MIPS: bootm: prepare a flattened device tree for the kernel

Add the initial code to prepare a flattened device tree for
the kernel like relocating the FDT blob and fixing up the
/chosen and /memory nodes.

The final hand over to the kernel is not yet implemented. After
the community agreed on the MIPS boot interface for device trees,
the corresponding code will be added.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>

arch/mips/Kconfig

@@ -136,6 +136,17 @@ config MIPS_BOOT_ENV_LEGACY
 	  address and size will be prepared as zero-terminated key/value list.
 	  The address of the enviroment is stored in register $a2.
 
+config MIPS_BOOT_FDT
+	bool "Hand over a flattened device tree to Linux kernel (INCOMPLETE)"
+	default n
+	help
+	  Enable this option if you want U-Boot to hand over a flattened
+	  device tree to the kernel.
+
+	  Note: the final hand over to the kernel is not yet implemented. After
+	        the community agreed on the MIPS boot interface for device trees,
+	        the corresponding code will be added.
+
 endmenu
 
 config SUPPORTS_BIG_ENDIAN

arch/mips/lib/bootm.c

@@ -7,6 +7,7 @@
 
 #include <common.h>
 #include <image.h>
+#include <fdt_support.h>
 #include <asm/addrspace.h>
 
 DECLARE_GLOBAL_DATA_PTR;
@@ -72,9 +73,39 @@ static int boot_setup_linux(bootm_headers_t *images)
 	if (ret)
 		return ret;
 
+#if defined(CONFIG_MIPS_BOOT_FDT) && defined(CONFIG_OF_LIBFDT)
+	if (images->ft_len) {
+		boot_fdt_add_mem_rsv_regions(&images->lmb, images->ft_addr);
+
+		ret = boot_relocate_fdt(&images->lmb, &images->ft_addr,
+			&images->ft_len);
+		if (ret)
+			return ret;
+	}
+#endif
+
 	return 0;
 }
 
+static void boot_setup_fdt(bootm_headers_t *images)
+{
+#if defined(CONFIG_MIPS_BOOT_FDT) && defined(CONFIG_OF_LIBFDT)
+	u64 mem_start = 0;
+	u64 mem_size = gd->ram_size;
+
+	debug("## setup FDT\n");
+
+	fdt_chosen(images->ft_addr, 1);
+	fdt_fixup_memory_banks(images->ft_addr, &mem_start, &mem_size, 1);
+	fdt_fixup_ethernet(images->ft_addr);
+	fdt_initrd(images->ft_addr, images->initrd_start, images->initrd_end, 1);
+
+#if defined(CONFIG_OF_BOARD_SETUP)
+	ft_board_setup(images->ft_addr, gd->bd);
+#endif
+#endif
+}
+
 static void linux_cmdline_init(void)
 {
 	linux_argc = 1;
@@ -168,7 +199,7 @@ static void linux_cmdline_append(bootm_headers_t *images)
 
 static void boot_cmdline_linux(bootm_headers_t *images)
 {
-	if (mips_boot_cmdline_legacy) {
+	if (mips_boot_cmdline_legacy && !images->ft_len) {
 		linux_cmdline_legacy(images);
 
 		if (!mips_boot_env_legacy)
@@ -259,8 +290,11 @@ static void linux_env_legacy(bootm_headers_t *images)
 
 static void boot_prep_linux(bootm_headers_t *images)
 {
-	if (mips_boot_env_legacy)
+	if (mips_boot_env_legacy && !images->ft_len)
 		linux_env_legacy(images);
+
+	if (images->ft_len)
+		boot_setup_fdt(images);
 }
 
 static void boot_jump_linux(bootm_headers_t *images)