mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-08-17 15:38:51 +09:00
![]() Otherwise NAND booting is likely to fail. Since this disables the NAND related
clocks and SPL can't load the main U-Boot from NAND.
This problem was introduced with this patch:
|
||
---|---|---|
.. | ||
eeprom.c | ||
gsc.c | ||
gsc.h | ||
gw_ventana_spl.c | ||
gw_ventana.c | ||
Kconfig | ||
MAINTAINERS | ||
Makefile | ||
README | ||
ventana_eeprom.h |
U-Boot for the Gateworks Ventana Product Family boards This file contains information for the port of U-Boot to the Gateworks Ventana Product family boards. 1. Secondary Program Loader (SPL) --------------------------------- The i.MX6 has a BOOT ROM PPL (Primary Program Loader) which supports loading an executable image from various boot devices. The Gateworks Ventana board config uses an SPL build configuration. This will build the following artifacts from u-boot source: - SPL - Secondary Program Loader that the i.MX6 BOOT ROM (Primary Program Loader) boots. This detects CPU/DRAM configuration, configures The DRAM controller, loads u-boot.img from the detected boot device, and jumps to it. As this is booted from the PPL, it has an IVT/DCD table. - u-boot.img - The main u-boot core which is u-boot.bin with a image header. 2. Build -------- To build U-Boot for the Gateworks Ventana product family: make gwventana_config make 3. Boot source, boot from NAND ------------------------------ The i.MX6 BOOT ROM expects some structures that provide details of NAND layout and bad block information (referred to as 'bootstreams') which are replicated multiple times in NAND. The number of replications and their spacing (referred to as search stride) is configurable through board strapping options and/or eFUSE settings (BOOT_SEARCH_COUNT / Pages in block from BOOT_CFG2). In addition, the i.MX6 BOOT ROM Flash Configuration Block (FCB) supports two copies of a bootloader in flash in the case that a bad block has corrupted one. The Freescale 'kobs-ng' application from the Freescale LTIB BSP, which runs under Linux and operates on an MTD partition, must be used to program the bootstream in order to setup this flash structure correctly. The Gateworks Ventana boards with NAND flash have been factory programmed such that their eFUSE settings expect 2 copies of the boostream (this is specified by providing kobs-ng with the --search_exponent=1 argument). Once in Linux with MTD support for the NAND on /dev/mtd0 you can program the SPL with: kobs-ng init -v -x --search_exponent=1 SPL The kobs-ng application uses an imximage which contains the Image Vector Table (IVT) and Device Configuration Data (DCD) structures that the i.MX6 BOOT ROM requires to boot. The kobs-ng adds the Firmware Configuration Block (FCB) and Discovered Bad Block Table (DBBT). The SPL build artifact from u-boot is an imximage. The u-boot.img, which is the non SPL u-boot binary appended to a u-boot image header must be programmed in the NAND flash boot device at an offset hard coded in the SPL. For the Ventana boards, this has been chosen to be 14MB. The image can be programmed from either u-boot or Linux: u-boot: Ventana > setenv mtdparts mtdparts=nand:14m(spl),2m(uboot),1m(env),-(rootfs) Ventana > tftp ${loadaddr} u-boot.img && nand erase.part uboot && \ nand write ${loadaddr} uboot ${filesize} Linux: nandwrite /dev/mtd1 u-boot.img The above assumes the default Ventana partitioning scheme which is configured via the mtdparts env var: - spl: 14MB - uboot: 2M - env: 1M - rootfs: the rest This information is taken from: http://trac.gateworks.com/wiki/ventana/bootloader#NANDFLASH More details about the i.MX6 BOOT ROM can be found in the IMX6 reference manual.