From 8115ce745fa26ccffe7d1a542ab4322acf4a682d Mon Sep 17 00:00:00 2001 From: Yoshihiro Shimoda Date: Wed, 11 Jul 2018 11:10:16 +0900 Subject: [PATCH] dmaengine: sh: rcar-dmac: Add dma_pause operation This patch adds dma_pause operation. This patch is based on Muhammad Hamza Farooq's patch. After this patch applied, an issue that the sh-sci driver with high baud rate might cause data lost disappeared because the DMAC is possible to transmit between [1] and [2] below, and then the residue of [1] is not true: In rx_timer_fn() of the sh-sci.c: dmaengine_pause(); ... dmaengine_tx_status(); /* [1] */ ... dmaengine_terminate_all(); /* [2] */ Signed-off-by: Yoshihiro Shimoda Signed-off-by: Vinod Koul --- drivers/dma/sh/rcar-dmac.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c index d3b7388645bc..be82d6997a55 100644 --- a/drivers/dma/sh/rcar-dmac.c +++ b/drivers/dma/sh/rcar-dmac.c @@ -834,6 +834,17 @@ static void rcar_dmac_stop_all_chan(struct rcar_dmac *dmac) } } +static int rcar_dmac_chan_pause(struct dma_chan *chan) +{ + unsigned long flags; + struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan); + + spin_lock_irqsave(&rchan->lock, flags); + rcar_dmac_clear_chcr_de(rchan); + spin_unlock_irqrestore(&rchan->lock, flags); + + return 0; +} /* ----------------------------------------------------------------------------- * Descriptors preparation @@ -1864,6 +1875,7 @@ static int rcar_dmac_probe(struct platform_device *pdev) engine->device_prep_slave_sg = rcar_dmac_prep_slave_sg; engine->device_prep_dma_cyclic = rcar_dmac_prep_dma_cyclic; engine->device_config = rcar_dmac_device_config; + engine->device_pause = rcar_dmac_chan_pause; engine->device_terminate_all = rcar_dmac_chan_terminate_all; engine->device_tx_status = rcar_dmac_tx_status; engine->device_issue_pending = rcar_dmac_issue_pending;