From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp2.infineon.com (smtp2.infineon.com [217.10.52.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D89003EA96E for ; Wed, 1 Jul 2026 09:50:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.10.52.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782899422; cv=none; b=JcLoNTppDDarZUYO9UH+pLdGhUIkTlER4jRsi0Ejzh83sRho0K6jAfNDyhUDhJFXeuber1Gewn83Uxy51YjTmBxcGfzCb5SkFXF01RGZrqbA/qxMZnkw9+t9LMdWQQO568h/X0DZHieruNRRY8xcDBoBsH3oD4X6M/iENhCyAhE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782899422; c=relaxed/simple; bh=bikzSr+NRQS0BStBxaDankRVM0j6fnovMuiAylead9M=; h=From:To:CC:Subject:Date:Message-ID:References:In-Reply-To: Content-Type:MIME-Version; b=aNxsDudKruNCTK++CUTMNjatE0U09kz/9D9mxkbeWTi61vUoieRcXo1TDXTZx7Sy7mVPtymJmNDD3fww4RDKj6OwdRO0mVFrE4hmdS1ewcsU3I1SbJ3+1DFXu8TmJSsIlsLQCOvgxv1olwJ6mIociw5m0AiS+TWmjojVxLYGxWE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=infineon.com; spf=pass smtp.mailfrom=infineon.com; dkim=pass (1024-bit key) header.d=infineon.com header.i=@infineon.com header.b=S/RN7J1e; arc=none smtp.client-ip=217.10.52.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=infineon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=infineon.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=infineon.com header.i=@infineon.com header.b="S/RN7J1e" DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=infineon.com; i=@infineon.com; q=dns/txt; s=IFXMAIL; t=1782899421; x=1814435421; h=from:to:cc:subject:date:message-id:references: in-reply-to:content-transfer-encoding:mime-version; bh=bikzSr+NRQS0BStBxaDankRVM0j6fnovMuiAylead9M=; b=S/RN7J1eTbu55vCX9TeVetYeFFTbQnGsWnZH0wD4tl8inN8QEVXGnsK0 pqsmnIaSezBdHNbIIlePf2R7MbRjpyyoetAu4857CpSA+5zWjUdeyIlUQ j2I4jEhOdGM1oyuM32OLrmpFCtFL8Z/IglQpAi7h/jZcsSUjbUahjRJxo o=; X-CSE-ConnectionGUID: g2aqPEuVQAeQXqvBZU2m+Q== X-CSE-MsgGUID: Sef72jcpQhG0MzYbXN0sVA== X-IronPort-AV: E=McAfee;i="6800,10657,11833"; a="165441956" X-IronPort-AV: E=Sophos;i="6.24,235,1774306800"; d="scan'208";a="165441956" X-Amp-Result: SKIPPED(no attachment in message) Received: from unknown (HELO MUCSE822.infineon.com) ([172.23.29.53]) by smtp2.infineon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Jul 2026 11:49:08 +0200 Received: from MUCSE816.infineon.com (172.23.29.42) by MUCSE822.infineon.com (172.23.29.53) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.43; Wed, 1 Jul 2026 11:49:07 +0200 Received: from MUCSE815.infineon.com (172.23.29.41) by MUCSE816.infineon.com (172.23.29.42) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.43; Wed, 1 Jul 2026 11:49:07 +0200 Received: from MUCSE815.infineon.com ([fe80::b54c:c0bd:546c:c9be]) by MUCSE815.infineon.com ([fe80::b54c:c0bd:546c:c9be%12]) with mapi id 15.02.2562.043; Wed, 1 Jul 2026 11:49:07 +0200 From: To: CC: , , , , , , , , Subject: RE: [PATCH v2 1/3] Revert "mtd: spi-nor: remove Fujitsu MB85RS1MT support" Thread-Topic: [PATCH v2 1/3] Revert "mtd: spi-nor: remove Fujitsu MB85RS1MT support" Thread-Index: AQHdBRKBdcAN9mfv+k6bdaeZDwvjfLZWt11QgADFb4CAAFitgP//+/8AgACbEMA= Date: Wed, 1 Jul 2026 09:49:07 +0000 Message-ID: <490fc98b2996487fba3abd62176bb1dd@infineon.com> References: <2b8390c0aaae4203af318f9a5edbb0eb@infineon.com> <20260701020856.217664-1-ronan.dalton@alliedtelesis.co.nz> In-Reply-To: <20260701020856.217664-1-ronan.dalton@alliedtelesis.co.nz> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Hi Ronan, > Hi Takahiro, >=20 > > We don't add any FRAM chips in SPI-NOR... >=20 > The SPI-NOR subsystem has support for the cy15x104q chips, which are > FRAM chips. There is also support for Everspin MRAM chips, which are > comparible to FRAM (and are also of small size). >=20 > Because of this, we thought there was precident to add support for this > chip. I was under the impression that the opcodes used to interact with > the chip had a greater significance than the underlying technology used, > and this chip fits in with the other spi-nor chips based on that. Feel > free to correct me if I'm wrong here. >=20 > > > The use is for a small amount of additional storage separate to the m= ain > > > system NAND flash for some small "critical" files that we don't want = to > > > lose. We've been using devices like the mchp23lcv1024 and mr25h40 on > > > other products for some time. > > > > > For that use, how about using tmpfs with NVMEM backup? >=20 > Could you elaborate on this? I'm familiar with tmpfs but not with using > NVMEM as a backup for it. Is there some method of syncing a tmpfs to > NVMEM that the kernel provides? >=20 I didn't mean any kernel features, but we can dump tmpfs contents from/to FRAM chip (exposed as NVMEM device) by 'dd'. Doesn't it meet your system's requirement? > Thanks, > Ronan.