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Message-ID: <cc269d9f-9a06-6623-e412-d04ecb7b4f74@gmail.com>
Date: Thu, 5 Feb 2026 20:41:11 -0500
From: Sean Anderson <seanga2@...il.com>
To: René Rebe <rene@...ctco.de>
Cc: Andrew Lunn <andrew+netdev@...n.ch>, "David S. Miller"
<davem@...emloft.net>, netdev@...r.kernel.org
Subject: Re: [PATCH] net: sunhme: Fix sbus regression
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@...ctco.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?
> ---
>
> --- linux-6.18/drivers/net/ethernet/sun/sunhme.c.vanilla 2026-02-05 11:50:33.288906134 +0100
> +++ linux-6.18/drivers/net/ethernet/sun/sunhme.c 2026-02-05 11:55:22.541384377 +0100
> @@ -2551,6 +2551,9 @@
> goto err_out_clear_quattro;
> }
>
> + /* BIGMAC may have bogus sizes */
> + if ((op->resource[3].end - op->resource[3].start) >= BMAC_REG_SIZE)
> + op->resource[3].end = op->resource[3].start + BMAC_REG_SIZE - 1;
> hp->bigmacregs = devm_platform_ioremap_resource(op, 3);
> if (IS_ERR(hp->bigmacregs)) {
> dev_err(&op->dev, "Cannot map BIGMAC registers.\n");
>
Reviewed-by: Sean Anderson <seanga2@...il.com>
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