Nicolas Pitre wrote at Friday, October 14, 2011 2:45 PM: > On Fri, 14 Oct 2011, Stephen Warren wrote: ... > > I did originally briefly look into getting U-Boot to boot a zImage, but > > that looked like a far more invasive patch. There were rumours of some > > chip's custom U-Boot already having such support, but I couldn't find > > it, nor any evidence of such support in mainline U-Boot. > > FRom my clone of the u-Boot repo: > > $ git grep -l zImage > README > arch/sh/lib/zimageboot.c > arch/x86/lib/zimage.c > ... > > Even the name of some of those files clearly hints zImage support. > > In any case, loading zImage should be even simpler than loading uImage. > It is the same as loading uImage except that you just have to skip the > checking and relocating steps. Just by way of background in case anyone is wondering why I wrote the patch I did: Those files both implement custom commands "zimageboot" and "zboot". I was looking for integration with the existing "bootm" command. The advantage of re-using "bootm" for this is that it already supports all the stuff like setting up kernel command-lines, initrds, knowing how to pass the FDT to the kernel, and whatever other OS-specific setup might be required. The disadvantage of adding zImage support to bootm is that I'd have to teach a bunch of U-Boot image handling code about a new image format; it already knows about "legacy uImage", "FIT" images, and I'd have to add a third "zImage" format. Doing so would at least require adding a lot of "case IMAGE_FORMAT_ZIMAGE" everywhere, but it'd probably be best to add some kind of vtable for image formats to move all the image-format knowledge into format-specific files, leaving the users of the images with much smaller code. I didn't feel like making such a large change. Hence, I chose to make a small change to the existing uImage support. Now admittedly I did say I didn't find any traces of zImage support, which isn't what I'm saying here; I guess I forgot about the stuff I did find soon after I chose the path of modifying the uImage formats. -- nvpublic -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
