target/linux/ramips/patches-4.14/0006-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 @@ -36,21 +40,53 @@ 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", sdev->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 inline unsigned int read_count(struct systick_device *sdev)
  52 +{
  53 +       return ioread32(sdev->membase + SYSTICK_COUNT);
  54 +}
  55 +
  56 +static inline unsigned int read_compare(struct systick_device *sdev)
  57 +{
  58 +       return ioread32(sdev->membase + SYSTICK_COMPARE);
  59 +}
  60 +
  61 +static inline void write_compare(struct systick_device *sdev, unsigned int val)
  62 +{
  63 +       iowrite32(val, sdev->membase + SYSTICK_COMPARE);
  64 +}
  65 +
  66  static int systick_next_event(unsigned long delta,
  67                                 struct clock_event_device *evt)
  68  {
  69         struct systick_device *sdev;
  70 -       u32 count;
  71 +       int res;
  72
  73         sdev = container_of(evt, struct systick_device, dev);
  74 -       count = ioread32(sdev->membase + SYSTICK_COUNT);
  75 -       count = (count + delta) % SYSTICK_FREQ;
  76 -       iowrite32(count, sdev->membase + SYSTICK_COMPARE);
  77 +       delta += read_count(sdev);
  78 +       write_compare(sdev, delta);
  79 +       res = ((int)(read_count(sdev) - delta) >= 0) ? -ETIME : 0;
  80
  81 -       return 0;
  82 +       return res;
  83  }
  84
  85  static void systick_event_handler(struct clock_event_device *dev)
  86 @@ -60,20 +96,25 @@ static void systick_event_handler(struct
  87
  88  static irqreturn_t systick_interrupt(int irq, void *dev_id)
  89  {
  90 -       struct clock_event_device *dev = (struct clock_event_device *) dev_id;
  91 +       int ret = 0;
  92 +       struct clock_event_device *cdev;
  93 +       struct systick_device *sdev;
  94
  95 -       dev->event_handler(dev);
  96 +       if (read_c0_cause() & STATUSF_IP7) {
  97 +               cdev = (struct clock_event_device *) dev_id;
  98 +               sdev = container_of(cdev, struct systick_device, dev);
  99 +
 100 +               /* Clear Count/Compare Interrupt */
 101 +               write_compare(sdev, read_compare(sdev));
 102 +               cdev->event_handler(cdev);
 103 +               ret = 1;
 104 +       }
 105
 106 -       return IRQ_HANDLED;
 107 +       return IRQ_RETVAL(ret);
 108  }
 109
 110  static struct systick_device systick = {
 111         .dev = {
 112 -               /*
 113 -                * cevt-r4k uses 300, make sure systick
 114 -                * gets used if available
 115 -                */
 116 -               .rating                 = 310,
 117                 .features               = CLOCK_EVT_FEAT_ONESHOT,
 118                 .set_next_event         = systick_next_event,
 119                 .set_state_shutdown     = systick_shutdown,
 120 @@ -95,9 +136,15 @@ static int systick_shutdown(struct clock
 121         sdev = container_of(evt, struct systick_device, dev);
 122
 123         if (sdev->irq_requested)
 124 -               free_irq(systick.dev.irq, &systick_irqaction);
 125 +               remove_irq(systick.dev.irq, &systick_irqaction);
 126         sdev->irq_requested = 0;
 127 -       iowrite32(0, systick.membase + SYSTICK_CONFIG);
 128 +       iowrite32(CFG_CNT_EN, systick.membase + SYSTICK_CONFIG);
 129 +
 130 +       if (systick_freq_scaling)
 131 +               systick_freq_scaling(sdev, 0);
 132 +
 133 +       if (systick_freq_scaling)
 134 +               systick_freq_scaling(sdev, 1);
 135
 136         return 0;
 137  }
 138 @@ -117,34 +164,48 @@ static int systick_set_oneshot(struct cl
 139         return 0;
 140  }
 141
 142 +static const struct of_device_id systick_match[] = {
 143 +       { .compatible = "ralink,mt7620a-systick", .data = mt7620_freq_scaling},
 144 +       {},
 145 +};
 146 +
 147  static int __init ralink_systick_init(struct device_node *np)
 148  {
 149 +       const struct of_device_id *match;
 150 +       int rating = 200;
 151         int ret;
 152
 153         systick.membase = of_iomap(np, 0);
 154         if (!systick.membase)
 155                 return -ENXIO;
 156
 157 -       systick_irqaction.name = np->name;
 158 -       systick.dev.name = np->name;
 159 -       clockevents_calc_mult_shift(&systick.dev, SYSTICK_FREQ, 60);
 160 -       systick.dev.max_delta_ns = clockevent_delta2ns(0x7fff, &systick.dev);
 161 -       systick.dev.max_delta_ticks = 0x7fff;
 162 -       systick.dev.min_delta_ns = clockevent_delta2ns(0x3, &systick.dev);
 163 -       systick.dev.min_delta_ticks = 0x3;
 164 +       match = of_match_node(systick_match, np);
 165 +       if (match) {
 166 +               systick_freq_scaling = match->data;
 167 +               /*
 168 +                * cevt-r4k uses 300, make sure systick
 169 +                * gets used if available
 170 +                */
 171 +               rating = 310;
 172 +       }
 173 +
 174 +       /* enable counter than register clock source */
 175 +       iowrite32(CFG_CNT_EN, systick.membase + SYSTICK_CONFIG);
 176 +       clocksource_mmio_init(systick.membase + SYSTICK_COUNT, np->name,
 177 +                       SYSTICK_FREQ, rating, 16, clocksource_mmio_readl_up);
 178 +
 179 +       /* register clock event */
 180         systick.dev.irq = irq_of_parse_and_map(np, 0);
 181         if (!systick.dev.irq) {
 182                 pr_err("%s: request_irq failed", np->name);
 183                 return -EINVAL;
 184         }
 185
 186 -       ret = clocksource_mmio_init(systick.membase + SYSTICK_COUNT, np->name,
 187 -                                   SYSTICK_FREQ, 301, 16,
 188 -                                   clocksource_mmio_readl_up);
 189 -       if (ret)
 190 -               return ret;
 191 -
 192 -       clockevents_register_device(&systick.dev);
 193 +       systick_irqaction.name = np->name;
 194 +       systick.dev.name = np->name;
 195 +       systick.dev.rating = rating;
 196 +       systick.dev.cpumask = cpumask_of(0);
 197 +       clockevents_config_and_register(&systick.dev, SYSTICK_FREQ, 0x3, 0x7fff);
 198
 199         pr_info("%s: running - mult: %d, shift: %d\n",
 200                         np->name, systick.dev.mult, systick.dev.shift);