From: Aleksander Jan Bajkowski <olek2@wp.pl>
Date: Tue, 14 Sep 2021 21:20:58 +0000 (+0200)
Subject: MIPS: lantiq: dma: add small delay after reset
X-Git-Tag: v4.19.218~236
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=9b872fdecc2d0ae42638062e68e406e3b25090a6;p=thirdparty%2Fkernel%2Fstable.git

MIPS: lantiq: dma: add small delay after reset

[ 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>
---

diff --git a/arch/mips/lantiq/xway/dma.c b/arch/mips/lantiq/xway/dma.c
index 664f2f7f55c1c..45a622b72cd13 100644
--- a/arch/mips/lantiq/xway/dma.c
+++ b/arch/mips/lantiq/xway/dma.c
@@ -22,6 +22,7 @@
 #include <linux/export.h>
 #include <linux/spinlock.h>
 #include <linux/clk.h>
+#include <linux/delay.h>
 #include <linux/err.h>
 
 #include <lantiq_soc.h>
@@ -233,6 +234,8 @@ 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);