1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/drivers/clocksource/zevio-timer.c 4 * 5 * Copyright (C) 2013 Daniel Tang <tangrs@tangrs.id.au> 6 */ 7 8 #include <linux/io.h> 9 #include <linux/irq.h> 10 #include <linux/of.h> 11 #include <linux/of_address.h> 12 #include <linux/of_irq.h> 13 #include <linux/clk.h> 14 #include <linux/clockchips.h> 15 #include <linux/cpumask.h> 16 #include <linux/interrupt.h> 17 #include <linux/slab.h> 18 19 #define IO_CURRENT_VAL 0x00 20 #define IO_DIVIDER 0x04 21 #define IO_CONTROL 0x08 22 23 #define IO_TIMER1 0x00 24 #define IO_TIMER2 0x0C 25 26 #define IO_MATCH_BEGIN 0x18 27 #define IO_MATCH(x) (IO_MATCH_BEGIN + ((x) << 2)) 28 29 #define IO_INTR_STS 0x00 30 #define IO_INTR_ACK 0x00 31 #define IO_INTR_MSK 0x04 32 33 #define CNTL_STOP_TIMER (1 << 4) 34 #define CNTL_RUN_TIMER (0 << 4) 35 36 #define CNTL_INC (1 << 3) 37 #define CNTL_DEC (0 << 3) 38 39 #define CNTL_TOZERO 0 40 #define CNTL_MATCH(x) ((x) + 1) 41 #define CNTL_FOREVER 7 42 43 /* There are 6 match registers but we only use one. */ 44 #define TIMER_MATCH 0 45 46 #define TIMER_INTR_MSK (1 << (TIMER_MATCH)) 47 #define TIMER_INTR_ALL 0x3F 48 49 struct zevio_timer { 50 void __iomem *base; 51 void __iomem *timer1, *timer2; 52 void __iomem *interrupt_regs; 53 54 struct clk *clk; 55 struct clock_event_device clkevt; 56 struct irqaction clkevt_irq; 57 58 char clocksource_name[64]; 59 char clockevent_name[64]; 60 }; 61 62 static int zevio_timer_set_event(unsigned long delta, 63 struct clock_event_device *dev) 64 { 65 struct zevio_timer *timer = container_of(dev, struct zevio_timer, 66 clkevt); 67 68 writel(delta, timer->timer1 + IO_CURRENT_VAL); 69 writel(CNTL_RUN_TIMER | CNTL_DEC | CNTL_MATCH(TIMER_MATCH), 70 timer->timer1 + IO_CONTROL); 71 72 return 0; 73 } 74 75 static int zevio_timer_shutdown(struct clock_event_device *dev) 76 { 77 struct zevio_timer *timer = container_of(dev, struct zevio_timer, 78 clkevt); 79 80 /* Disable timer interrupts */ 81 writel(0, timer->interrupt_regs + IO_INTR_MSK); 82 writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK); 83 /* Stop timer */ 84 writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL); 85 return 0; 86 } 87 88 static int zevio_timer_set_oneshot(struct clock_event_device *dev) 89 { 90 struct zevio_timer *timer = container_of(dev, struct zevio_timer, 91 clkevt); 92 93 /* Enable timer interrupts */ 94 writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_MSK); 95 writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK); 96 return 0; 97 } 98 99 static irqreturn_t zevio_timer_interrupt(int irq, void *dev_id) 100 { 101 struct zevio_timer *timer = dev_id; 102 u32 intr; 103 104 intr = readl(timer->interrupt_regs + IO_INTR_ACK); 105 if (!(intr & TIMER_INTR_MSK)) 106 return IRQ_NONE; 107 108 writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_ACK); 109 writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL); 110 111 if (timer->clkevt.event_handler) 112 timer->clkevt.event_handler(&timer->clkevt); 113 114 return IRQ_HANDLED; 115 } 116 117 static int __init zevio_timer_add(struct device_node *node) 118 { 119 struct zevio_timer *timer; 120 struct resource res; 121 int irqnr, ret; 122 123 timer = kzalloc(sizeof(*timer), GFP_KERNEL); 124 if (!timer) 125 return -ENOMEM; 126 127 timer->base = of_iomap(node, 0); 128 if (!timer->base) { 129 ret = -EINVAL; 130 goto error_free; 131 } 132 timer->timer1 = timer->base + IO_TIMER1; 133 timer->timer2 = timer->base + IO_TIMER2; 134 135 timer->clk = of_clk_get(node, 0); 136 if (IS_ERR(timer->clk)) { 137 ret = PTR_ERR(timer->clk); 138 pr_err("Timer clock not found! (error %d)\n", ret); 139 goto error_unmap; 140 } 141 142 timer->interrupt_regs = of_iomap(node, 1); 143 irqnr = irq_of_parse_and_map(node, 0); 144 145 of_address_to_resource(node, 0, &res); 146 scnprintf(timer->clocksource_name, sizeof(timer->clocksource_name), 147 "%llx.%pOFn_clocksource", 148 (unsigned long long)res.start, node); 149 150 scnprintf(timer->clockevent_name, sizeof(timer->clockevent_name), 151 "%llx.%pOFn_clockevent", 152 (unsigned long long)res.start, node); 153 154 if (timer->interrupt_regs && irqnr) { 155 timer->clkevt.name = timer->clockevent_name; 156 timer->clkevt.set_next_event = zevio_timer_set_event; 157 timer->clkevt.set_state_shutdown = zevio_timer_shutdown; 158 timer->clkevt.set_state_oneshot = zevio_timer_set_oneshot; 159 timer->clkevt.tick_resume = zevio_timer_set_oneshot; 160 timer->clkevt.rating = 200; 161 timer->clkevt.cpumask = cpu_possible_mask; 162 timer->clkevt.features = CLOCK_EVT_FEAT_ONESHOT; 163 timer->clkevt.irq = irqnr; 164 165 writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL); 166 writel(0, timer->timer1 + IO_DIVIDER); 167 168 /* Start with timer interrupts disabled */ 169 writel(0, timer->interrupt_regs + IO_INTR_MSK); 170 writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK); 171 172 /* Interrupt to occur when timer value matches 0 */ 173 writel(0, timer->base + IO_MATCH(TIMER_MATCH)); 174 175 timer->clkevt_irq.name = timer->clockevent_name; 176 timer->clkevt_irq.handler = zevio_timer_interrupt; 177 timer->clkevt_irq.dev_id = timer; 178 timer->clkevt_irq.flags = IRQF_TIMER | IRQF_IRQPOLL; 179 180 setup_irq(irqnr, &timer->clkevt_irq); 181 182 clockevents_config_and_register(&timer->clkevt, 183 clk_get_rate(timer->clk), 0x0001, 0xffff); 184 pr_info("Added %s as clockevent\n", timer->clockevent_name); 185 } 186 187 writel(CNTL_STOP_TIMER, timer->timer2 + IO_CONTROL); 188 writel(0, timer->timer2 + IO_CURRENT_VAL); 189 writel(0, timer->timer2 + IO_DIVIDER); 190 writel(CNTL_RUN_TIMER | CNTL_FOREVER | CNTL_INC, 191 timer->timer2 + IO_CONTROL); 192 193 clocksource_mmio_init(timer->timer2 + IO_CURRENT_VAL, 194 timer->clocksource_name, 195 clk_get_rate(timer->clk), 196 200, 16, 197 clocksource_mmio_readw_up); 198 199 pr_info("Added %s as clocksource\n", timer->clocksource_name); 200 201 return 0; 202 error_unmap: 203 iounmap(timer->base); 204 error_free: 205 kfree(timer); 206 return ret; 207 } 208 209 static int __init zevio_timer_init(struct device_node *node) 210 { 211 return zevio_timer_add(node); 212 } 213 214 TIMER_OF_DECLARE(zevio_timer, "lsi,zevio-timer", zevio_timer_init); 215