This patch actually fixes a bug, though it doesn't affect the two platforms supported currently. The fix implements GSI memory pointers a bit differently. For IPA version 4.5 and above, the address space for almost all GSI registers is adjusted downward by a fixed amount. This is currently handled by adjusting the I/O virtual address pointer after it has been mapped. The bug is that the pointer is not "de-adjusted" as it should be when it's unmapped. This patch fixes that error, but it does so by maintaining one "raw" pointer for the mapped memory range. This is assigned when the memory is mapped and used to unmap the memory. This pointer is also used to access the two registers that do *not* sit in the "adjusted" memory space. Rather than adjusting *that* pointer, we maintain a separate pointer that's an adjusted copy of the "raw" pointer, and that is used for most GSI register accesses. Signed-off-by: Alex Elder <elder@linaro.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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.
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