Hi George, Thank you for contributing.
On lun., avril 28, 2025 at 15:53, Casey Connolly <casey.conno...@linaro.org> wrote: > Hi George, > > Thanks a lot for the series, it's super exciting to see support for > booting Android on top of U-Boot :D > > On 4/27/25 13:25, George Chan via B4 Relay wrote: >> This is a series of patches to enable chainloading LineageOS on qcom SOC. >> >> First patch is to workaround kernel/ramdisk invalid addr by identify >> its physical memory address out-of-range. Since qcom SOC usually have >> 0x80000000 as start/base/real memory address but androidboot img >> specified to around 0x0. If other vendor bootloader behave similar then >> this patch can also workaround it as well. > > I'm curious to know what values are there, tbh I think U-Boot should > entirely ignore the values in the boot image but I guess that could > break some other platforms. Yes, some platforms actually use the values from the boot.img. We had some breakage on Khadas VIM3 in this area. See: https://lore.kernel.org/all/20241003-android-fix-boot-v2-v1-1-13e8e44af...@baylibre.com/ The above thread also mentions how to repack a boot.img, where we can specify a different ramdisk address. It's a bit unclear to me why it's impractical to repack the boot.img and specify the appropriate address. Could you elaborate ? > > How about adding a config option CONFIG_ANDROID_BOOTIMG_IGNORE_ADDRS and > just ORing it in all the places that have checks like > "img_data->kernel_addr == 0". Then you can enable this for > mach-snapdragon by selecting it in the ARCH_SNAPDRAGON config definition. If we need to add this in U-Boot, I'd prefer this option as suggested by Casey. > >> >> Second patch is enable bootmeth-android to have chance for extra mem block. >> Usually the fastboot mem block, to hold androidboot img, and loadaddr for >> unzipped kernel. If other SOC have extra mem block available but >> fastboot block, we can add extra logic to take care of it. > > There is a small hack in mach-snapdragon that we put kernel_addr_r and > loadaddr at the same address to avoid using up too much memory on > devices that only have 1GB which explains this crash because we try to > decompress the kernel to the same address it got loaded too. > > I think we can get away with giving loadaddr its own allocation of 64M > or so, maybe 96. This would make your second patch redundant (and feels > like the right fix to me) I was not aware of this hack, but I agree with Casey. > >> >> Third patch is optional to enable snapdragon board to have extra cmdline >> found from original bootloader that is required for LineageOS boot init. >> An alternate method is to put the append string into a dummy device-tree >> file, as /chosen/bootarg ofnode porperty, that also contain msm-id. Then >> encapsulate as androidboot img and let u-boot as kernel binary. Below is >> an example for Xiaomi Miatoll device. > > I assume you're chainloading U-Boot on this device? If so, isn't it > enough to just copy the boot args that ABL gives us and maybe tweak a few? > > I'd also rather keep this constrained, maybe an android specific board > callback to set boot args (if there isn't one already) and have the FDT > fixup code be alongside some other generic FDT fixup stuff. I'd rather > not have this stuff in board specific code. I also agree with Casey here. Looking at patch: "[PATCH 3/3] mach-snapdragon: Add support to append string to kernel cmdline", the android bootmethod already takes care of some androidboot.* arguments. See: https://source.denx.de/u-boot/u-boot/-/blob/master/boot/bootmeth_android.c?ref_type=heads#L504 For androidboot.verifiedbootstate=orange, this is done via avb_append_commandline_arg() when AVB is enabled in U-Boot. > > I hope this makes sense, feel free to ask for clarifications on anything. > > Thanks and kind regards, > >> >> /dts-v1/; >> >> / { >> qcom,msm-id = <443 0x0>; >> qcom,board-id = <0 0>, >> <0x10022 1>, >> <0x20022 1>, >> <0x30022 1>, >> <0x40022 1>, >> <0x50022 1>; >> >> #address-cells = <2>; >> #size-cells = <2>; >> >> memory { >> ddr_device_type = <0x07>; >> /* We expect the bootloader to fill in the size */ >> reg = <0 0 0 0>; >> }; >> >> chosen { >> bootargs = ""; >> }; >> }; >> >> Signed-off-by: George Chan <gchan9...@gmail.com> >> --- >> George Chan (3): >> boot/image-android.c: Workaround androidboot kernel/ramdisk addr >> boot/bootmeth-android.c: Reuse fastboot memory block for unzip kernel >> mach-snapdragon: Add support to append string to kernel cmdline >> >> arch/arm/mach-snapdragon/Kconfig | 11 +++++ >> arch/arm/mach-snapdragon/board.c | 97 >> ++++++++++++++++++++++++++++++++++++++++ >> boot/bootmeth_android.c | 12 +++++ >> boot/image-android.c | 10 +++++ >> 4 files changed, 130 insertions(+) >> --- >> base-commit: 5a0a93a768487e55ebe50a34cc90d751bf99cc56 >> change-id: 20250427-android-boot-ecbb768cda72 >> >> Best regards, > -- > Casey (she/they)
