ALTERA_AVGEN(4) | FreeBSD Kernel Interfaces Manual | ALTERA_AVGEN(4) |
NAME
altera_avgen — driver for generic Altera Avalon-bus-attached, memory-mapped devicesSYNOPSIS
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
The altera_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
authorizes PROT_WRITE;r
authorizes PROT_READ;x
authorizes PROT_EXEC. - devname
- specifies a device name relative to /dev.
- devunit
- specifies a device unit number; no unit number is used if this is unspecified.
HISTORY
The altera_avgen device driver first appeared in FreeBSD 10.0.AUTHORS
The altera_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 .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 | FreeBSD |