* H. Nikolaus Schaller <hns@xxxxxxxxxxxxx> [191021 18:08]: > > > Am 21.10.2019 um 19:25 schrieb Tony Lindgren <tony@xxxxxxxxxxx>: > > > > * H. Nikolaus Schaller <hns@xxxxxxxxxxxxx> [191021 15:46]: > >>> Am 21.10.2019 um 17:07 schrieb Rob Herring <robh+dt@xxxxxxxxxx>: > >>> On Fri, Oct 18, 2019 at 1:46 PM H. Nikolaus Schaller <hns@xxxxxxxxxxxxx> wrote: > >>>> +Optional properties: > >>>> +- timer: the timer to be used by the driver. > >>> > >>> Needs a better description and vendor prefix at least. > >> > >> I am not yet sure if it is vendor specific or if all > >> SGX implementations need some timer. > >> > >>> > >>> Why is this needed rather than using the OS's timers? > >> > >> Because nobody understands the current (out of tree and > >> planned for staging) driver well enough what the timer > >> is doing. It is currently hard coded that some omap refer > >> to timer7 and others use timer11. > > > > Just configure it in the driver based on the compatible > > value to keep it out of the dts. It's best to stick to > > standard bindings. > > IMHO leads to ugly code... Since the timer is not part of > the SGX IPR module but one of the OMAP timers it is sort > of hardware connection that can be chosen a little arbitrarily. > > This is the main reason why I think adding it to a device tree > source so that a board that really requires to use a timer > for a different purpose, can reassign it. This is not possible > if we hard-code that into the driver by scanning for > compatible. In that case the driver must check board compatible > names... > > But if we gain a better understanding of its role in the driver > (does it really need a dedicated timer and for what and which > properties the timer must have) we can probably replace it. Well how about just leave out the timer from the binding for now, and just carry a patch for it until it is known if/why it's really needed? If it's needed, yeah I agree a timer property should be used. > >>>> +- img,cores: number of cores. Defaults to <1>. > >>> > >>> Not discoverable? > >> > >> Not sure if it is. This is probably available in undocumented > >> registers of the sgx. > > > > This too, and whatever non-standrd other properities > > you might have. > > Here it is a feature of the SGX IPR of the SoC, i.e. > describes that the hardware has one or two cores. Here you can have a standard dts binding by putting this into driver struct of_device_id match .data. Then when somebody figures out how to read that from the hardware, it can be just dropped. Regards, Tony
