target/linux/sunxi/patches-3.12/118-sunxi-clk-core-clock-protect.patch

   1 From d1bcc34ce6cb7601ce27f3090aee0e8a3e8076e3 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Emilio=20L=C3=B3pez?= <emilio@elopez.com.ar>
   3 Date: Sat, 14 Sep 2013 20:54:42 -0300
   4 Subject: [PATCH] clk: sunxi: protect core clocks from accidental shutdown
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 Some important clocks may get disabled as a side effect of another clock
  10 being disabled, because they have no consumers. This patch implements a
  11 mechanism so those clocks can be claimed by the driver and therefore
  12 remain enabled at all times.
  13
  14 Signed-off-by: Emilio López <emilio@elopez.com.ar>
  15 ---
  16  drivers/clk/sunxi/clk-sunxi.c | 28 ++++++++++++++++++++++++++++
  17  1 file changed, 28 insertions(+)
  18
  19 diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c
  20 index 9bbd035..8fc1375 100644
  21 --- a/drivers/clk/sunxi/clk-sunxi.c
  22 +++ b/drivers/clk/sunxi/clk-sunxi.c
  23 @@ -616,6 +616,31 @@ static void __init of_sunxi_table_clock_setup(const struct of_device_id *clk_mat
  24         }
  25  }
  26
  27 +/**
  28 + * System clock protection
  29 + *
  30 + * By enabling these critical clocks, we prevent their accidental gating
  31 + * by the framework
  32 + */
  33 +static void __init sunxi_clock_protect(void)
  34 +{
  35 +       struct clk *clk;
  36 +
  37 +       /* memory bus clock - sun5i+ */
  38 +       clk = clk_get(NULL, "mbus");
  39 +       if (!IS_ERR(clk)) {
  40 +               clk_prepare_enable(clk);
  41 +               clk_put(clk);
  42 +       }
  43 +
  44 +       /* DDR clock - sun4i+ */
  45 +       clk = clk_get(NULL, "pll5_ddr");
  46 +       if (!IS_ERR(clk)) {
  47 +               clk_prepare_enable(clk);
  48 +               clk_put(clk);
  49 +       }
  50 +}
  51 +
  52  static void __init sunxi_init_clocks(struct device_node *np)
  53  {
  54         /* Register factor clocks */
  55 @@ -629,6 +654,9 @@ static void __init sunxi_init_clocks(struct device_node *np)
  56
  57         /* Register gate clocks */
  58         of_sunxi_table_clock_setup(clk_gates_match, sunxi_gates_clk_setup);
  59 +
  60 +       /* Enable core system clocks */
  61 +       sunxi_clock_protect();
  62  }
  63  CLK_OF_DECLARE(sun4i_a10_clk_init, "allwinner,sun4i-a10", sunxi_init_clocks);
  64  CLK_OF_DECLARE(sun5i_a10s_clk_init, "allwinner,sun5i-a10s", sunxi_init_clocks);
  65 --
  66 1.8.5.1
  67