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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Aleksander Jan Bajkowski <olek2@wp.pl>,
	"David S . Miller" <davem@davemloft.net>,
	Sasha Levin <sashal@kernel.org>,
	john@phrozen.org, tsbogend@alpha.franken.de, hauke@hauke-m.de,
	maz@kernel.org, linux-mips@vger.kernel.org
Subject: [PATCH AUTOSEL 5.14 010/138] MIPS: lantiq: dma: add small delay after reset
Date: Mon,  8 Nov 2021 12:44:36 -0500	[thread overview]
Message-ID: <20211108174644.1187889-10-sashal@kernel.org> (raw)
In-Reply-To: <20211108174644.1187889-1-sashal@kernel.org>

From: Aleksander Jan Bajkowski <olek2@wp.pl>

[ Upstream commit c12aa581f6d5e80c3c3675ab26a52c2b3b62f76e ]

Reading the DMA registers immediately after the reset causes
Data Bus Error. Adding a small delay fixes this issue.

Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/mips/lantiq/xway/dma.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/mips/lantiq/xway/dma.c b/arch/mips/lantiq/xway/dma.c
index 63dccb2ed08b2..2784715933d13 100644
--- a/arch/mips/lantiq/xway/dma.c
+++ b/arch/mips/lantiq/xway/dma.c
@@ -11,6 +11,7 @@
 #include <linux/export.h>
 #include <linux/spinlock.h>
 #include <linux/clk.h>
+#include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/of.h>
 
@@ -222,6 +223,8 @@ ltq_dma_init(struct platform_device *pdev)
 	clk_enable(clk);
 	ltq_dma_w32_mask(0, DMA_RESET, LTQ_DMA_CTRL);
 
+	usleep_range(1, 10);
+
 	/* disable all interrupts */
 	ltq_dma_w32(0, LTQ_DMA_IRNEN);
 
-- 
2.33.0


       reply	other threads:[~2021-11-09  1:03 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20211108174644.1187889-1-sashal@kernel.org>
2021-11-08 17:44 ` Sasha Levin [this message]
2021-11-08 17:44 ` [PATCH AUTOSEL 5.14 011/138] MIPS: lantiq: dma: reset correct number of channel Sasha Levin

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