[PATCH] net: sunhme: Fix sbus regression

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 <redacted>
---
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).
---

--- 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");

-- 
René Rebe, ExactCODE GmbH, Berlin, Germany
https://exactco.de • https://t2linux.com • https://patreon.com/renerebe