On Thu, Aug 28, 2014 at 10:54 AM, Rob Herring <robh@xxxxxxxxxx> wrote: > On Thu, Aug 28, 2014 at 12:19 PM, Olof Johansson <olof@xxxxxxxxx> wrote: >> On Thu, Aug 28, 2014 at 10:03 AM, Mark Rutland <mark.rutland@xxxxxxx> wrote: >>> On Thu, Aug 28, 2014 at 05:28:22PM +0100, Olof Johansson wrote: >>>> On Thu, Aug 28, 2014 at 2:48 AM, Mark Rutland <mark.rutland@xxxxxxx> wrote: >>>> > Hi, >>>> > >>>> >> > + cpus { >>>> >> > + #address-cells = <2>; >>>> >> > + #size-cells = <0>; >>>> >> >>>> >> Why size-cells=2? Can you not fit a cpuid in 32 bits? >>>> > >>>> > As of commit 72aea393a2e7 (arm64: smp: honour #address-size when parsing >>>> > CPU reg property) Linux can handle single-cell cpu node reg entries >>>> > where /cpus/#address-cells = <1>. >>>> > >>>> > I can't make any guarantees about other code (e.g. bootloaders) which >>>> > might try to do things with cpu nodes, YMMV. >>>> >>>> Ok. If address-cells is kept at 2 the unit address needs to be changed >>>> to "0,0". So one or the other has to be changed. >>> >>> I'm happy either way. >>> >>> I'm not sure the rest of the tree had "0," prefixes on all of the >>> unit-addresses for 64-bit addresses that were under 4GB, and I'm not >>> sure that existing dts consistently do that either. >>> >>> Do we want to enforce that for all 64-bit unit-addresses? >> >> Yeah, I believe that's the only valid format for a 2-address-cell unit address. > > But we don't do leading 0's anywhere else like single cell unit > addresses. Buses expressed with ranges and offsets are one example. > Also, I2C addresses have a 32-bit size in DT yet are only 8-bit and we > don't do leading zero's there. Ok, I'm happily proven wrong here, also by confirming how this is done on "real" OF. According to benh: 15:20 <benh> ojn: 0,0 is not quite right, it's supposed to be used when the two numbers are different things, like device,fn on PCI The same is true for >2^32 unit addresses, they just use the one integer instead of x,y. So, I take back all I've said on this in the last 72 hours. :) It looks like we might need to revisit some of the 32-bit DTs. Simon, drop the series you had. :) -Olof -- 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