xtensa: add SMP support

This is largely based on SMP code from the xtensa-2.6.29-smp tree by
Piet Delaney, Marc Gauthier, Joe Taylor, Christian Zankel (and possibly
other Tensilica folks).

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>

1 files changed, 36 insertions, 1 deletions

diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index fb140ae3860d..4b09c60b6b30 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -9,7 +9,6 @@ config XTENSA
         select GENERIC_CLOCKEVENTS
         select VIRT_TO_BUS
         select GENERIC_IRQ_SHOW
-        select GENERIC_CPU_DEVICES
         select GENERIC_SCHED_CLOCK
         select MODULES_USE_ELF_RELA
         select GENERIC_PCI_IOMAP
@@ -65,6 +64,9 @@ config MMU
 config VARIANT_IRQ_SWITCH
         def_bool n
 
+config MAY_HAVE_SMP
+        def_bool n
+
 menu "Processor type and features"
 
 choice
@@ -105,6 +107,39 @@ config XTENSA_UNALIGNED_USER
 
 source "kernel/Kconfig.preempt"
 
+config HAVE_SMP
+        bool "System Supports SMP (MX)"
+        depends on MAY_HAVE_SMP
+        select XTENSA_MX
+        help
+          This option is use to indicate that the system-on-a-chip (SOC)
+          supports Multiprocessing. Multiprocessor support implemented above
+          the CPU core definition and currently needs to be selected manually.
+
+          Multiprocessor support in implemented with external cache and
+          interrupt controlers.
+
+          The MX interrupt distributer adds Interprocessor Interrupts
+          and causes the IRQ numbers to be increased by 4 for devices
+          like the open cores ethernet driver and the serial interface.
+
+          You still have to select "Enable SMP" to enable SMP on this SOC.
+
+config SMP
+        bool "Enable Symmetric multi-processing support"
+        depends on HAVE_SMP
+        select USE_GENERIC_SMP_HELPERS
+        select GENERIC_SMP_IDLE_THREAD
+        help
+          Enabled SMP Software; allows more than one CPU/CORE
+          to be activated during startup.
+
+config NR_CPUS
+        depends on SMP
+        int "Maximum number of CPUs (2-32)"
+        range 2 32
+        default "4"
+
 config MATH_EMULATION
         bool "Math emulation"
         help