target/linux/ramips/patches-3.14/0021-MIPS-ralink-add-cpu-frequency-scaling.patch

   1 From e76ecd496c9b074ab21b17f12494d823a407e89a 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 21/57] 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 diff --git a/arch/mips/ralink/cevt-rt3352.c b/arch/mips/ralink/cevt-rt3352.c
  15 index 24bf057..4174b40 100644
  16 --- a/arch/mips/ralink/cevt-rt3352.c
  17 +++ b/arch/mips/ralink/cevt-rt3352.c
  18 @@ -29,6 +29,10 @@
  19  /* enable the counter */
  20  #define CFG_CNT_EN             0x1
  21
  22 +/* mt7620 frequency scaling defines */
  23 +#define CLK_LUT_CFG    0x40
  24 +#define SLEEP_EN       BIT(31)
  25 +
  26  struct systick_device {
  27         void __iomem *membase;
  28         struct clock_event_device dev;
  29 @@ -36,6 +40,8 @@ struct systick_device {
  30         int freq_scale;
  31  };
  32
  33 +static void (*systick_freq_scaling)(struct systick_device *sdev, int status);
  34 +
  35  static void systick_set_clock_mode(enum clock_event_mode mode,
  36                                 struct clock_event_device *evt);
  37
  38 @@ -87,6 +93,21 @@ static struct irqaction systick_irqaction = {
  39         .dev_id = &systick.dev,
  40  };
  41
  42 +static inline void mt7620_freq_scaling(struct systick_device *sdev, int status)
  43 +{
  44 +       if (sdev->freq_scale == status)
  45 +               return;
  46 +
  47 +       sdev->freq_scale = status;
  48 +
  49 +       pr_info("%s: %s autosleep mode\n", systick.dev.name,
  50 +                       (status) ? ("enable") : ("disable"));
  51 +       if (status)
  52 +               rt_sysc_w32(rt_sysc_r32(CLK_LUT_CFG) | SLEEP_EN, CLK_LUT_CFG);
  53 +       else
  54 +               rt_sysc_w32(rt_sysc_r32(CLK_LUT_CFG) & ~SLEEP_EN, CLK_LUT_CFG);
  55 +}
  56 +
  57  static void systick_set_clock_mode(enum clock_event_mode mode,
  58                                 struct clock_event_device *evt)
  59  {
  60 @@ -101,9 +122,13 @@ static void systick_set_clock_mode(enum clock_event_mode mode,
  61                 sdev->irq_requested = 1;
  62                 iowrite32(CFG_EXT_STK_EN | CFG_CNT_EN,
  63                                 systick.membase + SYSTICK_CONFIG);
  64 +               if (systick_freq_scaling)
  65 +                       systick_freq_scaling(sdev, 1);
  66                 break;
  67
  68         case CLOCK_EVT_MODE_SHUTDOWN:
  69 +               if (systick_freq_scaling)
  70 +                       systick_freq_scaling(sdev, 0);
  71                 if (sdev->irq_requested)
  72                         free_irq(systick.dev.irq, &systick_irqaction);
  73                 sdev->irq_requested = 0;
  74 @@ -116,12 +141,23 @@ static void systick_set_clock_mode(enum clock_event_mode mode,
  75         }
  76  }
  77
  78 +static const struct of_device_id systick_match[] = {
  79 +       { .compatible = "ralink,mt7620-systick", .data = mt7620_freq_scaling},
  80 +       {},
  81 +};
  82 +
  83  static void __init ralink_systick_init(struct device_node *np)
  84  {
  85 +       const struct of_device_id *match;
  86 +
  87         systick.membase = of_iomap(np, 0);
  88         if (!systick.membase)
  89                 return;
  90
  91 +       match = of_match_node(systick_match, np);
  92 +       if (match)
  93 +               systick_freq_scaling = match->data;
  94 +
  95         systick_irqaction.name = np->name;
  96         systick.dev.name = np->name;
  97         clockevents_calc_mult_shift(&systick.dev, SYSTICK_FREQ, 60);
  98 --
  99 1.7.10.4
 100