open-pic device tree node and subnodes for additional functionality?

open-pic device tree node and subnodes for additional functionality?

[Kumar Gala]

On Freescale open-pic controllers we have a number of additional  
features not spec'd per openpic.  (additional timers, perf mon, PCIe  
msi, message interrupts, ...).  The problem is how to identify these  
features in the device tree.

For example we have:

                 msi@41600 {
                         compatible = "fsl,mpc8572-msi", "fsl,mpic-msi";
                         reg = <0x41600 0x80>;
                         msi-available-ranges = <0 0x100>;
                         interrupts = <
                                 0xe0 0
                                 0xe1 0
                                 0xe2 0
                                 0xe3 0
                                 0xe4 0
                                 0xe5 0
                                 0xe6 0
                                 0xe7 0>;
                         interrupt-parent = <&mpic>;
                 };

                 mpic: pic@40000 {
                         interrupt-controller;
                         #address-cells = <0>;
                         #interrupt-cells = <2>;
                         reg = <0x40000 0x40000>;
                         compatible = "chrp,open-pic";
                         device_type = "open-pic";
                 };

---

should we put msi under the pic node as a child and add ranges, etc.   
The question that raises in my mind is what does the reg property end  
up meaning.  I assume it shouldn't stay as is.

- k

Re: open-pic device tree node and subnodes for additional functionality?

[Scott Wood]

On Mon, Feb 16, 2009 at 10:58:42AM -0600, Kumar Gala wrote:
> On Freescale open-pic controllers we have a number of additional  
> features not spec'd per openpic.  (additional timers, perf mon, PCIe  
> msi, message interrupts, ...).  The problem is how to identify these  
> features in the device tree.

How about adding compatible = "fsl,CHIP-mpic", "fsl,mpic" (or something
similar) to the mpic node?

> For example we have:
> 
>                 msi@41600 {
>                         compatible = "fsl,mpc8572-msi", "fsl,mpic-msi";
>                         reg = <0x41600 0x80>;
>                         msi-available-ranges = <0 0x100>;
>                         interrupts = <
>                                 0xe0 0
>                                 0xe1 0
>                                 0xe2 0
>                                 0xe3 0
>                                 0xe4 0
>                                 0xe5 0
>                                 0xe6 0
>                                 0xe7 0>;
>                         interrupt-parent = <&mpic>;
>                 };

How much of that node's content is going to differ from one Freescale
MPIC to another?

-Scott

Re: open-pic device tree node and subnodes for additional functionality?

[Kumar Gala]

On Feb 16, 2009, at 12:12 PM, Scott Wood wrote:

> On Mon, Feb 16, 2009 at 10:58:42AM -0600, Kumar Gala wrote:
>> On Freescale open-pic controllers we have a number of additional
>> features not spec'd per openpic.  (additional timers, perf mon, PCIe
>> msi, message interrupts, ...).  The problem is how to identify these
>> features in the device tree.
>
> How about adding compatible = "fsl,CHIP-mpic", "fsl,mpic" (or  
> something
> similar) to the mpic node?
>
>> For example we have:
>>
>>                msi@41600 {
>>                        compatible = "fsl,mpc8572-msi", "fsl,mpic- 
>> msi";
>>                        reg = <0x41600 0x80>;
>>                        msi-available-ranges = <0 0x100>;
>>                        interrupts = <
>>                                0xe0 0
>>                                0xe1 0
>>                                0xe2 0
>>                                0xe3 0
>>                                0xe4 0
>>                                0xe5 0
>>                                0xe6 0
>>                                0xe7 0>;
>>                        interrupt-parent = <&mpic>;
>>                };
>
> How much of that node's content is going to differ from one Freescale
> MPIC to another?

For MSI I doubt any.  I think on some parts we might have two (or  
more) groups of MSIs.

However I want to be able to handle timers and the slightly more  
generic message interrupts.

- k

Re: open-pic device tree node and subnodes for additional functionality?

[Benjamin Herrenschmidt]

> For MSI I doubt any.  I think on some parts we might have two (or  
> more) groups of MSIs.
> 
> However I want to be able to handle timers and the slightly more  
> generic message interrupts.

You can probably add a reg and a ranges, the reg remains the same
as today as to not inflict any collateral damage, and the ranges
represents downstream addresses to child nodes msi, timers, ...

(ie, it's no big deal if the parent "reg" somewhat overlap the
childs ranges... it's only a problem if the drivers try to request
the resources in ways that collide)

Ben.