On 10/09/15 10:54, Marc Zyngier wrote: > Hi Julian, Hi Marc, > On 09/09/15 20:23, Julien Grall wrote: >> Hi, >> >> I've been trying the latest linus/master (a794b4f), which include this >> patch, as baremetal kernel on X-gene. This is failing on early boot >> without much log. >> >> After bisecting the tree, I found the error coming from this patch. >> While this patch is valid, it made me remembered that X-Gene (at least >> the first version) as an odd GICv2. >> >> The GICC is divided in 2 area of 4K, each one aligned at a 64KB address. >> This means that, the address of GICC_DIR won't be 0x1000 but 0x10000. > > Not really. I already mentioned that one a while ago: > > http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/332249.html Sorry I haven't seen this thread on the ML. > The first page of GIC is aliased over the first 64kB, and the second > page aliased over the second 64kB. So you get a consistent mapping if > you use (base + 0xF000) to address GICC. Also, the DT that's in > mainline is showing a 4kB CPU interface, which doesn't enable > EOImode==1. > You must be using a firmware that's newer than mine, since > I'm perfectly able to boot my Mustang with these patches. My U-boot firmware is: U-Boot 2013.04-mustang_sw_1.15.12 (May 20 2015 - 10:03:33) The interrupt controller node looks like: interrupt-controller@78090000 { reg = <0x0 0x78090000 0x0 0x10000 0x0 0x780a0000 0x0 0x20000 0x0 0x780c0000 0x0 0x10000 0x0 0x780e0000 0x0 0x20000>; interrupts = <0x1 0x9 0xf04>; compatible = "arm,cortex-a15-gic"; #interrupt-cells = <0x3>; phandle = <0x1>; interrupt-controller; linux,phandle = <0x1>; }; Note that we have a recent firmware which correct the GICD region to use the non-secure one rather than the secure. See [1] for more details. > >> We had the same issue on Xen when we did the first port of X-gene [1]. >> Although, we choose to add a quirk in Xen for this platform in order to >> map contiguously in the virtual memory the 2 part of GICC. >> >> Note that, back then, Ian suggested to extend the bindings to support a >> such platform [2]. AFAICT, there was no follow-up on it. > > The main problem here is not to update the binding, but the fact that > you *cannot* update the DT on x-gene (the firmware will replace your > GIC node with what it thinks it is), and the APM guys can't be bothered > to fix their stuff. > > In the meantime, can you give the following patch a shot? My Mustang is > wired to a 4kB CPU interface, so I'll need your help to test it. I applied the two patches on top of linus/master and I'm able to boot correctly on X-gene. Thank you! Regards, [1] http://lists.xen.org/archives/html/xen-devel/2015-04/msg02816.html -- Julien Grall -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
