netdev - [PATCH net-next 1/8] MIPS: lantiq: dma: add small delay after reset

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Date:   Tue, 14 Sep 2021 23:20:58 +0200
From:   Aleksander Jan Bajkowski <olek2@...pl>
To:     john@...ozen.org, tsbogend@...ha.franken.de, olek2@...pl,
        maz@...nel.org, ralf@...ux-mips.org, ralph.hempel@...tiq.com,
        davem@...emloft.net, kuba@...nel.org, robh+dt@...nel.org,
        hauke@...ke-m.de, dev@...sin.me, arnd@...db.de, jgg@...pe.ca,
        netdev@...r.kernel.org, devicetree@...r.kernel.org,
        linux-mips@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH net-next 1/8] MIPS: lantiq: dma: add small delay after reset

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>
---
 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 63dccb2ed08b..2784715933d1 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);
 
-- 
2.30.2