mirror of
https://github.com/AsahiLinux/u-boot
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8e1c9fe243
This adds a boot method for loading the next stage from the host. It is mostly modeled off of spl_load_image_ext. I am not really sure why/how spl_load_image_fat uses three different methods to load the image, but the simple case seems to work OK for now. To control the presence of this boot method, we add a config symbol. While we're at it, we update the original semihosting config symbol. I think semihosting has some advantages of other forms of JTAG boot. Common other ways to boot from JTAG include: - Implementing DDR initialization through JTAG (typically with dozens of lines of TCL) and then loading U-Boot. The DDR initialization typically uses hard-coded register writes, and is not easily adapted to different boards. BOOT_DEVICE_SMH allows booting with SPL, leveraging U-Boot's existing DDR initialization code. This is the method used by NXP's CodeWarrior IDE on Layerscape processors (see AN12270). - Loading a bootloader into SDRAM, waiting for it to initialize DDR, and then loading U-Boot. This is tricky, because the debugger must stop the boot after the bootloader has completed its work. Trying to load U-Boot too early can cause failure to boot. This is the method used by Xilinx with its Zynq(MP) processors. - Loading SPL with BOOT_DEVICE_RAM and breaking before SPL loads the image to load U-Boot at the appropriate place. This can be a bit tricky, because the load address is dependent on the header size. An elf with symbols must also be used in order to stop at the appropriate point. BOOT_DEVICE_SMH can be viewed as an extension of this process, where SPL automatically stops and tells the host where to place the image. Signed-off-by: Sean Anderson <sean.anderson@seco.com> |
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.. | ||
cpu | ||
dts | ||
include | ||
lib | ||
mach-apple | ||
mach-aspeed | ||
mach-at91 | ||
mach-bcm283x | ||
mach-bcmstb | ||
mach-cortina | ||
mach-davinci | ||
mach-exynos | ||
mach-highbank | ||
mach-imx | ||
mach-integrator | ||
mach-ipq40xx | ||
mach-k3 | ||
mach-keystone | ||
mach-kirkwood | ||
mach-lpc32xx | ||
mach-mediatek | ||
mach-meson | ||
mach-mvebu | ||
mach-nexell | ||
mach-octeontx | ||
mach-octeontx2 | ||
mach-omap2 | ||
mach-orion5x | ||
mach-owl | ||
mach-qemu | ||
mach-rmobile | ||
mach-rockchip | ||
mach-s5pc1xx | ||
mach-snapdragon | ||
mach-socfpga | ||
mach-sti | ||
mach-stm32 | ||
mach-stm32mp | ||
mach-sunxi | ||
mach-tegra | ||
mach-u8500 | ||
mach-uniphier | ||
mach-versal | ||
mach-versatile | ||
mach-zynq | ||
mach-zynqmp | ||
mach-zynqmp-r5 | ||
thumb1/include/asm/proc-armv | ||
config.mk | ||
Kconfig | ||
Kconfig.debug | ||
Makefile |