Re: [PATCH v4 01/15] bindings: soc: ti: add documentation for k3 ringacc

[Peter Ujfalusi <peter.ujfalusi@ti.com>]

On 11/11/2019 6.07, Vinod Koul wrote:
> On 01-11-19, 10:41, Peter Ujfalusi wrote:
>> From: Grygorii Strashko <grygorii.strashko@ti.com>
>>
>> The Ring Accelerator (RINGACC or RA) provides hardware acceleration to
>> enable straightforward passing of work between a producer and a consumer.
>> There is one RINGACC module per NAVSS on TI AM65x and j721e.
>>
>> This patch introduces RINGACC device tree bindings.
>>
>> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
>> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
>> Reviewed-by: Rob Herring <robh@kernel.org>
>> ---
>>  .../devicetree/bindings/soc/ti/k3-ringacc.txt | 59 +++++++++++++++++++
>>  1 file changed, 59 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/soc/ti/k3-ringacc.txt
>>
>> diff --git a/Documentation/devicetree/bindings/soc/ti/k3-ringacc.txt b/Documentation/devicetree/bindings/soc/ti/k3-ringacc.txt
>> new file mode 100644
>> index 000000000000..86954cf4fa99
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/soc/ti/k3-ringacc.txt
>> @@ -0,0 +1,59 @@
>> +* Texas Instruments K3 NavigatorSS Ring Accelerator
>> +
>> +The Ring Accelerator (RA) is a machine which converts read/write accesses
>> +from/to a constant address into corresponding read/write accesses from/to a
>> +circular data structure in memory. The RA eliminates the need for each DMA
>> +controller which needs to access ring elements from having to know the current
>> +state of the ring (base address, current offset). The DMA controller
>> +performs a read or write access to a specific address range (which maps to the
>> +source interface on the RA) and the RA replaces the address for the transaction
>> +with a new address which corresponds to the head or tail element of the ring
>> +(head for reads, tail for writes).
>> +
>> +The Ring Accelerator is a hardware module that is responsible for accelerating
>> +management of the packet queues. The K3 SoCs can have more than one RA instances
>> +
>> +Required properties:
>> +- compatible	: Must be "ti,am654-navss-ringacc";
>> +- reg		: Should contain register location and length of the following
>> +		  named register regions.
>> +- reg-names	: should be
>> +		  "rt" - The RA Ring Real-time Control/Status Registers
>> +		  "fifos" - The RA Queues Registers
>> +		  "proxy_gcfg" - The RA Proxy Global Config Registers
>> +		  "proxy_target" - The RA Proxy Datapath Registers
>> +- ti,num-rings	: Number of rings supported by RA
>> +- ti,sci-rm-range-gp-rings : TI-SCI RM subtype for GP ring range
>> +- ti,sci	: phandle on TI-SCI compatible System controller node
>> +- ti,sci-dev-id	: TI-SCI device id
>> +- msi-parent	: phandle for "ti,sci-inta" interrupt controller
>> +
>> +Optional properties:
>> + -- ti,dma-ring-reset-quirk : enable ringacc / udma ring state interoperability
>> +		  issue software w/a
>> +
>> +Example:
>> +
>> +ringacc: ringacc@3c000000 {
>> +	compatible = "ti,am654-navss-ringacc";
>> +	reg =	<0x0 0x3c000000 0x0 0x400000>,
>> +		<0x0 0x38000000 0x0 0x400000>,
>> +		<0x0 0x31120000 0x0 0x100>,
>> +		<0x0 0x33000000 0x0 0x40000>;
>> +	reg-names = "rt", "fifos",
>> +		    "proxy_gcfg", "proxy_target";
>> +	ti,num-rings = <818>;
>> +	ti,sci-rm-range-gp-rings = <0x2>; /* GP ring range */
>> +	ti,dma-ring-reset-quirk;
>> +	ti,sci = <&dmsc>;
>> +	ti,sci-dev-id = <187>;
> 
> why do we need dev-id for? doesn't phandle the line above help?

the ti,sci-dev-id is the device ID of the ring accelerator which is
needed for the resource management implemented in sysfw.

This is based on how the ti,sci-inta binding has defined it:
Documentation/devicetree/bindings/interrupt-controller/ti,sci-inta.txt

I'll update the document to make it clear.

- Péter

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