On 29-6-2016 20:51, Arend Van Spriel wrote: > On 29-6-2016 20:01, Hans de Goede wrote: >> Hi, >> >> On 29-06-16 19:00, Kalle Valo wrote: >>> Hans de Goede <hdegoede@xxxxxxxxxx> writes: >>> >>>> Hi, >>>> >>>> On 29-06-16 16:42, Jonas Gorski wrote: >>>>> Hi, >>>>> >>>>> On 29 June 2016 at 16:04, Hans de Goede <hdegoede@xxxxxxxxxx> wrote: >>>>>> Add a brcm,nvram_file_name dt property to allow overruling the default >>>>>> nvram filename for sdio devices. The idea is that we can specify a >>>>>> board specific nvram file, e.g. brcmfmac43362-ap6210.txt for boards >>>>>> with an ap6210 wifi sdio module and ship this in linux-firmware, so >>>>>> that wifi will work out of the box, without requiring users to find >>>>>> and then manually install the right nvram file for their board. >>>>> >>>>> Directly defining a filename doesn't seem like a good OS-agnostic >>>>> approach. Maybe an alternative would be to add a model-property to the >>>>> nodes (this is allowed) and make brcmfmac to request >>>>> "FWFILENAME-<model>" as firmware if set? That would leave it to the OS >>>>> on how the filename is set. >>>> >>>> It only defines the base-filename, not the entire path, how / where >>>> this file is searched for / loaded-from is then left up to the os >>> >>> It's still a bad idea. The filename, including the path, should be >>> created in the driver. Can't you provide chipname (or similar) via >>> device tree and then the driver can choose what image to use? >> >> No, the driver already does that, but this is not ... >> >>> Can you tell more about the naming the firmware image, how does it work >>> exactly? >> >> About firmware, this is about the nvram file which is board specific, >> rather then chip specific. > > The nvram filename is determined pretty much the same as the firmware > filename, but indeed the nvram data is board specific. This is main > reason why we do not submit nvram files to linux-firmware, because we > simply do not have those files. > >> Typical wifi devices will have some sort of non volatile storage >> on board to not only store the ethernet(mac) address, but also >> to contain e.g. info about the antenna gain so that the firmware >> and/or the driver can take the antenna gain into account and ensure >> that they never exceed the maximum allowed broadcast strength. >> >> However on some embedded devices there is no non-volatile storage >> for the wifi (for cost reasons) and instead this configuration info >> (which is board / pcb specific) is loaded in the form of a >> file which contains the contents which would normally be in the >> non-volatile storage. >> >> Since we are dealing with a per-board config-file here, which is >> loaded from the os filesystem we really need to specify a basename >> here as the list of possible boards is endless, so we cannot >> have a lookup table in the driver. As a note: For BT Marcel was playing with the idea of having a lookup table on the file system which would be loaded by the driver. > As Jonas mentioned the general principle of device tree is to be > agnostic with regards to OS and/or driver as you undoubtedly know. His > proposal seems like a usable solution for your problem while complying > to the device tree principle. So instead of overriding the default > brcmfmac should modify it when dt specifies the "module" property, ie: > > no "module" in DT: nvram filename = brcm/brcmfmac43362-sdio.txt > "module=ap6210" in DT: nvram filename = brcm/brcmfmac43362-ap6210.txt > > By the way, the example in the bindings file does not seem to specify a > basename, but path+basename+fileext. Hans, Another btw: Kalle has taken over maintainer job from John. Regards, Arend -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
