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Date:      Sun, 14 Jun 2026 20:57:26 +0000
From:      Adrian Chadd <adrian@FreeBSD.org>
To:        src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org
Cc:        Abdelkader Boudih <freebsd@seuros.com>
Subject:   git: 142cba958b7a - main - bge: read MAC from loader hint for boards without NVRAM/EEPROM
Message-ID:  <6a2f15b6.38f19.50459a27@gitrepo.freebsd.org>
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The branch main has been updated by adrian:

URL: https://cgit.FreeBSD.org/src/commit/?id=142cba958b7a6dd11e4257740db03d335475ede8

commit 142cba958b7a6dd11e4257740db03d335475ede8
Author:     Abdelkader Boudih <freebsd@seuros.com>
AuthorDate: 2026-06-14 20:55:33 +0000
Commit:     Adrian Chadd <adrian@FreeBSD.org>
CommitDate: 2026-06-14 20:56:59 +0000

    bge: read MAC from loader hint for boards without NVRAM/EEPROM
    
    BCM57766 on Apple T2 Macs (Macmini8,1) has no dedicated EEPROM and the
    chip firmware handshake fails (the T2 intercepts PCI config space),
    leaving the SRAM mailbox unpopulated.  All four existing MAC retrieval
    paths (SRAM mailbox, NVRAM, EEPROM, firmware stub) fail, causing bge to
    abort attach with "failed to read station address".
    
    Work around this with two changes:
    
      1. Tolerate EEPROM read failure on BCM57766.  The chip is copper-only
         so hwcfg=0 is correct; skip the fatal error that aborts attach
         before bge_get_eaddr() is ever called.
    
      2. Implement bge_get_eaddr_fw() to read a "hint.bge.N.mac" string
         (e.g. "f0:18:98:f4:1e:2f") from loader(8) tunable / kenv.
    
    This is a workaround until the T2 BCE API is understood well enough to
    either poke the chip firmware into completing its handshake or read the
    MAC from the T2 directly.
    
    Reviewed by:    adrian
    Differential Revision:  https://reviews.freebsd.org/D57090
---
 sys/dev/bge/if_bge.c | 42 ++++++++++++++++++++++++++++++++++++------
 1 file changed, 36 insertions(+), 6 deletions(-)

diff --git a/sys/dev/bge/if_bge.c b/sys/dev/bge/if_bge.c
index 3551f10b2ae3..1fbf8bfb7e93 100644
--- a/sys/dev/bge/if_bge.c
+++ b/sys/dev/bge/if_bge.c
@@ -3766,11 +3766,19 @@ bge_attach(device_t dev)
 	    (sc->bge_asicrev != BGE_ASICREV_BCM5906)) {
 		if (bge_read_eeprom(sc, (caddr_t)&hwcfg, BGE_EE_HWCFG_OFFSET,
 		    sizeof(hwcfg))) {
-			device_printf(sc->bge_dev, "failed to read EEPROM\n");
-			error = ENXIO;
-			goto fail;
-		}
-		hwcfg = ntohl(hwcfg);
+			/*
+			 * BCM57766 on Apple T2 Macs has no dedicated EEPROM;
+			 * the chip is copper-only so hwcfg=0 is correct.
+			 */
+			if (sc->bge_asicrev != BGE_ASICREV_BCM57766) {
+				device_printf(sc->bge_dev,
+				    "failed to read EEPROM\n");
+				error = ENXIO;
+				goto fail;
+			}
+			hwcfg = 0;
+		} else
+			hwcfg = ntohl(hwcfg);
 	}
 
 	/* The SysKonnect SK-9D41 is a 1000baseSX card. */
@@ -6677,7 +6685,29 @@ bge_sysctl_mem_read(SYSCTL_HANDLER_ARGS)
 static int
 bge_get_eaddr_fw(struct bge_softc *sc, uint8_t ether_addr[])
 {
-	return (1);
+	const char *mac_str;
+	unsigned int o[ETHER_ADDR_LEN];
+	char trail;
+	int i, n, unit;
+
+	unit = device_get_unit(sc->bge_dev);
+	if (resource_string_value("bge", unit, "mac", &mac_str) != 0)
+		return (1);
+
+	/* Parse and validate; trailing-char check rejects garbage. */
+	n = sscanf(mac_str, "%x:%x:%x:%x:%x:%x%c",
+	    &o[0], &o[1], &o[2], &o[3], &o[4], &o[5], &trail);
+	if (n != 6)
+		return (1);
+	for (i = 0; i < ETHER_ADDR_LEN; i++) {
+		if (o[i] > 0xff)
+			return (1);
+		ether_addr[i] = (uint8_t)o[i];
+	}
+	if (ETHER_IS_MULTICAST(ether_addr) ||
+	    ETHER_IS_ZERO(ether_addr))
+		return (1);
+	return (0);
 }
 
 static int
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