common/board_f: factor out reserve_stacks

Introduce arch_reserve_stacks() to tailor gd->start_addr_sp and gd->irq_sp to
the architecture needs.

Signed-off-by: Andreas Bießmann <andreas.devel@googlemail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
index d74e4b8..da8ed72 100644
--- a/arch/arm/lib/Makefile
+++ b/arch/arm/lib/Makefile
@@ -35,6 +35,7 @@
 obj-$(CONFIG_SEMIHOSTING) += semihosting.o
 
 obj-y	+= sections.o
+obj-y	+= stack.o
 ifdef CONFIG_ARM64
 obj-y	+= gic_64.o
 obj-y	+= interrupts_64.o
diff --git a/arch/arm/lib/stack.c b/arch/arm/lib/stack.c
new file mode 100644
index 0000000..cf10a53
--- /dev/null
+++ b/arch/arm/lib/stack.c
@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2015 Andreas Bießmann <andreas.devel@googlemail.com>
+ *
+ * Copyright (c) 2011 The Chromium OS Authors.
+ * (C) Copyright 2002-2006
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ * (C) Copyright 2002
+ * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
+ * Marius Groeger <mgroeger@sysgo.de>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+#include <common.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+int arch_reserve_stacks(void)
+{
+#ifdef CONFIG_SPL_BUILD
+	gd->start_addr_sp -= 128;	/* leave 32 words for abort-stack */
+	gd->irq_sp = gd->start_addr_sp;
+#else
+	/* setup stack pointer for exceptions */
+	gd->irq_sp = gd->start_addr_sp;
+
+# if !defined(CONFIG_ARM64)
+#  ifdef CONFIG_USE_IRQ
+	gd->start_addr_sp -= (CONFIG_STACKSIZE_IRQ + CONFIG_STACKSIZE_FIQ);
+	debug("Reserving %zu Bytes for IRQ stack at: %08lx\n",
+	      CONFIG_STACKSIZE_IRQ + CONFIG_STACKSIZE_FIQ, gd->start_addr_sp);
+
+	/* 8-byte alignment for ARM ABI compliance */
+	gd->start_addr_sp &= ~0x07;
+#  endif
+	/* leave 3 words for abort-stack, plus 1 for alignment */
+	gd->start_addr_sp -= 16;
+# endif
+#endif
+
+	return 0;
+}