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From: Tudor Ambarus <tudor.ambarus@microchip.com>
To: <ludovic.desroches@microchip.com>, <vkoul@kernel.org>,
	<richard.genoud@gmail.com>, <gregkh@linuxfoundation.org>,
	<jirislaby@kernel.org>
Cc: <nicolas.ferre@microchip.com>, <alexandre.belloni@bootlin.com>,
	<mripard@kernel.org>, <linux-arm-kernel@lists.infradead.org>,
	<dmaengine@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-serial@vger.kernel.org>,
	Tudor Ambarus <tudor.ambarus@microchip.com>
Subject: [PATCH v2 01/13] dmaengine: at_xdmac: Don't start transactions at tx_submit level
Date: Thu, 25 Nov 2021 11:00:16 +0200	[thread overview]
Message-ID: <20211125090028.786832-2-tudor.ambarus@microchip.com> (raw)
In-Reply-To: <20211125090028.786832-1-tudor.ambarus@microchip.com>

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().
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.

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).

Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
---
 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 275a76f188ae..ccf796a3b9f3 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;
 }
-- 
2.25.1


  reply	other threads:[~2021-11-25  9:02 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-25  9:00 [PATCH v2 00/13] dmaengine: at_xdmac: Various fixes Tudor Ambarus
2021-11-25  9:00 ` Tudor Ambarus [this message]
2021-11-25  9:00 ` [PATCH v2 02/13] tty: serial: atmel: Check return code of dmaengine_submit() Tudor Ambarus
2021-11-25  9:00 ` [PATCH v2 03/13] tty: serial: atmel: Call dma_async_issue_pending() Tudor Ambarus
2021-11-25  9:00 ` [PATCH v2 04/13] dmaengine: at_xdmac: Start transfer for cyclic channels in issue_pending Tudor Ambarus
2021-11-25  9:00 ` [PATCH v2 05/13] dmaengine: at_xdmac: Print debug message after realeasing the lock Tudor Ambarus
2021-11-25  9:00 ` [PATCH v2 06/13] dmaengine: at_xdmac: Fix concurrency over chan's completed_cookie Tudor Ambarus
2021-11-25  9:00 ` [PATCH v2 07/13] dmaengine: at_xdmac: Fix race for the tx desc callback Tudor Ambarus
2021-11-25  9:00 ` [PATCH v2 08/13] dmaengine: at_xdmac: Move the free desc to the tail of the desc list Tudor Ambarus
2021-12-13  8:07   ` Vinod Koul
2021-12-13  8:51     ` Tudor.Ambarus
2021-12-13  8:59       ` Vinod Koul
2021-12-13  9:00         ` Vinod Koul
2021-12-13  9:22           ` Tudor.Ambarus
2021-12-13  9:27             ` Tudor.Ambarus
2021-11-25  9:00 ` [PATCH v2 09/13] dmaengine: at_xdmac: Fix concurrency over xfers_list Tudor Ambarus
2021-11-25  9:00 ` [PATCH v2 10/13] dmaengine: at_xdmac: Remove a level of indentation in at_xdmac_advance_work() Tudor Ambarus
2021-11-25  9:00 ` [PATCH v2 11/13] dmaengine: at_xdmac: Fix lld view setting Tudor Ambarus
2021-11-25  9:00 ` [PATCH v2 12/13] dmaengine: at_xdmac: Fix at_xdmac_lld struct definition Tudor Ambarus
2021-11-25  9:00 ` [PATCH v2 13/13] dmaengine: at_xdmac: Fix race over irq_status Tudor Ambarus

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