NAME

       altera_avgen — driver for generic Altera Avalon-bus-attached, memory-mapped devices

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

       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 to width.

       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.

SEE ALSO

       mmap(2), open(2), read(2), write(2)

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 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.

Debian                                           August 18, 2012                                 ALTERA_AVGEN(4)