Hi,
we observed a regression on our atmel platforms on branch 5.4.Y from
version 5.4.174.
uarts are no longer functional if DMA is enabled.
the following patch
Commit e6af9b05bec63cd4d1de2a33968cd0be2a91282a dmaengine: at_xdmac:
Start transfer for cyclic channels in issue_pending
Link:
https://lore.kernel.org/r/20211215110115.191749-3-tudor.ambarus@xxxxxxxxxxxxx
has not been backported but is needed if the patch
Commit 4f4b9b5895614eb2e2b5f4cab7858f44bd113e1b tty: serial: atmel: Call
dma_async_issue_pending()
Link:
https://lore.kernel.org/r/20211125090028.786832-4-tudor.ambarus@xxxxxxxxxxxxx
is applied.
enclosed commit fix this issue and work for me.
Best regards,
Mickael GARDET
From 9877f93c066be8c2f4e33a6edd4dfa3d6d6974d9 Mon Sep 17 00:00:00 2001
From: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>
Date: Wed, 15 Dec 2021 13:01:05 +0200
Subject: [PATCH] dmaengine: at_xdmac: Start transfer for cyclic channels
in issue_pending
commit e6af9b05bec63cd4d1de2a33968cd0be2a91282a upstream.
Cyclic channels must too call issue_pending in order to start a transfer.
Start the transfer in issue_pending regardless of the type of channel.
This wrongly worked before, because in the past the transfer was started
at tx_submit level when only a desc in the transfer list.
Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel
eXtended DMA Controller driver")
Change-Id: If1bf3e13329cebb9904ae40620f6cf2b7f06fe9f
Signed-off-by: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>
Link:
https://lore.kernel.org/r/20211215110115.191749-3-tudor.ambarus@xxxxxxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
---
drivers/dma/at_xdmac.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
index f63d141481a3..9aae6b3da356 100644
--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -1726,11 +1726,13 @@ static irqreturn_t at_xdmac_interrupt(int irq,
void *dev_id)
static void at_xdmac_issue_pending(struct dma_chan *chan)
{
struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan);
+ unsigned long flags;
dev_dbg(chan2dev(&atchan->chan), "%s\n", __func__);
- if (!at_xdmac_chan_is_cyclic(atchan))
- at_xdmac_advance_work(atchan);
+ spin_lock_irqsave(&atchan->lock, flags);
+ at_xdmac_advance_work(atchan);
+ spin_unlock_irqrestore(&atchan->lock, flags);
return;
}
base-commit: 7b3eb66d0daf61e91cccdb2fe5d271ae5adc5a76
--
2.35.1
