[PATCH v2 2/2] powerpc/mpic: add global timer support

[Wang Dongsheng-B40534]

> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Tuesday, August 14, 2012 10:19 AM
> To: Wang Dongsheng-B40534
> Cc: Wood Scott-B07421; benh at kernel.crashing.org; paulus at samba.org;
> linuxppc-dev at lists.ozlabs.org; Gala Kumar-B11780; Li Yang-R58472
> Subject: Re: [PATCH v2 2/2] powerpc/mpic: add global timer support
> 
> On 08/13/2012 09:15 PM, Wang Dongsheng-B40534 wrote:
> >
> >
> >> -----Original Message-----
> >> From: Wood Scott-B07421
> >> Sent: Tuesday, August 14, 2012 10:05 AM
> >> To: Wang Dongsheng-B40534
> >> Cc: Wood Scott-B07421; benh at kernel.crashing.org; paulus at samba.org;
> >> linuxppc-dev at lists.ozlabs.org; Gala Kumar-B11780; Li Yang-R58472
> >> Subject: Re: [PATCH v2 2/2] powerpc/mpic: add global timer support
> >>
> >> On 08/13/2012 09:00 PM, Wang Dongsheng-B40534 wrote:
> >>>
> >>>
> >>>> -----Original Message-----
> >>>> From: Wood Scott-B07421
> >>>> Sent: Tuesday, August 14, 2012 1:37 AM
> >>>> To: Wang Dongsheng-B40534
> >>>> Cc: Wood Scott-B07421; benh at kernel.crashing.org; paulus at samba.org;
> >>>> linuxppc-dev at lists.ozlabs.org; Gala Kumar-B11780; Li Yang-R58472
> >>>> Subject: Re: [PATCH v2 2/2] powerpc/mpic: add global timer support
> >>>>
> >>>> On 08/13/2012 01:18 AM, Wang Dongsheng-B40534 wrote:
> >>>>>>> +	p = of_get_property(np, "available-ranges", &len);
> >>>>>>> +	if (p && len % (2 * sizeof(u32)) != 0) {
> >>>>>>> +		pr_err("%s: malformed fsl,available-ranges property.\n",
> >>>>>>> +				np->full_name);
> >>>>>>> +		return -EINVAL;
> >>>>>>> +	}
> >>>>>>
> >>>>>> You need to support fsl,available-ranges since that's in an
> >>>>>> accepted binding and people could have partitioned setups already
> >> using it.
> >>>>>>
> >>>>> [Wang Dongsheng] FSL chip or OPEN-PIC specification(Only a group)
> >>>>> in each group only four timer. This is unified. So i use a generic
> name.
> >>>>> I think there is not compatible with existing mpic timer nodes.
> >>>>
> >>>> We need to be compatible with existing trees, so you'd need to
> >>>> check for both -- but I think any further discussion of the details
> >>>> is premature until we decide whether this is worthwhile to begin
> >>>> with (both the support of non-FSL timers, and the creation of a new
> >>>> device tree binding which will not be implemented by many of the
> >>>> machines that have non-FSL openpic because they run real Open
> Firmware).
> >>>>
> >>> [Wang Dongsheng]
> >>> 	p = of_get_property(np, "available-ranges", &len);
> >>> 	if (!p)
> >>> 		p = of_get_property(np, "fsl,available-ranges", &len);
> >>>
> >>> 	this code be compatible with existing trees.
> >>
> >> Yes, that's what I meant by checking both.
> >>
> >> I still think we need to discuss why we're doing this first.  What
> >> specific machines are going to have these new openpic timer nodes?
> >>
> > [Wang Dongsheng] It's support to power management awakening. At
> > present, the power management more and more important. This way is
> > important to wake up machine. At least need support power management
> > of machine still needs such a driver.
> 
> I mean specifically for the non-Freescale openpic nodes.
> 
[Wang Dongsheng] I think non-Freescale chips can also use this function
to wake up the machine. And There is also an important feature, It can 
periodically generate an interrupt. For example, the network periodically
check the hardware device(link status).
> -Scott