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 <errno.h> 12 #include <timer.h> 13 14 DECLARE_GLOBAL_DATA_PTR; 15 16 /* 17 * Implement a timer uclass to work with lib/time.c. The timer is usually 18 * a 32/64 bits free-running up counter. The get_rate() method is used to get 19 * the input clock frequency of the timer. The get_count() method is used 20 * to get the current 64 bits count value. If the hardware is counting down, 21 * the value should be inversed inside the method. There may be no real 22 * tick, and no timer interrupt. 23 */ 24 25 int timer_get_count(struct udevice *dev, u64 *count) 26 { 27 const struct timer_ops *ops = device_get_ops(dev); 28 29 if (!ops->get_count) 30 return -ENOSYS; 31 32 return ops->get_count(dev, count); 33 } 34 35 unsigned long timer_get_rate(struct udevice *dev) 36 { 37 struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev); 38 39 return uc_priv->clock_rate; 40 } 41 42 static int timer_pre_probe(struct udevice *dev) 43 { 44 struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev); 45 46 uc_priv->clock_rate = fdtdec_get_int(gd->fdt_blob, dev->of_offset, 47 "clock-frequency", 0); 48 49 return 0; 50 } 51 52 u64 timer_conv_64(u32 count) 53 { 54 /* increment tbh if tbl has rolled over */ 55 if (count < gd->timebase_l) 56 gd->timebase_h++; 57 gd->timebase_l = count; 58 return ((u64)gd->timebase_h << 32) | gd->timebase_l; 59 } 60 61 int notrace dm_timer_init(void) 62 { 63 const void *blob = gd->fdt_blob; 64 struct udevice *dev = NULL; 65 int node; 66 int ret; 67 68 if (gd->timer) 69 return 0; 70 71 /* Check for a chosen timer to be used for tick */ 72 node = fdtdec_get_chosen_node(blob, "tick-timer"); 73 if (node < 0) { 74 /* No chosen timer, trying first available timer */ 75 ret = uclass_first_device(UCLASS_TIMER, &dev); 76 if (ret) 77 return ret; 78 if (!dev) 79 return -ENODEV; 80 } else { 81 if (uclass_get_device_by_of_offset(UCLASS_TIMER, node, &dev)) { 82 /* 83 * If the timer is not marked to be bound before 84 * relocation, bind it anyway. 85 */ 86 if (node > 0 && 87 !lists_bind_fdt(gd->dm_root, blob, node, &dev)) { 88 ret = device_probe(dev); 89 if (ret) 90 return ret; 91 } 92 } 93 } 94 95 if (dev) { 96 gd->timer = dev; 97 return 0; 98 } 99 100 return -ENODEV; 101 } 102 103 UCLASS_DRIVER(timer) = { 104 .id = UCLASS_TIMER, 105 .name = "timer", 106 .pre_probe = timer_pre_probe, 107 .per_device_auto_alloc_size = sizeof(struct timer_dev_priv), 108 }; 109