Current C-SKY ASID mechanism is from mips and it doesn't work well
with multi-cores. ASID per core mechanism is not suitable for C-SKY
SMP tlb maintain operations, eg: tlbi.vas need share the same asid
in all processors and it'll invalid the tlb entry in all cores with
the same asid.

This patch is prepare for new ASID mechanism.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Arnd Bergmann <arnd@arndb.de>

Use task_stack_page instead of p->stack to get stack. Follow the coding
convention style. Also for init_stack, the same with other archs.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>

This is a simple implement of CPU-hotplug for power saving. CPU use
wait instruction to enter power saving mode and waiting for IPI wakeup
signal.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>

of_find_node_by_type() acquires a reference to the node returned by it
and that reference needs to be dropped by its caller. setup_smp()
doesn't do that, so fix it by converting to for_each_of_cpu_node().

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Guo Ren <guoren@kernel.org>

This patch adds boot, ipi, hotplug codes for SMP.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>