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Message-ID: <0051c8b8-f7dc-4da1-8c9a-8d8c07db5d31@quicinc.com>
Date: Mon, 28 Oct 2024 11:20:50 +0530
From: Jyothi Kumar Seerapu <quic_jseerapu@...cinc.com>
To: Vinod Koul <vkoul@...nel.org>
CC: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>,
Bjorn Andersson <andersson@...nel.org>,
Konrad Dybcio <konradybcio@...nel.org>,
Andi Shyti <andi.shyti@...nel.org>,
Sumit Semwal <sumit.semwal@...aro.org>,
Christian König
<christian.koenig@....com>,
<cros-qcom-dts-watchers@...omium.org>, <linux-arm-msm@...r.kernel.org>,
<dmaengine@...r.kernel.org>, <devicetree@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <linux-i2c@...r.kernel.org>,
<linux-media@...r.kernel.org>, <dri-devel@...ts.freedesktop.org>,
<linaro-mm-sig@...ts.linaro.org>, <quic_msavaliy@...cinc.com>,
<quic_vtanuku@...cinc.com>
Subject: Re: [PATCH v1 1/5] dt-bindings: dmaengine: qcom: gpi: Add additional
arg to dma-cell property
On 10/16/2024 10:24 AM, Vinod Koul wrote:
> On 15-10-24, 17:37, Jyothi Kumar Seerapu wrote:
>> When high performance with multiple i2c messages in a single transfer
>> is required, employ Block Event Interrupt (BEI) to trigger interrupts
>> after specific messages transfer and the last message transfer,
>> thereby reducing interrupts.
>>
>> For each i2c message transfer, a series of Transfer Request Elements(TREs)
>> must be programmed, including config tre for frequency configuration,
>> go tre for holding i2c address and dma tre for holding dma buffer address,
>> length as per the hardware programming guide. For transfer using BEI,
>> multiple I2C messages may necessitate the preparation of config, go,
>> and tx DMA TREs. However, a channel TRE size of 64 is often insufficient,
>> potentially leading to failures due to inadequate memory space.
>>
>> Add additional argument to dma-cell property for channel TRE size.
>> With this, adjust the channel TRE size via the device tree.
>> The default size is 64, but clients can modify this value based on
>> their specific requirements.
>>
>> Signed-off-by: Jyothi Kumar Seerapu <quic_jseerapu@...cinc.com>
>> ---
>> Documentation/devicetree/bindings/dma/qcom,gpi.yaml | 6 ++++--
>> 1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/dma/qcom,gpi.yaml b/Documentation/devicetree/bindings/dma/qcom,gpi.yaml
>> index 4df4e61895d2..002495921643 100644
>> --- a/Documentation/devicetree/bindings/dma/qcom,gpi.yaml
>> +++ b/Documentation/devicetree/bindings/dma/qcom,gpi.yaml
>> @@ -54,14 +54,16 @@ properties:
>> maxItems: 13
>>
>> "#dma-cells":
>> - const: 3
>> + minItems: 3
>> + maxItems: 4
>> description: >
>> DMA clients must use the format described in dma.txt, giving a phandle
>> - to the DMA controller plus the following 3 integer cells:
>> + to the DMA controller plus the following 4 integer cells:
>> - channel: if set to 0xffffffff, any available channel will be allocated
>> for the client. Otherwise, the exact channel specified will be used.
>> - seid: serial id of the client as defined in the SoC documentation.
>> - client: type of the client as defined in dt-bindings/dma/qcom-gpi.h
>> + - channel-tre-size: size of the channel TRE (transfer ring element)
>
> This is a firmware /software property, why should this be in hardware
> description?
>
Hi, Yes, this is a software property and added as a 4th argument of
"dma-cells" for configuring channel tre size, so added the description
for dma-cells.
In V2 patch, i reverted the changes and will handle with the default
channel tre size present in the GPI driver.
Regards,
JyothiKumar
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