From 89751d0a2a05197e0823eb0a363efd034175a76f Mon Sep 17 00:00:00 2001 From: Andy Gross Date: Fri, 30 May 2014 15:49:50 -0500 Subject: [PATCH] dmaengine: qcom_bam_dma: Add descriptor flags This patch adds support for end of transaction (EOT) and notify when done (NWD) hardware descriptor flags. The EOT flag requests that the peripheral assert an end of transaction interrupt when that descriptor is complete. It also results in special signaling protocol that is used between the attached peripheral and the core using the DMA controller. Clients will specify DMA_PREP_INTERRUPT to enable this flag. The NWD flag requests that the peripheral wait until the data has been fully processed by the peripheral before moving on to the next descriptor. Clients will specify DMA_PREP_FENCE to enable this flag. Signed-off-by: Andy Gross Signed-off-by: Vinod Koul --- drivers/dma/qcom_bam_dma.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/drivers/dma/qcom_bam_dma.c b/drivers/dma/qcom_bam_dma.c index 82c923146e49..7a4bbb0f80a5 100644 --- a/drivers/dma/qcom_bam_dma.c +++ b/drivers/dma/qcom_bam_dma.c @@ -61,12 +61,17 @@ struct bam_desc_hw { #define DESC_FLAG_INT BIT(15) #define DESC_FLAG_EOT BIT(14) #define DESC_FLAG_EOB BIT(13) +#define DESC_FLAG_NWD BIT(12) struct bam_async_desc { struct virt_dma_desc vd; u32 num_desc; u32 xfer_len; + + /* transaction flags, EOT|EOB|NWD */ + u16 flags; + struct bam_desc_hw *curr_desc; enum dma_transfer_direction dir; @@ -490,6 +495,14 @@ static struct dma_async_tx_descriptor *bam_prep_slave_sg(struct dma_chan *chan, if (!async_desc) goto err_out; + if (flags & DMA_PREP_FENCE) + async_desc->flags |= DESC_FLAG_NWD; + + if (flags & DMA_PREP_INTERRUPT) + async_desc->flags |= DESC_FLAG_EOT; + else + async_desc->flags |= DESC_FLAG_INT; + async_desc->num_desc = num_alloc; async_desc->curr_desc = async_desc->desc; async_desc->dir = direction; @@ -793,8 +806,11 @@ static void bam_start_dma(struct bam_chan *bchan) else async_desc->xfer_len = async_desc->num_desc; - /* set INT on last descriptor */ - desc[async_desc->xfer_len - 1].flags |= DESC_FLAG_INT; + /* set any special flags on the last descriptor */ + if (async_desc->num_desc == async_desc->xfer_len) + desc[async_desc->xfer_len - 1].flags = async_desc->flags; + else + desc[async_desc->xfer_len - 1].flags |= DESC_FLAG_INT; if (bchan->tail + async_desc->xfer_len > MAX_DESCRIPTORS) { u32 partial = MAX_DESCRIPTORS - bchan->tail; -- 2.45.2