spu_create

Sommaire

NAME

spu_create - create a new spu context

SYNOPSIS

 #include <sys/types.h>
 #include <sys/spu.h>
 
 int spu_create(const char *pathname, int flags, mode_t mode);

DESCRIPTION

The 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 pathname and returns a file descriptor associated with it. pathname must point to a non-existing directory in the mount point of the SPU file system (SPUFS). If spu_create() is successful, a directory is created in pathname and it is populated with the files described in spufs(7).

The returned file handler can only be passed to 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 flags can be zero or the following constant:

SPU_RAWIO
Allow mapping of some of the hardware registers of the SPU into user space. This flag requires the CAP_SYS_RAWIO capability.

The new directory and files are created in the SPUFS with the permissions set by the mode argument minus those set in the process's umask(2). The actual permissions set for each file also depend on whether the file supports read and/or write accesses.

RETURN VALUE

On success, spu_create(2) returns a new file descriptor. On error, -1 is returned and errno is set to one of the error codes listed below.

ERRORS

EACCESS
The current user does not have write access to the SPUFS mount point.
EEXIST
An SPU context already exists in the given path name.
EFAULT
pathname is not a valid string pointer in the current address space.
EINVAL
pathname is not a directory in the SPUFS mount point.
ELOOP
Too many symlinks were found while resolving pathname.
EMFILE
The process has reached its maximum open files limit.
ENAMETOOLONG
pathname is too long.
ENFILE
The system has reached the global open files limit.
ENOENT
Part of pathname could not be resolved.
ENOMEM
The kernel could not allocate all resources required.
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.
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.
ENOTDIR
A part of pathname is not a directory.

FILES

pathname must point to a location beneath the mount point of the SPUFS. By convention, it gets mounted in /spu.

VERSIONS

The spu_create(2) system call was added to Linux in kernel 2.6.16.

CONFORMING TO

This call is Linux specific and only implemented by the ppc64 architecture. Programs using this system call are not portable.

NOTES

Glibc does not provide a wrapper for this system call; call it using syscall(2). Note however, that 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 http://www.bsc.es/projects/deepcomputing/linuxoncell/ for the recommended libraries.

BUGS

The code does not yet fully implement all features outlined here.

SEE ALSO

close(2), spu_run(2), capabilities(7), spufs(7)