netdev - Re: [PATCH v2 06/29] mtd: Add support for reading MTD devices via the nvmem API

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <e4ea4614-4673-020c-641d-30c94e7b761a@linaro.org>
Date:   Tue, 21 Aug 2018 14:37:37 +0100
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     Boris Brezillon <boris.brezillon@...tlin.com>
Cc:     Alban <albeu@...e.fr>, Bartosz Golaszewski <brgl@...ev.pl>,
        Jonathan Corbet <corbet@....net>, Sekhar Nori <nsekhar@...com>,
        Kevin Hilman <khilman@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        David Woodhouse <dwmw2@...radead.org>,
        Brian Norris <computersforpeace@...il.com>,
        Marek Vasut <marek.vasut@...il.com>,
        Richard Weinberger <richard@....at>,
        Grygorii Strashko <grygorii.strashko@...com>,
        "David S . Miller" <davem@...emloft.net>,
        Naren <naren.kernel@...il.com>,
        Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Lukas Wunner <lukas@...ner.de>,
        Dan Carpenter <dan.carpenter@...cle.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Ivan Khoronzhuk <ivan.khoronzhuk@...aro.org>,
        Sven Van Asbroeck <svendev@...x.com>,
        Paolo Abeni <pabeni@...hat.com>, Rob Herring <robh@...nel.org>,
        David Lechner <david@...hnology.com>,
        Andrew Lunn <andrew@...n.ch>, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-i2c@...r.kernel.org, linux-mtd@...ts.infradead.org,
        linux-omap@...r.kernel.org, netdev@...r.kernel.org,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Subject: Re: [PATCH v2 06/29] mtd: Add support for reading MTD devices via the
 nvmem API



On 21/08/18 14:34, Srinivas Kandagatla wrote:
> 
> 
> On 21/08/18 12:31, Boris Brezillon wrote:
>>>     * struct nvmem_config - NVMEM device configuration
>>> @@ -58,6 +62,7 @@ struct nvmem_config {
>>>           bool                    root_only;
>>>           nvmem_reg_read_t        reg_read;
>>>           nvmem_reg_write_t       reg_write;
>>> +       nvmem_match_t           match;
>>>           int     size;
>>>           int     word_size;
>>>           int     stride;
>>>
>> That might work if nvmem cells are defined directly under the mtdnode.
> Layout should not matter! which is the purpose of this callback.
> 
> The only purpose of this callback is to tell nvmem core that the 
> node(nvmem cell) belongs to that provider or not, if it is then we 
> successfully found the provider. Its up to the provider on which layout 
> it describes nvmem cells. Additionally the provider can add additional 
> sanity checks in this match function to ensure that cell is correctly 
> represented.
> 
> 
>> If we go for this approach, I'd recommend replacing this ->match() hook
>> by ->is_nvmem_cell() and pass it the cell node instead of the nvmem
>> node, because what we're really after here is knowing which subnode is
>> an nvmem cell and which subnode is not.
> 
> I agree on passing cell node instead of its parent. Regarding basic 
> validating if its nvmem cell or not, we can check compatible string in 
> nvmem core if we decide to use "nvmem-cell" compatible.
> 
> Also just in case if you missed this, nvmem would not iterate the
Sorry !! i hit send button too quickly I guess.

What I meant to say here, is that nvmem core would not iterate the 
provider node in any case.

Only time it looks at the cell node is when a consumer requests for the 
cell.

--srini