Xenomai

ipipe on A20

Cubietruck works with ipipe on mainline kernel 3.18.12.

download kernel source from kernel.org 3.18.12 download ipipe-core-patch for arm 3.18.12

unpack kernel

patch -p1 < ../ipipe-core-3.18.12-arm-1.patch

You need also to patch these files

--- a/arch/arm/Kconfig     2015-05-12 09:05:30.566224133 +0200
+++ b/arch/arm/Kconfig     2015-05-06 14:47:39.464380270 +0200
@@ -1018,7 +1018,7 @@ config IPIPE_ARM_KUSER_TSC
        bool
        select GENERIC_TIME_VSYSCALL
        select IPIPE_HAVE_HOSTRT if IPIPE
-       default y if ARCH_AT91 || ARM_TIMER_SP804 || ARCH_MXC || ARCH_OMAP || PLAT_PXA || PLAT_S3C24XX || ARCH_SA1100
+       default y if ARCH_AT91 || ARM_TIMER_SP804 || ARCH_MXC || ARCH_OMAP || PLAT_PXA || PLAT_S3C24XX || ARCH_SA1100 || ARCH_SUNXI
 endif

--- a/arch/arm/mach-sunxi/Kconfig  2015-04-20 21:48:02.000000000 +0200
+++ b/arch/arm/mach-sunxi/Kconfig  2015-05-06 14:47:45.554380273 +0200
@@ -33,6 +33,7 @@ config MACH_SUN7I
        select ARM_PSCI
        select HAVE_ARM_ARCH_TIMER
        select SUN5I_HSTIMER
+       select IPIPE_ARM_KUSER_TSC if IPIPE

config MACH_SUN8I
        bool "Allwinner A23 (sun8i) SoCs support"

--- a/drivers/irqchip/irq-sunxi-nmi.c      2015-04-20 21:48:02.000000000 +0200
+++ b/drivers/irqchip/irq-sunxi-nmi.c      2015-05-07 10:09:31.639805322 +0200
@@ -77,8 +77,10 @@ static int sunxi_sc_nmi_set_type(struct
        u32 ctrl_off = ct->regs.type;
        unsigned int src_type;
        unsigned int i;
+       unsigned long flags;

-       irq_gc_lock(gc);
+       /* Disable interrupt */
+       flags = irq_gc_lock(gc);

        switch (flow_type & IRQF_TRIGGER_MASK) {
        case IRQ_TYPE_EDGE_FALLING:
@@ -95,7 +97,7 @@ static int sunxi_sc_nmi_set_type(struct
                src_type = SUNXI_SRC_TYPE_LEVEL_LOW;
                break;
        default:
-               irq_gc_unlock(gc);
+               irq_gc_unlock(gc, flags);
                pr_err("%s: Cannot assign multiple trigger modes to IRQ %d.\n",
                        __func__, data->irq);
                return -EBADR;
@@ -113,7 +115,7 @@ static int sunxi_sc_nmi_set_type(struct
        src_type_reg |= src_type;
        sunxi_sc_nmi_write(gc, ctrl_off, src_type_reg);

-       irq_gc_unlock(gc);
+       irq_gc_unlock(gc, flags);

        return IRQ_SET_MASK_OK;
 }

make defconfig cubietruck
make menuconfig

enable ipipe patches

compile kernel

then you can try to boot your kernel If that works add xenomai patches to kernel source