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Wed, 14 Oct 2026 07:05:44 -0700 (PDT) X-Received: by 2002:a05:6122:4659:20b0:5c9:f6b0:e5e0 with SMTP id 71dfb90a1353d-5e91f45e3edmr3449553e0c.3.1791986744082; Wed, 14 Oct 2026 07:05:44 -0700 (PDT) Received: from [192.168.226.26] ([178.235.128.140]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-6b203862c4esm1222206a12.16.2026.10.14.07.05.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 14 Oct 2026 07:05:43 -0700 (PDT) Message-ID: Date: Wed, 14 Oct 2026 16:05:41 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC 0/5] nvmem: Add a UEFI variable backed NVMEM provider To: Abel Vesa , Srinivas Kandagatla , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Bartosz Golaszewski , Marcel Holtmann , Luiz Augusto von Dentz , Jeff Johnson , Konrad Dybcio , Abel Vesa Cc: Bjorn Andersson , Dmitry Baryshkov , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-bluetooth@vger.kernel.org, linux-wireless@vger.kernel.org, ath12k@lists.infradead.org References: <20261014-b4-nvmem-efivar-v1-0-187c85f65018@oss.qualcomm.com> Content-Language: en-US From: Konrad Dybcio In-Reply-To: <20261014-b4-nvmem-efivar-v1-0-187c85f65018@oss.qualcomm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Proofpoint-ORIG-GUID: qMd6ksh4UxHafVI13f1AzC-t4EcgiEYf X-Proofpoint-GUID: qMd6ksh4UxHafVI13f1AzC-t4EcgiEYf X-Proofpoint-Spam-Info: AW1haW4tMjYxMDE0MDA1NiBTYWx0ZWRfX32KmbtjHRIto QR7o3GQ9vKZt2YlAcZn21ppTDKCoKqMSDXcj6l0Nm8zI9cEx3rsgok7Pq98txO7lFBaf43AMVCY LLvi3PzGCDsxMkY4SsAyUwBos4HfAYw= X-Authority-Analysis: v=2.4 cv=NctzRGD4 c=1 sm=1 tr=0 ts=6acf8c3a cx=c_pps a=+D9SDfe9YZWTjADjLiQY5g==:117 a=PRfkaYvzSr8QmIIGAkY2Sg==:17 a=IkcTkHD0fZMA:10 a=660iZSQnnn4A:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=ZpdpYltYx_vBUK5n70dp:22 a=VwQbUJbxAAAA:8 a=EUspDBNiAAAA:8 a=PngBsCrCUa3bum75zpkA:9 a=QEXdDO2ut3YA:10 a=vmgOmaN-Xu0dpDh8OwbV:22 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMDE0MDA1NiBTYWx0ZWRfXxjgI5mJ0WciZ xuNDYQ9hw3buQAUiYsqILdQE+1b5epqoVytK+YiKqvDgTPTd+9rJHpX1Fc66AR9hWu4OBaL+kXD cT2lzUpt6uSWLA4P+zln6Ka3lX7ScPLHmpH6xkMq3pYNSDz70h0WLogByq6Mzrg7QnTunf+aRY1 YF70+Of9mPY8YzBSpWkYNPr7MK+us0ixLebzuNUmpUJgu2mOiukd1LlX1ihNkoXcQIV3zS+umK1 5EC/70hZIEp1O7g5H/+MUpS9Xqpe8benHahSqjnrRj4ugEXhwqhgBtbbsQVVICLGwgKW1YtPwC3 mKKAagcXZocFVsiGmSNYl8QFL5KAq3QX+gwU737Pu2yKnzBJ8LCqAlU6x9pOEoG1ZhG59vunwlm mQmKd4A62WD6W7CSkfwtoOsLIbV7HBXye6IuxPiIwtEyqHw3J7nUp7J+mGgWw2dKapTwQK7NBZ7 M5hSktKcAbmEZutOSxw== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-10-13_01,2026-10-09_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 clxscore=1015 suspectscore=0 lowpriorityscore=0 spamscore=0 phishscore=0 impostorscore=0 bulkscore=0 malwarescore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2610080000 definitions=main-2610140056 On 10/14/26 3:02 PM, Abel Vesa wrote: > This is an RFC: I do not expect it to be merged as-is, it is sent to get > feedback on the approach. > > Some values a platform needs (for example the WLAN and Bluetooth MAC > addresses on the Qualcomm laptops) are not always available to the kernel > in a convenient form. They may live in firmware-owned SPI-NOR storage > (e.g. a DPP partition) for which there is no straightforward, universally > working way to read them from the non-secure world. > > As an alternative, this series allows such values to be provisioned once > into a UEFI variable and consumed in the kernel. It adds a generic NVMEM > provider that exposes the contents of a UEFI variable as an NVMEM device, > so the data can be consumed through the standard nvmem-cells bindings. > MAC addresses are just the motivating use case; the provider itself is > generic. > > The first two patches are the actual proposal: > > - dt-bindings: nvmem: Add UEFI variable NVMEM provider > - nvmem: Add UEFI variable NVMEM provider > > The remaining three patches are included only to illustrate how a > consumer would use the provider; they are not meant for merging as part > of this series: > > - Bluetooth: hci_qca: consume a "bd-address" nvmem cell > - wifi: ath12k: consume a "mac-address" cell > - arm64: dts: qcom: glymur-crd: wire both to a "MacAddresses" variable I think we can take advantage of Loic's work here https://lore.kernel.org/linux-arm-msm/20260507-block-as-nvmem-v2-0-bf17edd5134e@oss.qualcomm.com/ Konrad