On Mon, Jan 05, 2015 at 10:37:47AM +0000, Geert Uytterhoeven wrote: > A while ago, I wondered: > > | It's my understanding GIC_CPU_MASK_SIMPLE should reflect the actual number > | of CPU cores the interrupt is wired too. Is that correct? > | > | [Fixes for incorrect masks on shmobile] > | > | Should it be "GIC_CPU_MASK_SIMPLE(8)" on big.LITTLE configurations > | with four Cortex-A15 cores and four Cortex-A7 cores? > | Or should the interrupts be delivered to the four Cortex-A15 cores > | only by default? > | > | Note that incorrect masks for GIC PPI interrupts are not limited to > | shmobile. Presumably the interrupt specifiers got copied around a lot, > | cfr. the proliferation of "GIC_CPU_MASK_SIMPLE(4)" (and the older > | hardcoded "0xf0x" variant) in various dtsi files, not always limited to > | quad-core CPUs. > > In the mean time, arch/arm64/boot/dts/arm/juno.dts got added, which has 2 A57 > cores and 4 A53 cores, and uses GIC_CPU_MASK_SIMPLE(6), so it seems like > my two RFC patches to use GIC_CPU_MASK_SIMPLE(8) for 4 A15 cores and 4 > A7 cores are actually correct? > > Thanks for your comments! > > References: > 1. Original RFC series: > [PATCH/RFC 0/4] ARM: shmobile: Correct masks for GIC PPI interrupts > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-November/306743.html > 2. RFC patches: > a. [PATCH/RFC 3/4] ARM: shmobile: r8a7790: Correct mask for GIC > PPI interrupts > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-November/306741.html > b. [PATCH/RFC 4/4] ARM: shmobile: r8a73a4: Correct mask for GIC > PPI interrupts > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-November/306740.html > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds > Hi Geert, Sorry for delay in responding, I'm just coming back online. Your patches are correct, the mask should reflect the number of CPUs present *and* they way they are wired in the GIC. AFAIK, HW designers have been sane so far and wired the CPUs in sequence in the GIC, but I lack inside knowledge of the shmobile design. Best regards, Liviu -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯ -- 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
