On Tue, Sep 24, 2013 at 5:19 AM, Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx> wrote: > On Tue, Sep 24, 2013 at 08:01:52AM -0400, Jason Cooper wrote: >> On Tue, Sep 24, 2013 at 12:55:19PM +0200, Gerlando Falauto wrote: >> > So it shouldn't be such a crazy idea to create a dtbuImage.<dtb> >> > within Kbuild (as opposed to from an external wrapper for make). >> >> Yes :) The problem is that we are moving to multiplatform zImages. In >> that scenario, the uImage target isn't very helpful because it needs to >> be custom to each board. Additionally, appended-dtb was intended as a >> developer tool and isn't intended as a deployable item. It also >> defeats the purpose of multiplatform. > > And we've already taken the decision that we will not be augmenting > kbuild with any more ubooot specific stuff, especially with anything > that goes against the long term goal of having a single kernel image > which is bootable across multiple platforms. > > Having kbuild wrap the zImage + DTB up into a uImage goes directly > against this goal, because it turns the produced kernel into something > which is specific to a single target. It's much worse than what we > had before we went to DT, because with this it can only be used on a > _single_ target, whereas prior to DT we could boot a single kernel > on a variety of compatible targets. > > Moreover, the support for appending the DTB to the zImage is a stop-gap > solution for the transition to a full DT based environment - don't > expect it to be around into the long term future. Modern platforms > should be using a DT compatible boot loader, which means you don't > want to use the DTB appended to zImage method. > What is the long-term mechanism/methodology for creating a kernel that runs on a single system? So many drivers now have device-tree dependencies that it seems unlikely we'll be able to avoid using device tree. But if we don't care or don't want to support more than a single platform, what should we do (if appending DTB to the zImage will eventually go away). Will the requirement be that all future Linux bootloaders will be DT-aware? -- Tim Bird Senior Software Engineer, Sony Mobile Architecture Group Chair, CE Workgroup, Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
