Re: [RFC PATCH 11/17] hw/sd: Add eMMC support

["Cédric Le Goater" <clg@kaod.org>]

Hello Jerome,

On 3/28/22 14:10, Jerome Forissier wrote:
> Hi Cédric,
> 
> On 3/18/22 14:28, Cédric Le Goater wrote:
>> The initial eMMC support from Vincent Palatin was largely reworked to
>> match the current SD framework. The parameters mimick a real 4GB eMMC,
>> but it can be set to various sizes.
>>
>> This adds a new QOM object class for EMMC devices.
> 
> That is interesting. 

This series is really a pre-pre-alpha-0. It's a mixed of changes from
Joel and I on top of Vincent Palatin patches sent ~10 years ago. I
reworked them recently to take into account a proposal of Philippe to
improve the sd models and possibly add eMMC support. They are good
enough to boot a rainier-bmc board.

> Is RPMB emulation implemented? I doesn't look like so, although...

no. it's not.

> 
> 
>> +    sd->ext_csd[EXT_CSD_RPMB_MULT] = 0x1; /* RPMB size */
> 
> ...this indicates that the device has one block (128 KB) of RPMB if I'm
> not mistaken.
> 
> 
> I would be quite interested in testing and possibly helping out
> implement RPMB, although I must admit don't know much about QEMU
> internals. I have written some quick & dirty emulation code for RPMB at
> the Linux ioctl() level, see [1]. This code is useful for CI testing of
> the OP-TEE OS project [2], but having a lower level emulation in QEMU
> would be much better since the Linux kernel would "see" the device and
> report it in sysfs etc.
> 
> [1] https://github.com/OP-TEE/optee_client/blob/3.16.0/tee-supplicant/src/rpmb.c#L494-L571
> [2] https://github.com/OP-TEE/optee_os/


You can give these patches a try using this branch:

   https://github.com/legoater/qemu/commits/aspeed-7.0

Using the above QEMU, I would run a rainier-bmc machine which requires eMMC
support :

   qemu-system-arm -M rainier-bmc \
	-nic user,mac=C0:FF:EE:00:00:02,hostfwd=::2222-:22 \
	-drive file=/path/to/mmc-p10bmc.qcow2,format=qcow2,if=sd,id=sd0,index=2 \
         -nographic -nodefaults -snapshot -serial mon:stdio
	
The bootable qcow2 image :

   https://www.kaod.org/qemu/aspeed/mmc-p10bmc.qcow2

was created from :

   https://jenkins.openbmc.org/view/latest/job/latest-master/label=docker-builder,target=p10bmc/lastSuccessfulBuild/artifact/openbmc/build/tmp/deploy/images/p10bmc/

Booting from the eMMC is a topic by itself but instead of booting
from the eMMC, I would use a custom kernel and userspace.

Compile an AST2600 kernel or grab :

   https://www.kaod.org/qemu/aspeed/zImage
   https://www.kaod.org/qemu/aspeed/aspeed-bmc-ibm-rainier.dtb

Compile a buildroot image or grab :

   https://www.kaod.org/qemu/aspeed/rootfs.cpio.xz
   
and run :

   qemu-system-arm -M rainier-bmc \
	-kernel /path/to/linux/build_ast2600/arch/arm/boot/zImage \
	-initrd /path/to/rootfs.cpio.xz \
	-dtb /path/to/linux/build_ast2600/arch/arm/boot/dts/aspeed-bmc-ibm-rainier.dtb \
	-append 'console=ttyS4,115200n8 root=/dev/ram ro' \
	-nic user,mac=C0:FF:EE:00:00:02,hostfwd=::2222-:22 \
	-drive file=/path/to/mmc-p10bmc.qcow2,format=qcow2,if=sd,id=sd0,index=2 \
         -nographic -nodefaults -serial mon:stdio
  
root/0penBmc to login.

 From there, modify the kernel and the buildroot image, you can scp
some binary, do your testing and possibly send patches to improve QEMU
support !

C.