SPL: Port SPL framework to powerpc

This patch enables the SPL framework to be used on powerpc platforms
and not only ARM.

timer_init() does not exist on PPC systems. The timer (decrementer) is
initialized and enabled in interrupt_init() here. And currently
interrupt_init() is called after relocation to SDRAM. Since the only
powerpc SPL implementation (a3m071) doesn't need a timer, let's remove
this timer_init() call for PPC systems.

Signed-off-by: Stefan Roese <sr@denx.de>

arch/powerpc/lib/Makefile

@@ -79,6 +79,10 @@ endif
 
 endif # not minimal
 
+ifdef CONFIG_SPL_BUILD
+COBJS-$(CONFIG_SPL_FRAMEWORK) += spl.o
+endif
+
 COBJS	+= $(sort $(COBJS-y))
 
 SRCS	:= $(GLSOBJS:.o=.S) $(GLCOBJS:.o=.c) \

arch/powerpc/lib/spl.c

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2012 Stefan Roese <sr@denx.de>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+#include <common.h>
+#include <config.h>
+#include <spl.h>
+#include <image.h>
+#include <linux/compiler.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/*
+ * This function jumps to an image with argument. Normally an FDT or ATAGS
+ * image.
+ * arg: Pointer to paramter image in RAM
+ */
+#ifdef CONFIG_SPL_OS_BOOT
+void __noreturn jump_to_image_linux(void *arg)
+{
+	debug("Entering kernel arg pointer: 0x%p\n", arg);
+	typedef void (*image_entry_arg_t)(void *, ulong r4, ulong r5, ulong r6,
+					  ulong r7, ulong r8, ulong r9)
+		__attribute__ ((noreturn));
+	image_entry_arg_t image_entry =
+		(image_entry_arg_t)spl_image.entry_point;
+
+	image_entry(arg, 0, 0, EPAPR_MAGIC, CONFIG_SYS_BOOTMAPSZ, 0, 0);
+}
+#endif /* CONFIG_SPL_OS_BOOT */

common/spl/spl.c

@@ -74,6 +74,16 @@ __weak int spl_start_uboot(void)
 }
 #endif
 
+/*
+ * Weak default function for board specific cleanup/preparation before
+ * Linux boot. Some boards/platforms might not need it, so just provide
+ * an empty stub here.
+ */
+__weak void spl_board_prepare_for_linux(void)
+{
+	/* Nothing to do! */
+}
+
 void spl_parse_image_header(const struct image_header *header)
 {
 	u32 header_size = sizeof(struct image_header);
@@ -155,7 +165,13 @@ void board_init_r(gd_t *dummy1, ulong dummy2)
 			CONFIG_SYS_SPL_MALLOC_SIZE);
 #endif
 
+#ifndef CONFIG_PPC
+	/*
+	 * timer_init() does not exist on PPC systems. The timer is initialized
+	 * and enabled (decrementer) in interrupt_init() here.
+	 */
 	timer_init();
+#endif
 
 #ifdef CONFIG_SPL_BOARD_INIT
 	spl_board_init();