[PATCH v6 01/11] mtd: core: always create master device

[Guenter Roeck]

On 6/8/25 12:37, Miquel Raynal wrote:
> Hi Guenter,
> 
> On 08/06/2025 at 07:00:10 GMT, "Usyskin, Alexander" <alexander.usyskin at intel.com> wrote:
> 
>>> Subject: Re: [PATCH v6 01/11] mtd: core: always create master device
>>>
>>> Hi,
>>>
>>> On Sun, Mar 02, 2025 at 04:09:11PM +0200, Alexander Usyskin wrote:
>>>> Create master device without partition when
>>>> CONFIG_MTD_PARTITIONED_MASTER flag is unset.
>>>>
>>>> This streamlines device tree and allows to anchor
>>>> runtime power management on master device in all cases.
>>>>
>>>> Signed-off-by: Alexander Usyskin <alexander.usyskin at intel.com>
>>>
>>> Several of my qemu boot tests fail to boot from mtd devices with this patch
>>> in the mainline kernel. Reverting it fixes the problem. As far as I can
>>> see this affects configurations with CONFIG_MTD_PARTITIONED_MASTER=y
>>> when
>>> trying to boot from an mtd partition other than mtdblock0, with the
>>> mtd partition data in devicetree (.../aspeed/openbmc-flash-layout.dtsi).
>>> Is there a guidance describing the changed behavior, by any chance,
>>> and how the boot command line now needs to look like when using one of
>>> the flash partitions as root file system ?
>>>
>>> Thanks,
>>> Guenter
>>
>> I've tried to make is as transparent as possible for the existing users.
>> Only change is that now every partition has master that is not partitioned.
>> Is the CONFIG_MTD_PARTITIONED_MASTER=n fixed the problem for you?
> 
> No change is expected, can you please describe the devices that you
> observe with and without the patch? Maybe there is something wrong in
> the core logic.
> 

I am trying to boot supermicro-x11spi-bmc in qemu from flash partition 6.
The qemu command line is something like

     qemu-system-arm -M supermicro-x11spi-bmc,fmc-model=n25q256a13,spi-model=n25q256a13 \
	-kernel arch/arm/boot/zImage -no-reboot -snapshot \
	-audio none \
	-drive file=/tmp/flash,format=raw,if=mtd,index=1 \
	-nic user \
	--append "root=/dev/mtdblock6 rootwait console=ttyS4,115200 earlycon=uart8250,mmio32,0x1e784000,115200n8" \
	-dtb arch/arm/boot/dts/aspeed/aspeed-bmc-supermicro-x11spi.dtb \
	-nographic -monitor null -serial stdio

This is with aspeed_g5_defconfig. Note that the flash models need to be specified.
The default flashes are no longer recognized when booting from qemu since commit
947c86e481a0 ("mtd: spi-nor: macronix: Drop the redundant flash info fields").

The above only works with this patch reverted (or with v6.15 and older, of course).

Guenter