dda44eb29c
On power9, userspace can send GZIP compression requests directly to NX once kernel establishes NX channel / window with VAS. This patch provides user space API which allows user space to establish channel using open VAS_TX_WIN_OPEN ioctl, mmap and close operations. Each window corresponds to file descriptor and application can open multiple windows. After the window is opened, VAS_TX_WIN_OPEN icoctl to open a window on specific VAS instance, mmap() system call to map the hardware address of engine's request queue into the application's virtual address space. Then the application can then submit one or more requests to the the engine by using the copy/paste instructions and pasting the CRBs to the virtual address (aka paste_address) returned by mmap(). Only NX GZIP coprocessor type is supported right now and allow GZIP engine access via /dev/crypto/nx-gzip device node. Thanks to Michael Ellerman for his changes and suggestions to make the ioctl generic to support any coprocessor type. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by: Haren Myneni <haren@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/1587114121.2275.1109.camel@hbabu-laptop
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.