From 4e8331317e73902e8b2663352c8766227e633901 Mon Sep 17 00:00:00 2001 From: Jyothi Kumar Seerapu Date: Thu, 25 Sep 2025 17:30:34 +0530 Subject: [PATCH] dmaengine: qcom: gpi: Add GPI Block event interrupt support GSI hardware generates an interrupt for each transfer completion. For multiple messages within a single transfer, this results in N interrupts for N messages, leading to significant software interrupt latency. To mitigate this latency, utilize Block Event Interrupt (BEI) mechanism. Enabling BEI instructs the GSI hardware to prevent interrupt generation and BEI is disabled when an interrupt is necessary. Large I2C transfer can be divided into chunks of messages internally. Interrupts are not expected for the messages for which BEI bit set, only the last message triggers an interrupt, indicating the completion of N messages. This BEI mechanism enhances overall transfer efficiency. Signed-off-by: Jyothi Kumar Seerapu Reviewed-by: Dmitry Baryshkov Signed-off-by: Vinod Koul --- drivers/dma/qcom/gpi.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/dma/qcom/gpi.c b/drivers/dma/qcom/gpi.c index 8e87738086b25..66bfea1f156d1 100644 --- a/drivers/dma/qcom/gpi.c +++ b/drivers/dma/qcom/gpi.c @@ -1619,7 +1619,8 @@ gpi_peripheral_config(struct dma_chan *chan, struct dma_slave_config *config) } static int gpi_create_i2c_tre(struct gchan *chan, struct gpi_desc *desc, - struct scatterlist *sgl, enum dma_transfer_direction direction) + struct scatterlist *sgl, enum dma_transfer_direction direction, + unsigned long flags) { struct gpi_i2c_config *i2c = chan->config; struct device *dev = chan->gpii->gpi_dev->dev; @@ -1684,6 +1685,9 @@ static int gpi_create_i2c_tre(struct gchan *chan, struct gpi_desc *desc, tre->dword[3] = u32_encode_bits(TRE_TYPE_DMA, TRE_FLAGS_TYPE); tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_IEOT); + + if (!(flags & DMA_PREP_INTERRUPT)) + tre->dword[3] |= u32_encode_bits(1, TRE_FLAGS_BEI); } for (i = 0; i < tre_idx; i++) @@ -1827,6 +1831,9 @@ gpi_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, return NULL; } + if (!(flags & DMA_PREP_INTERRUPT) && (nr - nr_tre < 2)) + return NULL; + gpi_desc = kzalloc(sizeof(*gpi_desc), GFP_NOWAIT); if (!gpi_desc) return NULL; @@ -1835,7 +1842,7 @@ gpi_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, if (gchan->protocol == QCOM_GPI_SPI) { i = gpi_create_spi_tre(gchan, gpi_desc, sgl, direction); } else if (gchan->protocol == QCOM_GPI_I2C) { - i = gpi_create_i2c_tre(gchan, gpi_desc, sgl, direction); + i = gpi_create_i2c_tre(gchan, gpi_desc, sgl, direction, flags); } else { dev_err(dev, "invalid peripheral: %d\n", gchan->protocol); kfree(gpi_desc); -- 2.47.3