man-pages/man2/spu_create.2

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.\" HISTORY:
.\" 2005-09-28, created by Arnd Bergmann <arndb@de.ibm.com>
.\" 2006-06-16, revised by Eduardo M. Fleury <efleury@br.ibm.com>
.\" 2007-07-10, some polishing by mtk
.\"
.TH SPU_CREATE 2 2007-07-10 "Linux" "Linux Programmer's Manual"
.SH NAME
spu_create \- create a new spu context
.SH SYNOPSIS
.nf
.B #include <sys/types.h>
.B #include <sys/spu.h>

.BI "int spu_create(const char *" pathname ", int " flags ", mode_t " mode ");"
.fi
.SH DESCRIPTION
The
.BR spu_create ()
system call is used on PowerPC machines that implement the
Cell Broadband Engine Architecture in order to access Synergistic
Processor Units (SPUs).
It creates a new logical context for an
SPU in
.I pathname
and returns a file descriptor associated with it.
.I pathname
must point to a non-existing directory in the mount point of the
SPU file system (SPUFS).
If
.BR spu_create ()
is successful, a directory is created in
.I pathname
and it is populated with the files described in
.BR spufs (7).

The returned file handler can only be passed to
.BR spu_run (2)
or closed;
other operations are not defined on it.
A logical SPU
context is destroyed when its file descriptor is closed as well as
all the file descriptors pointing to files inside it.
When an SPU context is destroyed all its directory entries in the
SPUFS are removed.

The argument
.I flags
can be zero or the following
constant:
.TP
.B SPU_RAWIO
Allow mapping of some of the hardware registers of the SPU into user
space.
This flag requires the
.B CAP_SYS_RAWIO
capability.
.PP
The new directory and files are created in the SPUFS with the
permissions set by the
.I mode
argument minus those set in the process's
.BR umask (2).
The actual permissions set for each file also depend on whether the
file supports read and/or write accesses.
.SH RETURN VALUE
On success,
.BR spu_create (2)
returns a new file descriptor.
On error, \-1 is returned and
.I errno
is set to one of the error codes listed below.
.SH ERRORS
.TP
.B EACCESS
The current user does not have write access to the SPUFS mount point.
.TP
.B EEXIST
An SPU context already exists in the given path name.
.TP
.B EFAULT
.I pathname
is not a valid string pointer in the current address space.
.TP
.B EINVAL
.I pathname
is not a directory in the SPUFS mount point.
.TP
.B ELOOP
Too many symlinks were found while resolving
.IR pathname .
.TP
.B EMFILE
The process has reached its maximum open files limit.
.TP
.B ENAMETOOLONG
.I pathname
is too long.
.TP
.B ENFILE
The system has reached the global open files limit.
.TP
.B ENOENT
Part of
.I pathname
could not be resolved.
.TP
.B ENOMEM
The kernel could not allocate all resources required.
.TP
.B ENOSPC
There are not enough SPU resources available to create
a new context or the user specific limit for the number
of SPU contexts has been reached.
.TP
.B ENOSYS
The functionality is not provided by the current system, because
either the hardware does not provide SPUs or the spufs module is not
loaded.
.TP
.B ENOTDIR
A part of
.I pathname
is not a directory.
.SH FILES
.I pathname
must point to a location beneath the mount point of the SPUFS.
By convention, it gets mounted in
.IR /spu .
.SH VERSIONS
The
.BR spu_create (2)
system call was added to Linux in kernel 2.6.16.
.SH CONFORMING TO
This call is Linux specific and only implemented by the ppc64
architecture.
Programs using this system call are not portable.
.SH NOTES
Glibc does not provide a wrapper for this system call; call it using
.BR syscall (2).
Note however, that
.BR spu_create ()
is meant to be used from libraries that implement a more abstract
interface to SPUs, not to be used from regular applications.
See
.I http://www.bsc.es/projects/deepcomputing/linuxoncell/
for the recommended libraries.
.SH BUGS
The code does not yet fully implement all features outlined here.
.\" .SH AUTHOR
.\" Arnd Bergmann <arndb@de.ibm.com>
.SH SEE ALSO
.BR close (2),
.BR spu_run (2),
.BR capabilities (7),
.BR spufs (7)