1 /* 2 * Copyright (C) 2012 Altera Corporation 3 * Copyright (c) 2011 Picochip Ltd., Jamie Iles 4 * 5 * Modified from mach-picoxcell/time.c 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program. If not, see <http://www.gnu.org/licenses/>. 18 */ 19 #include <linux/dw_apb_timer.h> 20 #include <linux/of.h> 21 #include <linux/of_address.h> 22 #include <linux/of_irq.h> 23 24 #include <asm/mach/time.h> 25 #include <asm/sched_clock.h> 26 27 static void timer_get_base_and_rate(struct device_node *np, 28 void __iomem **base, u32 *rate) 29 { 30 *base = of_iomap(np, 0); 31 32 if (!*base) 33 panic("Unable to map regs for %s", np->name); 34 35 if (of_property_read_u32(np, "clock-freq", rate) && 36 of_property_read_u32(np, "clock-frequency", rate)) 37 panic("No clock-frequency property for %s", np->name); 38 } 39 40 static void add_clockevent(struct device_node *event_timer) 41 { 42 void __iomem *iobase; 43 struct dw_apb_clock_event_device *ced; 44 u32 irq, rate; 45 46 irq = irq_of_parse_and_map(event_timer, 0); 47 if (irq == NO_IRQ) 48 panic("No IRQ for clock event timer"); 49 50 timer_get_base_and_rate(event_timer, &iobase, &rate); 51 52 ced = dw_apb_clockevent_init(0, event_timer->name, 300, iobase, irq, 53 rate); 54 if (!ced) 55 panic("Unable to initialise clockevent device"); 56 57 dw_apb_clockevent_register(ced); 58 } 59 60 static void add_clocksource(struct device_node *source_timer) 61 { 62 void __iomem *iobase; 63 struct dw_apb_clocksource *cs; 64 u32 rate; 65 66 timer_get_base_and_rate(source_timer, &iobase, &rate); 67 68 cs = dw_apb_clocksource_init(300, source_timer->name, iobase, rate); 69 if (!cs) 70 panic("Unable to initialise clocksource device"); 71 72 dw_apb_clocksource_start(cs); 73 dw_apb_clocksource_register(cs); 74 } 75 76 static void __iomem *sched_io_base; 77 78 static u32 read_sched_clock(void) 79 { 80 return __raw_readl(sched_io_base); 81 } 82 83 static const struct of_device_id sptimer_ids[] __initconst = { 84 { .compatible = "picochip,pc3x2-rtc" }, 85 { .compatible = "snps,dw-apb-timer-sp" }, 86 { /* Sentinel */ }, 87 }; 88 89 static void init_sched_clock(void) 90 { 91 struct device_node *sched_timer; 92 u32 rate; 93 94 sched_timer = of_find_matching_node(NULL, sptimer_ids); 95 if (!sched_timer) 96 panic("No RTC for sched clock to use"); 97 98 timer_get_base_and_rate(sched_timer, &sched_io_base, &rate); 99 of_node_put(sched_timer); 100 101 setup_sched_clock(read_sched_clock, 32, rate); 102 } 103 104 static const struct of_device_id osctimer_ids[] __initconst = { 105 { .compatible = "picochip,pc3x2-timer" }, 106 { .compatible = "snps,dw-apb-timer-osc" }, 107 {}, 108 }; 109 110 static void __init timer_init(void) 111 { 112 struct device_node *event_timer, *source_timer; 113 114 event_timer = of_find_matching_node(NULL, osctimer_ids); 115 if (!event_timer) 116 panic("No timer for clockevent"); 117 add_clockevent(event_timer); 118 119 source_timer = of_find_matching_node(event_timer, osctimer_ids); 120 if (!source_timer) 121 panic("No timer for clocksource"); 122 add_clocksource(source_timer); 123 124 of_node_put(source_timer); 125 126 init_sched_clock(); 127 } 128 129 struct sys_timer dw_apb_timer = { 130 .init = timer_init, 131 }; 132