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

[Sean Anderson <seanga2@gmail.com>]

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?

> ---
> 
> --- 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@gmail.com>