From bccfb96b59179d4f96cbbd1ddff8fac6d335eae4 Mon Sep 17 00:00:00 2001

From: Tudor Ambarus <tudor.ambarus@microchip.com>

Date: Wed, 15 Dec 2021 13:01:04 +0200

Subject: [PATCH] dmaengine: at_xdmac: Don't start transactions at tx_submit level

Git-commit: bccfb96b59179d4f96cbbd1ddff8fac6d335eae4

Patch-mainline: v5.17-rc1

References: git-fixes

tx_submit is supposed to push the current transaction descriptor to a

pending queue, waiting for issue_pending() to be called. issue_pending()

must start the transfer, not tx_submit(), thus remove

at_xdmac_start_xfer() from at_xdmac_tx_submit(). Clients of at_xdmac that

assume that tx_submit() starts the transfer must be updated and call

dma_async_issue_pending() if they miss to call it (one example is

atmel_serial).

As the at_xdmac_start_xfer() is now called only from

at_xdmac_advance_work() when !at_xdmac_chan_is_enabled(), the

at_xdmac_chan_is_enabled() check is no longer needed in

at_xdmac_start_xfer(), thus remove it.

Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>

Link: https://lore.kernel.org/r/20211215110115.191749-2-tudor.ambarus@microchip.com

Signed-off-by: Vinod Koul <vkoul@kernel.org>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 drivers/dma/at_xdmac.c | 6 ------

 1 file changed, 6 deletions(-)

diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c

index e42dede5b243..4ff12b083136 100644

--- a/drivers/dma/at_xdmac.c

+++ b/drivers/dma/at_xdmac.c

@@ -385,9 +385,6 @@ static void at_xdmac_start_xfer(struct at_xdmac_chan *atchan,

 	dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, first);

-	if (at_xdmac_chan_is_enabled(atchan))

-		return;

-

 	/* Set transfer as active to not try to start it again. */

 	first->active_xfer = true;

@@ -479,9 +476,6 @@ static dma_cookie_t at_xdmac_tx_submit(struct dma_async_tx_descriptor *tx)

 	dev_vdbg(chan2dev(tx->chan), "%s: atchan 0x%p, add desc 0x%p to xfers_list\n",

 		 __func__, atchan, desc);

 	list_add_tail(&desc->xfer_node, &atchan->xfers_list);

-	if (list_is_singular(&atchan->xfers_list))

-		at_xdmac_start_xfer(atchan, desc);

-

 	spin_unlock_irqrestore(&atchan->lock, irqflags);

 	return cookie;

 }

-- 

2.31.1