forked from Minki/linux
mainlining shenanigans
7948efc27f
As described by Haren: Power9 processor supports Virtual Accelerator Switchboard (VAS) which allows kernel and userspace to send compression requests to Nest Accelerator (NX) directly. The NX unit comprises of 2 842 compression engines and 1 GZIP engine. Linux kernel already has 842 compression support on kernel. This patch series adds GZIP compression support from user space. The GZIP Compression engine implements the ZLIB and GZIP compression algorithms. No plans of adding NX-GZIP compression support in kernel right now. Applications can send requests to NX directly with COPY/PASTE instructions. But kernel has to establish channel / window on NX-GZIP device for the userspace. So userspace access to the GZIP engine is provided through /dev/crypto/nx-gzip device with several operations. An application must open the this device to obtain a file descriptor (fd). Using the fd, application should issue the VAS_TX_WIN_OPEN ioctl to establish a connection to the engine. Once window is opened, should use mmap() system call to map the hardware address of engine's request queue into the application's virtual address space. Then user space forms the request as co-processor Request Block (CRB) and paste this CRB on the mapped HW address using COPY/PASTE instructions. Application can poll on status flags (part of CRB) with timeout for request completion. For VAS_TX_WIN_OPEN ioctl, if user space passes vas_id = -1 (struct vas_tx_win_open_attr), kernel determines the VAS instance on the corresponding chip based on the CPU on which the process is executing. Otherwise, the specified VAS instance is used if application passes the proper VAS instance (vas_id listed in /proc/device-tree/vas@*/ibm,vas_id). Process can open multiple windows with different FDs or can send several requests to NX on the same window at the same time. |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| 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 | ||
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.