Re: [PATCH 1/2] bcma: register bcma as device tree driver

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On 09/13/2014 05:13 PM, Arend van Spriel wrote:
> On 09/13/14 15:37, Hauke Mehrtens wrote:
>> This driver is used by the bcm53xx ARM SoC code. Now it is possible to
>> give the address of the chipcommon core in device tree and bcma will
>> search for all the other cores.
>>
>> Signed-off-by: Hauke Mehrtens<hauke@xxxxxxxxxx>
>> ---
>>   Documentation/devicetree/bindings/bus/bcma.txt | 41 +++++++++++++
>>   drivers/bcma/bcma_private.h                    | 16 +++++
>>   drivers/bcma/host_soc.c                        | 82
>> ++++++++++++++++++++++++++
>>   drivers/bcma/main.c                            | 10 ++++
>>   include/linux/bcma/bcma.h                      |  2 +
>>   5 files changed, 151 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/bus/bcma.txt
>>
>> This is based on wireless-testing and should go into that tree.
>>
>> changes since:
>> RFC:
>>   - reworded the irq description
>>   - improved the example
>>   - hocked into bcma_modeinit() and bcma_modexit()
>>
>> diff --git a/Documentation/devicetree/bindings/bus/bcma.txt
>> b/Documentation/devicetree/bindings/bus/bcma.txt
>> new file mode 100644
>> index 0000000..17e095f
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/bus/bcma.txt
>> @@ -0,0 +1,41 @@
>> +Broadcom AIX SoC bcma bus driver
> 
> Hi Hauke,
> 
> First of all a typo used all over the place: AIX should be AXI.

I will fix that.

> The backplane in Broadcom SoC is ARM AXI with additional plugin option
> to make it discoverable. Indeed the IRQ info is not included, but I see
> no reason for specifying the register space for the cores in device-tree
> as that is discoverable by bcma.

I specified the register space to make it possible to connect the device
tree entry with the core. After the cores are automatically discovered,
bcma searches for entry core found, for an device tree entry with the
same address space and uses the irq number from that entry. If there is
a core defined in device tree which is not found by bcma it will just be
ignored. If a core is not specified in device tree it will get
registered, but it will not get an IRQ.
This was the most stable way I came up with, I also thought about using
the core number, like assign the this IRQ to core number 5, but the core
numbers could change when we do changes to bcma.

In the Broadcom vendor code there is a list with the IRQ numbers which
get assigned to a specific core type. For example there is a list with 4
IRQ numbers which get assigned to the first 4 Ethernet cores. This would
also work, but I do not know how to do this in device tree.

Hauke
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