8c0d51592f
On LoPAR "DMA Window Manipulation Calls", it's recommended to remove the default DMA window for the device, before attempting to configure a DDW, in order to make the maximum resources available for the next DDW to be created. This is a requirement for using DDW on devices in which hypervisor allows only one DMA window. If setting up a new DDW fails anywhere after the removal of this default DMA window, it's needed to restore the default DMA window. For this, an implementation of ibm,reset-pe-dma-windows rtas call is needed: Platforms supporting the DDW option starting with LoPAR level 2.7 implement ibm,ddw-extensions. The first extension available (index 2) carries the token for ibm,reset-pe-dma-windows rtas call, which is used to restore the default DMA window for a device, if it has been deleted. It does so by resetting the TCE table allocation for the PE to it's boot time value, available in "ibm,dma-window" device tree node. Signed-off-by: Leonardo Bras <leobras.c@gmail.com> Tested-by: David Dai <zdai@linux.vnet.ibm.com> Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200805030455.123024-5-leobras.c@gmail.com |
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| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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 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.