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 #if !CONFIG_IS_ENABLED(OF_PLATDATA) 46 struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev); 47 struct clk timer_clk; 48 int err; 49 ulong ret; 50 51 err = clk_get_by_index(dev, 0, &timer_clk); 52 if (!err) { 53 ret = clk_get_rate(&timer_clk); 54 if (IS_ERR_VALUE(ret)) 55 return ret; 56 uc_priv->clock_rate = ret; 57 } else 58 uc_priv->clock_rate = fdtdec_get_int(gd->fdt_blob, 59 dev_of_offset(dev), "clock-frequency", 0); 60 #endif 61 62 return 0; 63 } 64 65 static int timer_post_probe(struct udevice *dev) 66 { 67 struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev); 68 69 if (!uc_priv->clock_rate) 70 return -EINVAL; 71 72 return 0; 73 } 74 75 u64 timer_conv_64(u32 count) 76 { 77 /* increment tbh if tbl has rolled over */ 78 if (count < gd->timebase_l) 79 gd->timebase_h++; 80 gd->timebase_l = count; 81 return ((u64)gd->timebase_h << 32) | gd->timebase_l; 82 } 83 84 int notrace dm_timer_init(void) 85 { 86 __maybe_unused const void *blob = gd->fdt_blob; 87 struct udevice *dev = NULL; 88 int node = -ENOENT; 89 int ret; 90 91 if (gd->timer) 92 return 0; 93 94 #if !CONFIG_IS_ENABLED(OF_PLATDATA) 95 /* Check for a chosen timer to be used for tick */ 96 node = fdtdec_get_chosen_node(blob, "tick-timer"); 97 #endif 98 if (node < 0) { 99 /* No chosen timer, trying first available timer */ 100 ret = uclass_first_device_err(UCLASS_TIMER, &dev); 101 if (ret) 102 return ret; 103 } else { 104 if (uclass_get_device_by_of_offset(UCLASS_TIMER, node, &dev)) { 105 /* 106 * If the timer is not marked to be bound before 107 * relocation, bind it anyway. 108 */ 109 if (node > 0 && 110 !lists_bind_fdt(gd->dm_root, offset_to_ofnode(node), 111 &dev)) { 112 ret = device_probe(dev); 113 if (ret) 114 return ret; 115 } 116 } 117 } 118 119 if (dev) { 120 gd->timer = dev; 121 return 0; 122 } 123 124 return -ENODEV; 125 } 126 127 UCLASS_DRIVER(timer) = { 128 .id = UCLASS_TIMER, 129 .name = "timer", 130 .pre_probe = timer_pre_probe, 131 .flags = DM_UC_FLAG_SEQ_ALIAS, 132 .post_probe = timer_post_probe, 133 .per_device_auto_alloc_size = sizeof(struct timer_dev_priv), 134 }; 135