Re: [PATCH v5 01/11] hw: arm: Add bananapi M2-Ultra and allwinner-r40 support

[Guenter Roeck]

On Sun, Jun 18, 2023 at 08:40:28AM +0800, qianfan wrote:
> 
> 在 2023/6/18 0:29, Guenter Roeck 写道:
> > Hi,
> > 
> > On Tue, May 23, 2023 at 06:04:58PM +0800, qianfanguijin@163.com wrote:
> > > From: qianfan Zhao <qianfanguijin@163.com>
> > > 
> > > Allwinner R40 (sun8i) SoC features a Quad-Core Cortex-A7 ARM CPU,
> > > and a Mali400 MP2 GPU from ARM. It's also known as the Allwinner T3
> > > for In-Car Entertainment usage, A40i and A40pro are variants that
> > > differ in applicable temperatures range (industrial and military).
> > > 
> > > Signed-off-by: qianfan Zhao <qianfanguijin@163.com>
> > > Reviewed-by: Niek Linnenbank <nieklinnenbank@gmail.com>
> > I tried this in mainline linux with the following command.
> > 
> > qemu-system-arm -M bpim2u \
> >     -kernel arch/arm/boot/zImage -no-reboot \
> >     -snapshot -drive file=rootfs-armv7a.ext2,format=raw,if=sd \
> >     -nic user \
> >     --append "root=/dev/mmcblk0 rootwait console=ttyS0,115200" \
> >     -dtb arch/arm/boot/dts/sun8i-r40-bananapi-m2-ultra.dtb \
> >     -nographic -monitor null -serial stdio
> > 
> > Main problem is that the SD card gets instantiated randomly to
> > mmc0, mmc1, or mmc2, making it all but impossible to specify a
> > root file system device. The non-instantiated cards are always
> > reported as non-removable, including mmc0. Example:
> > 
> > mmc0: Failed to initialize a non-removable card
> > 
> > Using "-sd <file>" instead of "-drive file=<file>" does not
> > make a difference.
> > 
> > I can fix (work around ?) the problem by adding the following information
> > to the devicetree file.
> > 
> >          aliases {
> >                  ethernet0 = &gmac;
> >                  serial0 = &uart0;
> > +               mmc0 = &mmc0;
> > +               mmc1 = &mmc1;
> > +               mmc2 = &mmc2;
> >          };
> > 
> > Linux upstream commits fa2d0aa96941 and 2a43322ca7f3 describe the
> > logic behind this change.
> > 
> > Is this a bug in the Linux kernel, or a problem with the qemu emulation ?
> 
> On my work, the linux kenrel doesn't startup ext4 rootfs directly, it start
> 
> a custom ramdisk and we can handle this in ramdisk scripts.
> 

That won't help for automated testing.
I guess that means the answer to my question below is "no".

Thanks,
Guenter

> > Either case, is there a way to specify a qemu command line that doesn't
> > result in random assignments of the provided drive to mmc0/1/2 ?
> > 
> > Thanks,
> > Guenter
>