> Subject: Re: [PATCH v3 2/3] fpga: dfl: add the userspace I/O device support > for DFL devices > > On 12/18/20 12:05 AM, Wu, Hao wrote: > >> Subject: [PATCH v3 2/3] fpga: dfl: add the userspace I/O device support > for > >> DFL devices > >> > >> This patch supports the DFL drivers be written in userspace. This is > >> realized by exposing the userspace I/O device interfaces. > >> > >> The driver leverages the uio_pdrv_genirq, it adds the uio_pdrv_genirq > >> platform device with the DFL device's resources, and let the generic UIO > >> platform device driver provide support to userspace access to kernel > >> interrupts and memory locations. > >> > >> The driver matches DFL devices in a different way. It has no device id > >> table, instead it matches any DFL device which could not be handled by > >> other DFL drivers. > > Looks like we want to build UIO driver as the default/generic driver for DFL, > > it seems fine but my concern is that UIO has its own limitation, if some day, > > dfl device is extended, but UIO has limitation, then we may need to select > > another one as the default driver.. or we can just match them using > > id_table as we know UIO meets the requirement for those DFL devices? > > When we have multiple defaults, could this be handled in the configury ? Do you mean select it using configuration options? But if people have already created the software stack on the old one, then it's a valid requirement that we need both old and new defaults working at the same time... it's hard to ask everybody to switch to the new one. Hao > > Tom >
