Re: [PATCH v5 4/5] ARM: dts: mt8135: enable basic SMP bringup for mt8135

[Kevin Hilman <khilman@kernel.org>]

Hi Eddie,

Kevin Hilman <khilman@kernel.org> writes:

> Eddie Huang <eddie.huang@mediatek.com> writes:
>
>> On Tue, 2015-11-10 at 17:16 -0800, Kevin Hilman wrote:
>>> Hi Eddie,
>>> 
>>> [...]
>>> 
>>> > I check the log [0],
>>> 
>>> Thanks for checking into this boot failure.
>>> 
>>> > it seems first time mt8135-evbp1 boot to kernel
>>> > shell successfully, then boot again. In the second time, mt8135 stay in
>>> > fastboot mode, waiting host send boot image, then timeout.
>>> 
>>> Actually, it never gets to a shell the first time.  If you look closely,
>>> the target reboots as soon as userspace starts.   Look for the PYBOOT
>>> line which says "finished booting, starting userspace"
>>> 
>>> Later on, pyboot thinks it finds a root shell due to finding '#'
>>> characters, but clearly it never got to a shell.
>>> 
>>> > I download zImage and dtb in [1], and kernel run to shell successfully
>>> > on my platform.
>>> 
>>> Are you can you try using a ramdisk as well?  You can use the pre-built
>>> one here:
>>> http://storage.kernelci.org/images/rootfs/buildroot/armel/rootfs.cpio.gz
>>> 
>>
>> Yes, I tried this ramdisk, and I can reproduce fail issue.
>>
>
> OK, good.   Thanks for looking into it.
>
>>> Please check my boot logs to see how I'm generating the boot.img file
>>> (search for mkbootimg) with a kernel/dtb/ramdisk.  It may be possible
>>> that the kernel image size with a ramdisk is breaking some of the
>>> assumptions in the fastboot mode.  I've seen problems like this on other
>>> platforms due to hard-coded sizes/addresses in the boot firmware.
>>> 
>>
>> MT8135 allocate 10MB for BOOT partition, but the test boot.img is 11MB,
>> thus cause user space fail.
>
> Aha, I was right!  ;)

Also notice in kernelci.org that the mt8173 board has also been failing
to boot in mainline[1].  I wonder if this same limitation exists in the
mt8173 boot firmware?

Kevin

[1] http://kernelci.org/boot/mt8173-evb/job/mainline/kernel/v4.3-11553-g8d3de01cfa37/defconfig/defconfig/lab/lab-khilman/?_id=5643bc3959b5145c9e0918f4