README - OpenGrok cross reference for /openbmc/u-boot/board/gateworks/gw_ventana/README

1 U-Boot for the Gateworks Ventana Product Family boards
3 This file contains information for the port of U-Boot to the Gateworks
7 is supported by a single bootloader build by using a common SPL and U-Boot
10 all of the various boot mediums available.
15 The i.MX6 has a BOOT ROM PPL (Primary Program Loader) which supports loading
16 an executable image from various boot devices.
19 will build the following artifacts from U-Boot source:
20  - SPL - Secondary Program Loader that the i.MX6 BOOT ROM (Primary Program
22          The DRAM controller, loads u-boot.img from the detected boot device,
25  - u-boot.img - The main U-Boot core which is u-boot.bin with a image header.
31 To build U-Boot for the Gateworks Ventana product family:
42 3. Boot source:
46 on the board model. The IMX6 BOOT ROM will choose a boot media based on eFUSE
49 Boards with NAND flash will always boot from NAND, and NAND-less boards will
50 always boot from micro-SD. However, it is possible to use the U-Boot bmode
51 command (or the technique it uses) to essentially bootstrap to another boot
54 3.1. boot from NAND
57 The i.MX6 BOOT ROM expects some structures that provide details of NAND layout
62 addition, the i.MX6 BOOT ROM Flash Configuration Block (FCB) supports two
77 (IVT) and Device Configuration Data (DCD) structures that the i.MX6 BOOT ROM
78 requires to boot.  The kobs-ng adds the Firmware Configuration Block (FCB) and
79 Discovered Bad Block Table (DBBT).  The SPL build artifact from U-Boot is
82 The u-boot.img, which is the non SPL U-Boot binary appended to a U-Boot image
83 header must be programmed in the NAND flash boot device at an offset hard
85 The image can be programmed from either U-Boot or Linux:
87 U-Boot:
89 Ventana > tftp ${loadaddr} u-boot.img && nand erase.part uboot && \
93 nandwrite /dev/mtd1 u-boot.img
105 More details about the i.MX6 BOOT ROM can be found in the IMX6 reference manual.
107 3.1. boot from MMC (eMMC/microSD)
110 When the IMX6 eFUSE settings have been factory programmed to boot from
112 booted, it will load and execute U-Boot (u-boot.img) from offset 69KB
116 U-Boot from a file on a FAT/EXT filesystem on the micro-SD, we chose to
117 use raw micro-SD access to keep the code-size and boot time of the SPL down.
119 For these reasons an MMC device that will be used as an IMX6 primary boot
130  # copy U-Boot to 69KB offset
131  sudo dd if=u-boot.img of=$DEV bs=1K seek=69 oflag=sync status=none && sync
144  - spl    :   1KB-69KB  (68KB)  required by IMX6 BOOT ROM
155 More details about the i.MX6 BOOT ROM can be found in the IMX6 reference manual.
161 which allows the SPL to boot directly to an OS instead of to U-Boot
162 (u-boot.img) thus acheiving a faster overall boot time. The time savings
163 depends on your boot medium (ie NAND Flash vs micro-SD) and size/storage
167 The Gateworks Ventana board supports Falcon mode for the following boot
172 For all boot mediums, raw mode is used. While support of more complex storage
178 The SPL decides to boot either U-Boot (u-boot.img) or the OS (args + kernel)
182 set to '0' will choose to boot to U-Boot and otherwise it will boot to OS.
185 that is stored on your boot medium along with the kernel (which can be any
188 by U-Boot's 'bootm' command. To achieve this for SPL we use the
189 'spl export fdt' command in U-Boot after loading the kernel and dtb which
210 The following steps executed in U-Boot will configure Falcon mode for NAND
238  # set i2c register 0x50:0x00=0 to boot to Linux
252 To prepare a Gateworks Ventana board with a primary boot device of micro-SD
253 you first need to make sure you build U-Boot with CONFIG_ENV_IS_IN_MMC
266 IMX6 BOOT ROM (fixed offset of 1KB), and U-Boot can be loaded by the SPL
277  # copy U-Boot to 69KB offset
278  sudo dd if=u-boot.img of=$DEV bs=1K seek=69 oflag=sync status=none && sync
291 raw 'args' and 'kernel' data boot the board with the prepared micro-SD, break
292 out in U-Boot and use the following to enable Falcon mode:
295  Ventana > ext2load mmc 0:1 ${fdt_addr} boot/${fdt_file2}
298  Ventana > ext2load mmc 0:1 ${loadaddr} boot/uImage
312  # set i2c register 0x50:0x00=0 to boot to Linux