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Message-Id: <20211115165317.696734143@linuxfoundation.org>
Date: Mon, 15 Nov 2021 18:00:44 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Aleksander Jan Bajkowski <olek2@...pl>,
"David S. Miller" <davem@...emloft.net>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.4 120/355] MIPS: lantiq: dma: add small delay after reset
From: Aleksander Jan Bajkowski <olek2@...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@...pl>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.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 aeb1b989cd4ee..24c6267f78698 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 <lantiq_soc.h>
@@ -221,6 +222,8 @@ 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
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