1.. SPDX-License-Identifier: GPL-2.0
2
3==========
4spu_create
5==========
6
7Name
8====
9       spu_create - create a new spu context
10
11
12Synopsis
13========
14
15       ::
16
17         #include <sys/types.h>
18         #include <sys/spu.h>
19
20         int spu_create(const char *pathname, int flags, mode_t mode);
21
22Description
23===========
24       The  spu_create  system call is used on PowerPC machines that implement
25       the Cell Broadband Engine Architecture in order to  access  Synergistic
26       Processor  Units (SPUs). It creates a new logical context for an SPU in
27       pathname and returns a handle to associated  with  it.   pathname  must
28       point  to  a  non-existing directory in the mount point of the SPU file
29       system (spufs).  When spu_create is successful, a directory  gets  cre-
30       ated on pathname and it is populated with files.
31
32       The  returned  file  handle can only be passed to spu_run(2) or closed,
33       other operations are not defined on it. When it is closed, all  associ-
34       ated  directory entries in spufs are removed. When the last file handle
35       pointing either inside  of  the  context  directory  or  to  this  file
36       descriptor is closed, the logical SPU context is destroyed.
37
38       The  parameter flags can be zero or any bitwise or'd combination of the
39       following constants:
40
41       SPU_RAWIO
42              Allow mapping of some of the hardware registers of the SPU  into
43              user space. This flag requires the CAP_SYS_RAWIO capability, see
44              capabilities(7).
45
46       The mode parameter specifies the permissions used for creating the  new
47       directory  in  spufs.   mode is modified with the user's umask(2) value
48       and then used for both the directory and the files contained in it. The
49       file permissions mask out some more bits of mode because they typically
50       support only read or write access. See stat(2) for a full list  of  the
51       possible mode values.
52
53
54Return Value
55============
56       spu_create  returns a new file descriptor. It may return -1 to indicate
57       an error condition and set errno to  one  of  the  error  codes  listed
58       below.
59
60
61Errors
62======
63       EACCES
64              The  current  user does not have write access on the spufs mount
65              point.
66
67       EEXIST An SPU context already exists at the given path name.
68
69       EFAULT pathname is not a valid string pointer in  the  current  address
70              space.
71
72       EINVAL pathname is not a directory in the spufs mount point.
73
74       ELOOP  Too many symlinks were found while resolving pathname.
75
76       EMFILE The process has reached its maximum open file limit.
77
78       ENAMETOOLONG
79              pathname was too long.
80
81       ENFILE The system has reached the global open file limit.
82
83       ENOENT Part of pathname could not be resolved.
84
85       ENOMEM The kernel could not allocate all resources required.
86
87       ENOSPC There  are  not  enough  SPU resources available to create a new
88              context or the user specific limit for the number  of  SPU  con-
89              texts has been reached.
90
91       ENOSYS the functionality is not provided by the current system, because
92              either the hardware does not provide SPUs or the spufs module is
93              not loaded.
94
95       ENOTDIR
96              A part of pathname is not a directory.
97
98
99
100Notes
101=====
102       spu_create  is  meant  to  be used from libraries that implement a more
103       abstract interface to SPUs, not to be used from  regular  applications.
104       See  http://www.bsc.es/projects/deepcomputing/linuxoncell/ for the rec-
105       ommended libraries.
106
107
108Files
109=====
110       pathname must point to a location beneath the mount point of spufs.  By
111       convention, it gets mounted in /spu.
112
113
114Conforming to
115=============
116       This call is Linux specific and only implemented by the ppc64 architec-
117       ture. Programs using this system call are not portable.
118
119
120Bugs
121====
122       The code does not yet fully implement all features lined out here.
123
124
125Author
126======
127       Arnd Bergmann <arndb@de.ibm.com>
128
129See Also
130========
131       capabilities(7), close(2), spu_run(2), spufs(7)
132