Re: [PATCH] net: sunhme: Fix sbus regression

[Paolo Abeni <pabeni@redhat.com>]

On 2/6/26 3:49 PM, Sean Anderson wrote:
> On 2/6/26 04:05, René Rebe wrote:
>> On Thu, 5 Feb 2026 20:41:11 -0500, Sean Anderson <seanga2@gmail.com> wrote:
>>
>>> On 2/5/26 11:09, René Rebe wrote:
>>>> Commit cc216e4b44ce ("net: sunhme: Switch SBUS to devres") changed
>>>> explicit sized of_ioremap with BMAC_REG_SIZEs to
>>>> devm_platform_ioremap_resource mapping all the resource. However,
>>>> this does not work on my Sun Ultra 2 with SBUS HMEs:
>>>> hme f0072f38: error -EBUSY: can't request region for resource [mem
>>>> 0x1ffe8c07000-0x1ffe8c0701f]
>>>> hme f0072f38: Cannot map TCVR registers.
>>>> hme f0072f38: probe with driver hme failed with error -16
>>>> hme f007ab44: error -EBUSY: can't request region for resource [mem
>>>> 0x1ff28c07000-0x1ff28c0701f]
>>>> hme f007ab44: Cannot map TCVR registers.
>>>> hme f007ab44: probe with driver hme failed with error -16
>>>> Turns out the open-firmware resources overlap, at least on this
>>>> machines and PROM version:
>>>> hexdump /proc/device-tree/sbus@1f,0/SUNW,hme@2,8c00000/reg:
>>>> 00 00 00 02 08 c0 00 00  00 00 01 08
>>>> 00 00 00 02 08 c0 20 00  00 00 20 00
>>>> 00 00 00 02 08 c0 40 00  00 00 20 00
>>>> 00 00 00 02 08 c0 60 00  00 00 20 00
>>>> 00 00 00 02 08 c0 70 00  00 00 00 20
>>>> And the driver previously explicitly mapped way smaller mmio regions:
>>>> /proc/iomem:
>>>> 1ff28c00000-1ff28c00107 : HME Global Regs
>>>> 1ff28c02000-1ff28c02033 : HME TX Regs
>>>> 1ff28c04000-1ff28c0401f : HME RX Regs
>>>> 1ff28c06000-1ff28c0635f : HME BIGMAC Regs
>>>> 1ff28c07000-1ff28c0701f : HME Tranceiver Regs
>>>> Quirk this specific issue by truncating the previous resource to not
>>>> overlap into the TCVR registers.
>>>> Fixes: cc216e4b44ce ("net: sunhme: Switch SBUS to devres")
>>>> Signed-off-by: René Rebe <rene@exactco.de>
>>>> ---
>>>> Tested on Sun Ultra 2 running T2/Linux.
>>>> Alternatively we could explicitly size all regions, or check overlap
>>>> in startup code (I also already have a patch for that, too).
>>>
>>> What does this look like?
>>
>> This only checks for "sorted" overlaps w/ the previous res, but given
>> they probably usually are and it catches this case, ...
>>
>> The downside is, it may break other devices, I only test booted this
>> on an Ultra 2 and Ultra 30. On the U2 it fixes the hme ethernet,
>> too. On the U30 it causes an eprom region to be truncated. I probably
>> should investiage that and test boot on all my SPARC systems before we
>> consider this. That's why I sent the trivial hme driver hotfix first.
>> Alternatively we could also overwrite all sbus res in the hme driver
>> with the previously used known good sizes. I can send a patch for
>> that, too if you like:
> 
> I'm not really familiar enough with SPARC to say whether this is reasonable
> or not. I've added the SPARC maintainers to CC so maybe they can comment.

FTR, I think we are better off applying this patch as quick fix and
eventually follow-up with the more complete/less trivial solution.

/P