1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Time related functions for Hexagon architecture 4 * 5 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. 6 */ 7 8 #include <linux/init.h> 9 #include <linux/clockchips.h> 10 #include <linux/clocksource.h> 11 #include <linux/interrupt.h> 12 #include <linux/err.h> 13 #include <linux/platform_device.h> 14 #include <linux/ioport.h> 15 #include <linux/of.h> 16 #include <linux/of_address.h> 17 #include <linux/of_irq.h> 18 #include <linux/module.h> 19 20 #include <asm/delay.h> 21 #include <asm/hexagon_vm.h> 22 #include <asm/time.h> 23 24 #define TIMER_ENABLE BIT(0) 25 26 /* 27 * For the clocksource we need: 28 * pcycle frequency (600MHz) 29 * For the loops_per_jiffy we need: 30 * thread/cpu frequency (100MHz) 31 * And for the timer, we need: 32 * sleep clock rate 33 */ 34 35 cycles_t pcycle_freq_mhz; 36 cycles_t thread_freq_mhz; 37 cycles_t sleep_clk_freq; 38 39 /* 40 * 8x50 HDD Specs 5-8. Simulator co-sim not fixed until 41 * release 1.1, and then it's "adjustable" and probably not defaulted. 42 */ 43 #define RTOS_TIMER_INT 3 44 #define RTOS_TIMER_REGS_ADDR 0xAB000000UL 45 46 static struct resource rtos_timer_resources[] = { 47 { 48 .start = RTOS_TIMER_REGS_ADDR, 49 .end = RTOS_TIMER_REGS_ADDR+PAGE_SIZE-1, 50 .flags = IORESOURCE_MEM, 51 }, 52 }; 53 54 static struct platform_device rtos_timer_device = { 55 .name = "rtos_timer", 56 .id = -1, 57 .num_resources = ARRAY_SIZE(rtos_timer_resources), 58 .resource = rtos_timer_resources, 59 }; 60 61 /* A lot of this stuff should move into a platform specific section. */ 62 struct adsp_hw_timer_struct { 63 u32 match; /* Match value */ 64 u32 count; 65 u32 enable; /* [1] - CLR_ON_MATCH_EN, [0] - EN */ 66 u32 clear; /* one-shot register that clears the count */ 67 }; 68 69 /* Look for "TCX0" for related constants. */ 70 static __iomem struct adsp_hw_timer_struct *rtos_timer; 71 72 static u64 timer_get_cycles(struct clocksource *cs) 73 { 74 return (u64) __vmgettime(); 75 } 76 77 static struct clocksource hexagon_clocksource = { 78 .name = "pcycles", 79 .rating = 250, 80 .read = timer_get_cycles, 81 .mask = CLOCKSOURCE_MASK(64), 82 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 83 }; 84 85 static int set_next_event(unsigned long delta, struct clock_event_device *evt) 86 { 87 /* Assuming the timer will be disabled when we enter here. */ 88 89 iowrite32(1, &rtos_timer->clear); 90 iowrite32(0, &rtos_timer->clear); 91 92 iowrite32(delta, &rtos_timer->match); 93 iowrite32(TIMER_ENABLE, &rtos_timer->enable); 94 return 0; 95 } 96 97 #ifdef CONFIG_SMP 98 /* Broadcast mechanism */ 99 static void broadcast(const struct cpumask *mask) 100 { 101 send_ipi(mask, IPI_TIMER); 102 } 103 #endif 104 105 /* XXX Implement set_state_shutdown() */ 106 static struct clock_event_device hexagon_clockevent_dev = { 107 .name = "clockevent", 108 .features = CLOCK_EVT_FEAT_ONESHOT, 109 .rating = 400, 110 .irq = RTOS_TIMER_INT, 111 .set_next_event = set_next_event, 112 #ifdef CONFIG_SMP 113 .broadcast = broadcast, 114 #endif 115 }; 116 117 #ifdef CONFIG_SMP 118 static DEFINE_PER_CPU(struct clock_event_device, clock_events); 119 120 void setup_percpu_clockdev(void) 121 { 122 int cpu = smp_processor_id(); 123 struct clock_event_device *ce_dev = &hexagon_clockevent_dev; 124 struct clock_event_device *dummy_clock_dev = 125 &per_cpu(clock_events, cpu); 126 127 memcpy(dummy_clock_dev, ce_dev, sizeof(*dummy_clock_dev)); 128 INIT_LIST_HEAD(&dummy_clock_dev->list); 129 130 dummy_clock_dev->features = CLOCK_EVT_FEAT_DUMMY; 131 dummy_clock_dev->cpumask = cpumask_of(cpu); 132 133 clockevents_register_device(dummy_clock_dev); 134 } 135 136 /* Called from smp.c for each CPU's timer ipi call */ 137 void ipi_timer(void) 138 { 139 int cpu = smp_processor_id(); 140 struct clock_event_device *ce_dev = &per_cpu(clock_events, cpu); 141 142 ce_dev->event_handler(ce_dev); 143 } 144 #endif /* CONFIG_SMP */ 145 146 static irqreturn_t timer_interrupt(int irq, void *devid) 147 { 148 struct clock_event_device *ce_dev = &hexagon_clockevent_dev; 149 150 iowrite32(0, &rtos_timer->enable); 151 ce_dev->event_handler(ce_dev); 152 153 return IRQ_HANDLED; 154 } 155 156 /* 157 * time_init_deferred - called by start_kernel to set up timer/clock source 158 * 159 * Install the IRQ handler for the clock, setup timers. 160 * This is done late, as that way, we can use ioremap(). 161 * 162 * This runs just before the delay loop is calibrated, and 163 * is used for delay calibration. 164 */ 165 static void __init time_init_deferred(void) 166 { 167 struct resource *resource = NULL; 168 struct clock_event_device *ce_dev = &hexagon_clockevent_dev; 169 unsigned long flag = IRQF_TIMER | IRQF_TRIGGER_RISING; 170 171 ce_dev->cpumask = cpu_all_mask; 172 173 if (!resource) 174 resource = rtos_timer_device.resource; 175 176 /* ioremap here means this has to run later, after paging init */ 177 rtos_timer = ioremap(resource->start, resource_size(resource)); 178 179 if (!rtos_timer) { 180 release_mem_region(resource->start, resource_size(resource)); 181 } 182 clocksource_register_khz(&hexagon_clocksource, pcycle_freq_mhz * 1000); 183 184 /* Note: the sim generic RTOS clock is apparently really 18750Hz */ 185 186 /* 187 * Last arg is some guaranteed seconds for which the conversion will 188 * work without overflow. 189 */ 190 clockevents_calc_mult_shift(ce_dev, sleep_clk_freq, 4); 191 192 ce_dev->max_delta_ns = clockevent_delta2ns(0x7fffffff, ce_dev); 193 ce_dev->max_delta_ticks = 0x7fffffff; 194 ce_dev->min_delta_ns = clockevent_delta2ns(0xf, ce_dev); 195 ce_dev->min_delta_ticks = 0xf; 196 197 #ifdef CONFIG_SMP 198 setup_percpu_clockdev(); 199 #endif 200 201 clockevents_register_device(ce_dev); 202 if (request_irq(ce_dev->irq, timer_interrupt, flag, "rtos_timer", NULL)) 203 pr_err("Failed to register rtos_timer interrupt\n"); 204 } 205 206 void __init time_init(void) 207 { 208 late_time_init = time_init_deferred; 209 } 210 211 void __delay(unsigned long cycles) 212 { 213 unsigned long long start = __vmgettime(); 214 215 while ((__vmgettime() - start) < cycles) 216 cpu_relax(); 217 } 218 EXPORT_SYMBOL(__delay); 219 220 /* 221 * This could become parametric or perhaps even computed at run-time, 222 * but for now we take the observed simulator jitter. 223 */ 224 static long long fudgefactor = 350; /* Maybe lower if kernel optimized. */ 225 226 void __udelay(unsigned long usecs) 227 { 228 unsigned long long start = __vmgettime(); 229 unsigned long long finish = (pcycle_freq_mhz * usecs) - fudgefactor; 230 231 while ((__vmgettime() - start) < finish) 232 cpu_relax(); /* not sure how this improves readability */ 233 } 234 EXPORT_SYMBOL(__udelay); 235