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