1 /* 2 * Copyright (c) 2017, Linaro Ltd. All rights reserved. 3 * 4 * Author: Daniel Lezcano <daniel.lezcano@linaro.org> 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms and conditions of the GNU General Public License, 8 * version 2, as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 13 * more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program. If not, see <http://www.gnu.org/licenses/>. 17 */ 18 #include <linux/clk.h> 19 #include <linux/interrupt.h> 20 #include <linux/of.h> 21 #include <linux/of_address.h> 22 #include <linux/of_irq.h> 23 #include <linux/slab.h> 24 25 #include "timer-of.h" 26 27 /** 28 * timer_of_irq_exit - Release the interrupt 29 * @of_irq: an of_timer_irq structure pointer 30 * 31 * Free the irq resource 32 */ 33 static __init void timer_of_irq_exit(struct of_timer_irq *of_irq) 34 { 35 struct timer_of *to = container_of(of_irq, struct timer_of, of_irq); 36 37 struct clock_event_device *clkevt = &to->clkevt; 38 39 of_irq->percpu ? free_percpu_irq(of_irq->irq, clkevt) : 40 free_irq(of_irq->irq, clkevt); 41 } 42 43 /** 44 * timer_of_irq_init - Request the interrupt 45 * @np: a device tree node pointer 46 * @of_irq: an of_timer_irq structure pointer 47 * 48 * Get the interrupt number from the DT from its definition and 49 * request it. The interrupt is gotten by falling back the following way: 50 * 51 * - Get interrupt number by name 52 * - Get interrupt number by index 53 * 54 * When the interrupt is per CPU, 'request_percpu_irq()' is called, 55 * otherwise 'request_irq()' is used. 56 * 57 * Returns 0 on success, < 0 otherwise 58 */ 59 static __init int timer_of_irq_init(struct device_node *np, 60 struct of_timer_irq *of_irq) 61 { 62 int ret; 63 struct timer_of *to = container_of(of_irq, struct timer_of, of_irq); 64 struct clock_event_device *clkevt = &to->clkevt; 65 66 if (of_irq->name) { 67 of_irq->irq = ret = of_irq_get_byname(np, of_irq->name); 68 if (ret < 0) { 69 pr_err("Failed to get interrupt %s for %s\n", 70 of_irq->name, np->full_name); 71 return ret; 72 } 73 } else { 74 of_irq->irq = irq_of_parse_and_map(np, of_irq->index); 75 } 76 if (!of_irq->irq) { 77 pr_err("Failed to map interrupt for %pOF\n", np); 78 return -EINVAL; 79 } 80 81 ret = of_irq->percpu ? 82 request_percpu_irq(of_irq->irq, of_irq->handler, 83 np->full_name, clkevt) : 84 request_irq(of_irq->irq, of_irq->handler, 85 of_irq->flags ? of_irq->flags : IRQF_TIMER, 86 np->full_name, clkevt); 87 if (ret) { 88 pr_err("Failed to request irq %d for %pOF\n", of_irq->irq, np); 89 return ret; 90 } 91 92 clkevt->irq = of_irq->irq; 93 94 return 0; 95 } 96 97 /** 98 * timer_of_clk_exit - Release the clock resources 99 * @of_clk: a of_timer_clk structure pointer 100 * 101 * Disables and releases the refcount on the clk 102 */ 103 static __init void timer_of_clk_exit(struct of_timer_clk *of_clk) 104 { 105 of_clk->rate = 0; 106 clk_disable_unprepare(of_clk->clk); 107 clk_put(of_clk->clk); 108 } 109 110 /** 111 * timer_of_clk_init - Initialize the clock resources 112 * @np: a device tree node pointer 113 * @of_clk: a of_timer_clk structure pointer 114 * 115 * Get the clock by name or by index, enable it and get the rate 116 * 117 * Returns 0 on success, < 0 otherwise 118 */ 119 static __init int timer_of_clk_init(struct device_node *np, 120 struct of_timer_clk *of_clk) 121 { 122 int ret; 123 124 of_clk->clk = of_clk->name ? of_clk_get_by_name(np, of_clk->name) : 125 of_clk_get(np, of_clk->index); 126 if (IS_ERR(of_clk->clk)) { 127 pr_err("Failed to get clock for %pOF\n", np); 128 return PTR_ERR(of_clk->clk); 129 } 130 131 ret = clk_prepare_enable(of_clk->clk); 132 if (ret) { 133 pr_err("Failed for enable clock for %pOF\n", np); 134 goto out_clk_put; 135 } 136 137 of_clk->rate = clk_get_rate(of_clk->clk); 138 if (!of_clk->rate) { 139 ret = -EINVAL; 140 pr_err("Failed to get clock rate for %pOF\n", np); 141 goto out_clk_disable; 142 } 143 144 of_clk->period = DIV_ROUND_UP(of_clk->rate, HZ); 145 out: 146 return ret; 147 148 out_clk_disable: 149 clk_disable_unprepare(of_clk->clk); 150 out_clk_put: 151 clk_put(of_clk->clk); 152 153 goto out; 154 } 155 156 static __init void timer_of_base_exit(struct of_timer_base *of_base) 157 { 158 iounmap(of_base->base); 159 } 160 161 static __init int timer_of_base_init(struct device_node *np, 162 struct of_timer_base *of_base) 163 { 164 of_base->base = of_base->name ? 165 of_io_request_and_map(np, of_base->index, of_base->name) : 166 of_iomap(np, of_base->index); 167 if (IS_ERR(of_base->base)) { 168 pr_err("Failed to iomap (%s)\n", of_base->name); 169 return PTR_ERR(of_base->base); 170 } 171 172 return 0; 173 } 174 175 int __init timer_of_init(struct device_node *np, struct timer_of *to) 176 { 177 int ret = -EINVAL; 178 int flags = 0; 179 180 if (to->flags & TIMER_OF_BASE) { 181 ret = timer_of_base_init(np, &to->of_base); 182 if (ret) 183 goto out_fail; 184 flags |= TIMER_OF_BASE; 185 } 186 187 if (to->flags & TIMER_OF_CLOCK) { 188 ret = timer_of_clk_init(np, &to->of_clk); 189 if (ret) 190 goto out_fail; 191 flags |= TIMER_OF_CLOCK; 192 } 193 194 if (to->flags & TIMER_OF_IRQ) { 195 ret = timer_of_irq_init(np, &to->of_irq); 196 if (ret) 197 goto out_fail; 198 flags |= TIMER_OF_IRQ; 199 } 200 201 if (!to->clkevt.name) 202 to->clkevt.name = np->name; 203 204 to->np = np; 205 206 return ret; 207 208 out_fail: 209 if (flags & TIMER_OF_IRQ) 210 timer_of_irq_exit(&to->of_irq); 211 212 if (flags & TIMER_OF_CLOCK) 213 timer_of_clk_exit(&to->of_clk); 214 215 if (flags & TIMER_OF_BASE) 216 timer_of_base_exit(&to->of_base); 217 return ret; 218 } 219 220 /** 221 * timer_of_cleanup - release timer_of ressources 222 * @to: timer_of structure 223 * 224 * Release the ressources that has been used in timer_of_init(). 225 * This function should be called in init error cases 226 */ 227 void __init timer_of_cleanup(struct timer_of *to) 228 { 229 if (to->flags & TIMER_OF_IRQ) 230 timer_of_irq_exit(&to->of_irq); 231 232 if (to->flags & TIMER_OF_CLOCK) 233 timer_of_clk_exit(&to->of_clk); 234 235 if (to->flags & TIMER_OF_BASE) 236 timer_of_base_exit(&to->of_base); 237 } 238