target/linux/ramips/patches-3.10/0021-MIPS-ralink-add-cpu-frequency-scaling.patch

   1 From f6dc5d40c766e5ff9b18b93a1b6f7a576655f9c4 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 21/25] 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 |   36 ++++++++++++++++++++++++++++++++++++
  12  1 file changed, 36 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 @@ -36,6 +40,8 @@ struct systick_device {
  28         int freq_scale;
  29  };
  30
  31 +static void (*systick_freq_scaling)(struct systick_device *sdev, int status);
  32 +
  33  static void systick_set_clock_mode(enum clock_event_mode mode,
  34                                 struct clock_event_device *evt);
  35
  36 @@ -87,6 +93,21 @@ static struct irqaction systick_irqactio
  37         .dev_id = &systick.dev,
  38  };
  39
  40 +static inline void mt7620_freq_scaling(struct systick_device *sdev, int status)
  41 +{
  42 +       if (sdev->freq_scale == status)
  43 +               return;
  44 +
  45 +       sdev->freq_scale = status;
  46 +
  47 +       pr_info("%s: %s autosleep mode\n", systick.dev.name,
  48 +                       (status) ? ("enable") : ("disable"));
  49 +       if (status)
  50 +               rt_sysc_w32(rt_sysc_r32(CLK_LUT_CFG) | SLEEP_EN, CLK_LUT_CFG);
  51 +       else
  52 +               rt_sysc_w32(rt_sysc_r32(CLK_LUT_CFG) & ~SLEEP_EN, CLK_LUT_CFG);
  53 +}
  54 +
  55  static void systick_set_clock_mode(enum clock_event_mode mode,
  56                                 struct clock_event_device *evt)
  57  {
  58 @@ -101,9 +122,13 @@ static void systick_set_clock_mode(enum
  59                 sdev->irq_requested = 1;
  60                 iowrite32(CFG_EXT_STK_EN | CFG_CNT_EN,
  61                                 systick.membase + SYSTICK_CONFIG);
  62 +               if (systick_freq_scaling)
  63 +                       systick_freq_scaling(sdev, 1);
  64                 break;
  65
  66         case CLOCK_EVT_MODE_SHUTDOWN:
  67 +               if (systick_freq_scaling)
  68 +                       systick_freq_scaling(sdev, 0);
  69                 if (sdev->irq_requested)
  70                         free_irq(systick.dev.irq, &systick_irqaction);
  71                 sdev->irq_requested = 0;
  72 @@ -116,12 +141,23 @@ static void systick_set_clock_mode(enum
  73         }
  74  }
  75
  76 +static const struct of_device_id systick_match[] = {
  77 +       { .compatible = "ralink,mt7620-systick", .data = mt7620_freq_scaling},
  78 +       {},
  79 +};
  80 +
  81  static void __init ralink_systick_init(struct device_node *np)
  82  {
  83 +       const struct of_device_id *match;
  84 +
  85         systick.membase = of_iomap(np, 0);
  86         if (!systick.membase)
  87                 return;
  88
  89 +       match = of_match_node(systick_match, np);
  90 +       if (match)
  91 +               systick_freq_scaling = match->data;
  92 +
  93         systick_irqaction.name = np->name;
  94         systick.dev.name = np->name;
  95         clockevents_calc_mult_shift(&systick.dev, SYSTICK_FREQ, 60);