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>

arch/arm/lib/Makefile

@@ -35,6 +35,7 @@ endif
 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

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;
+}

arch/powerpc/lib/Makefile

@@ -40,6 +40,7 @@ obj-y	+= extable.o
 obj-y	+= interrupts.o
 obj-$(CONFIG_CMD_KGDB) += kgdb.o
 obj-$(CONFIG_CMD_IDE) += ide.o
+obj-y	+= stack.o
 obj-y	+= time.o
 
 # Don't include the MPC5xxx special memcpy into the

arch/powerpc/lib/stack.c

@@ -0,0 +1,31 @@
+/*
+ * 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)
+{
+	ulong *s;
+
+	/* setup stack pointer for exceptions */
+	gd->irq_sp = gd->start_addr_sp;
+
+	/* Clear initial stack frame */
+	s = (ulong *)gd->start_addr_sp;
+	*s = 0; /* Terminate back chain */
+	*++s = 0; /* NULL return address */
+
+	return 0;
+}

common/board_f.c

@@ -573,48 +573,22 @@ static int reserve_fdt(void)
 	return 0;
 }
 
+int arch_reserve_stacks(void)
+{
+	return 0;
+}
+
 static int reserve_stacks(void)
 {
-#ifdef CONFIG_SPL_BUILD
-# ifdef CONFIG_ARM
-	gd->start_addr_sp -= 128;	/* leave 32 words for abort-stack */
-	gd->irq_sp = gd->start_addr_sp;
-# endif
-#else
-# ifdef CONFIG_PPC
-	ulong *s;
-# endif
-
-	/* setup stack pointer for exceptions */
+	/* make stack pointer 16-byte aligned */
 	gd->start_addr_sp -= 16;
 	gd->start_addr_sp &= ~0xf;
-	gd->irq_sp = gd->start_addr_sp;
 
 	/*
-	 * Handle architecture-specific things here
-	 * TODO(sjg@chromium.org): Perhaps create arch_reserve_stack()
-	 * to handle this and put in arch/xxx/lib/stack.c
+	 * let the architecture specific code tailor gd->start_addr_sp and
+	 * gd->irq_sp
 	 */
-# if defined(CONFIG_ARM) && !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;
-# elif defined(CONFIG_PPC)
-	/* Clear initial stack frame */
-	s = (ulong *) gd->start_addr_sp;
-	*s = 0; /* Terminate back chain */
-	*++s = 0; /* NULL return address */
-# endif /* Architecture specific code */
-
-	return 0;
-#endif
+	return arch_reserve_stacks();
 }
 
 static int display_new_sp(void)

include/common.h

@@ -252,6 +252,24 @@ static inline int print_cpuinfo(void)
 int update_flash_size(int flash_size);
 int arch_early_init_r(void);
 
+/**
+ * Reserve all necessary stacks
+ *
+ * This is used in generic board init sequence in common/board_f.c. Each
+ * architecture could provide this function to tailor the required stacks.
+ *
+ * On entry gd->start_addr_sp is pointing to the suggested top of the stack.
+ * The callee ensures gd->start_add_sp is 16-byte aligned, so architectures
+ * require only this can leave it untouched.
+ *
+ * On exit gd->start_addr_sp and gd->irq_sp should be set to the respective
+ * positions of the stack. The stack pointer(s) will be set to this later.
+ * gd->irq_sp is only required, if the architecture needs it.
+ *
+ * @return 0 if no error
+ */
+__weak int arch_reserve_stacks(void);
+
 /**
  * Show the DRAM size in a board-specific way
  *