Lines Matching +full:wait +full:- +full:on +full:- +full:read
1 .. SPDX-License-Identifier: GPL-2.0
10 spufs - the SPU file system
16 The SPU file system is used on PowerPC machines that implement the Cell
21 message queues. Users that have write permissions on the file system
26 logical SPU. Users can change permissions on those files, but not actu-
43 The files in spufs mostly follow the standard behavior for regular sys-
44 tem calls like read(2) or write(2), but often support only a subset of
45 the operations supported on regular file systems. This list details the
49 All files that support the read(2) operation also support readv(2) and
55 All files support the chmod(2)/fchmod(2) and chown(2)/fchown(2) opera-
57 possible operations, e.g. read access on the wbox file.
65 data in the address space of the SPU. The possible operations on an
68 read(2), pread(2), write(2), pwrite(2), lseek(2)
81 The first SPU to CPU communication mailbox. This file is read-only and
82 can be read in units of 32 bits. The file can only be used in non-
83 blocking mode and it even poll() will not block on it. The possible
84 operations on an open mbox file are:
86 read(2)
87 If a count smaller than four is requested, read returns -1 and
89 box, the return value is set to -1 and errno becomes EAGAIN.
90 When data has been read successfully, four bytes are placed in
96 the first mailbox file, but can be read in blocking I/O mode, and the
97 poll family of system calls can be used to wait for it. The possible
98 operations on an open ibox file are:
100 read(2)
101 If a count smaller than four is requested, read returns -1 and
104 return value is set to -1 and errno becomes EAGAIN.
109 When data has been read successfully, four bytes are placed in
113 Poll on the ibox file returns (POLLIN | POLLRDNORM) whenever
118 The CPU to SPU communation mailbox. It is write-only and can be written
120 poll can be used to wait for it becoming empty again. The possible
121 operations on an open wbox file are: write(2) If a count smaller than
122 four is requested, write returns -1 and sets errno to EINVAL. If there
124 opened with O_NONBLOCK, the return value is set to -1 and errno becomes
129 reads from its PPE mailbox channel. When data has been read success-
134 Poll on the ibox file returns (POLLOUT | POLLWRNORM) whenever
139 Read-only files that contain the length of the current queue, i.e. how
140 many words can be read from mbox or ibox or how many words can be
141 written to wbox without blocking. The files can be read only in 4-byte
142 units and return a big-endian binary integer number. The possible
143 operations on an open ``*box_stat`` file are:
145 read(2)
146 If a count smaller than four is requested, read returns -1 and
149 read from (for mbox_stat and ibox_stat) or written to (for
157 can be used in read/write mode for debugging, but normal operation of
158 programs should not rely on them because access to any of them except
173 The possible operations on an open npc, decr, decr_status,
176 read(2)
177 When the count supplied to the read call is shorter than the
181 a running SPU task. When a complete string has been read, all
182 subsequent read operations will return zero bytes and a new file
183 descriptor needs to be opened to read the value again.
186 A write operation on the file results in setting the register to
188 beginning to the first non-numeric character or the end of the
194 This file gives access to the Floating Point Status and Control Regis-
195 ter as a four byte long file. The operations on the fpcr file are:
197 read(2)
198 If a count smaller than four is requested, read returns -1 and
200 the data buffer, containing the current value of the fpcr regis-
204 If a count smaller than four is requested, write returns -1 and
210 The two signal notification channels of an SPU. These are read-write
211 files that operate on a 32 bit word. Writing to one of these files
212 triggers an interrupt on the SPU. The value written to the signal
213 files can be read from the SPU through a channel read or from host user
214 space through the file. After the value has been read by the SPU, it
215 is reset to zero. The possible operations on an open signal1 or sig-
218 read(2)
219 If a count smaller than four is requested, read returns -1 and
225 If a count smaller than four is requested, write returns -1 and
230 bitwise OR of the old value and the input data, depending on the
236 These two files change the behavior of the signal1 and signal2 notifi-
237 cation files. The contain a numerical ASCII string which is read as
240 mode 1 (logical OR), the hardware accumulates the bits that are subse-
241 quently written to it. The possible operations on an open signal1_type
244 read(2)
245 When the count supplied to the read call is shorter than the
246 required length for the digit plus a newline character, subse-
247 quent reads from the same file descriptor will result in com-
248 pleting the string. When a complete string has been read, all
249 subsequent read operations will return zero bytes and a new file
250 descriptor needs to be opened to read the value again.
253 A write operation on the file results in setting the register to
255 beginning to the first non-numeric character or the end of the