blob: 047b2bd145ed17c13aa3e2331bc7ee53213ecce3 [file] [log] [blame]
From afe6b324aa933ef81755430b6204cca9ab518a15 Mon Sep 17 00:00:00 2001
From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Date: Wed, 11 Jul 2018 11:10:16 +0900
Subject: [PATCH 1619/1795] 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 <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
(cherry picked from commit 8115ce745fa26ccffe7d1a542ab4322acf4a682d)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
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;
--
2.19.0