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Date:   Sat, 30 Jul 2022 09:36:31 +0200
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Subject: Re: fw_devlink=on breaks probing devices when of_platform_populate()
 is used
From:   =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= <zajec5@gmail.com>
To:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Saravana Kannan <saravanak@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>
Cc:     "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        Ansuel Smith <ansuelsmth@gmail.com>
References: <696cb2da-20b9-b3dd-46d9-de4bf91a1506@gmail.com>
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Hi guys,

On 16.07.2022 22:50, Rafał Miłecki wrote:
> I added of_platform_populate() calls in mtd subsystem in the commit
> bcdf0315a61a2 ("mtd: call of_platform_populate() for MTD partitions"):
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=bcdf0315a61a29eb753a607d3a85a4032de72d94
> 
> I recently backported that commit in OpenWrt to kernels 5.10 and 5.15.
> We started receiving reports that probing Ethernet devices stopped
> working in kernel 5.15. I bisected it down to the kernel 5.13 change:
> 
> commit ea718c699055c8566eb64432388a04974c43b2ea (refs/bisect/bad)
> Author: Saravana Kannan <saravanak@google.com>
> Date:   Tue Mar 2 13:11:32 2021 -0800
> 
>      Revert "Revert "driver core: Set fw_devlink=on by default""
> 
>      This reverts commit 3e4c982f1ce75faf5314477b8da296d2d00919df.
> 
>      Since all reported issues due to fw_devlink=on should be addressed by
>      this series, revert the revert. fw_devlink=on Take II.
> 
>      Signed-off-by: Saravana Kannan <saravanak@google.com>
>      Link: https://lore.kernel.org/r/20210302211133.2244281-4-saravanak@google.com
>      Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> 
> For me with above commit kernel just never calls bcm4908_enet_probe().
> Reverting it from the top of 5.13.19 and 5.15.50 fixes it. I believe the
> same issue happens with other drivers.
> 
> Critical detail is that in DT Ethernet block node references NVMEM cell
> of MTD partition (see below).
> 
> Could you help me dealing with this issue, please? Can you see something
> obvious breaking fw_devlink=on + of_platform_populate() case? Can I
> provide some extra information to help fixing it?

Any ideas about this problem / solution?


> Relevant DT part:
> 
> partitions {
>      compatible = "fixed-partitions";
>      #address-cells = <1>;
>      #size-cells = <1>;
> 
>      partition@0 {
>          compatible = "nvmem-cells";
>          reg = <0x0 0x100000>;
>          label = "bootloader";
> 
>          #address-cells = <1>;
>          #size-cells = <1>;
>          ranges = <0 0x0 0x100000>;
> 
>          base_mac_addr: mac@106a0 {
>              reg = <0x106a0 0x6>;
>          };
>      };
> 
>      partition@100000 {
>          reg = <0x100000 0x5700000>;
>          label = "firmware";
>      };
> };
> 
> ethernet@2000 {
>      compatible = "brcm,bcm4908-enet";
>      reg = <0x2000 0x1000>;
> 
>      interrupts = <GIC_SPI 86 IRQ_TYPE_LEVEL_HIGH>,
>              <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>;
>      interrupt-names = "rx", "tx";
> 
>      nvmem-cells = <&base_mac_addr>;
>      nvmem-cell-names = "mac-address";
> };
> 
> OpenWrt bug report:
> https://github.com/openwrt/openwrt/issues/10232