diff options
| author | Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> | 2018-07-11 11:10:16 +0900 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2018-07-11 10:47:31 +0530 |
| commit | 8115ce745fa26ccffe7d1a542ab4322acf4a682d (patch) | |
| tree | 5c516be732e1479e3d6f37a2a21bd47c6d0f23fe | |
| parent | 4de1247a9826cec0ba054479124bd9aa60fb71a5 (diff) | |
| download | linux-8115ce745fa26ccffe7d1a542ab4322acf4a682d.tar.gz linux-8115ce745fa26ccffe7d1a542ab4322acf4a682d.tar.bz2 linux-8115ce745fa26ccffe7d1a542ab4322acf4a682d.zip | |
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>
| -rw-r--r-- | drivers/dma/sh/rcar-dmac.c | 12 |
1 files changed, 12 insertions, 0 deletions
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; |