timer-gx6605s.c (4091B)
1// SPDX-License-Identifier: GPL-2.0 2// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. 3 4#include <linux/init.h> 5#include <linux/interrupt.h> 6#include <linux/sched_clock.h> 7 8#include "timer-of.h" 9 10#define CLKSRC_OFFSET 0x40 11 12#define TIMER_STATUS 0x00 13#define TIMER_VALUE 0x04 14#define TIMER_CONTRL 0x10 15#define TIMER_CONFIG 0x20 16#define TIMER_DIV 0x24 17#define TIMER_INI 0x28 18 19#define GX6605S_STATUS_CLR BIT(0) 20#define GX6605S_CONTRL_RST BIT(0) 21#define GX6605S_CONTRL_START BIT(1) 22#define GX6605S_CONFIG_EN BIT(0) 23#define GX6605S_CONFIG_IRQ_EN BIT(1) 24 25static irqreturn_t gx6605s_timer_interrupt(int irq, void *dev) 26{ 27 struct clock_event_device *ce = dev; 28 void __iomem *base = timer_of_base(to_timer_of(ce)); 29 30 writel_relaxed(GX6605S_STATUS_CLR, base + TIMER_STATUS); 31 writel_relaxed(0, base + TIMER_INI); 32 33 ce->event_handler(ce); 34 35 return IRQ_HANDLED; 36} 37 38static int gx6605s_timer_set_oneshot(struct clock_event_device *ce) 39{ 40 void __iomem *base = timer_of_base(to_timer_of(ce)); 41 42 /* reset and stop counter */ 43 writel_relaxed(GX6605S_CONTRL_RST, base + TIMER_CONTRL); 44 45 /* enable with irq and start */ 46 writel_relaxed(GX6605S_CONFIG_EN | GX6605S_CONFIG_IRQ_EN, 47 base + TIMER_CONFIG); 48 49 return 0; 50} 51 52static int gx6605s_timer_set_next_event(unsigned long delta, 53 struct clock_event_device *ce) 54{ 55 void __iomem *base = timer_of_base(to_timer_of(ce)); 56 57 /* use reset to pause timer */ 58 writel_relaxed(GX6605S_CONTRL_RST, base + TIMER_CONTRL); 59 60 /* config next timeout value */ 61 writel_relaxed(ULONG_MAX - delta, base + TIMER_INI); 62 writel_relaxed(GX6605S_CONTRL_START, base + TIMER_CONTRL); 63 64 return 0; 65} 66 67static int gx6605s_timer_shutdown(struct clock_event_device *ce) 68{ 69 void __iomem *base = timer_of_base(to_timer_of(ce)); 70 71 writel_relaxed(0, base + TIMER_CONTRL); 72 writel_relaxed(0, base + TIMER_CONFIG); 73 74 return 0; 75} 76 77static struct timer_of to = { 78 .flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK, 79 .clkevt = { 80 .rating = 300, 81 .features = CLOCK_EVT_FEAT_DYNIRQ | 82 CLOCK_EVT_FEAT_ONESHOT, 83 .set_state_shutdown = gx6605s_timer_shutdown, 84 .set_state_oneshot = gx6605s_timer_set_oneshot, 85 .set_next_event = gx6605s_timer_set_next_event, 86 .cpumask = cpu_possible_mask, 87 }, 88 .of_irq = { 89 .handler = gx6605s_timer_interrupt, 90 .flags = IRQF_TIMER | IRQF_IRQPOLL, 91 }, 92}; 93 94static u64 notrace gx6605s_sched_clock_read(void) 95{ 96 void __iomem *base; 97 98 base = timer_of_base(&to) + CLKSRC_OFFSET; 99 100 return (u64)readl_relaxed(base + TIMER_VALUE); 101} 102 103static void gx6605s_clkevt_init(void __iomem *base) 104{ 105 writel_relaxed(0, base + TIMER_DIV); 106 writel_relaxed(0, base + TIMER_CONFIG); 107 108 clockevents_config_and_register(&to.clkevt, timer_of_rate(&to), 2, 109 ULONG_MAX); 110} 111 112static int gx6605s_clksrc_init(void __iomem *base) 113{ 114 writel_relaxed(0, base + TIMER_DIV); 115 writel_relaxed(0, base + TIMER_INI); 116 117 writel_relaxed(GX6605S_CONTRL_RST, base + TIMER_CONTRL); 118 119 writel_relaxed(GX6605S_CONFIG_EN, base + TIMER_CONFIG); 120 121 writel_relaxed(GX6605S_CONTRL_START, base + TIMER_CONTRL); 122 123 sched_clock_register(gx6605s_sched_clock_read, 32, timer_of_rate(&to)); 124 125 return clocksource_mmio_init(base + TIMER_VALUE, "gx6605s", 126 timer_of_rate(&to), 200, 32, clocksource_mmio_readl_up); 127} 128 129static int __init gx6605s_timer_init(struct device_node *np) 130{ 131 int ret; 132 133 /* 134 * The timer driver is for nationalchip gx6605s SOC and there are two 135 * same timer in gx6605s. We use one for clkevt and another for clksrc. 136 * 137 * The timer is mmio map to access, so we need give mmio address in dts. 138 * 139 * It provides a 32bit countup timer and interrupt will be caused by 140 * count-overflow. 141 * So we need set-next-event by ULONG_MAX - delta in TIMER_INI reg. 142 * 143 * The counter at 0x0 offset is clock event. 144 * The counter at 0x40 offset is clock source. 145 * They are the same in hardware, just different used by driver. 146 */ 147 ret = timer_of_init(np, &to); 148 if (ret) 149 return ret; 150 151 gx6605s_clkevt_init(timer_of_base(&to)); 152 153 return gx6605s_clksrc_init(timer_of_base(&to) + CLKSRC_OFFSET); 154} 155TIMER_OF_DECLARE(csky_gx6605s_timer, "csky,gx6605s-timer", gx6605s_timer_init);