target/linux/lantiq/patches-5.4/0110-MIPS-lantiq-dma-add-small-delay-after-reset.patch

   1 From 497acc03cd3918baabe25d46e30c5c62b998e24d Mon Sep 17 00:00:00 2001
   2 From: Aleksander Jan Bajkowski <olek2@wp.pl>
   3 Date: Sat, 19 Jun 2021 13:38:12 +0200
   4 Subject: [PATCH 1/5] MIPS: lantiq: dma: add small delay after reset
   5
   6 Reading the DMA registers immediately after the reset causes
   7 Data Bus Error. Adding a small delay fixes this problem.
   8
   9 Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
  10 ---
  11  arch/mips/lantiq/xway/dma.c | 3 +++
  12  1 file changed, 3 insertions(+)
  13
  14 --- a/arch/mips/lantiq/xway/dma.c
  15 +++ b/arch/mips/lantiq/xway/dma.c
  16 @@ -11,6 +11,7 @@
  17  #include <linux/export.h>
  18  #include <linux/spinlock.h>
  19  #include <linux/clk.h>
  20 +#include <linux/delay.h>
  21  #include <linux/err.h>
  22
  23  #include <lantiq_soc.h>
  24 @@ -221,6 +222,8 @@ ltq_dma_init(struct platform_device *pde
  25         clk_enable(clk);
  26         ltq_dma_w32_mask(0, DMA_RESET, LTQ_DMA_CTRL);
  27
  28 +       usleep_range(1, 10);
  29 +
  30         /* disable all interrupts */
  31         ltq_dma_w32(0, LTQ_DMA_IRNEN);
  32