On Fri, 26 Apr 2013 16:17:52 -0700, Stepan Moskovchenko <stepanm@xxxxxxxxxxxxxx> wrote: > > Hello. I am creating a DTS file for an ARM (Qualcomm MSM) target which > supports LPAE, meaning that the target is capable of addressing memory > beyond the standard 4GB boundary. To account for the fact that the > memory node can contain reg addresses that exceed 32 bits, I am setting > #address-cells and #size-cells to 2 at the top level of my tree, since > this is what the kernel will use when parsing the memory node. > > However, my internal tree contains multiple DTSI files with definitions > for some hardware blocks that are used across multiple MSM targets, > including ones that have #address-cells and #size-cells set to 1 at the > top level, I would like to re-use some of these files in the tree for my > LPAE-based target. Additionally, most MSM I/O devices are declared at > the top level of the tree, rather than on a dedicated simple-bus. > > To allow reuse of common hardware block definitions, I am considering > moving all the MSM memory-mapped I/O devices to a dedicated /soc node > (per the Power spec), declaring this node as a simple-bus with > #address-cells and #size-cells of 1, and using the ranges property to > map this bus into the top-level address space. Since MSM I/O devices are > located at addresses below 4GB, I believe it is okay to keep them on a > simple-bus with #address-cells=1. > > Does this seem like a reasonable approach? Yes. g. -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
