dmaengine: sh: rcar-dmac: Add dma_pause operation (8115ce74) · Commits · 戴 / test

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 <yoshihiro.shimoda.uh@renesas.com> Signed-off-by:

Vinod Koul <vkoul@kernel.org>

drivers/dma/sh/rcar-dmac.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -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;

Admin message