target/linux/ramips/patches-4.4/0006-MIPS-ralink-add-cpu-frequency-scaling.patch

   1 From bd30f19a006fb52bac80c6463c49dd2f4159f4ac Mon Sep 17 00:00:00 2001
   2 From: John Crispin <blogic@openwrt.org>
   3 Date: Sun, 28 Jul 2013 16:26:41 +0200
   4 Subject: [PATCH 06/53] MIPS: ralink: add cpu frequency scaling
   5
   6 This feature will break udelay() and cause the delay loop to have longer delays
   7 when the frequency is scaled causing a performance hit.
   8
   9 Signed-off-by: John Crispin <blogic@openwrt.org>
  10 ---
  11  arch/mips/ralink/cevt-rt3352.c |   38 ++++++++++++++++++++++++++++++++++++++
  12  1 file changed, 38 insertions(+)
  13
  14 --- a/arch/mips/ralink/cevt-rt3352.c
  15 +++ b/arch/mips/ralink/cevt-rt3352.c
  16 @@ -29,6 +29,10 @@
  17  /* enable the counter */
  18  #define CFG_CNT_EN             0x1
  19
  20 +/* mt7620 frequency scaling defines */
  21 +#define CLK_LUT_CFG    0x40
  22 +#define SLEEP_EN       BIT(31)
  23 +
  24  struct systick_device {
  25         void __iomem *membase;
  26         struct clock_event_device dev;
  27 @@ -36,9 +40,26 @@ struct systick_device {
  28         int freq_scale;
  29  };
  30
  31 +static void (*systick_freq_scaling)(struct systick_device *sdev, int status);
  32 +
  33  static int systick_set_oneshot(struct clock_event_device *evt);
  34  static int systick_shutdown(struct clock_event_device *evt);
  35
  36 +static inline void mt7620_freq_scaling(struct systick_device *sdev, int status)
  37 +{
  38 +       if (sdev->freq_scale == status)
  39 +               return;
  40 +
  41 +       sdev->freq_scale = status;
  42 +
  43 +       pr_info("%s: %s autosleep mode\n", systick.dev.name,
  44 +                       (status) ? ("enable") : ("disable"));
  45 +       if (status)
  46 +               rt_sysc_w32(rt_sysc_r32(CLK_LUT_CFG) | SLEEP_EN, CLK_LUT_CFG);
  47 +       else
  48 +               rt_sysc_w32(rt_sysc_r32(CLK_LUT_CFG) & ~SLEEP_EN, CLK_LUT_CFG);
  49 +}
  50 +
  51  static int systick_next_event(unsigned long delta,
  52                                 struct clock_event_device *evt)
  53  {
  54 @@ -99,6 +120,9 @@ static int systick_shutdown(struct clock
  55         sdev->irq_requested = 0;
  56         iowrite32(0, systick.membase + SYSTICK_CONFIG);
  57
  58 +       if (systick_freq_scaling)
  59 +               systick_freq_scaling(sdev, 0);
  60 +
  61         return 0;
  62  }
  63
  64 @@ -114,15 +138,29 @@ static int systick_set_oneshot(struct cl
  65         iowrite32(CFG_EXT_STK_EN | CFG_CNT_EN,
  66                   systick.membase + SYSTICK_CONFIG);
  67
  68 +       if (systick_freq_scaling)
  69 +               systick_freq_scaling(sdev, 1);
  70 +
  71         return 0;
  72  }
  73
  74 +static const struct of_device_id systick_match[] = {
  75 +       { .compatible = "ralink,mt7620-systick", .data = mt7620_freq_scaling},
  76 +       {},
  77 +};
  78 +
  79  static void __init ralink_systick_init(struct device_node *np)
  80  {
  81 +       const struct of_device_id *match;
  82 +
  83         systick.membase = of_iomap(np, 0);
  84         if (!systick.membase)
  85                 return;
  86
  87 +       match = of_match_node(systick_match, np);
  88 +       if (match)
  89 +               systick_freq_scaling = match->data;
  90 +
  91         systick_irqaction.name = np->name;
  92         systick.dev.name = np->name;
  93         clockevents_calc_mult_shift(&systick.dev, SYSTICK_FREQ, 60);