ppc4xx: Add SPL support

This patch adds SPL booting support (NOR flash) for the
PPC4xx platforms.

This SPL booting (Falcon mode) will be used by the upcoming
lcd4_lwmon5 board port (lwmon5 variant).

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

arch/powerpc/cpu/ppc4xx/Makefile

@@ -68,6 +68,10 @@ COBJS	+= miiphy.o
 COBJS	+= uic.o
 endif
 
+ifdef CONFIG_SPL_BUILD
+COBJS-y += spl_boot.o
+endif
+
 SRCS	:= $(START:.o=.S) $(SOBJS:.o=.S) $(COBJS:.o=.c)
 OBJS	:= $(addprefix $(obj),$(SOBJS) $(COBJS) $(COBJS-y))
 START	:= $(addprefix $(obj),$(START))

arch/powerpc/cpu/ppc4xx/spl_boot.c

@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2013 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 <spl.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/*
+ * Return selected boot device. On PPC4xx its only NOR flash right now.
+ */
+u32 spl_boot_device(void)
+{
+	return BOOT_DEVICE_NOR;
+}
+
+/*
+ * SPL version of board_init_f()
+ */
+void board_init_f(ulong bootflag)
+{
+	/*
+	 * First we need to initialize the SDRAM, so that the real
+	 * U-Boot or the OS (Linux) can be loaded
+	 */
+	initdram(0);
+
+	/* Clear bss */
+	memset(__bss_start, '\0', __bss_end - __bss_start);
+
+	/*
+	 * Init global_data pointer. Has to be done before calling
+	 * get_clocks(), as it stores some clock values into gd needed
+	 * later on in the serial driver.
+	 */
+	/* Pointer is writable since we allocated a register for it */
+	gd = (gd_t *)(CONFIG_SYS_INIT_RAM_ADDR + CONFIG_SYS_GBL_DATA_OFFSET);
+	/* Clear initial global data */
+	memset((void *)gd, 0, sizeof(gd_t));
+
+	/*
+	 * get_clocks() needs to be called so that the serial driver
+	 * works correctly
+	 */
+	get_clocks();
+
+	/*
+	 * Do rudimental console / serial setup
+	 */
+	preloader_console_init();
+
+	/*
+	 * Call board_init_r() (SPL framework version) to load and boot
+	 * real U-Boot or OS
+	 */
+	board_init_r(NULL, 0);
+	/* Does not return!!! */
+}

arch/powerpc/cpu/ppc4xx/start.S

@@ -232,7 +232,7 @@
  *
  * Use r12 to access the GOT
  */
-#if !defined(CONFIG_NAND_SPL)
+#if !defined(CONFIG_NAND_SPL) && !defined(CONFIG_SPL_BUILD)
 	START_GOT
 	GOT_ENTRY(_GOT2_TABLE_)
 	GOT_ENTRY(_FIXUP_TABLE_)
@@ -248,7 +248,8 @@
 	END_GOT
 #endif /* CONFIG_NAND_SPL */
 
-#if defined(CONFIG_NAND_U_BOOT) && !defined(CONFIG_NAND_SPL)
+#if defined(CONFIG_NAND_U_BOOT) && !defined(CONFIG_NAND_SPL) && \
+	!defined(CONFIG_SPL_BUILD)
 	/*
 	 * NAND U-Boot image is started from offset 0
 	 */
@@ -270,6 +271,18 @@
 	bl	_start_440
 #endif
 
+#if defined(CONFIG_SPL) && !defined(CONFIG_SPL_BUILD)
+	/*
+	 * This is the entry of the real U-Boot from a board port
+	 * that supports SPL booting on the PPC4xx. We only need
+	 * to call board_init_f() here. Everything else has already
+	 * been done in the SPL u-boot version.
+	 */
+	GET_GOT			/* initialize GOT access		*/
+	bl	board_init_f	/* run 1st part of board init code (in Flash)*/
+	/* NOTREACHED - board_init_f() does not return */
+#endif
+
 /*
  * 440 Startup -- on reset only the top 4k of the effective
  * address space is mapped in by an entry in the instruction
@@ -539,7 +552,7 @@ tlbnx2:	addi	r4,r4,1		/* Next TLB */
  * r3 - 1st arg to board_init(): IMMP pointer
  * r4 - 2nd arg to board_init(): boot flag
  */
-#ifndef CONFIG_NAND_SPL
+#if !defined(CONFIG_NAND_SPL) && !defined(CONFIG_SPL_BUILD)
 	.text
 	.long	0x27051956		/* U-Boot Magic Number			*/
 	.globl	version_string
@@ -612,6 +625,18 @@ _end_of_vectors:
 	.globl	_start
 _start:
 
+#if defined(CONFIG_SPL) && !defined(CONFIG_SPL_BUILD)
+	/*
+	 * This is the entry of the real U-Boot from a board port
+	 * that supports SPL booting on the PPC4xx. We only need
+	 * to call board_init_f() here. Everything else has already
+	 * been done in the SPL u-boot version.
+	 */
+	GET_GOT			/* initialize GOT access		*/
+	bl	board_init_f	/* run 1st part of board init code (in Flash)*/
+	/* NOTREACHED - board_init_f() does not return */
+#endif
+
 /*****************************************************************************/
 #if defined(CONFIG_440)
 
@@ -796,7 +821,9 @@ _start:
 #ifdef CONFIG_NAND_SPL
 	bl	nand_boot_common	/* will not return */
 #else
+#ifndef CONFIG_SPL_BUILD
 	GET_GOT
+#endif
 
 	bl	cpu_init_f	/* run low-level CPU init code	   (from Flash) */
 	bl	board_init_f
@@ -1080,7 +1107,7 @@ _start:
 	/*----------------------------------------------------------------------- */
 
 
-#ifndef CONFIG_NAND_SPL
+#if !defined(CONFIG_NAND_SPL) && !defined(CONFIG_SPL_BUILD)
 /*
  * This code finishes saving the registers to the exception frame
  * and jumps to the appropriate handler for the exception.
@@ -1262,6 +1289,7 @@ in32r:
 	lwbrx	r3,r0,r3
 	blr
 
+#if !defined(CONFIG_SPL_BUILD)
 /*
  * void relocate_code (addr_sp, gd, addr_moni)
  *
@@ -1626,6 +1654,7 @@ __440_msr_continue:
 
 	mtlr	r4			/* restore link register	*/
 	blr
+#endif /* CONFIG_SPL_BUILD */
 
 #if defined(CONFIG_440)
 /*----------------------------------------------------------------------------+

arch/powerpc/cpu/ppc4xx/u-boot-spl.lds

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2012-2013 Stefan Roese <sr@denx.de>
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+MEMORY
+{
+	sdram : ORIGIN = CONFIG_SPL_BSS_START_ADDR,
+		LENGTH = CONFIG_SPL_BSS_MAX_SIZE
+	flash : ORIGIN = CONFIG_SPL_TEXT_BASE,
+		LENGTH = CONFIG_SYS_SPL_MAX_LEN
+}
+
+OUTPUT_ARCH(powerpc)
+ENTRY(_start)
+SECTIONS
+{
+#ifdef CONFIG_440
+	.bootpg 0xfffff000 :
+	{
+		arch/powerpc/cpu/ppc4xx/start.o	(.bootpg)
+
+		/*
+		 * PPC440 board need a board specific object with the
+		 * TLB definitions. This needs to get included right after
+		 * start.o, since the first shadow TLB only covers 4k
+		 * of address space.
+		 */
+		CONFIG_BOARDDIR/init.o	(.bootpg)
+	} > flash
+#endif
+
+	.resetvec 0xFFFFFFFC :
+	{
+		KEEP(*(.resetvec))
+	} > flash
+
+	.text :
+	{
+		__start = .;
+		arch/powerpc/cpu/ppc4xx/start.o	(.text)
+		CONFIG_BOARDDIR/init.o	(.text)
+		*(.text*)
+	} > flash
+
+	. = ALIGN(4);
+	.data : { *(SORT_BY_ALIGNMENT(.data*)) } > flash
+
+	. = ALIGN(4);
+	.rodata : { *(SORT_BY_ALIGNMENT(.rodata*)) } > flash
+
+	.bss :
+	{
+		. = ALIGN(4);
+		__bss_start = .;
+		*(.bss*)
+		. = ALIGN(4);
+		__bss_end = .;
+	} > sdram
+}

arch/powerpc/cpu/ppc4xx/u-boot.lds

@@ -96,6 +96,7 @@ SECTIONS
   . = ALIGN(256);
   __init_end = .;
 
+#ifndef CONFIG_SPL
 #ifdef CONFIG_440
   .bootpg RESET_VECTOR_ADDRESS - 0xffc :
   {
@@ -132,6 +133,7 @@ SECTIONS
 #if (RESET_VECTOR_ADDRESS == 0xfffffffc)
   . |= 0x10;
 #endif
+#endif /* CONFIG_SPL */
 
   __bss_start = .;
   .bss (NOLOAD)       :