在 2023/6/18 0:29, Guenter Roeck 写道:
Hi,
On Tue, May 23, 2023 at 06:04:58PM +0800, qianfangui...@163.com wrote:
From: qianfan Zhao <qianfangui...@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 <qianfangui...@163.com>
Reviewed-by: Niek Linnenbank <nieklinnenb...@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.
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
