On Tue, Oct 15, 2024 at 03:33:00PM GMT, Krzysztof Kozlowski wrote:
On 15/10/2024 14:07, 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.
Adjust the channel TRE size through the device tree. The default size is 64, but clients can modify this value based on their heigher channel TRE size requirements.
Signed-off-by: Jyothi Kumar Seerapu quic_jseerapu@quicinc.com
arch/arm64/boot/dts/qcom/sc7280.dtsi | 132 +++++++++++++-------------- 1 file changed, 66 insertions(+), 66 deletions(-)
diff --git a/arch/arm64/boot/dts/qcom/sc7280.dtsi b/arch/arm64/boot/dts/qcom/sc7280.dtsi index 3d8410683402..c7c0e15ff9d3 100644 --- a/arch/arm64/boot/dts/qcom/sc7280.dtsi +++ b/arch/arm64/boot/dts/qcom/sc7280.dtsi @@ -1064,7 +1064,7 @@ }; gpi_dma0: dma-controller@900000 {
#dma-cells = <3>;
#dma-cells = <4>; compatible = "qcom,sc7280-gpi-dma", "qcom,sm6350-gpi-dma"; reg = <0 0x00900000 0 0x60000>; interrupts = <GIC_SPI 244 IRQ_TYPE_LEVEL_HIGH>,@@ -1114,8 +1114,8 @@ "qup-memory"; power-domains = <&rpmhpd SC7280_CX>; required-opps = <&rpmhpd_opp_low_svs>;
dmas = <&gpi_dma0 0 0 QCOM_GPI_I2C>,<&gpi_dma0 1 0 QCOM_GPI_I2C>;
dmas = <&gpi_dma0 0 0 QCOM_GPI_I2C 64>,<&gpi_dma0 1 0 QCOM_GPI_I2C 64>;So everywhere is 64, thus this is fixed. Deduce it from the compatible
If I understand correctly, it's a software tunable property, used to balance how many TRE elements that should be preallocated.
If so, it would not be a property of the hardware/compatible, but rather a result of profiling and a balance between memory "waste" and performance.
Regards, Bjorn
Best regards, Krzysztof