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);