target/linux/xburst/patches-3.10/013-MIPS-JZ4740-Acquire-and-enable-DMA-controller-clock.patch

   1 From b1ab71156cd49b2389397d3be54b93fe394a1cb2 Mon Sep 17 00:00:00 2001
   2 From: Maarten ter Huurne <maarten@treewalker.org>
   3 Date: Tue, 9 Oct 2012 13:09:57 +0200
   4 Subject: [PATCH 13/16] MIPS: JZ4740: Acquire and enable DMA controller clock
   5
   6 Previously, it was assumed that the DMA controller clock is not gated
   7 when the kernel starts running. While that is the power-on state, it is
   8 safer to not rely on that.
   9
  10 Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
  11 ---
  12  arch/mips/jz4740/clock.c |    2 +-
  13  arch/mips/jz4740/dma.c   |   24 ++++++++++++++++++++++--
  14  2 files changed, 23 insertions(+), 3 deletions(-)
  15
  16 --- a/arch/mips/jz4740/clock.c
  17 +++ b/arch/mips/jz4740/clock.c
  18 @@ -921,4 +921,4 @@ static int jz4740_clock_init(void)
  19
  20         return 0;
  21  }
  22 -arch_initcall(jz4740_clock_init);
  23 +postcore_initcall(jz4740_clock_init);
  24 --- a/arch/mips/jz4740/dma.c
  25 +++ b/arch/mips/jz4740/dma.c
  26 @@ -16,6 +16,7 @@
  27  #include <linux/kernel.h>
  28  #include <linux/module.h>
  29  #include <linux/spinlock.h>
  30 +#include <linux/clk.h>
  31  #include <linux/interrupt.h>
  32
  33  #include <linux/dma-mapping.h>
  34 @@ -268,6 +269,7 @@ static irqreturn_t jz4740_dma_irq(int ir
  35
  36  static int jz4740_dma_init(void)
  37  {
  38 +       struct clk *clk;
  39         unsigned int ret;
  40
  41         jz4740_dma_base = ioremap(JZ4740_DMAC_BASE_ADDR, 0x400);
  42 @@ -277,11 +279,29 @@ static int jz4740_dma_init(void)
  43
  44         spin_lock_init(&jz4740_dma_lock);
  45
  46 -       ret = request_irq(JZ4740_IRQ_DMAC, jz4740_dma_irq, 0, "DMA", NULL);
  47 +       clk = clk_get(NULL, "dma");
  48 +       if (IS_ERR(clk)) {
  49 +               ret = PTR_ERR(clk);
  50 +               printk(KERN_ERR "JZ4740 DMA: Failed to request clock: %d\n",
  51 +                               ret);
  52 +               goto err_iounmap;
  53 +       }
  54
  55 -       if (ret)
  56 +       ret = request_irq(JZ4740_IRQ_DMAC, jz4740_dma_irq, 0, "DMA", NULL);
  57 +       if (ret) {
  58                 printk(KERN_ERR "JZ4740 DMA: Failed to request irq: %d\n", ret);
  59 +               goto err_clkput;
  60 +       }
  61 +
  62 +       clk_enable(clk);
  63 +
  64 +       return 0;
  65 +
  66 +err_clkput:
  67 +       clk_put(clk);
  68
  69 +err_iounmap:
  70 +       iounmap(jz4740_dma_base);
  71         return ret;
  72  }
  73  arch_initcall(jz4740_dma_init);