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