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(dev), "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 }; 130