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 #define LOG_CATEGORY UCLASS_TIMER
   7
   8 #include <common.h>
   9 #include <clk.h>
  10 #include <cpu.h>
  11 #include <dm.h>
  12 #include <asm/global_data.h>
  13 #include <dm/lists.h>
  14 #include <dm/device_compat.h>
  15 #include <dm/device-internal.h>
  16 #include <dm/root.h>
  17 #include <errno.h>
  18 #include <init.h>
  19 #include <timer.h>
  20 #include <linux/err.h>
  21 #include <relocate.h>
  22
  23 DECLARE_GLOBAL_DATA_PTR;
  24
  25 /*
  26  * Implement a timer uclass to work with lib/time.c. The timer is usually
  27  * a 32/64 bits free-running up counter. The get_rate() method is used to get
  28  * the input clock frequency of the timer. The get_count() method is used
  29  * to get the current 64 bits count value. If the hardware is counting down,
  30  * the value should be inversed inside the method. There may be no real
  31  * tick, and no timer interrupt.
  32  */
  33
  34 int notrace timer_get_count(struct udevice *dev, u64 *count)
  35 {
  36         struct timer_ops *ops = timer_get_ops(dev);
  37
  38         if (!ops->get_count)
  39                 return -ENOSYS;
  40
  41         *count = ops->get_count(dev);
  42         return 0;
  43 }
  44
  45 unsigned long notrace timer_get_rate(struct udevice *dev)
  46 {
  47         struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  48
  49         return uc_priv->clock_rate;
  50 }
  51
  52 static int timer_pre_probe(struct udevice *dev)
  53 {
  54         if (CONFIG_IS_ENABLED(OF_REAL)) {
  55                 struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  56                 struct clk timer_clk;
  57                 int err;
  58                 ulong ret;
  59
  60                 /*
  61                  * It is possible that a timer device has a null ofnode
  62                  */
  63                 if (!dev_has_ofnode(dev))
  64                         return 0;
  65
  66                 err = clk_get_by_index(dev, 0, &timer_clk);
  67                 if (!err) {
  68                         ret = clk_get_rate(&timer_clk);
  69                         if (IS_ERR_VALUE(ret))
  70                                 return ret;
  71                         uc_priv->clock_rate = ret;
  72                 } else {
  73                         uc_priv->clock_rate =
  74                                 dev_read_u32_default(dev, "clock-frequency", 0);
  75                 }
  76         }
  77
  78         return 0;
  79 }
  80
  81 static int timer_post_probe(struct udevice *dev)
  82 {
  83         struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  84
  85         if (!uc_priv->clock_rate)
  86                 return -EINVAL;
  87
  88         return 0;
  89 }
  90
  91 #if CONFIG_IS_ENABLED(CPU)
  92 int timer_timebase_fallback(struct udevice *dev)
  93 {
  94         struct udevice *cpu;
  95         struct cpu_plat *cpu_plat;
  96         struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
  97
  98         /* Did we get our clock rate from the device tree? */
  99         if (uc_priv->clock_rate)
 100                 return 0;
 101
 102         /* Fall back to timebase-frequency */
 103         dev_dbg(dev, "missing clocks or clock-frequency property; falling back on timebase-frequency\n");
 104         cpu = cpu_get_current_dev();
 105         if (!cpu)
 106                 return -ENODEV;
 107
 108         cpu_plat = dev_get_parent_plat(cpu);
 109         if (!cpu_plat)
 110                 return -ENODEV;
 111
 112         uc_priv->clock_rate = cpu_plat->timebase_freq;
 113         return 0;
 114 }
 115 #endif
 116
 117 u64 timer_conv_64(u32 count)
 118 {
 119         /* increment tbh if tbl has rolled over */
 120         if (count < gd->timebase_l)
 121                 gd->timebase_h++;
 122         gd->timebase_l = count;
 123         return ((u64)gd->timebase_h << 32) | gd->timebase_l;
 124 }
 125
 126 int dm_timer_init(void)
 127 {
 128         struct udevice *dev = NULL;
 129         __maybe_unused ofnode node;
 130         int ret;
 131
 132         if (gd->timer)
 133                 return 0;
 134
 135         /*
 136          * Directly access gd->dm_root to suppress error messages, if the
 137          * virtual root driver does not yet exist.
 138          */
 139         if (gd->dm_root == NULL)
 140                 return -EAGAIN;
 141
 142         if (CONFIG_IS_ENABLED(OF_REAL)) {
 143                 /* Check for a chosen timer to be used for tick */
 144                 node = ofnode_get_chosen_node("tick-timer");
 145
 146                 if (ofnode_valid(node) &&
 147                     uclass_get_device_by_ofnode(UCLASS_TIMER, node, &dev)) {
 148                         /*
 149                          * If the timer is not marked to be bound before
 150                          * relocation, bind it anyway.
 151                          */
 152                         if (!lists_bind_fdt(dm_root(), node, &dev, NULL, false)) {
 153                                 ret = device_probe(dev);
 154                                 if (ret)
 155                                         return ret;
 156                         }
 157                 }
 158         }
 159
 160         if (!dev) {
 161                 /* Fall back to the first available timer */
 162                 ret = uclass_first_device_err(UCLASS_TIMER, &dev);
 163                 if (ret)
 164                         return ret;
 165         }
 166
 167         if (dev) {
 168                 gd->timer = dev;
 169                 return 0;
 170         }
 171
 172         return -ENODEV;
 173 }
 174
 175 UCLASS_DRIVER(timer) = {
 176         .id             = UCLASS_TIMER,
 177         .name           = "timer",
 178         .pre_probe      = timer_pre_probe,
 179         .flags          = DM_UC_FLAG_SEQ_ALIAS,
 180         .post_probe     = timer_post_probe,
 181         .per_device_auto        = sizeof(struct timer_dev_priv),
 182 };