Hi Mark,
On Mon, Jun 6, 2016 at 10:29 AM, Mark Rutland <mark.rutland@xxxxxxx> wrote:
> On Tue, May 31, 2016 at 06:25:56PM -0700, Tai Tri Nguyen wrote:
>> Hi Mark,
>
> [...]
>
>> I'm facing a problem after removing the index for MCU and MC sub-nodes.
>> The MCUs and MCs aren't always enabled depending on how DRAM DIMMs are
>> installed on the system.
>> I still need a way to associate the MCU with its indicator bit in the
>> enable mask retrieved from CSR.
>
> Ah, I see.
>
> Can you elaborate on how the indicator bits are laid out? From the
> example binding, I see multiple nodes with the same index property, so
> I'm a little confused.
>
> I guess that there's a CSR per class of node (e.g. all MCBs in one CSR
> register)? Or do several nodes share the same bit?
>
> Is there a single CSR register? Are there several? Is that bit index
> used in other registers?
In our current XGene platforms, there are 2 MCBs and each MCB has 2 MCs.
MCB0 --> MC0 and MC1
MCB1 --> MC2 and MC3
There are 2 CSR are being used (each uses 1 bit) together as indicators:
CSR1 indicates if both MCBs are active.
CSR2 indicates if both MCs of the same MCB are active.
This is the true table:
dual MCB dual MC
0 0 --> MC0 active
0 1 --> MC0/MC1 active
1 0 --> MC0/MC2 active
1 1 --> MC0/MC1/MC2/MC3 active
At the time the driver initializes, I check the 2 CSRs to come up with
the mcb_active_mask and mc_active_mask.
The index bits are used to compare against the mcb_active_mask/mc_active_mask.
>
>> For MC and MCB nodes only, can I introduce an "enable-mask" field?
>> For example:
>> "
>> pmucmcb@7e710000 {
>> compatible = "apm,xgene-pmu-mcb";
>> reg = <0x0 0x7e710000 0x0 0x1000>;
>> enable-mask = <0x00000001>;
>> };
>>
>> pmucmcb@7e730000 {
>> compatible = "apm,xgene-pmu-mcb";
>> reg = <0x0 0x7e730000 0x0 0x1000>;
>> enable-mask = <0x00000002>;
>> };
>> "
>> Or can you please give a suggestion how I can fix it?
>
> Assuming it's always a single bit, a *-bit-index property may be fine,
> and probably preferable.
>
Yes, it's always a single bit. I'll use *-bit-index for these sub-nodes.
Thanks,
--
Tai
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
