Add four main boot methods to developer build

include/configs/chromeos/tegra2/developer.h

 /*
  * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef __configs_chromeos_tegra2_developer_h__
 #define __configs_chromeos_tegra2_developer_h__
 
 #include <configs/chromeos/developer.h>
 #include <configs/chromeos/tegra2/common.h>
 
 #include <configs/chromeos/tegra2/parts/usb.h>
 
-#define CONFIG_EXTRA_ENV_SETTINGS_ARCH CONFIG_EXTRA_ENV_SETTINGS_ARCH_COMMON
-
 /*
  * We expect all Tegra2 machines to have SPI flash as defined by the
  * firmware_layout.h config file. The environment will go there.
  */
 #define CONFIG_ENV_IS_IN_SPI_FLASH 1
 
 #define CONFIG_ENV_SECT_SIZE    CONFIG_LENGTH_ENV
 #define CONFIG_ENV_OFFSET       CONFIG_OFFSET_ENV
 
 #define CONFIG_SYS_MEMTEST_START       0x0000
 #define CONFIG_SYS_MEMTEST_END         0x1000
 
+
+/*
+ * Developer-friendly booting options:
+ *
+ * dhcp_boot: get IP address from DHCP, then boot with NFS root.
+ * keynfs_boot: get kernel from USB stick ext2 partition 1, then NFS root.
+ * usb_boot: boot from a USB image made with image_to_usb.sh.
+ * mmc_boot: boot from an image installed in eMMC,
+ *
+ * regen_all sets up the bootargs, so must be run after any change to
+ * environment variables.
+ *
+ * The network adapter must be available before starting an dhcp_boot. You
+ * may need to use 'usb start' first if you are using a USB ethernet adapter.
+ * The same applies for usb_boot.
+ */
+
+#define CONFIG_EXTRA_ENV_SETTINGS_ARCH \
+        "console=ttyS0,115200n8\0"\
+        "cros_bootfile=/boot/vmlinux.uimg\0"\
+        "user=user\0"\
+        "board=arm\0"\
+        "serial#=1\0"\
+        "tftppath=/tftpboot/uImage\0"\
+        "tftpserverip=10.0.0.1\0"\
+        "nfsserverip=10.0.0.1\0"\
+        "mmcdev=0\0"\
+        "regen_all="\
+                "setenv common_bootargs console=${console} "\
+                "${platform_extras} noinitrd; "\
+                "setenv bootargs ${common_bootargs} ${extra_bootargs} "\
+                "${bootdev_bootargs}\0"\
+        "regen_net_bootargs=setenv bootdev_bootargs "\
+                        "dev=/dev/nfs4 rw nfsroot=${nfsserverip}:${rootpath} "\
+                        "ip=dhcp; "\
+                "run regen_all\0"\
+        \
+        "dhcp_setup=setenv tftppath "\
+                        "/tftpboot/uImage-${user}-${board}-${serial#}; "\
+                "setenv rootpath " CONFIG_ROOTPATH "; "\
+                "setenv autoload n; "\
+                "run regen_net_bootargs\0"\
+        "dhcp_boot=run dhcp_setup; "\
+                "bootp; tftpboot ${loadaddr} ${tftpserverip}:${tftppath}; "\
+                "bootm ${loadaddr}\0"\
+        \
+        "keynfs_setup="\
+                "setenv rootpath " CONFIG_ROOTPATH "; "\
+                "run regen_net_bootargs\0" \
+        "keynfs_boot=run keynfs_setup; "\
+                "ext2load usb 0:1 ${loadaddr} uImage; "\
+                "bootm ${loadaddr}\0" \
+        \
+        "usb_setup=setenv bootdev_bootargs "\
+                "root=/dev/sda3; "\
+                "run regen_all\0"\
+        "usb_boot=run usb_setup; "\
+                "ext2load usb 0:3 ${loadaddr} ${cros_bootfile}; "\
+                "bootm ${loadaddr}\0" \
+        \
+        "mmc_setup=mmc init ${mmcdev}; setenv bootdev_bootargs "\
+                "root=/dev/mmcblk0p5; "\
+                "run regen_all\0"\
+        "mmc_boot=run mmc_setup; "\
+                "ext2load mmc ${mmcdev}:3 ${loadaddr} ${cros_bootfile}; "\
+                "bootm ${loadaddr}\0"
+
+/*
+ * Our developer-friendly boot process tries a number of things in sequence
+ * until it finds a kernel. Network booting is tried first if we have Ethernet.
+ */
+#define CONFIG_BOOTCOMMAND \
+  "usb start; "\
+  "if test ${ethact} != \"\"; then "\
+    "run dhcp_boot ; " \
+  "fi ; " \
+  "run keynfs_boot ; " \
+  "run usb_boot ; " \
+  "run mmc_boot"
+
 #endif //__configs_chromeos_tegra2_developer_h__