From: "Rafał Miłecki" <zajec5@gmail.com>
To: Rob Herring <robh@kernel.org>
Cc: "Florian Fainelli" <f.fainelli@gmail.com>,
"Vivek Unune" <npcomplete13@gmail.com>,
linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org,
devicetree@vger.kernel.org,
bcm-kernel-feedback-list@broadcom.com,
linux-kernel@vger.kernel.org, "Rafał Miłecki" <rafal@milecki.pl>
Subject: Re: [PATCH stblinux.git 1/2] dt-bindings: firmware: add Broadcom's NVRAM memory mapping
Date: Mon, 8 Mar 2021 22:37:42 +0100 [thread overview]
Message-ID: <93f1d985-54ae-9cbe-ef42-9e62b86d2633@gmail.com> (raw)
In-Reply-To: <20210308184308.GA2762703@robh.at.kernel.org>
On 08.03.2021 19:43, Rob Herring wrote:
> On Tue, Mar 02, 2021 at 08:44:04AM +0100, Rafał Miłecki wrote:
>> From: Rafał Miłecki <rafal@milecki.pl>
>>
>> NVRAM structure contains device data and can be accessed using MMIO.
>>
>> Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
>> ---
>> .../bindings/firmware/brcm,nvram.yaml | 41 +++++++++++++++++++
>> 1 file changed, 41 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/firmware/brcm,nvram.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/firmware/brcm,nvram.yaml b/Documentation/devicetree/bindings/firmware/brcm,nvram.yaml
>> new file mode 100644
>> index 000000000000..12af8e2e7c9c
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/firmware/brcm,nvram.yaml
>> @@ -0,0 +1,41 @@
>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: "http://devicetree.org/schemas/firmware/brcm,nvram.yaml#"
>> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
>> +
>> +title: Broadcom's NVRAM
>> +
>> +maintainers:
>> + - Rafał Miłecki <rafal@milecki.pl>
>> +
>> +description: |
>> + NVRAM is a structure containing device specific environment variables.
>> + It is used for storing device configuration, booting parameters and
>> + calibration data.
>
> The structure of the data is fully discoverable just from a genericish
> 'brcm,nvram'?
Yes, NVRAM structure is a header (with magic and length) and a list of
key-value pairs separated by \0. If you map memory at given address you
should verify magic and start reading key-value pairs.
Content example: foo=bar\0baz=qux\0quux(...)
There is no predefined order of pairs, set of keys or anything similar I
could think of. I can't think of anything more worth describing in DT.
> And it's a dedicated memory outside of regular RAM?
Yes
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next prev parent reply other threads:[~2021-03-08 21:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-02 7:44 [PATCH stblinux.git 1/2] dt-bindings: firmware: add Broadcom's NVRAM memory mapping Rafał Miłecki
2021-03-02 7:44 ` [PATCH stblinux.git 2/2] firmware: bcm47xx_nvram: support platform device "brcm, nvram" Rafał Miłecki
2021-03-02 16:59 ` [PATCH stblinux.git 2/2] firmware: bcm47xx_nvram: support platform device "brcm,nvram" Florian Fainelli
2021-03-03 11:44 ` Rafał Miłecki
2021-03-08 18:43 ` [PATCH stblinux.git 1/2] dt-bindings: firmware: add Broadcom's NVRAM memory mapping Rob Herring
2021-03-08 21:37 ` Rafał Miłecki [this message]
2021-03-08 21:41 ` Rafał Miłecki
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