From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f171.google.com (mail-pg1-f171.google.com [209.85.215.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 42A54305070 for ; Wed, 22 Oct 2025 08:21:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761121319; cv=none; b=LZaxxIYVHWKlt9rnaFG2PZsiLT7rTQnmZ6cjewbHuHNoQdhVsz0wFcth1KwLmTHWYQiIHZ6fScLGvhQ7id7xD7oQ3E3/klYoZALPh+zY04Win9l9DoZZ+C+R00B+nhSfzMHQm5QM8puKNRbIeyRu8ncMgLMdz0ibHZ36CCF+12c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761121319; c=relaxed/simple; bh=lv2uVhZqfWH9WVsgYRtW9amrl5GZHACKCdqnmaRN7GY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=VCWAtQD42HO1Z6XEcI6POqnWeOY6ZQ/IdbpNbNl9X7SFvUiboe+9Fr0Va1aszZzcdFJt+5UUDJ9S8ZU071xRL4cAGXmD3tU7JdRwbyklo18iPs6XXtziqf8kHb9rQhUi+qAMZcSdw1nTWFYV7iVaNbHnzoMpR3RHzbFaAa7SdBM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=arista.com; spf=pass smtp.mailfrom=arista.com; dkim=pass (2048-bit key) header.d=arista.com header.i=@arista.com header.b=PxBc25pC; arc=none smtp.client-ip=209.85.215.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=arista.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arista.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=arista.com header.i=@arista.com header.b="PxBc25pC" Received: by mail-pg1-f171.google.com with SMTP id 41be03b00d2f7-b47174b335bso447484a12.2 for ; Wed, 22 Oct 2025 01:21:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=google; t=1761121316; x=1761726116; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=rbLHC9QwAR9eOpe2xgT+y+OECBmxM2cqKB9QacBZTUs=; b=PxBc25pCLCfHnGVE4yrG9ZdK3XFrGGJb5WstUYZDRNgXjPBqy1ztPTURS9jo24QQcf 3DE6JXdAWWZ+1NThIw3bUBUxjrP2M+Jf7G/CRKNFSzCcNTK1cktWM3GC23L95FQpozIm F3i4Y/mo5+aEBYfAFDiEEveENp1TTddYHwGRT7blxj8eUf9GL2S9JNZOWsHdQYYZMX+3 lTqyyjvUuVXPM6LuRveBxrjshIgltC11lfnLiUMntUsrhas6Dx1Sc6pAcPvvKuOOT7FZ TBdnYUXVzyGm5gHp7v6tE9LmOFwqM+s/Wqa/NKnsaxl3wRZK12NW6cOurZPAxz706xB4 z82g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1761121316; x=1761726116; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=rbLHC9QwAR9eOpe2xgT+y+OECBmxM2cqKB9QacBZTUs=; b=mhzVuUkvFF95SCSurZe5zYUa5+MlEXzUGzgZFjZORnR2tnYp3d6ouduzqKveTYBllm Q4kWIUYzgOPVjtENUKAkmWFUwO81kuDEGk85m75Nrfm/Jz3KFp7FarBjSZZyZDJ/4t/7 jmq6k34khcnuShol5fhbT2EgBZ+FC9C78uIqtKaAETpD8Qw0V3X33Vm11ZYbkKCOdzJD 0xwZtbUKopEkgbjBtqENHThJToUBWLVQGwBgfq4U9pw8V0nr5CHtwRGUhncjjPiNu5/g 8zMxmj7T3tMEGZPjr8deJXdy6na8hsoAoqFlP6a3870qqLO4okn6em9z7DwrcKoiucdU lrgw== X-Forwarded-Encrypted: i=1; AJvYcCV/TR3JuqVsCPRqB+E/QA4makC9Lc6ntm2RFZrxKpfwF0jqY4CRUKb3ZW34tLQC/zGyhOScXPWXuJQm@vger.kernel.org X-Gm-Message-State: AOJu0YzcKraMHWmI1O+oRq2Oh6leEYn89ucmMfOC4ZmiUUpQ4qz86S3q OYvo9QqdCxx0BiiVIwb11G5JMKoGfe9c4/3PFc4EE0DLuRgys8dsFppul/WGy/k8pw== X-Gm-Gg: ASbGncsBSn2pTiZTXP5EfpmvjvxIPoY8qVZoHCcc0+7KSCP0zyNwlX+xEe1tCGsZvOT jd8h+jYwVRxh8cEqaxk35p6TgBY56e0ErgaJP48ODcaxSnrHU2qcZMXiZ0CBj4HZC/ZrXFDmC5G kBm4y8YeN7Tobj6bTZF0mA1x7FSXnKIlPteSNQfC4TiMZOnO8OzXVo2+eCvdc9/1lfXle8JgxD7 GlMSqjX/DltiEMCSYZq1w0ZpqeB/E5206NXjblc+JCVZ0aMvuCEOHHpfZ8FyJM1WgCtSQBl6cSZ i9N/XsRpU8+nqzW23AFUT4dj1I7iUBZn3ktV58BotyX7G/IyYdN0NVgMqVde91a6N2v/306nMcK Im3uck3+nDzL2xfpjfiTtSfpf0PJfkbD/BLJU0ihj6tkH8RejsrFRqbkxo8Bkmf2kMtlye7DZRb RoMbsPRXGFmr2VOnXvr7Si04MtrKQQorGZ5E7wIPx/WezkIk52yBewMw== X-Google-Smtp-Source: AGHT+IEq1VTnJQxlOmueu6s2GebaKNeFLbAzcYm2sgg1sCqMQhIRzeaeT1dxwWuPL3kl8Wo0a8Ua8A== X-Received: by 2002:a05:6a20:430a:b0:334:8d22:f94a with SMTP id adf61e73a8af0-3392f61dc01mr4867714637.1.1761121316207; Wed, 22 Oct 2025 01:21:56 -0700 (PDT) Received: from adriana-show-mem3.sjc.aristanetworks.com ([74.123.28.13]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-33e223cba14sm1854292a91.2.2025.10.22.01.21.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Oct 2025 01:21:55 -0700 (PDT) From: adriana@arista.com To: linux-arm-kernel@lists.infradead.org, jdelvare@suse.com, devicetree@vger.kernel.org, robh+dt@kernel.org, frowand.list@gmail.com Cc: linux-kernel@vger.kernel.org, vasilykh@arista.com, Adriana Nicolae Subject: [PATCH 1/1] DMI: Scan for DMI table from DTS info Date: Wed, 22 Oct 2025 01:21:29 -0700 Message-ID: <20251022082129.138217-1-adriana@arista.com> X-Mailer: git-send-email 2.47.0 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Some bootloaders like U-boot, particularly for the ARM architecture, provide SMBIOS/DMI tables at a specific memory address. However, these systems often do not boot using a full UEFI environment, which means the kernel's standard EFI DMI scanner cannot find these tables. The bootloader can specify the physical addresses of the SMBIOS and SMBIOS3 tables in the /chosen node using the "linux,smbios-table" and linux,smbios3-table properties. This patch hooks into the DMI initialization process to read these properties, map the tables, and parse the DMI information. This extra scan is performed after the standard EFI check fails but before the fallback memory scan, not to alter the order of DMI scanning for current implementation. Signed-off-by: Adriana Nicolae diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c index 70d39adf50dc..ea3ed40d0370 100644 --- a/drivers/firmware/dmi_scan.c +++ b/drivers/firmware/dmi_scan.c @@ -10,6 +10,9 @@ #include #include #include +#if IS_ENABLED(CONFIG_OF) +#include +#endif #ifndef SMBIOS_ENTRY_POINT_SCAN_START #define SMBIOS_ENTRY_POINT_SCAN_START 0xF0000 @@ -670,6 +673,70 @@ static int __init dmi_smbios3_present(const u8 *buf) return 1; } +#if IS_ENABLED(CONFIG_OF) +/** + * dmi_scan_from_dt - Find and parse DMI/SMBIOS tables from the Device Tree + * + * Checks if the bootloader has passed SMBIOS table addresses via the /chosen + * node in the Device Tree. This follows the standard kernel DT bindings and + * assumes a fixed 32-byte mapping for the entry point. + * Returns true if a valid table is found and successfully parsed. + */ +static bool __init dmi_scan_from_dt(void) +{ + struct device_node *chosen; + const __be64 *prop; + char buf[32]; + void __iomem *p; + bool dmi_available = false; + u64 addr; + int len; + + chosen = of_find_node_by_path("/chosen"); + if (!chosen) + return false; + + /* SMBIOSv3 (64-bit entry point) has priority */ + prop = of_get_property(chosen, "linux,smbios3-table", &len); + if (prop && len >= sizeof(u64)) { + addr = be64_to_cpup(prop); + + p = dmi_early_remap(addr, 32); + if (p == NULL) + goto out; + + memcpy_fromio(buf, p, sizeof(buf)); + dmi_early_unmap(p, 32); + + if (!dmi_smbios3_present(buf)) { + dmi_available = true; + goto out; + } + } + + prop = of_get_property(chosen, "linux,smbios-table", &len); + if (prop && len >= sizeof(u64)) { + addr = be64_to_cpup(prop); + + p = dmi_early_remap(addr, 32); + if (p == NULL) + goto out; + + memcpy_fromio(buf, p, sizeof(buf)); + dmi_early_unmap(p, 32); + + if (!dmi_present(buf)) + dmi_available = true; + } + +out: + of_node_put(chosen); + return dmi_available; +} +#else +static bool __init dmi_scan_from_dt(void) { return false; } +#endif /* IS_ENABLED(CONFIG_OF) */ + static void __init dmi_scan_machine(void) { char __iomem *p, *q; @@ -718,6 +785,13 @@ static void __init dmi_scan_machine(void) dmi_available = 1; return; } + } else if (IS_ENABLED(CONFIG_OF) && dmi_scan_from_dt()) { + /* + * If EFI is not present or failed, try getting SMBIOS + * tables from the Device Tree. + */ + dmi_available = 1; + return; } else if (IS_ENABLED(CONFIG_DMI_SCAN_MACHINE_NON_EFI_FALLBACK)) { p = dmi_early_remap(SMBIOS_ENTRY_POINT_SCAN_START, 0x10000); if (p == NULL)