Re: [PATCH 2/6] dt-bindings: dma: qcom-gpi: Add QSPI protocol identifier

[Jyothi Kumar Seerapu <jyothi.seerapu@oss.qualcomm.com>]

On 11/11/2026 6:07 PM, Krzysztof Kozlowski wrote:
> On Mon, Nov 09, 2026 at 08:03:29PM +0530, Jyothi Kumar Seerapu wrote:
>>
>>
>> On 11/9/2026 7:12 PM, Krzysztof Kozlowski wrote:
>>> On Fri, Nov 06, 2026 at 08:31:20PM +0530, Jyothi Kumar Seerapu wrote:
>>>> Add QCOM_GPI_QSPI to identify QSPI (Quad SPI) channels in GPI DMA
>>>> specifiers. Its value, 9, matches the GENI serial engine firmware
>>>> protocol ID for QSPI.
>>>
>>> What is GENI serial engine firmware? How does the Linux rely on it that
>>> we add bindings for it?
>>
>> Hi Krzysztof,
>> GENI firmware runs on the serial engine’s programmable sequencers and
>> implements protocols such as SPI and QSPI. Linux configures the engine and
>> submits transfers to it.
>> The existing GPI DMA specifier includes a client protocol ID. Linux programs
>> this ID into the DMA channel and selects the corresponding descriptor
>> format. QCOM_GPI_QSPI adds the QSPI protocol encoding 9 to that interface.
>> I will clarify this in the commit description in V2.
> 
> Does not really answer. I see no reason why GENI firmware needs ABI for
> Linux.
> 
This extends the existing GPI DMA binding, not a GENI firmware ABI.

The third argument of the DMA specifier in the dmas property selects
the peripheral protocol. The GPI driver programs this value into the
channel's SCRATCH_0 PROTO field and selects the corresponding transfer
descriptor format. QCOM_GPI_QSPI adds the QSPI selector to this interface.

My reference to the GENI firmware ID was misleading. I will clarify
the GPI channel requirement in v2.

> Best regards,
> Krzysztof