On Fri, Jan 4, 2019 at 7:54 PM Brian Norris <briannorris@xxxxxxxxxxxx> wrote: > > Hi again, > > On Thu, Jan 03, 2019 at 04:11:58PM -0800, Brian Norris wrote: > > On Thu, Jan 03, 2019 at 04:01:45PM -0800, Bjorn Andersson wrote: > > > I share your concern about this, but I came to suggest this as the > > > driver cares about platforms but the firmware is (often?) > > > device/product-specific. > > > > > > E.g. we will serve the MTP and Pixel 3 with the qcom,sdm845-adsp-pas > > > compatible, but they are unlikely to run the same adsp firmware. This > > > allows the individual dtb to specify which firmware the driver should > > > use. > > > > I understand this, but that still doesn't mean we should be suggesting > > each DTB to clutter the top-level firmware search path, especially since > > lazy people will probably just use "modem.mdt" and similar. That means > > you no longer can ship the same rootfs that supports both QCOM and > > <other> modems, if <other> modem also uses the same lazy format. > > > > It seems like a much better practice to at least enforce a particular > > prefix to things. e.g., the driver could assume: > > > > qcom/sdm845-adsp-pas/ (or if you must, just qcom/) > > > > and your DTB only gets to add .../<your-string-here> to that path. > > > > In case it isn't clear: I think it's also severely misguided that the > > existing driver gets away with lines like > > > > request_firmware(&fw, "modem.mdt", ...); > > > > today ;) > > To add to my thoughts, since I think maybe Sibi was a little unclear of > my thoughts: > > One of my primary concerns with the existing approach is that it's > basically a complete free-for-all. We should have some minimal standards > (enforced in code) such that our DTB can never point us at something > like /lib/firmware/<other-vendor>/foo.bin (or /lib/firmware/modem.mdt; > or lots of other bad examples). This could probably be done simply by > always prefixing 'qcom/' (I don't remember -- does request_firmware() > follow '..'? e.g., 'firmware-name = "../bar/foo.bin"'.) We can write a schema to enforce some of this: firmware-name: pattern: "^\w.*" And you can have a device specific schema to enforce a subdir and/or filename(s). I tend to think we should not put part of the path in drivers. No real good reason other than we already allow that for other users of 'firmware-name'. > As a bonus: it would be very nice if we can provide a little more > structure by default, and avoid arbitrary hierarchy in the DTS. That's > where I brought up ath10k's "variant" as an example; if we can use > 'compatible' to capture most of this particular Hexagon core's > properties, then we only leave a single level of variability to the DTS. Some bindings use compatible to determine/construct the firmware name. If you want to restrict things, then that's probably how you should do it IMO. Rob
