ALTERA_AVGEN(4) | Device Drivers Manual | ALTERA_AVGEN(4) |
NAME¶
altera_avgen
—
SYNOPSIS¶
device altera_avgen
In /boot/device.hints:
hint.altera_avgen.0.at="nexus0"
hint.altera_avgen.0.maddr=0x7f00a000
hint.altera_avgen.0.msize=20
hint.altera_avgen.0.width=4
hint.altera_avgen.0.fileio="rw"
hint.altera_avgen.0.devname="berirom"
DESCRIPTION¶
Thealtera_avgen
device driver provides generic support
for memory-mapped devices on the Altera Avalon bus.
device.hints entries configure the address, size, I/O
disposition, and /dev device node name that will be
used. The open(2), read(2),
write(2), and mmap(2) system calls (and
variations) may be used on altera_avgen
device nodes,
subject to constraints imposed using device.hints
entries. Although reading and writing mapped memory is supported,
altera_avgen
does not currently support directing
device interrupts to userspace.
A number of device.hints sub-fields are
available to configure altera_avgen
device
instances:
- maddr
- base physical address of the memory region to export; must be aligned to
width
- msize
- length of the memory region export; must be aligned to
width
- width
- Granularity at which read(2) and
write(2) operations will be performed. Larger requests
will be broken down into
width -sized
operations; smaller requests will be rejected. I/O operations must be aligned towidth
. - fileio
- allowed file descriptor operations;
r
authorizes read(2);w
authorizes write(2). - mmapio
- allowed mmap(2) permissions;
w
authorizesPROT_WRITE
;r
authorizesPROT_READ
;x
authorizesPROT_EXEC
. - devname
- specifies a device name relative to /dev.
- devunit
- specifies a device unit number; no unit number is used if this is unspecified.
SEE ALSO¶
mmap(2), open(2), read(2), write(2)HISTORY¶
Thealtera_avgen
device driver first appeared in
FreeBSD 10.0.
AUTHORS¶
Thealtera_avgen
device driver and this manual page were
developed by SRI International and the University of Cambridge Computer
Laboratory under DARPA/AFRL contract (FA8750-10-C-0237)
(“CTSRD”), as part of the DARPA CRASH research programme. This
device driver was written by Robert N. M. Watson.
BUGS¶
altera_avgen
is intended to support the writing of
userspace device drivers; however, it does not permit directing interrupts to
userspace, only memory-mapped I/O.
altera_avgen
supports only a
nexus
bus attachment, which is appropriate for
system-on-chip busses such as Altera's Avalon bus. If the target device is
off of another bus type, then additional bus attachments will be
required.
August 18, 2012 | Linux 4.19.0-10-amd64 |