1 /* 2 * 3 * Copyright (C) 2015 Numascale AS. All rights reserved. 4 * 5 * This software is licensed under the terms of the GNU General Public 6 * License version 2, as published by the Free Software Foundation, and 7 * may be copied, distributed, and modified under those terms. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 */ 15 16 #include <linux/clockchips.h> 17 18 #include <asm/irq.h> 19 #include <asm/numachip/numachip.h> 20 #include <asm/numachip/numachip_csr.h> 21 22 static DEFINE_PER_CPU(struct clock_event_device, numachip2_ced); 23 24 static cycles_t numachip2_timer_read(struct clocksource *cs) 25 { 26 return numachip2_read64_lcsr(NUMACHIP2_TIMER_NOW); 27 } 28 29 static struct clocksource numachip2_clocksource = { 30 .name = "numachip2", 31 .rating = 295, 32 .read = numachip2_timer_read, 33 .mask = CLOCKSOURCE_MASK(64), 34 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 35 .mult = 1, 36 .shift = 0, 37 }; 38 39 static int numachip2_set_next_event(unsigned long delta, struct clock_event_device *ced) 40 { 41 numachip2_write64_lcsr(NUMACHIP2_TIMER_DEADLINE + numachip2_timer(), 42 delta); 43 return 0; 44 } 45 46 static const struct clock_event_device numachip2_clockevent __initconst = { 47 .name = "numachip2", 48 .rating = 400, 49 .set_next_event = numachip2_set_next_event, 50 .features = CLOCK_EVT_FEAT_ONESHOT, 51 .mult = 1, 52 .shift = 0, 53 .min_delta_ns = 1250, 54 .min_delta_ticks = 1250, 55 .max_delta_ns = LONG_MAX, 56 .max_delta_ticks = LONG_MAX, 57 }; 58 59 static void numachip_timer_interrupt(void) 60 { 61 struct clock_event_device *ced = this_cpu_ptr(&numachip2_ced); 62 63 ced->event_handler(ced); 64 } 65 66 static __init void numachip_timer_each(struct work_struct *work) 67 { 68 unsigned local_apicid = __this_cpu_read(x86_cpu_to_apicid) & 0xff; 69 struct clock_event_device *ced = this_cpu_ptr(&numachip2_ced); 70 71 /* Setup IPI vector to local core and relative timing mode */ 72 numachip2_write64_lcsr(NUMACHIP2_TIMER_INT + numachip2_timer(), 73 (3 << 22) | (X86_PLATFORM_IPI_VECTOR << 14) | 74 (local_apicid << 6)); 75 76 *ced = numachip2_clockevent; 77 ced->cpumask = cpumask_of(smp_processor_id()); 78 clockevents_register_device(ced); 79 } 80 81 static int __init numachip_timer_init(void) 82 { 83 if (numachip_system != 2) 84 return -ENODEV; 85 86 /* Reset timer */ 87 numachip2_write64_lcsr(NUMACHIP2_TIMER_RESET, 0); 88 clocksource_register_hz(&numachip2_clocksource, NSEC_PER_SEC); 89 90 /* Setup per-cpu clockevents */ 91 x86_platform_ipi_callback = numachip_timer_interrupt; 92 schedule_on_each_cpu(&numachip_timer_each); 93 94 return 0; 95 } 96 97 arch_initcall(numachip_timer_init); 98