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 void zevio_timer_set_mode(enum clock_event_mode mode, 80 struct clock_event_device *dev) 81{ 82 struct zevio_timer *timer = container_of(dev, struct zevio_timer, 83 clkevt); 84 85 switch (mode) { 86 case CLOCK_EVT_MODE_RESUME: 87 case CLOCK_EVT_MODE_ONESHOT: 88 /* Enable timer interrupts */ 89 writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_MSK); 90 writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK); 91 break; 92 case CLOCK_EVT_MODE_SHUTDOWN: 93 case CLOCK_EVT_MODE_UNUSED: 94 /* Disable timer interrupts */ 95 writel(0, timer->interrupt_regs + IO_INTR_MSK); 96 writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK); 97 /* Stop timer */ 98 writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL); 99 break; 100 case CLOCK_EVT_MODE_PERIODIC: 101 default: 102 /* Unsupported */ 103 break; 104 } 105} 106 107static irqreturn_t zevio_timer_interrupt(int irq, void *dev_id) 108{ 109 struct zevio_timer *timer = dev_id; 110 u32 intr; 111 112 intr = readl(timer->interrupt_regs + IO_INTR_ACK); 113 if (!(intr & TIMER_INTR_MSK)) 114 return IRQ_NONE; 115 116 writel(TIMER_INTR_MSK, timer->interrupt_regs + IO_INTR_ACK); 117 writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL); 118 119 if (timer->clkevt.event_handler) 120 timer->clkevt.event_handler(&timer->clkevt); 121 122 return IRQ_HANDLED; 123} 124 125static int __init zevio_timer_add(struct device_node *node) 126{ 127 struct zevio_timer *timer; 128 struct resource res; 129 int irqnr, ret; 130 131 timer = kzalloc(sizeof(*timer), GFP_KERNEL); 132 if (!timer) 133 return -ENOMEM; 134 135 timer->base = of_iomap(node, 0); 136 if (!timer->base) { 137 ret = -EINVAL; 138 goto error_free; 139 } 140 timer->timer1 = timer->base + IO_TIMER1; 141 timer->timer2 = timer->base + IO_TIMER2; 142 143 timer->clk = of_clk_get(node, 0); 144 if (IS_ERR(timer->clk)) { 145 ret = PTR_ERR(timer->clk); 146 pr_err("Timer clock not found! (error %d)\n", ret); 147 goto error_unmap; 148 } 149 150 timer->interrupt_regs = of_iomap(node, 1); 151 irqnr = irq_of_parse_and_map(node, 0); 152 153 of_address_to_resource(node, 0, &res); 154 scnprintf(timer->clocksource_name, sizeof(timer->clocksource_name), 155 "%llx.%s_clocksource", 156 (unsigned long long)res.start, node->name); 157 158 scnprintf(timer->clockevent_name, sizeof(timer->clockevent_name), 159 "%llx.%s_clockevent", 160 (unsigned long long)res.start, node->name); 161 162 if (timer->interrupt_regs && irqnr) { 163 timer->clkevt.name = timer->clockevent_name; 164 timer->clkevt.set_next_event = zevio_timer_set_event; 165 timer->clkevt.set_mode = zevio_timer_set_mode; 166 timer->clkevt.rating = 200; 167 timer->clkevt.cpumask = cpu_all_mask; 168 timer->clkevt.features = CLOCK_EVT_FEAT_ONESHOT; 169 timer->clkevt.irq = irqnr; 170 171 writel(CNTL_STOP_TIMER, timer->timer1 + IO_CONTROL); 172 writel(0, timer->timer1 + IO_DIVIDER); 173 174 /* Start with timer interrupts disabled */ 175 writel(0, timer->interrupt_regs + IO_INTR_MSK); 176 writel(TIMER_INTR_ALL, timer->interrupt_regs + IO_INTR_ACK); 177 178 /* Interrupt to occur when timer value matches 0 */ 179 writel(0, timer->base + IO_MATCH(TIMER_MATCH)); 180 181 timer->clkevt_irq.name = timer->clockevent_name; 182 timer->clkevt_irq.handler = zevio_timer_interrupt; 183 timer->clkevt_irq.dev_id = timer; 184 timer->clkevt_irq.flags = IRQF_TIMER | IRQF_IRQPOLL; 185 186 setup_irq(irqnr, &timer->clkevt_irq); 187 188 clockevents_config_and_register(&timer->clkevt, 189 clk_get_rate(timer->clk), 0x0001, 0xffff); 190 pr_info("Added %s as clockevent\n", timer->clockevent_name); 191 } 192 193 writel(CNTL_STOP_TIMER, timer->timer2 + IO_CONTROL); 194 writel(0, timer->timer2 + IO_CURRENT_VAL); 195 writel(0, timer->timer2 + IO_DIVIDER); 196 writel(CNTL_RUN_TIMER | CNTL_FOREVER | CNTL_INC, 197 timer->timer2 + IO_CONTROL); 198 199 clocksource_mmio_init(timer->timer2 + IO_CURRENT_VAL, 200 timer->clocksource_name, 201 clk_get_rate(timer->clk), 202 200, 16, 203 clocksource_mmio_readw_up); 204 205 pr_info("Added %s as clocksource\n", timer->clocksource_name); 206 207 return 0; 208error_unmap: 209 iounmap(timer->base); 210error_free: 211 kfree(timer); 212 return ret; 213} 214 215static void __init zevio_timer_init(struct device_node *node) 216{ 217 BUG_ON(zevio_timer_add(node)); 218} 219 220CLOCKSOURCE_OF_DECLARE(zevio_timer, "lsi,zevio-timer", zevio_timer_init); 221