linux-kernel - [PATCH v2 0/3] Add Block event interrupt support for I2C protocol

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Message-ID: <20241025181010.7555-1-quic_jseerapu@quicinc.com>
Date: Fri, 25 Oct 2024 23:40:07 +0530
From: Jyothi Kumar Seerapu <quic_jseerapu@...cinc.com>
To: Vinod Koul <vkoul@...nel.org>, Andi Shyti <andi.shyti@...nel.org>,
        "Sumit
 Semwal" <sumit.semwal@...aro.org>,
        Christian König
	<christian.koenig@....com>
CC: <linux-arm-msm@...r.kernel.org>, <dmaengine@...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: [PATCH v2 0/3] Add Block event interrupt support for I2C protocol

The I2C driver gets an interrupt upon transfer completion.
For multiple messages in a single transfer, N interrupts will be
received for N messages, leading to significant software interrupt
latency. To mitigate this latency, utilize Block Event Interrupt (BEI)
only when an interrupt is necessary. This means large transfers can be
split into multiple chunks of 8 messages internally, without expecting
interrupts for the first 7 messages completion, only the last one will
trigger an interrupt indicating 8 messages completed.

By implementing BEI, multi-message transfers can be divided into
chunks of 8 messages, improving overall transfer time.
This optimization reduces transfer time from 168 ms to 48 ms for a
series of 200 I2C write messages in a single transfer, with a
clock frequency support of 100 kHz.

BEI optimizations are currently implemented for I2C write transfers only,
as there is no use case for multiple I2C read messages in a single transfer
at this time.

v1 -> v2:
  - DT changes are reverted for adding dma channel size as a new arg of
    dma-cells property.
  - DT binding change reveted for ma channel size as a new arg of
    dma-cells property.
  - In GPI driver, reverted the changes to parse the channel TRE size
    from device tree.
  - Made the changes in QCOM I2C geni driver to support the BEI
    functionality with the existing TRE size of 64.
  - Made changes in QCOM I2C geni driver as per the review comments.
  - Fixed Kernel test robot reported compiltion issues

Jyothi Kumar Seerapu (3):
  dmaengine: qcom: gpi: Add GPI Block event interrupt support
  i2c: qcom_geni: Update compile dependenices for qcom geni
  i2c: i2c-qcom-geni: Add Block event interrupt support

 drivers/dma/qcom/gpi.c             |  49 +++++++
 drivers/i2c/busses/Kconfig         |   1 +
 drivers/i2c/busses/i2c-qcom-geni.c | 203 +++++++++++++++++++++++++----
 include/linux/dma/qcom-gpi-dma.h   |  37 ++++++
 4 files changed, 265 insertions(+), 25 deletions(-)

base-commit: 55bcd2e0d04c1171d382badef1def1fd04ef66c5
-- 
2.17.1