drivers/timer/timer-uclass.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2015 Thomas Chou <thomas@wytron.com.tw>
   4  */
   5
   6 #include <common.h>
   7 #include <dm.h>
   8 #include <dm/lists.h>
   9 #include <dm/device-internal.h>
  10 #include <dm/root.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 =
  59                         dev_read_u32_default(dev, "clock-frequency", 0);
  60         }
  61 #endif
  62
  63         return 0;
  64 }
  65
  66 static int timer_post_probe(struct udevice *dev)
  67 {
  68         struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  69
  70         if (!uc_priv->clock_rate)
  71                 return -EINVAL;
  72
  73         return 0;
  74 }
  75
  76 u64 timer_conv_64(u32 count)
  77 {
  78         /* increment tbh if tbl has rolled over */
  79         if (count < gd->timebase_l)
  80                 gd->timebase_h++;
  81         gd->timebase_l = count;
  82         return ((u64)gd->timebase_h << 32) | gd->timebase_l;
  83 }
  84
  85 int notrace dm_timer_init(void)
  86 {
  87         struct udevice *dev = NULL;
  88         __maybe_unused ofnode node;
  89         int ret;
  90
  91         if (gd->timer)
  92                 return 0;
  93
  94         /*
  95          * Directly access gd->dm_root to suppress error messages, if the
  96          * virtual root driver does not yet exist.
  97          */
  98         if (gd->dm_root == NULL)
  99                 return -EAGAIN;
 100
 101 #if !CONFIG_IS_ENABLED(OF_PLATDATA)
 102         /* Check for a chosen timer to be used for tick */
 103         node = ofnode_get_chosen_node("tick-timer");
 104
 105         if (ofnode_valid(node) &&
 106             uclass_get_device_by_ofnode(UCLASS_TIMER, node, &dev)) {
 107                 /*
 108                  * If the timer is not marked to be bound before
 109                  * relocation, bind it anyway.
 110                  */
 111                 if (!lists_bind_fdt(dm_root(), node, &dev)) {
 112                         ret = device_probe(dev);
 113                         if (ret)
 114                                 return ret;
 115                 }
 116         }
 117 #endif
 118
 119         if (!dev) {
 120                 /* Fall back to the first available timer */
 121                 ret = uclass_first_device_err(UCLASS_TIMER, &dev);
 122                 if (ret)
 123                         return ret;
 124         }
 125
 126         if (dev) {
 127                 gd->timer = dev;
 128                 return 0;
 129         }
 130
 131         return -ENODEV;
 132 }
 133
 134 UCLASS_DRIVER(timer) = {
 135         .id             = UCLASS_TIMER,
 136         .name           = "timer",
 137         .pre_probe      = timer_pre_probe,
 138         .flags          = DM_UC_FLAG_SEQ_ALIAS,
 139         .post_probe     = timer_post_probe,
 140         .per_device_auto_alloc_size = sizeof(struct timer_dev_priv),
 141 };