Add pre-bootloader (pbl) image support

This allows for creating a pre-bootloader binary for
 - nand boot
 - mmc boot
 - compressed image

The pbl will be incharge of the lowlevel init if needed.
The barebox will skip it.

Import string functions from linux 3.4 (arch/arm/boot/compressed/string.c) and
implement a dummy panic.

For now on introduce dummy zbarebox* targets and c code that will contain later
the decompressor. This only implemeted on ARM.

This patch is based on Sascha Hauer <s.hauer@pengutronix.de>
Add compressed image support patch

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

1 files changed, 80 insertions, 0 deletions

diff --git a/arch/arm/cpu/start-pbl.c b/arch/arm/cpu/start-pbl.c
new file mode 100644
index 0000000000..28d6f34449
--- /dev/null
+++ b/arch/arm/cpu/start-pbl.c
@@ -0,0 +1,80 @@
+/*
+ * start-pbl.c
+ *
+ * Copyright (c) 2010-2012 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
+ * Copyright (c) 2012 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
+ *
+ * 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 version 2
+ * as published by the Free Software Foundation.
+ *
+ * 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
+ */
+
+#include <common.h>
+#include <init.h>
+#include <asm/barebox-arm.h>
+#include <asm/barebox-arm-head.h>
+#include <asm-generic/memory_layout.h>
+#include <asm/sections.h>
+
+void __naked __section(.text_head_entry) pbl_start(void)
+{
+	barebox_arm_head();
+}
+
+void barebox_pbl(uint32_t offset)
+{
+}
+
+/*
+ * Board code can jump here by either returning from board_init_lowlevel
+ * or by calling this function directly.
+ */
+void __naked __section(.text_ll_return) board_init_lowlevel_return(void)
+{
+	uint32_t r, addr, offset;
+
+	/*
+	 * Get runtime address of this function. Do not
+	 * put any code above this.
+	 */
+	__asm__ __volatile__("1: adr %0, 1b":"=r"(addr));
+
+	/* Setup the stack */
+	r = STACK_BASE + STACK_SIZE - 16;
+	__asm__ __volatile__("mov sp, %0" : : "r"(r));
+
+	/* Get offset between linked address and runtime address */
+	offset = (uint32_t)__ll_return - addr;
+
+	/* relocate to link address if necessary */
+	if (offset)
+		memcpy((void *)_text, (void *)(_text - offset),
+				__bss_start - _text);
+
+	/* clear bss */
+	memset(__bss_start, 0, __bss_stop - __bss_start);
+
+	/* flush I-cache before jumping to the copied binary */
+	__asm__ __volatile__("mcr p15, 0, %0, c7, c5, 0" : : "r" (0));
+
+	r = (unsigned int)&barebox_pbl;
+	/* call barebox_uncompress with its absolute address */
+	__asm__ __volatile__(
+		"mov r0, %1\n"
+		"mov pc, %0\n"
+		:
+		: "r"(r), "r"(offset),
+		: "r0");
+}