... 0x1_0000_0000 0x1_0000_0000 (No change) Additionally, the iommu consumers always use the CPU phyiscal address. The PA in the iova_to_phys that is got from v7s always is u32, But from the CPU point of view, PA only need add BIT(32) when PA < 0x4000_0000. Fixes:30e2fccf95("iommu/mediatek: Enlarge the validate PA range for 4GB mode") Signed-off-by: Yong Wu <yong.wu@mediatek.com> Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Sasha Levin <sashal@kernel.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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.