Signed-off-by: Michael Spang mspang@csclub.uwaterloo.ca --- doc/README.ts7800 | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 84 insertions(+), 0 deletions(-) create mode 100644 doc/README.ts7800
diff --git a/doc/README.ts7800 b/doc/README.ts7800 new file mode 100644 index 0000000..6a6ab94 --- /dev/null +++ b/doc/README.ts7800 @@ -0,0 +1,84 @@ +Booting +------- + +The TS-7800 boots initially from a proprietary bootloader on the FPGA +called TS-BOOTROM. TS-BOOTROM loads a small image from the MBR of the +onboard NAND or SD card into RAM, and executes it. The default MBR is +intended to boot a Linux kernel. + +The TS-7800 port of U-Boot takes the place of the Linux kernel in this +configuration, and is therefore loaded and executed by the MBR. The +MBR also creates an ATAG structure intended for Linux, but U-Boot +ignores it. + +NAND layout +----------- + +NAND support is not enabled by default because U-Boot will overwrite +part of it with its environment. To enable NAND support, enable +CONFIG_USE_NAND in include/configs/ts7800.h. + +The default NAND partition layout used by Technologic and Linux is: + + 128k(mbr),4m(linux),4m(initrd),-(rootfs) + +For U-Boot, we split the linux partition into a partition for the +U-Boot code and a partition for the U-Boot environment. The initrd +partition is not used, and is renamed to "linux". The new layout is: + + 128k(mbr),3m(uboot),1m(env),4m(linux),-(rootfs) + +When NAND support is enabled, this string is available in the U-Boot +default environment as the "mtdparts" variable. You may wish to use +this layout for Linux as well by adding it to the Linux command line. +For example: + + setenv bootargs console=ttyS0,115200n8 ${mtdparts} + +Installing U-Boot +----------------- + +To install U-Boot to the onboard flash, write u-boot.bin to the kernel +partition on the flash. From Linux this might be done as follows: + + flash_eraseall /dev/mtd1 + nandwrite --pad /dev/mtd1 u-boot.bin + +When running from onboard flash, you may wish to enable NAND support +as described in the previous section. The environment is not preserved +unless you enable NAND support. + +To install U-Boot to an SD card, write u-boot.bin to the kernel +partition on the card. + +Booting Technologic Kernels +--------------------------- + +Technologic's kernels use a different machine type ID than upstream +kernels. U-Boot uses the upstream ID, so Technologic kernels will +not boot from U-Boot without the following workaround: + + setenv machid 0x20e + +The following commands will convert a Technologic kernel image +into U-Boot format: + + mkimage -A arm -O linux -T kernel -C none -a 0x8000 \ + -d kernel-image-latest.dd uImage + + mkimage -A arm -O linux -T ramdisk -C none -a 0x1000000 \ + -d initrd-busybox-rootfs-latest.dd initrd + +Then pass both images to the bootm command to boot. Note that with +U-Boot installed there is only one partition available for the kernel +and initrd. To use both changing the NAND partitioning may be +required. To do so you can use the mtdparts command in U-Boot and pass +${mtdparts} to linux. + +TS-7800 Wiki +------------ + +A useful resource about the TS-7800 is the TS-7800 wiki [1], +maintained by Alexander Clouter. + +[1] http://www.digriz.org.uk/ts78xx