Re: [PATCH v4 15/23] dt-bindings: PCI: dra7xx: Add dt bindings to enable unaligned access

[Kishon Vijay Abraham I]

Hi Rob,

On Tuesday 21 March 2017 03:13 AM, Rob Herring wrote:
> On Mon, Mar 13, 2017 at 07:52:51PM +0530, Kishon Vijay Abraham I wrote:
>> Update device tree binding documentation of TI's dra7xx PCI
>> controller to include property for enabling unaligned mem access.
>>
>> Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx>
>> ---
>>  Documentation/devicetree/bindings/pci/ti-pci.txt | 5 +++++
>>  1 file changed, 5 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/pci/ti-pci.txt b/Documentation/devicetree/bindings/pci/ti-pci.txt
>> index 190828a5f32a..b69dd7dbd29e 100644
>> --- a/Documentation/devicetree/bindings/pci/ti-pci.txt
>> +++ b/Documentation/devicetree/bindings/pci/ti-pci.txt
>> @@ -39,6 +39,11 @@ DEVICE MODE
>>   - interrupts : one interrupt entries must be specified for main interrupt.
>>   - num-ib-windows : number of inbound address translation windows
>>   - num-ob-windows : number of outbound address translation windows
>> + - ti,syscon-unaligned-access: phandle to the syscon dt node. The 1st argument
>> +			       should contain the register offset within syscon
>> +			       and the 2nd argument should contain the bit field
>> +			       for setting the bit to enable unaligned
>> +			       access.
> 
> This should be setup by the firmware/bootloader or some platform code. 
> Why does the PCI host need to configure this?

That would create a dependency between the bootloader and kernel which is
usually avoided in platforms like dra7xx.

Thanks
Kishon