From db60a63eb6850fce081c1a22e7318e5d37f4dcf5 Mon Sep 17 00:00:00 2001 From: Amelie Delaunay Date: Thu, 5 May 2022 13:56:08 +0200 Subject: [PATCH] dmaengine: stm32-dma: introduce stm32_dma_sg_inc to manage chan->next_sg chan->next_sg is used to know which transfer will start after the ongoing one. It is incremented for each new transfer, either on transfer start for non-cyclic transfers, or on transfer complete interrupt for cyclic transfers. For cyclic transfer, when the last item is reached, chan->next_sg must be reinitialized to the first item. Signed-off-by: Amelie Delaunay Link: https://lore.kernel.org/r/20220505115611.38845-2-amelie.delaunay@foss.st.com Signed-off-by: Vinod Koul --- drivers/dma/stm32-dma.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c index d2365fa..5afe420 100644 --- a/drivers/dma/stm32-dma.c +++ b/drivers/dma/stm32-dma.c @@ -535,6 +535,13 @@ static void stm32_dma_dump_reg(struct stm32_dma_chan *chan) dev_dbg(chan2dev(chan), "SFCR: 0x%08x\n", sfcr); } +static void stm32_dma_sg_inc(struct stm32_dma_chan *chan) +{ + chan->next_sg++; + if (chan->desc->cyclic && (chan->next_sg == chan->desc->num_sgs)) + chan->next_sg = 0; +} + static void stm32_dma_configure_next_sg(struct stm32_dma_chan *chan); static void stm32_dma_start_transfer(struct stm32_dma_chan *chan) @@ -575,7 +582,7 @@ static void stm32_dma_start_transfer(struct stm32_dma_chan *chan) stm32_dma_write(dmadev, STM32_DMA_SM1AR(chan->id), reg->dma_sm1ar); stm32_dma_write(dmadev, STM32_DMA_SNDTR(chan->id), reg->dma_sndtr); - chan->next_sg++; + stm32_dma_sg_inc(chan); /* Clear interrupt status if it is there */ status = stm32_dma_irq_status(chan); @@ -606,9 +613,6 @@ static void stm32_dma_configure_next_sg(struct stm32_dma_chan *chan) dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(id)); if (dma_scr & STM32_DMA_SCR_DBM) { - if (chan->next_sg == chan->desc->num_sgs) - chan->next_sg = 0; - sg_req = &chan->desc->sg_req[chan->next_sg]; if (dma_scr & STM32_DMA_SCR_CT) { @@ -630,7 +634,7 @@ static void stm32_dma_handle_chan_done(struct stm32_dma_chan *chan) if (chan->desc) { if (chan->desc->cyclic) { vchan_cyclic_callback(&chan->desc->vdesc); - chan->next_sg++; + stm32_dma_sg_inc(chan); stm32_dma_configure_next_sg(chan); } else { chan->busy = false; -- 2.7.4