From f454b38d6ed1dec77ae6ebcf2f17991950814468 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Wed, 18 May 2016 08:35:27 -0600
Subject: [PATCH] ARMv7-A SMP: Allow CONFIG_SMP_NCPUS=1 for testing purposes

---
 arch/arm/src/armv7-a/arm_cpuidlestack.c | 8 ++++++--
 configs/sabre-6quad/README.txt          | 4 ++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/arm/src/armv7-a/arm_cpuidlestack.c b/arch/arm/src/armv7-a/arm_cpuidlestack.c
index 09e9f0d12e..dd264d25c1 100644
--- a/arch/arm/src/armv7-a/arm_cpuidlestack.c
+++ b/arch/arm/src/armv7-a/arm_cpuidlestack.c
@@ -47,7 +47,7 @@
 #include "smp.h"
 #include "up_internal.h"
 
-#if defined(CONFIG_SMP) && CONFIG_SMP_NCPUS > 1
+#ifdef CONFIG_SMP
 
 /****************************************************************************
  * Pre-processor Definitions
@@ -61,6 +61,7 @@
  * Private Data
  ****************************************************************************/
 
+#if CONFIG_SMP_NCPUS > 1
 static FAR const uint32_t *g_cpu_stackalloc[CONFIG_SMP_NCPUS] =
 {
     0
@@ -72,6 +73,7 @@ static FAR const uint32_t *g_cpu_stackalloc[CONFIG_SMP_NCPUS] =
 #endif /* CONFIG_SMP_NCPUS > 3 */
 #endif /* CONFIG_SMP_NCPUS > 2 */
 };
+#endif
 
 /****************************************************************************
  * Public Functions
@@ -122,6 +124,7 @@ static FAR const uint32_t *g_cpu_stackalloc[CONFIG_SMP_NCPUS] =
 
 int up_cpu_idlestack(int cpu, FAR struct tcb_s *tcb, size_t stack_size)
 {
+#if CONFIG_SMP_NCPUS > 1
   uintptr_t stack_alloc;
   uintptr_t top_of_stack;
 
@@ -138,8 +141,9 @@ int up_cpu_idlestack(int cpu, FAR struct tcb_s *tcb, size_t stack_size)
   tcb->adj_stack_size  = SMP_STACK_SIZE;
   tcb->stack_alloc_ptr = (FAR uint32_t *)stack_alloc;
   tcb->adj_stack_ptr   = (FAR uint32_t *)top_of_stack;
+#endif
 
   return OK;
 }
 
-#endif /* CONFIG_SMP && CONFIG_SMP_NCPUS > 1 */
+#endif /* CONFIG_SMP */
diff --git a/configs/sabre-6quad/README.txt b/configs/sabre-6quad/README.txt
index 62739fadd0..462fbad32a 100644
--- a/configs/sabre-6quad/README.txt
+++ b/configs/sabre-6quad/README.txt
@@ -63,6 +63,10 @@ logic.
 
 At this point, I would say that the basic NSH port is complete.
 
+2016-05-18: Started looking at the SMP configuration.  Initially, I verfied
+that the NSH configuration works with CONFIG_SMP_NCPUS=1.  Not a very
+interesting case, but this does exercise a lot of the basic SMP logic.
+
 Platform Features
 =================