1/* 2 * linux/drivers/clocksource/zevio-timer.c 3 * 4 * Copyright (C) 2013 Daniel Tang <tangrs@tangrs.id.au> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2, as 8 * published by the Free Software Foundation. 9 * 10 */ 11 12#include <linux/io.h> 13#include <linux/irq.h> 14#include <linux/of.h> 15#include <linux/of_address.h> 16#include <linux/of_irq.h> 17#include <linux/clk.h> 18#include <linux/clockchips.h> 19#include <linux/cpumask.h> 20#include <linux/interrupt.h> 21#include <linux/slab.h> 22 23#define IO_CURRENT_VAL 0x00 24#define IO_DIVIDER 0x04 25#define IO_CONTROL 0x08 26 27#define IO_TIMER1 0x00 28#define IO_TIMER2 0x0C 29 30#define IO_MATCH_BEGIN 0x18 31#define IO_MATCH(x) (IO_MATCH_BEGIN + ((x) << 2)) 32 33#define IO_INTR_STS 0x00 34#define IO_INTR_ACK 0x00 35#define IO_INTR_MSK 0x04 36 37#define CNTL_STOP_TIMER (1 << 4) 38#define CNTL_RUN_TIMER (0 << 4) 39 40#define CNTL_INC (1 << 3) 41#define CNTL_DEC (0 << 3) 42 43#define CNTL_TOZERO 0 44#define CNTL_MATCH(x) ((x) + 1) 45#define CNTL_FOREVER 7 46 47/* There are 6 match registers but we only use one. */ 48#define TIMER_MATCH 0 49 50#define TIMER_INTR_MSK (1 << (TIMER_MATCH)) 51#define TIMER_INTR_ALL 0x3F 52 53struct zevio_timer { 54 void __iomem *base; 55 void __iomem *timer1, *timer2; 56 void __iomem *interrupt_regs; 57 58 struct clk *clk; 59 struct clock_event_device clkevt; 60 struct irqaction clkevt_irq; 61 62 char clocksource_name[64]; 63 char clockevent_name[64]; 64}; 65 66static int zevio_timer_set_event(unsigned long delta, 67 struct clock_event_device *dev) 68{ 69 struct zevio_timer *timer = container_of(dev, struct zevio_timer, 70 clkevt); 71 72 writel(delta, timer->timer1 + IO_CURRENT_VAL); 73 writel(CNTL_RUN_TIMER | CNTL_DEC | CNTL_MATCH(TIMER_MATCH), 74 timer->timer1 + IO_CONTROL); 75 76 return 0; 77} 78 79static int zevio_timer_shutdown(struct clock_event_device *dev) 80{ 81 struct zevio_timer *timer = container_of(dev, struct zevio_timer, 82 clkevt); 83 84 /* Disable timer interrupts */ 85 writel(0, timer->interrupt_regs + IO_INTR_MSK); 86 writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK); 87 /* Stop timer */ 88 writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL); 89 return 0; 90} 91 92static int zevio_timer_set_oneshot(struct clock_event_device *dev) 93{ 94 struct zevio_timer *timer = container_of(dev, struct zevio_timer, 95 clkevt); 96 97 /* Enable timer interrupts */ 98 writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_MSK); 99 writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK); 100 return 0; 101} 102 103static irqreturn_t zevio_timer_interrupt(int irq, void *dev_id) 104{ 105 struct zevio_timer *timer = dev_id; 106 u32 intr; 107 108 intr = readl(timer->interrupt_regs + IO_INTR_ACK); 109 if (!(intr & TIMER_INTR_MSK)) 110 return IRQ_NONE; 111 112 writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_ACK); 113 writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL); 114 115 if (timer->clkevt.event_handler) 116 timer->clkevt.event_handler(&timer->clkevt); 117 118 return IRQ_HANDLED; 119} 120 121static int __init zevio_timer_add(struct device_node *node) 122{ 123 struct zevio_timer *timer; 124 struct resource res; 125 int irqnr, ret; 126 127 timer = kzalloc(sizeof(*timer), GFP_KERNEL); 128 if (!timer) 129 return -ENOMEM; 130 131 timer->base = of_iomap(node, 0); 132 if (!timer->base) { 133 ret = -EINVAL; 134 goto error_free; 135 } 136 timer->timer1 = timer->base + IO_TIMER1; 137 timer->timer2 = timer->base + IO_TIMER2; 138 139 timer->clk = of_clk_get(node, 0); 140 if (IS_ERR(timer->clk)) { 141 ret = PTR_ERR(timer->clk); 142 pr_err("Timer clock not found! (error %d)\n", ret); 143 goto error_unmap; 144 } 145 146 timer->interrupt_regs = of_iomap(node, 1); 147 irqnr = irq_of_parse_and_map(node, 0); 148 149 of_address_to_resource(node, 0, &res); 150 scnprintf(timer->clocksource_name, sizeof(timer->clocksource_name), 151 "%llx.%s_clocksource", 152 (unsigned long long)res.start, node->name); 153 154 scnprintf(timer->clockevent_name, sizeof(timer->clockevent_name), 155 "%llx.%s_clockevent", 156 (unsigned long long)res.start, node->name); 157 158 if (timer->interrupt_regs && irqnr) { 159 timer->clkevt.name = timer->clockevent_name; 160 timer->clkevt.set_next_event = zevio_timer_set_event; 161 timer->clkevt.set_state_shutdown = zevio_timer_shutdown; 162 timer->clkevt.set_state_oneshot = zevio_timer_set_oneshot; 163 timer->clkevt.tick_resume = zevio_timer_set_oneshot; 164 timer->clkevt.rating = 200; 165 timer->clkevt.cpumask = cpu_all_mask; 166 timer->clkevt.features = CLOCK_EVT_FEAT_ONESHOT; 167 timer->clkevt.irq = irqnr; 168 169 writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL); 170 writel(0, timer->timer1 + IO_DIVIDER); 171 172 /* Start with timer interrupts disabled */ 173 writel(0, timer->interrupt_regs + IO_INTR_MSK); 174 writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK); 175 176 /* Interrupt to occur when timer value matches 0 */ 177 writel(0, timer->base + IO_MATCH(TIMER_MATCH)); 178 179 timer->clkevt_irq.name = timer->clockevent_name; 180 timer->clkevt_irq.handler = zevio_timer_interrupt; 181 timer->clkevt_irq.dev_id = timer; 182 timer->clkevt_irq.flags = IRQF_TIMER | IRQF_IRQPOLL; 183 184 setup_irq(irqnr, &timer->clkevt_irq); 185 186 clockevents_config_and_register(&timer->clkevt, 187 clk_get_rate(timer->clk), 0x0001, 0xffff); 188 pr_info("Added %s as clockevent\n", timer->clockevent_name); 189 } 190 191 writel(CNTL_STOP_TIMER, timer->timer2 + IO_CONTROL); 192 writel(0, timer->timer2 + IO_CURRENT_VAL); 193 writel(0, timer->timer2 + IO_DIVIDER); 194 writel(CNTL_RUN_TIMER | CNTL_FOREVER | CNTL_INC, 195 timer->timer2 + IO_CONTROL); 196 197 clocksource_mmio_init(timer->timer2 + IO_CURRENT_VAL, 198 timer->clocksource_name, 199 clk_get_rate(timer->clk), 200 200, 16, 201 clocksource_mmio_readw_up); 202 203 pr_info("Added %s as clocksource\n", timer->clocksource_name); 204 205 return 0; 206error_unmap: 207 iounmap(timer->base); 208error_free: 209 kfree(timer); 210 return ret; 211} 212 213static void __init zevio_timer_init(struct device_node *node) 214{ 215 BUG_ON(zevio_timer_add(node)); 216} 217 218CLOCKSOURCE_OF_DECLARE(zevio_timer, "lsi,zevio-timer", zevio_timer_init); 219