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         struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  46         struct clk timer_clk;
  47         int err;
  48         ulong ret;
  49
  50         err = clk_get_by_index(dev, 0, &timer_clk);
  51         if (!err) {
  52                 ret = clk_get_rate(&timer_clk);
  53                 if (IS_ERR_VALUE(ret))
  54                         return ret;
  55                 uc_priv->clock_rate = ret;
  56         } else
  57                 uc_priv->clock_rate = fdtdec_get_int(gd->fdt_blob,
  58                                 dev->of_offset, "clock-frequency", 0);
  59
  60         return 0;
  61 }
  62
  63 static int timer_post_probe(struct udevice *dev)
  64 {
  65         struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  66
  67         if (!uc_priv->clock_rate)
  68                 return -EINVAL;
  69
  70         return 0;
  71 }
  72
  73 u64 timer_conv_64(u32 count)
  74 {
  75         /* increment tbh if tbl has rolled over */
  76         if (count < gd->timebase_l)
  77                 gd->timebase_h++;
  78         gd->timebase_l = count;
  79         return ((u64)gd->timebase_h << 32) | gd->timebase_l;
  80 }
  81
  82 int notrace dm_timer_init(void)
  83 {
  84         const void *blob = gd->fdt_blob;
  85         struct udevice *dev = NULL;
  86         int node;
  87         int ret;
  88
  89         if (gd->timer)
  90                 return 0;
  91
  92         /* Check for a chosen timer to be used for tick */
  93         node = fdtdec_get_chosen_node(blob, "tick-timer");
  94         if (node < 0) {
  95                 /* No chosen timer, trying first available timer */
  96                 ret = uclass_first_device_err(UCLASS_TIMER, &dev);
  97                 if (ret)
  98                         return ret;
  99         } else {
 100                 if (uclass_get_device_by_of_offset(UCLASS_TIMER, node, &dev)) {
 101                         /*
 102                          * If the timer is not marked to be bound before
 103                          * relocation, bind it anyway.
 104                          */
 105                         if (node > 0 &&
 106                             !lists_bind_fdt(gd->dm_root, blob, node, &dev)) {
 107                                 ret = device_probe(dev);
 108                                 if (ret)
 109                                         return ret;
 110                         }
 111                 }
 112         }
 113
 114         if (dev) {
 115                 gd->timer = dev;
 116                 return 0;
 117         }
 118
 119         return -ENODEV;
 120 }
 121
 122 UCLASS_DRIVER(timer) = {
 123         .id             = UCLASS_TIMER,
 124         .name           = "timer",
 125         .pre_probe      = timer_pre_probe,
 126         .flags          = DM_UC_FLAG_SEQ_ALIAS,
 127         .post_probe     = timer_post_probe,
 128         .per_device_auto_alloc_size = sizeof(struct timer_dev_priv),
 129 };