GSoC Linux UIO driver for PRU
nilhoel1 at gmail.com
Mon Jul 15 08:10:04 UTC 2019
Thanks this is very helpful.
But has anyone an existing example of a similar driver?
I wasn't able find one in /bsps, maybe I didn't search long enough.
On Mon, 15 Jul 2019 at 08:47, Sebastian Huber <
sebastian.huber at embedded-brains.de> wrote:
> On 14/07/2019 01:34, Joel Sherrill wrote:
> > On Sat, Jul 13, 2019 at 1:42 PM Chris Johns <chrisj at rtems.org
> > <mailto:chrisj at rtems.org>> wrote:
> > On 13/7/19 5:16 pm, Nils Hölscher wrote:
> > > Hi,
> > >
> > > After I made sure that my fdt is correct I wondered why the pruss
> > was still not
> > > accessible.
> > > When I researched more about userspace drivers in Linux I found
> > out, that I have
> > > overseen the pru UIO module in Linux.
> > > This is the part that links the PRUs to the /dev/uio[0-7].
> > > Which then would be used by the sources I currently use.
> > > The UIO source is available here:
> > >
> > > However this requires the linux UIO lib to load the modules and
> > abstract the
> > > device into a file.
> > >
> > > While researching I also found that BSD has a PRU driver.
> > > Also this driver is more feature rich as it support PRU debugging.
> > > The sources can be found her:
> > > https://bitbucket.org/rpaulo/libpru/src/default/
> > > Additionally I found these sources in the FreeBSD tree:
> > >
> > > This code also registers the PRUs in /dev/.
> > > On the other hand the BSD drivers have no documentation at all.
> > >
> > > These are the code lines that will fail without a file in /dev.
> > > Linux:
> > https://github.com/nilhoel1/rtems-pru/blob/master/ti/prussdrv.c#L265
> > > BSD:
> > >
> > > So my questions are:
> > > 1. How are drivers registered to /dev in RTEMS? (examples)
> > I suggest you look at cpukit/include/rtems/io.h and then for
> > examples of this
> > interface being used in the bsp directory.
> > There is a helper in the IO Manager which is implemented as a call to
> > mknod()
> > which is a standard call.
> In libbsd devices should be added with IMFS_make_generic_node():
> freebsd/sys/net/bpf.c: rv = IMFS_make_generic_node("/dev/bpf", mode,
> &bpf_imfs_control, NULL);
> freebsd/sys/kern/uipc_usrreq.c: rv = IMFS_make_generic_node(soun->sun_path,
> rtemsbsd/sys/fs/devfs/devfs_devs.c: rv =
> IMFS_make_generic_node(dev->si_path, mode, &devfs_imfs_control,
> Sebastian Huber, embedded brains GmbH
> Address : Dornierstr. 4, D-82178 Puchheim, Germany
> Phone : +49 89 189 47 41-16
> Fax : +49 89 189 47 41-09
> E-Mail : sebastian.huber at embedded-brains.de
> PGP : Public key available on request.
> Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
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