SPL: Add XIP booting support

Enable support for XIP (execute in place) of U-Boot or kernel image. There is
no need to copy image from flash to ram if flash supports execute in place.

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
Reviewed-by: Alexandru Gagniuc <alex.g@adaptrum.com>

arch/arm/include/asm/spl.h

@@ -29,6 +29,7 @@ enum {
 	BOOT_DEVICE_I2C,
 	BOOT_DEVICE_BOARD,
 	BOOT_DEVICE_DFU,
+	BOOT_DEVICE_XIP,
 	BOOT_DEVICE_NONE
 };
 #endif

common/spl/Kconfig

@@ -437,6 +437,15 @@ config SPL_NOR_SUPPORT
 	  a memory-mapped device makes it very easy to access. Loading from
 	  NOR is typically achieved with just a memcpy().
 
+config SPL_XIP_SUPPORT
+	bool "Support XIP"
+	depends on SPL
+	help
+	  Enable support for execute in place of U-Boot or kernel image. There
+	  is no need to copy image from flash to ram if flash supports execute
+	  in place. Its very useful in systems having enough flash but not
+	  enough ram to load the image.
+
 config SPL_ONENAND_SUPPORT
 	bool "Support OneNAND flash"
 	help

common/spl/Makefile

@@ -12,6 +12,7 @@ ifdef CONFIG_SPL_BUILD
 obj-$(CONFIG_SPL_FRAMEWORK) += spl.o
 obj-$(CONFIG_SPL_LOAD_FIT) += spl_fit.o
 obj-$(CONFIG_SPL_NOR_SUPPORT) += spl_nor.o
+obj-$(CONFIG_SPL_XIP_SUPPORT) += spl_xip.o
 obj-$(CONFIG_SPL_YMODEM_SUPPORT) += spl_ymodem.o
 ifndef CONFIG_SPL_UBI
 obj-$(CONFIG_SPL_NAND_SUPPORT) += spl_nand.o

common/spl/spl_xip.c

@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2017 Vikas Manocha <vikas.manocha@st.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <spl.h>
+
+static int spl_xip(struct spl_image_info *spl_image,
+		   struct spl_boot_device *bootdev)
+{
+#ifdef CONFIG_SPL_OS_BOOT
+	if (!spl_start_uboot()) {
+		spl_image->arg = (void *)CONFIG_SYS_FDT_BASE;
+		spl_image->name = "Linux";
+		spl_image->os = IH_OS_LINUX;
+		spl_image->load_addr = CONFIG_SYS_LOAD_ADDR;
+		spl_image->entry_point = CONFIG_SYS_LOAD_ADDR;
+		debug("spl: payload xipImage, load addr: 0x%lx\n",
+		      spl_image->load_addr);
+		return 0;
+	}
+#endif
+	return(spl_parse_image_header(spl_image, (const struct image_header *)
+	       CONFIG_SYS_UBOOT_BASE));
+}
+SPL_LOAD_IMAGE_METHOD("XIP", 0, BOOT_DEVICE_XIP, spl_xip);