From: Martyn Welch <martyn.welch@gefanuc•com>
To: Milton Miller <miltonm@bga•com>,
linuxppc-dev list <linuxppc-dev@ozlabs•org>
Subject: Re: [PATCH] powerpc: Add support to access the flash on SLOF based systems
Date: Mon, 12 Jan 2009 17:05:16 +0000 [thread overview]
Message-ID: <496B784C.5010800@gefanuc.com> (raw)
In-Reply-To: <20090110195040.GA19945@lisas.de>
Adrian Reber wrote:
> On Sat, Jan 10, 2009 at 11:52:56AM -0600, Milton Miller wrote:
>> Normally such drivers are written and mtd drivers.
>>
>> If slof were not an of implementation I would just say put the right
>> properties on the node in the device tree, but the kernel should adapt
>> to real OF. It should be easy to write a driver to hook up a mtd
>> platform device if this is a direct mapped flash.
>
> The reason why I did not use mtd is that part of the flash is used by
> the firmware image and I do not know if that works with mtd, if only a
> part of the flash can be used. SLOF does also a "CRC" check over the
> firmware image, so that image must have valid SLOF "CRC". The flash is
> a direct mapped flash, but the size of the firmware can vary.
>
It can. MTD can create "partitions" within the flash, for an example see lines 84-110 of arch/powerpc/bootdts/sbc8641d.dts (http://tinyurl.com/7k2kym)
Partitions can also be labeled as read-only, I guess the CRC could be checked from userspace as necessary.
HTH,
Martyn
--
Martyn Welch MEng MPhil MIET (Principal Software Engineer) T:+44(0)1327322748
GE Fanuc Intelligent Platforms Ltd, |Registered in England and Wales
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next prev parent reply other threads:[~2009-01-12 17:05 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-10 15:31 [PATCH] powerpc: Add support to access the flash on SLOF based systems Adrian Reber
2009-01-10 17:52 ` Milton Miller
2009-01-10 19:50 ` Adrian Reber
2009-01-12 15:51 ` Milton Miller
2009-01-14 15:56 ` Adrian Reber
2009-01-12 17:05 ` Martyn Welch [this message]
2009-01-12 17:29 ` Arnd Bergmann
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