From 5881826ded79cf3c3314ee2d84c3bfa94e111b42 Mon Sep 17 00:00:00 2001 From: Nandor Han Date: Mon, 8 Aug 2016 15:38:26 +0300 Subject: dmaengine: imx-sdma - update the residue calculation for cyclic channels The calculation of the DMA transaction residue supports only fixed size data transfers. This implementation is not covering all operations (e.g. data receiving) when we need to know the exact amount of bytes transferred. The loop channels handling was changed to clear the buffer descriptor errors and use the bd->mode.count to calculate the residue. Tested-by: Peter Senna Tschudin Acked-by: Peter Senna Tschudin Reviewed-by: Vinod Koul Signed-off-by: Nandor Han Signed-off-by: Greg Kroah-Hartman --- drivers/dma/imx-sdma.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) (limited to 'drivers/dma/imx-sdma.c') diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c index aa35a77773ef..3cb47386fbb9 100644 --- a/drivers/dma/imx-sdma.c +++ b/drivers/dma/imx-sdma.c @@ -651,6 +651,8 @@ static void sdma_event_disable(struct sdma_channel *sdmac, unsigned int event) static void sdma_update_channel_loop(struct sdma_channel *sdmac) { struct sdma_buffer_descriptor *bd; + int error = 0; + enum dma_status old_status = sdmac->status; /* * loop mode. Iterate over descriptors, re-setup them and @@ -662,10 +664,20 @@ static void sdma_update_channel_loop(struct sdma_channel *sdmac) if (bd->mode.status & BD_DONE) break; - if (bd->mode.status & BD_RROR) + if (bd->mode.status & BD_RROR) { + bd->mode.status &= ~BD_RROR; sdmac->status = DMA_ERROR; + error = -EIO; + } + /* + * We use bd->mode.count to calculate the residue, since contains + * the number of bytes present in the current buffer descriptor. + */ + + sdmac->chn_real_count = bd->mode.count; bd->mode.status |= BD_DONE; + bd->mode.count = sdmac->period_len; /* * The callback is called from the interrupt context in order @@ -679,6 +691,9 @@ static void sdma_update_channel_loop(struct sdma_channel *sdmac) sdmac->buf_tail++; sdmac->buf_tail %= sdmac->num_bd; + + if (error) + sdmac->status = old_status; } } @@ -1349,7 +1364,8 @@ static enum dma_status sdma_tx_status(struct dma_chan *chan, u32 residue; if (sdmac->flags & IMX_DMA_SG_LOOP) - residue = (sdmac->num_bd - sdmac->buf_tail) * sdmac->period_len; + residue = (sdmac->num_bd - sdmac->buf_tail) * + sdmac->period_len - sdmac->chn_real_count; else residue = sdmac->chn_count - sdmac->chn_real_count; -- cgit