From: Sergei Shtylyov <sshtylyov@ru•mvista.com>
To: Laurent Pinchart <laurentp@cse-semaphore•com>
Cc: ben@simtec•co.uk, linuxppc-dev@ozlabs•org,
linux-mtd@lists•infradead.org,
David Gibson <david@gibson•dropbear.id.au>
Subject: Re: OF compatible MTD platform RAM driver ?
Date: Tue, 25 Mar 2008 19:23:23 +0300 [thread overview]
Message-ID: <47E926FB.3030900@ru.mvista.com> (raw)
In-Reply-To: <200803251651.42608.laurentp@cse-semaphore.com>
Laurent Pinchart wrote:
>>>We're talking about a very specific type of RAM, used for permanent storage
>>>with a battery backup. The RAM is really meant to be used as an MTD device
>>>and as such I think it makes sense to describe it as an mtd-compatible device
>>>on the local bus.
>>>What about the following definition for the RAM node ?
>>> nvram@2,0000 {
>> Note that there's a OF "device_type" of "nvram", so your (generic) device
>>name seems to add some mess. (IIRC, that OF device type didn't actually
>>represent a "real" device, and only served to provide access to NVRAM for OF).
> Ok.
Well, I might have gone too far here -- it should be a real device
(spec'ed in Device Support Extensions recommended practice). It's just that
the spec didn't mention "reg" property, only "#bytes" (the device capacity).
So, it may be worth considering...
>>> compatible = "mtd,ram";
>> The part before comma should be a company name or a stock ticker. What did
>>you mean here?
> I didn't know that. Let's say I meant "mtd-ram" :-)
>>> reg = <2 0x0000 0x00100000>;
>>> bank-width = <2>;
>>> };
>>>Or should the node have a device-type property of either 'ram' or 'rom' with
>>>the compatible property just referencing MTD ?
>> The "device_type" properties are not required and their further creation
>>has been discouraged on liunxppc-dev.
> What about
> mtdram@2,0000 {
> compatible = "mtd-ram";
> reg = <2 0x0000 0x00100000>;
> bank-width = <2>;
> };
> ROMs could use "mtd-rom" for their compatible property.
Heh, there was a whole company against mentioning "mtd" when we started
working on this (of course, the first idea was to call the flash device type
"mtd"). I don't think "mtd" looks good here -- I'd suggest "flash-ram" (if
this is just a linearly mapped NVRAM).
> Best regards,
WBR, Sergei
next prev parent reply other threads:[~2008-03-25 16:22 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-10 15:06 OF compatible MTD platform RAM driver ? Laurent Pinchart
2008-03-10 17:00 ` Rune Torgersen
2008-03-11 0:45 ` David Gibson
2008-03-11 10:39 ` Laurent Pinchart
2008-03-11 22:40 ` David Gibson
2008-03-25 14:36 ` Laurent Pinchart
2008-03-25 15:29 ` Sergei Shtylyov
2008-03-25 15:51 ` Laurent Pinchart
2008-03-25 16:23 ` Sergei Shtylyov [this message]
2008-03-25 16:44 ` Laurent Pinchart
2008-03-25 17:02 ` Sergei Shtylyov
2008-03-25 17:23 ` Laurent Pinchart
2008-03-25 17:37 ` Sergei Shtylyov
2008-03-25 17:56 ` Rune Torgersen
2008-03-25 18:14 ` Laurent Pinchart
2008-03-26 12:53 ` Sergei Shtylyov
2008-03-27 9:13 ` Laurent Pinchart
2008-03-27 10:03 ` David Gibson
2008-03-27 12:23 ` Sergei Shtylyov
2008-03-28 0:07 ` David Gibson
2008-03-28 12:31 ` Sergei Shtylyov
2008-03-27 14:31 ` Laurent Pinchart
2008-03-28 0:09 ` David Gibson
2008-03-30 18:15 ` Segher Boessenkool
2008-03-30 21:16 ` Paul Mackerras
2008-03-30 22:39 ` Segher Boessenkool
2008-03-31 0:42 ` Paul Mackerras
2008-03-31 0:59 ` Segher Boessenkool
2008-03-31 1:24 ` Segher Boessenkool
2008-03-31 8:21 ` Laurent Pinchart
2008-03-31 12:21 ` Segher Boessenkool
2008-03-26 15:06 ` Segher Boessenkool
2008-03-26 15:40 ` Sergei Shtylyov
2008-03-27 9:24 ` Laurent Pinchart
2008-03-30 18:12 ` Segher Boessenkool
2008-03-26 15:09 ` Segher Boessenkool
2008-03-11 15:00 ` Rune Torgersen
2008-03-11 22:41 ` David Gibson
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