Hi Federico, On Thu, Aug 16, 2018 at 11:21:32PM +0200, Federico Vaga wrote: > Hi, > > On Thursday, August 16, 2018 10:04:51 PM CEST Alan Tull wrote: > > On Thu, Aug 16, 2018 at 1:59 PM, Moritz Fischer <mdf@xxxxxxxxxx> wrote: > > > Hi Alan, > > > > Hi Moritz, > > > > > comments inline. While I see how this is useful, I have the > > > suspicion that from the moment this gets merged vendor kernels > > > will just default to use this ... > > > > Yeah, I have that suspicion as well. That's probably why I sat on > > this and didn't upstream it for 2 years. But on the other hand, I > > keep hearing of lots of cases of people implementing this > > independently anyway. At least if it is debugfs, it makes it clear > > that it's not intended for production use. > > I'm one of those guys who implemented this independently. We all have in one way or another ;) Most people on ARM run an out of tree patch using devicetree overlays these days I hope rather than /dev/mem and UIO ... or other vender solutions... > > @Mortiz > I do not see how this can be a bad thing (from what you wrote I guess you > prefer another interface). Which interface to use depends on the use case. > If you have this suspicion it's, I guess, because such interface it is > extremely easy to use. What happens to a kernel driver doing MMIO with devices while you reload the entire FPGA from userland? > > @Alan > DebugFS can be a first step, but I would go for a normal device in /dev at > some point. I do not see why this should not be used in production I'm not against having a userland interface to reprogram the FPGA, the Intel DFL code is a good example of a sensible one, doing so in a safe manner. Ideally we'll get around to have a more generic interface, as we get time to work on it. - Moritz
