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 <dm/root.h> 12 #include <clk.h> 13 #include <errno.h> 14 #include <timer.h> 15 16 DECLARE_GLOBAL_DATA_PTR; 17 18 /* 19 * Implement a timer uclass to work with lib/time.c. The timer is usually 20 * a 32/64 bits free-running up counter. The get_rate() method is used to get 21 * the input clock frequency of the timer. The get_count() method is used 22 * to get the current 64 bits count value. If the hardware is counting down, 23 * the value should be inversed inside the method. There may be no real 24 * tick, and no timer interrupt. 25 */ 26 27 int notrace timer_get_count(struct udevice *dev, u64 *count) 28 { 29 const struct timer_ops *ops = device_get_ops(dev); 30 31 if (!ops->get_count) 32 return -ENOSYS; 33 34 return ops->get_count(dev, count); 35 } 36 37 unsigned long notrace timer_get_rate(struct udevice *dev) 38 { 39 struct timer_dev_priv *uc_priv = dev->uclass_priv; 40 41 return uc_priv->clock_rate; 42 } 43 44 static int timer_pre_probe(struct udevice *dev) 45 { 46 #if !CONFIG_IS_ENABLED(OF_PLATDATA) 47 struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev); 48 struct clk timer_clk; 49 int err; 50 ulong ret; 51 52 err = clk_get_by_index(dev, 0, &timer_clk); 53 if (!err) { 54 ret = clk_get_rate(&timer_clk); 55 if (IS_ERR_VALUE(ret)) 56 return ret; 57 uc_priv->clock_rate = ret; 58 } else { 59 uc_priv->clock_rate = 60 dev_read_u32_default(dev, "clock-frequency", 0); 61 } 62 #endif 63 64 return 0; 65 } 66 67 static int timer_post_probe(struct udevice *dev) 68 { 69 struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev); 70 71 if (!uc_priv->clock_rate) 72 return -EINVAL; 73 74 return 0; 75 } 76 77 u64 timer_conv_64(u32 count) 78 { 79 /* increment tbh if tbl has rolled over */ 80 if (count < gd->timebase_l) 81 gd->timebase_h++; 82 gd->timebase_l = count; 83 return ((u64)gd->timebase_h << 32) | gd->timebase_l; 84 } 85 86 int notrace dm_timer_init(void) 87 { 88 struct udevice *dev = NULL; 89 __maybe_unused ofnode node; 90 int ret; 91 92 if (gd->timer) 93 return 0; 94 95 /* 96 * Directly access gd->dm_root to suppress error messages, if the 97 * virtual root driver does not yet exist. 98 */ 99 if (gd->dm_root == NULL) 100 return -EAGAIN; 101 102 #if !CONFIG_IS_ENABLED(OF_PLATDATA) 103 /* Check for a chosen timer to be used for tick */ 104 node = ofnode_get_chosen_node("tick-timer"); 105 106 if (ofnode_valid(node) && 107 uclass_get_device_by_ofnode(UCLASS_TIMER, node, &dev)) { 108 /* 109 * If the timer is not marked to be bound before 110 * relocation, bind it anyway. 111 */ 112 if (!lists_bind_fdt(dm_root(), node, &dev)) { 113 ret = device_probe(dev); 114 if (ret) 115 return ret; 116 } 117 } 118 #endif 119 120 if (!dev) { 121 /* Fall back to the first available timer */ 122 ret = uclass_first_device_err(UCLASS_TIMER, &dev); 123 if (ret) 124 return ret; 125 } 126 127 if (dev) { 128 gd->timer = dev; 129 return 0; 130 } 131 132 return -ENODEV; 133 } 134 135 UCLASS_DRIVER(timer) = { 136 .id = UCLASS_TIMER, 137 .name = "timer", 138 .pre_probe = timer_pre_probe, 139 .flags = DM_UC_FLAG_SEQ_ALIAS, 140 .post_probe = timer_post_probe, 141 .per_device_auto_alloc_size = sizeof(struct timer_dev_priv), 142 }; 143