This review aims at introducing ubldr (loader with U-Boot interface) for MIPS

(32 and 64-bit, LE and BE).
The changes were tested with QEMU's 'mips' target.

Most of the implementation was lifted from the ARM version, the appropriate
MIPS-specific things were implemented.

With these changes I am able to go all the way through the u-boot->ubldr->kernel
boot chain in QEMU on all combinations of bit-ness and endian-ness.

For the tests I've used FAT32 disk images (as FAT32 is supported by U-boot),
which include /boot/kernel/kernel and /boot/kernel/ubldr.bin

In U-boot I do:
fatload ide 0 <LOAD_ADDR> /boot/kernel/ubldr.bin; go <LOAD_ADDR>
where LOAD_ADDR is 80800000 for 32-bit and ffffffff80800000 for 64-bit

Then it's the usual ubldr that takes over and loads and starts a kernel.

Approved by:	adrian (mentor)
Sponsored by:	Smartcom - Bulgaria AD
Differential Revision:	https://reviews.freebsd.org/D5313

9 files changed, 540 insertions, 1 deletions

diff --git a/sys/boot/Makefile.mips b/sys/boot/Makefile.mips
index 6e69d1e..46fc574 100644
--- a/sys/boot/Makefile.mips
+++ b/sys/boot/Makefile.mips
@@ -3,3 +3,5 @@
 .if ${MK_FDT} != "no"
 SUBDIR+=		fdt
 .endif
+
+SUBDIR+=		uboot
diff --git a/sys/boot/mips/Makefile b/sys/boot/mips/Makefile
index 1fe066b..760c557 100644
--- a/sys/boot/mips/Makefile
+++ b/sys/boot/mips/Makefile
@@ -1,12 +1,14 @@
 # $FreeBSD$
 
+SUBDIR= 	uboot
+
 #
 # The BERI boot loader port works only on 64-bit MIPS; not a hard port to
 # 32-bit if someone is interested.  Build on all 64-bit MIPS platforms to
 # ensure it gets adequate build-test coverage.
 #
 .if ${MACHINE_ARCH} == "mips64"
-SUBDIR=	beri
+SUBDIR+=	beri
 .endif
 
 .include <bsd.subdir.mk>
diff --git a/sys/boot/mips/uboot/Makefile b/sys/boot/mips/uboot/Makefile
new file mode 100644
index 0000000..b350ae4
--- /dev/null
+++ b/sys/boot/mips/uboot/Makefile
@@ -0,0 +1,165 @@
+# $FreeBSD$
+
+.include <src.opts.mk>
+
+FILES=		ubldr
+
+NEWVERSWHAT=	"U-Boot loader" ${MACHINE_ARCH}
+BINDIR?=	/boot
+INSTALLFLAGS=	-b
+WARNS?=		1
+# Address at which ubldr will be loaded.
+# This varies for different boards and SOCs.
+UBLDR_LOADADDR?=	0xffffffff80800000
+
+# Architecture-specific loader code
+SRCS=		start.S conf.c vers.c
+
+.if !defined(LOADER_NO_DISK_SUPPORT)
+LOADER_DISK_SUPPORT?=	yes
+.else
+LOADER_DISK_SUPPORT=	no
+.endif
+LOADER_MSDOS_SUPPORT?=	yes
+LOADER_UFS_SUPPORT?=	yes
+LOADER_CD9660_SUPPORT?=	no
+LOADER_EXT2FS_SUPPORT?=	no
+.if ${MK_NAND} != "no"
+LOADER_NANDFS_SUPPORT?= yes
+.else
+LOADER_NANDFS_SUPPORT?= no
+.endif
+LOADER_NET_SUPPORT?=	yes
+LOADER_NFS_SUPPORT?=	yes
+LOADER_TFTP_SUPPORT?=	no
+LOADER_GZIP_SUPPORT?=	no
+LOADER_BZIP2_SUPPORT?=	no
+.if ${MK_FDT} != "no"
+LOADER_FDT_SUPPORT=	yes
+.else
+LOADER_FDT_SUPPORT=	no
+.endif
+
+.if ${LOADER_DISK_SUPPORT} == "yes"
+CFLAGS+=	-DLOADER_DISK_SUPPORT
+.endif
+.if ${LOADER_MSDOS_SUPPORT} == "yes"
+CFLAGS+=	-DLOADER_MSDOS_SUPPORT
+.endif
+.if ${LOADER_UFS_SUPPORT} == "yes"
+CFLAGS+=	-DLOADER_UFS_SUPPORT
+.endif
+.if ${LOADER_CD9660_SUPPORT} == "yes"
+CFLAGS+=	-DLOADER_CD9660_SUPPORT
+.endif
+.if ${LOADER_EXT2FS_SUPPORT} == "yes"
+CFLAGS+=	-DLOADER_EXT2FS_SUPPORT
+.endif
+.if ${LOADER_NANDFS_SUPPORT} == "yes"
+CFLAGS+=	-DLOADER_NANDFS_SUPPORT
+.endif
+.if ${LOADER_GZIP_SUPPORT} == "yes"
+CFLAGS+=	-DLOADER_GZIP_SUPPORT
+.endif
+.if ${LOADER_BZIP2_SUPPORT} == "yes"
+CFLAGS+=	-DLOADER_BZIP2_SUPPORT
+.endif
+.if ${LOADER_NET_SUPPORT} == "yes"
+CFLAGS+=	-DLOADER_NET_SUPPORT
+.endif
+.if ${LOADER_NFS_SUPPORT} == "yes"
+CFLAGS+=	-DLOADER_NFS_SUPPORT
+.endif
+.if ${LOADER_TFTP_SUPPORT} == "yes"
+CFLAGS+=	-DLOADER_TFTP_SUPPORT
+.endif
+.if ${LOADER_FDT_SUPPORT} == "yes"
+CFLAGS+=	-I${.CURDIR}/../../fdt
+CFLAGS+=	-I${.OBJDIR}/../../fdt
+CFLAGS+=	-DLOADER_FDT_SUPPORT
+LIBUBOOT_FDT=	${.OBJDIR}/../../uboot/fdt/libuboot_fdt.a
+LIBFDT=		${.OBJDIR}/../../fdt/libfdt.a
+.endif
+
+CFLAGS+=	-DNETIF_OPEN_CLOSE_ONCE
+
+.if ${MK_FORTH} != "no"
+# Enable BootForth
+BOOT_FORTH=	yes
+CFLAGS+=	-DBOOT_FORTH -I${.CURDIR}/../../ficl
+.if ${MACHINE_ARCH} == "mips64" || ${MACHINE_ARCH} == "mips64el"
+CFLAGS+=	-I${.CURDIR}/../../ficl/mips64
+.else
+CFLAGS+=	-I${.CURDIR}/../../ficl/mips
+.endif
+LIBFICL=	${.OBJDIR}/../../ficl/libficl.a
+.endif
+
+# Always add MI sources
+.PATH:		${.CURDIR}/../../common
+.include	"${.CURDIR}/../../common/Makefile.inc"
+CFLAGS+=	-I${.CURDIR}/../../common
+CFLAGS+=	-I.
+
+CLEANFILES+=	vers.c loader.help
+
+CFLAGS+=	-ffreestanding -msoft-float -g
+
+LDFLAGS=	-nostdlib -static -T ${.CURDIR}/ldscript.${MACHINE_CPUARCH}
+
+# Pull in common loader code
+.PATH:		${.CURDIR}/../../uboot/common
+.include	"${.CURDIR}/../../uboot/common/Makefile.inc"
+CFLAGS+=	-I${.CURDIR}/../../uboot/common
+
+# U-Boot standalone support library
+LIBUBOOT=	${.OBJDIR}/../../uboot/lib/libuboot.a
+CFLAGS+=	-I${.CURDIR}/../../uboot/lib
+CFLAGS+=	-I${.OBJDIR}/../../uboot/lib
+
+# where to get libstand from
+CFLAGS+=	-I${.CURDIR}/../../../../lib/libstand/
+LIBSTAND=	${.OBJDIR}/../../../../lib/libstand/libstand.a
+
+# clang doesn't understand %D as a specifier to printf
+#NO_WERROR.clang=
+#NO_WERROR=
+
+DPADD=		${LIBFICL} ${LIBUBOOT} ${LIBFDT} ${LIBUBOOT_FDT} ${LIBSTAND}
+LDADD=		${LIBFICL} ${LIBUBOOT} ${LIBFDT} ${LIBUBOOT_FDT} ${LIBSTAND}
+
+OBJS+=  ${SRCS:N*.h:R:S/$/.o/g}
+
+vers.c:	${.CURDIR}/../../common/newvers.sh ${.CURDIR}/version
+	sh ${.CURDIR}/../../common/newvers.sh ${.CURDIR}/version ${NEWVERSWHAT}
+
+loader.help: help.common help.uboot ${.CURDIR}/../../fdt/help.fdt
+	cat ${.ALLSRC} | \
+	    awk -f ${.CURDIR}/../../common/merge_help.awk > ${.TARGET}
+
+ldscript.abs:
+	echo "UBLDR_LOADADDR = ${UBLDR_LOADADDR};" >${.TARGET}
+
+ldscript.pie:
+	echo "UBLDR_LOADADDR = 0;" >${.TARGET}
+
+ubldr: ${OBJS} ldscript.abs ${.CURDIR}/ldscript.${MACHINE_CPUARCH} ${DPADD}
+	${CC} ${CFLAGS} -T ldscript.abs ${LDFLAGS} \
+	    -o ${.TARGET} ${OBJS} ${LDADD}
+	${OBJCOPY} -S -O binary ubldr ubldr.bin
+
+CLEANFILES+=	ldscript.abs ldscript.pie ubldr ubldr.pie ubldr.bin
+
+.if !defined(LOADER_ONLY)
+.PATH: ${.CURDIR}/../../forth
+.include	"${.CURDIR}/../../forth/Makefile.inc"
+
+# Install loader.rc.
+FILES+=	loader.rc
+# Put sample menu.rc on disk but don't enable it by default.
+FILES+=	menu.rc
+FILESNAME_menu.rc=	menu.rc.sample
+.endif
+
+.include <bsd.stand.mk>
+.include <bsd.prog.mk>
diff --git a/sys/boot/mips/uboot/conf.c b/sys/boot/mips/uboot/conf.c
new file mode 100644
index 0000000..30c9261
--- /dev/null
+++ b/sys/boot/mips/uboot/conf.c
@@ -0,0 +1,115 @@
+/*-
+ * Copyright (c) 2008 Semihalf, Rafal Jaworowski
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <stand.h>
+#include "bootstrap.h"
+#include "libuboot.h"
+
+#if defined(LOADER_NET_SUPPORT)
+#include "dev_net.h"
+#endif
+
+struct devsw *devsw[] = {
+#if defined(LOADER_DISK_SUPPORT) || defined(LOADER_CD9660_SUPPORT)
+	&uboot_storage,
+#endif
+#if defined(LOADER_NET_SUPPORT)
+	&netdev,
+#endif
+	NULL
+};
+
+struct fs_ops *file_system[] = {
+#if defined(LOADER_MSDOS_SUPPORT)
+	&dosfs_fsops,
+#endif
+#if defined(LOADER_UFS_SUPPORT)
+	&ufs_fsops,
+#endif
+#if defined(LOADER_CD9660_SUPPORT)
+	&cd9660_fsops,
+#endif
+#if defined(LOADER_EXT2FS_SUPPORT)
+	&ext2fs_fsops,
+#endif
+#if defined(LOADER_NANDFS_SUPPORT)
+	&nandfs_fsops,
+#endif
+#if defined(LOADER_NFS_SUPPORT)
+	&nfs_fsops,
+#endif
+#if defined(LOADER_TFTP_SUPPORT)
+	&tftp_fsops,
+#endif
+#if defined(LOADER_GZIP_SUPPORT)
+	&gzipfs_fsops,
+#endif
+#if defined(LOADER_BZIP2_SUPPORT)
+	&bzipfs_fsops,
+#endif
+	NULL
+};
+
+struct netif_driver *netif_drivers[] = {
+#if defined(LOADER_NET_SUPPORT)
+	&uboot_net,
+#endif
+	NULL,
+};
+
+struct file_format *file_formats[] = {
+	&uboot_elf,
+	NULL
+};
+
+extern struct console uboot_console;
+
+struct console *consoles[] = {
+	&uboot_console,
+	NULL
+};
+
+void
+abort(void)
+{
+ 
+	printf("error: loader abort\n");
+	while (1);
+}
+
+void
+longjmperror(void)
+{
+ 
+	printf("error: loader longjmp error\n");
+	while (1);
+}
+
+int debug = 1;
diff --git a/sys/boot/mips/uboot/help.uboot b/sys/boot/mips/uboot/help.uboot
new file mode 100644
index 0000000..c1574af
--- /dev/null
+++ b/sys/boot/mips/uboot/help.uboot
@@ -0,0 +1,27 @@
+$FreeBSD$
+
+###############################################################################
+# Tubenv DShow or import U-Boot environment variables
+
+	ubenv <import | show> [varname ...]
+
+	Display U-Boot environment variables, or import them into the
+	loader environment (which makes them available in the kernel).
+
+###############################################################################
+# Tubenv Simport DImport U-Boot env vars
+
+	ubenv import [varname ...]
+
+	If no variable names are specified, all U-Boot environment
+	variables are imported.  Each variable is prefixed with "uboot."
+	to avoid any possible conflicts with loader or kernel variables.
+
+###############################################################################
+# Tubenv Sshow DShow U-Boot env vars
+
+	ubenv show [varname ...]
+
+	If no variable names are specified, all U-Boot environment
+	variables are shown.
+
diff --git a/sys/boot/mips/uboot/ldscript.mips b/sys/boot/mips/uboot/ldscript.mips
new file mode 100644
index 0000000..5ead260
--- /dev/null
+++ b/sys/boot/mips/uboot/ldscript.mips
@@ -0,0 +1,135 @@
+/* $FreeBSD$ */
+
+OUTPUT_ARCH(mips)
+ENTRY(_start)
+SECTIONS
+{
+  /* Read-only sections, merged into text segment: */
+  /*. = UBLDR_LOADADDR + SIZEOF_HEADERS;*/
+  . = UBLDR_LOADADDR;
+  .text      :
+  {
+    start.o(.text*)
+    *(EXCLUDE_FILE (start.o) .text*)
+    /* .gnu.warning sections are handled specially by elf32.em.  */
+    *(.gnu.warning)
+    *(.gnu.linkonce.t*)
+  } =0
+  _etext = .;
+  PROVIDE (etext = .);
+  .interp     : { *(.interp) 	}
+  .hash          : { *(.hash)		}
+  .dynsym        : { *(.dynsym)		}
+  .dynstr        : { *(.dynstr)		}
+  .gnu.version   : { *(.gnu.version)	}
+  .gnu.version_d   : { *(.gnu.version_d)	}
+  .gnu.version_r   : { *(.gnu.version_r)	}
+  .rela.text     :
+    { *(.rela.text) *(.rela.gnu.linkonce.t*) }
+  .rela.data     :
+    { *(.rela.data) *(.rela.gnu.linkonce.d*) }
+  .rela.rodata   :
+    { *(.rela.rodata) *(.rela.gnu.linkonce.r*) }
+  .rela.got      : { *(.rela.got)		}
+  .rela.got1     : { *(.rela.got1)		}
+  .rela.got2     : { *(.rela.got2)		}
+  .rela.ctors    : { *(.rela.ctors)	}
+  .rela.dtors    : { *(.rela.dtors)	}
+  .rela.init     : { *(.rela.init)	}
+  .rela.fini     : { *(.rela.fini)	}
+  .rela.bss      : { *(.rela.bss)		}
+  .rela.plt      : { *(.rela.plt)		}
+  .rela.sdata    : { *(.rela.sdata)		}
+  .rela.sbss     : { *(.rela.sbss)		}
+  .rela.sdata2   : { *(.rela.sdata2)		}
+  .rela.sbss2    : { *(.rela.sbss2)		}
+  .init      : { *(.init)    } =0
+  .fini      : { *(.fini)    } =0
+  .rodata    : { *(.rodata) *(.gnu.linkonce.r*) }
+  .rodata1   : { *(.rodata1) }
+  .sdata2    : { *(.sdata2)  }
+  .sbss2     : { *(.sbss2)   }
+  /* Adjust the address for the data segment to the next page up. */
+  . = ((. + 0x1000) & ~(0x1000 - 1));
+  .data    :
+  {
+    *(.data)
+    *(.gnu.linkonce.d*)
+    CONSTRUCTORS
+  }
+  .data1   : { *(.data1) }
+  .got1           : { *(.got1) }
+  .dynamic        : { *(.dynamic) }
+  /* Put .ctors and .dtors next to the .got2 section, so that the pointers
+     get relocated with -mrelocatable. Also put in the .fixup pointers.
+     The current compiler no longer needs this, but keep it around for 2.7.2  */
+                PROVIDE (_GOT2_START_ = .);
+  .got2           :  { *(.got2) }
+                PROVIDE (__CTOR_LIST__ = .);
+  .ctors          : { *(.ctors) }
+                PROVIDE (__CTOR_END__ = .);
+                PROVIDE (__DTOR_LIST__ = .);
+  .dtors          : { *(.dtors) }
+                PROVIDE (__DTOR_END__ = .);
+                PROVIDE (_FIXUP_START_ = .);
+  .fixup          : { *(.fixup) }
+                PROVIDE (_FIXUP_END_ = .);
+                PROVIDE (_GOT2_END_ = .);
+                PROVIDE (_GOT_START_ = .);
+  .got            : { *(.got) }
+  .got.plt        : { *(.got.plt) }
+                PROVIDE (_GOT_END_ = .);
+  /* We want the small data sections together, so single-instruction offsets
+     can access them all, and initialized data all before uninitialized, so
+     we can shorten the on-disk segment size.  */
+  .sdata     : { *(.sdata) }
+  _edata  =  .;
+  PROVIDE (edata = .);
+  .sbss      :
+  {
+    PROVIDE (__sbss_start = .);
+    *(.sbss)
+    *(.scommon)
+    *(.dynsbss)
+    PROVIDE (__sbss_end = .);
+  }
+  .plt   : { *(.plt) }
+  .bss       :
+  {
+   PROVIDE (__bss_start = .);
+   *(.dynbss)
+   *(.bss)
+   *(COMMON)
+  }
+  _end = . ;
+  PROVIDE (end = .);
+  /* Stabs debugging sections.  */
+  .stab 0 : { *(.stab) }
+  .stabstr 0 : { *(.stabstr) }
+  /* DWARF debug sections.
+     Symbols in the DWARF debugging sections are relative to the beginning
+     of the section so we begin them at 0.  */
+  /* DWARF 1 */
+  .debug          0 : { *(.debug) }
+  .line           0 : { *(.line) }
+  /* GNU DWARF 1 extensions */
+  .debug_srcinfo  0 : { *(.debug_srcinfo) }
+  .debug_sfnames  0 : { *(.debug_sfnames) }
+  /* DWARF 1.1 and DWARF 2 */
+  .debug_aranges  0 : { *(.debug_aranges) }
+  .debug_pubnames 0 : { *(.debug_pubnames) }
+  /* DWARF 2 */
+  .debug_info     0 : { *(.debug_info) }
+  .debug_abbrev   0 : { *(.debug_abbrev) }
+  .debug_line     0 : { *(.debug_line) }
+  .debug_frame    0 : { *(.debug_frame) }
+  .debug_str      0 : { *(.debug_str) }
+  .debug_loc      0 : { *(.debug_loc) }
+  .debug_macinfo  0 : { *(.debug_macinfo) }
+  /* SGI/MIPS DWARF 2 extensions */
+  .debug_weaknames 0 : { *(.debug_weaknames) }
+  .debug_funcnames 0 : { *(.debug_funcnames) }
+  .debug_typenames 0 : { *(.debug_typenames) }
+  .debug_varnames  0 : { *(.debug_varnames) }
+  /* These must appear regardless of  .  */
+}
diff --git a/sys/boot/mips/uboot/loader.conf b/sys/boot/mips/uboot/loader.conf
new file mode 100644
index 0000000..4154ab7
--- /dev/null
+++ b/sys/boot/mips/uboot/loader.conf
@@ -0,0 +1,13 @@
+# This is defaults/loader.conf for ARM, containing defaults for loader(8).
+# Do not modify the contents of this file, instead put your customizations
+# into /boot/loader.conf or /boot/loader.conf.local
+# $FreeBSD$
+
+autoboot_delay=10
+bootfile="kernel"      # Kernel name (possibly absolute path)
+kernel="kernel"        # /boot sub-directory containing kernel and modules
+loader_conf_files="/boot/loader.conf /boot/loader.conf.local"
+module_path="/boot/kernel;/boot/modules;/boot/dtb"
+nextboot_conf="/boot/nextboot.conf"
+nextboot_enable="NO"
+verbose_loading="NO"
diff --git a/sys/boot/mips/uboot/start.S b/sys/boot/mips/uboot/start.S
new file mode 100644
index 0000000..2ca68b2
--- /dev/null
+++ b/sys/boot/mips/uboot/start.S
@@ -0,0 +1,71 @@
+/*-
+ * Copyright (c) 2016 Stanislav Galabov
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <machine/asm.h>
+
+	.text
+	.extern _C_LABEL(main)
+	.weak	_DYNAMIC
+
+/*
+ * Entry point to the loader that U-Boot passes control to.
+ */
+ENTRY(_start)
+	PTR_S	sp, uboot_address
+	j	main
+	nop
+END(_start)
+
+/*
+ * syscall()
+ */
+ENTRY(syscall)
+	PTR_S	ra, ret_address
+	PTR_L	t9, syscall_ptr
+	jalr	t9
+	nop
+	PTR_L	ra, ret_address
+	jr	ra
+	nop
+END(syscall)
+
+/*
+ * Data section
+ */
+	.data
+	.align	8
+	.globl	syscall_ptr
+syscall_ptr:
+	.dword	0
+
+	.globl	uboot_address
+uboot_address:
+	.dword	0
+
+ret_address:
+	.dword	0
diff --git a/sys/boot/mips/uboot/version b/sys/boot/mips/uboot/version
new file mode 100644
index 0000000..486c412
--- /dev/null
+++ b/sys/boot/mips/uboot/version
@@ -0,0 +1,9 @@
+$FreeBSD$
+
+NOTE ANY CHANGES YOU MAKE TO THE BOOTBLOCKS HERE.  The format of this
+file is important.  Make sure the current version number is on line 6.
+
+1.2:	Extended with NAND FS support.
+1.1:	Flattened Device Tree blob support.
+1.0:	Added storage support. Booting from HDD, USB, etc. is now possible.
+0.5:	Initial U-Boot/arm version (netbooting only).