[PATCHv5 0/3] Introduce the /proc/socinfo and use it to export OMAP data

Maxime Coquelin maxime.coquelin-nonst at stericsson.com
Wed Mar 2 03:23:03 EST 2011

On 03/02/2011 03:55 AM, Saravana Kannan wrote:
> On 03/01/2011 06:41 PM, Ryan Mallon wrote:
>> On 03/02/2011 03:23 PM, Saravana Kannan wrote:
>>> I don't have any attachment to the "arch" file suggestion. If there is a
>>> better solution to identify the different implementations of socinfo
>>> without having to maintain some "unique id" list in the kernel, then I'm
>>> all for it. But cpuinfo is not it.
>> Sorry I am confusing the 'arch' and 'mach' bits here. I definitely have
>> an objection to having an 'arch' file (i.e. ARM). A 'mach' (i.e. omap)
>> file makes a bit more sense, but should probably be called 'mach' rather
>> than 'arch' to avoid this confusion :-).
> Sorry for the confusion. Sure, I don't care much for the filename as
> long as we can all agree on it. I care more about the content of the
> file (using names very close to xxxx in mach-xxxx). I like "soc-family"
> better since it's generic enough to not force, say omap3 and omap4, to
> report different values.
> Linus Walleij, Eduardo, Maxime, Andrei,
> Would like to hear your opinion on the file name (soc-family vs. mach vs
> <somethingelse>) and the path /sys/devices/system/soc/.
> If we settle on this, may be it would be easier to get this through.

I think we should have a tree like this :

/sys/devices/system/soc/unique_id<- Unified way to export an ID for all machs
/sys/devices/system/soc/mach/name<- Name of the mach
/sys/devices/system/soc/mach/bar_id<- Vendors may have several/different IDs to export (IDCODE for OMAP, Production ID...)

Linus, do you agree?

>> I still think it is a solution in search of a problem though. What
>> userspace programs need to know what specific SoC they are on? My
>> feeling is that if userspace needs to know this information, then it is
>> probably dicking around with things that should be managed by the
>> kernel. Differences in available peripherals, etc can be determined by
>> looking at existing sysfs files.
> I certainly have seen several use cases. Couple of easy examples:
> * A lot of test scripts would find this very useful. For example, some
> clock (present is all/most MSMs) shouldn't be tested on some SOCs as it
> would lock up the system if you try to turn it off while the CPU is running.
> * Some of the user space tools might want to report different "product
> id/type" (nothing to do with USB, etc) depending on what SOC it is
> running on.

For example, we have some user-space tools which need to have serial 
number to write it in logs.

> Thank,
> Saravana
> P.S: Removed felipe.balbi at nokia.com<felipe.balbi at nokia.com>  since I
> keep getting delivery failure emails.

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