bcm4708-smartrg-sr400ac boot failures in next/arm-soc

[arnd@arndb.de (Arnd Bergmann)]

On Friday 08 January 2016 14:33:39 Tyler Baker wrote:
> Hi Hauke, Rafal, Alison,
> 
> The kernelci.org bot detected a boot regression[1] in -next/arm-soc
> which bisected to b02ec7658c ("ARM: multi_v7_defconfig: Enable some
> drivers for LS1021A"). Reverting this patch fixes the issue I was
> seeing.
> 
> After a bit of investigation, I determined that CONFIG_BLK_DEV_RAM was
> causing the issue and disabling it fixed the boot issue. Essentially,
> the kernel cannot find the initrd that has been loaded into memory by
> CFE bootloader with this option enabled as I inject the following
> command line into the DT before it's loaded over tftp.
> 
> Loaded in CFE by: 'load -raw -tftp -addr=0x4000000 -max=0x900000
> 192.168.2.2:tmpqC9zOv/ramdisk.cpio.gz'
> 
> Kernel arguments injected into DT: 'console=ttyS0,115200
> initrd=0x4000000,8M root=/dev/ram0 ip=dhcp'
> 
> I'm wondering how we should proceed forward here. Alison, Is it a firm
> requirement you need CONFIG_BLK_DEV_RAM enabled by default? Hauke,
> Rafal, Is there another way to configure this platform to boot a
> kernel/ramdisk without passing the initrd option on the command line?

I would hope that we can actually do both, and turn off CONFIG_BLK_DEV_RAM
again: Nothing should rely on that these days, we can use initramfs and
tmpfs, which are both more efficient. At the same time, the boot loader
really needs to have a way to configure the command line properly, 
and the bcm4708 machine should also not use a fixed-size ramdisk but
use initramfs instead.

	Arnd