Re: uio_pci_generic driver

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Mar 20, 2012 at 09:17:00PM +0100, Hans J. Koch wrote:
> On Tue, Mar 20, 2012 at 10:48:25PM +0400, tochansky@tochlab.net wrote:
> > > On Tue, Mar 20, 2012 at 09:56:03PM +0400, tochansky@tochlab.net wrote:
> > >> Hello!
> > >> I have a question about uio_pci_generic driver. I'm trying to use it in
> > >> my
> > >> project, but have no luck.
> > >> There are very little information on the subject. If you have a few
> > >> minutes, I would like to ask a few questions.
> > >> I need to mmap() memory of my board to work with it. I did
> > >> # modprobe uio_pci_generic
> > >> # echo "xxxx xxxx" > /sys/bus/pci/drivers/uio_pci_generic/new_id
> > >>
> > >> Files in /sys/class/uio/uio0 appears, but there no directory named
> > >> /sys/class/uio/uio0/maps/.
> > >> Anyway I tryed to mmap with code:
> > >>
> > >> #include <sys/types.h>
> > >> #include <sys/stat.h>
> > >> #include <fcntl.h>
> > >>
> > >> #include <sys/mman.h>
> > >> #include <stdio.h>
> > >>
> > >> int main()
> > >> {
> > >>         int fd = open("/dev/uio0", O_RDWR | O_SYNC);
> > >>         printf("fd = %d\n", fd);
> > >>         void *addr = mmap(NULL, 1024, PROT_READ, MAP_SHARED, fd, 0);
> > >>         printf("addr = %p\n", addr);
> > >> }
> > >>
> > >> Ofcourse, mmap() failes with error "Invalid argument". Nothing criminal
> > >> in
> > >> dmesg and any other hints of error.
> > >>
> > >> --
> > >> Dmitriy
> > >
> > >
> > > Map memory through /sys/bus/pci/devices/......
> > >
> > > Also copy questions to mailing lists please.
> > >
> > Thanks, it works now.
> > 
> > #include <sys/types.h>
> > #include <sys/stat.h>
> > #include <fcntl.h>
> > 
> > #include <sys/mman.h>
> > #include <stdio.h>
> > 
> > int main() {
> >         int fd =
> > open("/sys/class/pci_bus/0000:03/device/0000:03:00.0/resource5",
> > O_RDWR | O_SYNC);
> >         printf("fd = %d\n", fd);
> >         void *addr = mmap(NULL, 512, PROT_READ, MAP_SHARED, fd, 0);
> >         if(addr == MAP_FAILED)  {
> >                 perror("mmap");
> >         }
> >         else {
> >                 printf("addr = %p\n", addr);
> >         }
> > }
> > 
> > May be its time to add some hints in documentation? :-)
> 
> Good idea. Michael, are you in the mood to hack something up for
> Documentation/DocBook/uio-howto.tmpl ?
> 
> Thanks,
> Hans

I'll see what can be done.