On Tue, 2017-09-12 at 05:37 -0700, gre...@linuxfoundation.org wrote: > On Tue, Sep 12, 2017 at 12:18:27PM +0000, Joakim Tjernlund wrote: > > Hi > > > > I am trying to use the uio_dmem_genirq.c driver for allocating DMA memory > > to a PCI device > > using the uio_pci_generic.c driver. > > > > I got as far as defining an UIO dev containing only Dynamic DMA memory and > > now I am stuck. > > I can see how DMA memory is allocated when opening the /dev/uio device but > > I cannot > > figure out how to mmap this memory to User space as well so I can share this > > memory with the PCI device and my user space driver. > > > > What am I missing? > > Why can't you call mmap() on the fd you created when you opened > /dev/uio? What happens when you do that?
Haven't tried that as I figured it had to be something similar as UIO PCI where you can have several memory regions and therefore must mmap one of the resource files under sys: # > pwd /sys/bus/pci/drivers/uio_pci_generic/0000:01:00.0/uio/uio8/device leipzig device # cat /sys/devices/platform/ffe250000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/resource 0x0000000c10000000 0x0000000c11ffffff 0x0000000000140204 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 leipzig device # pwd /sys/bus/pci/drivers/uio_pci_generic/0000:01:00.0/uio/uio8/device leipzig device # cat resource 0x0000000c10000000 0x0000000c11ffffff 0x0000000000140204 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 leipzig device # ls resource* resource resource0 Here one opens and mmaps resource0 to get at 0x0000000c10000000 0x0000000c11ffffff 0x0000000000140204 Jocke
