drivers/timer/timer-uclass.c

   1 /*
   2  * Copyright (C) 2015 Thomas Chou <thomas@wytron.com.tw>
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6
   7 #include <common.h>
   8 #include <dm.h>
   9 #include <dm/lists.h>
  10 #include <dm/device-internal.h>
  11 #include <clk.h>
  12 #include <errno.h>
  13 #include <timer.h>
  14
  15 DECLARE_GLOBAL_DATA_PTR;
  16
  17 /*
  18  * Implement a timer uclass to work with lib/time.c. The timer is usually
  19  * a 32/64 bits free-running up counter. The get_rate() method is used to get
  20  * the input clock frequency of the timer. The get_count() method is used
  21  * to get the current 64 bits count value. If the hardware is counting down,
  22  * the value should be inversed inside the method. There may be no real
  23  * tick, and no timer interrupt.
  24  */
  25
  26 int notrace timer_get_count(struct udevice *dev, u64 *count)
  27 {
  28         const struct timer_ops *ops = device_get_ops(dev);
  29
  30         if (!ops->get_count)
  31                 return -ENOSYS;
  32
  33         return ops->get_count(dev, count);
  34 }
  35
  36 unsigned long notrace timer_get_rate(struct udevice *dev)
  37 {
  38         struct timer_dev_priv *uc_priv = dev->uclass_priv;
  39
  40         return uc_priv->clock_rate;
  41 }
  42
  43 static int timer_pre_probe(struct udevice *dev)
  44 {
  45 #if !CONFIG_IS_ENABLED(OF_PLATDATA)
  46         struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  47         struct clk timer_clk;
  48         int err;
  49         ulong ret;
  50
  51         err = clk_get_by_index(dev, 0, &timer_clk);
  52         if (!err) {
  53                 ret = clk_get_rate(&timer_clk);
  54                 if (IS_ERR_VALUE(ret))
  55                         return ret;
  56                 uc_priv->clock_rate = ret;
  57         } else
  58                 uc_priv->clock_rate = fdtdec_get_int(gd->fdt_blob,
  59                                 dev_of_offset(dev),     "clock-frequency", 0);
  60 #endif
  61
  62         return 0;
  63 }
  64
  65 static int timer_post_probe(struct udevice *dev)
  66 {
  67         struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  68
  69         if (!uc_priv->clock_rate)
  70                 return -EINVAL;
  71
  72         return 0;
  73 }
  74
  75 u64 timer_conv_64(u32 count)
  76 {
  77         /* increment tbh if tbl has rolled over */
  78         if (count < gd->timebase_l)
  79                 gd->timebase_h++;
  80         gd->timebase_l = count;
  81         return ((u64)gd->timebase_h << 32) | gd->timebase_l;
  82 }
  83
  84 int notrace dm_timer_init(void)
  85 {
  86         __maybe_unused const void *blob = gd->fdt_blob;
  87         struct udevice *dev = NULL;
  88         int node = -ENOENT;
  89         int ret;
  90
  91         if (gd->timer)
  92                 return 0;
  93
  94 #if !CONFIG_IS_ENABLED(OF_PLATDATA)
  95         /* Check for a chosen timer to be used for tick */
  96         node = fdtdec_get_chosen_node(blob, "tick-timer");
  97 #endif
  98         if (node < 0) {
  99                 /* No chosen timer, trying first available timer */
 100                 ret = uclass_first_device_err(UCLASS_TIMER, &dev);
 101                 if (ret)
 102                         return ret;
 103         } else {
 104                 if (uclass_get_device_by_of_offset(UCLASS_TIMER, node, &dev)) {
 105                         /*
 106                          * If the timer is not marked to be bound before
 107                          * relocation, bind it anyway.
 108                          */
 109                         if (node > 0 &&
 110                             !lists_bind_fdt(gd->dm_root, offset_to_ofnode(node),
 111                                             &dev)) {
 112                                 ret = device_probe(dev);
 113                                 if (ret)
 114                                         return ret;
 115                         }
 116                 }
 117         }
 118
 119         if (dev) {
 120                 gd->timer = dev;
 121                 return 0;
 122         }
 123
 124         return -ENODEV;
 125 }
 126
 127 UCLASS_DRIVER(timer) = {
 128         .id             = UCLASS_TIMER,
 129         .name           = "timer",
 130         .pre_probe      = timer_pre_probe,
 131         .flags          = DM_UC_FLAG_SEQ_ALIAS,
 132         .post_probe     = timer_post_probe,
 133         .per_device_auto_alloc_size = sizeof(struct timer_dev_priv),
 134 };