From: alexandre.belloni@free-electrons•com (Alexandre Belloni)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] misc: atmel-secumod: Driver for Atmel "security module".
Date: Sun, 31 Jan 2016 12:34:09 +0100 [thread overview]
Message-ID: <20160131113409.GI20165@piout.net> (raw)
In-Reply-To: <alpine.LNX.2.00.1601291055520.23683@nippy.intranet>
On 29/01/2016 at 11:13:05 +1100, Finn Thain wrote :
>
> On Mon, 25 Jan 2016, David Mosberger wrote:
>
> > On Mon, Jan 25, 2016 at 4:09 AM, Alexandre Belloni
> > <alexandre.belloni@free-electrons•com> wrote:
> >
> > > I know this does more than that but I think those thre sections should
> > > be registered using the nvmem framework. The sysfs file creation and
> > > accesses then comes for free.
> >
> > I think Finn's patches would have to go in for that first, since the
> > existing nvram code is a mess. Even with Finn's patches in, I think it
> > could go either way.
>
> I think Alexandre is speaking of the nvmem subsystem (not nvram).
> Documentation/devicetree/bindings/nvmem
> Documentation/nvmem
> drivers/nvmem
>
absolutely.
> > I'm not exactly sure how some of the features of the security module
> > would be used: key management, auto erasing, there is a strange "backup
> > mode" vs "normal mode" which is not well documented, etc. So I think it
> > may well end up being sufficiently different to warrant a separate
> > driver.
>
> nvmem is not a subsystem I am familiar with, so it's not immediately clear
> to me what your driver would look like if re-written that way.
>
> Maybe it would become simpler. But if you did end up needing a separate
> misc driver as well, maybe use of the nvmem framework would actually
> increase complexity.
>
> It would depend on your requirements. But I would focus on the actual
> requirement rather than uncertain future possibilities.
>
> >
> > > Another idea is also to expose it using a genpool so it can be
> > > accessed as sram from inside the kernel.
> >
> > That may be a fine idea, but as far as our application is concerned, we
> > need user-level access to the battery-backed RAM.
>
> Right. I don't see how adding a memory allocator would help either.
>
While the immediate need is to use that sram from userspace, I think
this is valuable to already think that at some point we will need to be
able to partition and access that sram from the kernel.
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
next prev parent reply other threads:[~2016-01-31 11:34 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-21 3:57 [PATCH] misc: atmel-secumod: Driver for Atmel "security module" David Mosberger-Tang
2016-01-25 11:09 ` Alexandre Belloni
2016-01-25 16:24 ` David Mosberger
2016-01-29 0:13 ` Finn Thain
2016-01-31 11:34 ` Alexandre Belloni [this message]
2016-05-23 12:04 ` Boris Brezillon
2016-05-23 12:53 ` Boris Brezillon
2016-05-23 13:59 ` Alexandre Belloni
2016-05-10 19:02 ` [PATCH] drivers: nvmem: atmel-secumod: New driver for Atmel Secumod nvram David Mosberger-Tang
2016-05-12 5:06 ` Finn Thain
2016-05-16 20:17 ` David Mosberger-Tang
2016-05-18 16:42 ` Rob Herring
2016-05-18 20:46 ` David Mosberger
2016-05-18 21:06 ` David Mosberger-Tang
2016-05-20 19:21 ` Rob Herring
2016-05-23 8:50 ` Srinivas Kandagatla
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