OF compatible MTD platform RAM driver ?

[Laurent Pinchart]

On Wednesday 26 March 2008 13:53, Sergei Shtylyov wrote:
> Laurent Pinchart wrote:
> 
> >>>Regarding non-volatility nothing prevents a user from using a 
> >>>volatile RAM as an MTD device, but there's little point in doing so.
> >>>Would it be acceptable for the "linear-nvram" specification
> >>>not to include > volatile RAM ? ROM chips would be excluded too. Is
> 
> >>that an issue ?
> 
> >>We actually use a volatile ram (SRAM) as an MTD device. We use it to
> >>store info from bootloader and system specific values between resets.
> 
> > So we're left with two main options.
> 
> > - Reusing the nvram device type from the Device Support Extensions. 
Volatile 
> > devices wouldn't be supported, and we'd need a separate device 
specification 
> > for linear-mapped volatile RAMs. I'm not very happy with that.
> 
> > - Using another device node with a compatible value set to "linear-ram" 
(or 
> > something similar). This would support both volatile and non-volatile 
> > devices, and a property could be added to specify if the device is 
volatile 
> > or not.
> 
> > I'd go for the second option, and I'd specify a "linear-rom" compatible 
value 
> > as well while we're at it.
> 
> > Both volatile and non-volatile RAMs can be handled by the physmap_of MTD 
> > driver. They both use the same map probe type ("map_ram"). Volatility 
isn't 
> > handled there.
> 
> > ROMs should be handled by the same driver and should use the "mtd_rom" map 
> > probe type.
> 
>     OK, let's go with it.
> 
> > As all those devices use the physmap_of MTD driver, what about 
> > using "physmap-ram" and "physmap-rom" as compatibility names ?
> 
>     Heh, we've gone thru "physmap" before -- it was labelled Linux-specific 
> name (well, I'd agree with that).

physmap stands for physically mapped. That doesn't sound Linux-specific to me, 
the fact that the MTD driver has the same name is a pure coincidence. 
linmap-rom and linmap-rom sound even more Linux-specific :-)

Could we agree on a name ? I'd like to submit a new patch.

-- 
Laurent Pinchart
CSE Semaphore Belgium

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