drivers/clocksource/timer-rda.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * RDA8810PL SoC timer driver
   4  *
   5  * Copyright RDA Microelectronics Company Limited
   6  * Copyright (c) 2017 Andreas Färber
   7  * Copyright (c) 2018 Manivannan Sadhasivam
   8  *
   9  * RDA8810PL has two independent timers: OSTIMER (56 bit) and HWTIMER (64 bit).
  10  * Each timer provides optional interrupt support. In this driver, OSTIMER is
  11  * used for clockevents and HWTIMER is used for clocksource.
  12  */
  13
  14 #include <linux/init.h>
  15 #include <linux/interrupt.h>
  16
  17 #include "timer-of.h"
  18
  19 #define RDA_OSTIMER_LOADVAL_L   0x000
  20 #define RDA_OSTIMER_CTRL        0x004
  21 #define RDA_HWTIMER_LOCKVAL_L   0x024
  22 #define RDA_HWTIMER_LOCKVAL_H   0x028
  23 #define RDA_TIMER_IRQ_MASK_SET  0x02c
  24 #define RDA_TIMER_IRQ_MASK_CLR  0x030
  25 #define RDA_TIMER_IRQ_CLR       0x034
  26
  27 #define RDA_OSTIMER_CTRL_ENABLE         BIT(24)
  28 #define RDA_OSTIMER_CTRL_REPEAT         BIT(28)
  29 #define RDA_OSTIMER_CTRL_LOAD           BIT(30)
  30
  31 #define RDA_TIMER_IRQ_MASK_OSTIMER      BIT(0)
  32
  33 #define RDA_TIMER_IRQ_CLR_OSTIMER       BIT(0)
  34
  35 static int rda_ostimer_start(void __iomem *base, bool periodic, u64 cycles)
  36 {
  37         u32 ctrl, load_l;
  38
  39         load_l = (u32)cycles;
  40         ctrl = ((cycles >> 32) & 0xffffff);
  41         ctrl |= RDA_OSTIMER_CTRL_LOAD | RDA_OSTIMER_CTRL_ENABLE;
  42         if (periodic)
  43                 ctrl |= RDA_OSTIMER_CTRL_REPEAT;
  44
  45         /* Enable ostimer interrupt first */
  46         writel_relaxed(RDA_TIMER_IRQ_MASK_OSTIMER,
  47                        base + RDA_TIMER_IRQ_MASK_SET);
  48
  49         /* Write low 32 bits first, high 24 bits are with ctrl */
  50         writel_relaxed(load_l, base + RDA_OSTIMER_LOADVAL_L);
  51         writel_relaxed(ctrl, base + RDA_OSTIMER_CTRL);
  52
  53         return 0;
  54 }
  55
  56 static int rda_ostimer_stop(void __iomem *base)
  57 {
  58         /* Disable ostimer interrupt first */
  59         writel_relaxed(RDA_TIMER_IRQ_MASK_OSTIMER,
  60                        base + RDA_TIMER_IRQ_MASK_CLR);
  61
  62         writel_relaxed(0, base + RDA_OSTIMER_CTRL);
  63
  64         return 0;
  65 }
  66
  67 static int rda_ostimer_set_state_shutdown(struct clock_event_device *evt)
  68 {
  69         struct timer_of *to = to_timer_of(evt);
  70
  71         rda_ostimer_stop(timer_of_base(to));
  72
  73         return 0;
  74 }
  75
  76 static int rda_ostimer_set_state_oneshot(struct clock_event_device *evt)
  77 {
  78         struct timer_of *to = to_timer_of(evt);
  79
  80         rda_ostimer_stop(timer_of_base(to));
  81
  82         return 0;
  83 }
  84
  85 static int rda_ostimer_set_state_periodic(struct clock_event_device *evt)
  86 {
  87         struct timer_of *to = to_timer_of(evt);
  88         unsigned long cycles_per_jiffy;
  89
  90         rda_ostimer_stop(timer_of_base(to));
  91
  92         cycles_per_jiffy = ((unsigned long long)NSEC_PER_SEC / HZ *
  93                              evt->mult) >> evt->shift;
  94         rda_ostimer_start(timer_of_base(to), true, cycles_per_jiffy);
  95
  96         return 0;
  97 }
  98
  99 static int rda_ostimer_tick_resume(struct clock_event_device *evt)
 100 {
 101         return 0;
 102 }
 103
 104 static int rda_ostimer_set_next_event(unsigned long evt,
 105                                       struct clock_event_device *ev)
 106 {
 107         struct timer_of *to = to_timer_of(ev);
 108
 109         rda_ostimer_start(timer_of_base(to), false, evt);
 110
 111         return 0;
 112 }
 113
 114 static irqreturn_t rda_ostimer_interrupt(int irq, void *dev_id)
 115 {
 116         struct clock_event_device *evt = dev_id;
 117         struct timer_of *to = to_timer_of(evt);
 118
 119         /* clear timer int */
 120         writel_relaxed(RDA_TIMER_IRQ_CLR_OSTIMER,
 121                        timer_of_base(to) + RDA_TIMER_IRQ_CLR);
 122
 123         if (evt->event_handler)
 124                 evt->event_handler(evt);
 125
 126         return IRQ_HANDLED;
 127 }
 128
 129 static struct timer_of rda_ostimer_of = {
 130         .flags = TIMER_OF_IRQ | TIMER_OF_BASE,
 131
 132         .clkevt = {
 133                 .name = "rda-ostimer",
 134                 .rating = 250,
 135                 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
 136                             CLOCK_EVT_FEAT_DYNIRQ,
 137                 .set_state_shutdown = rda_ostimer_set_state_shutdown,
 138                 .set_state_oneshot = rda_ostimer_set_state_oneshot,
 139                 .set_state_periodic = rda_ostimer_set_state_periodic,
 140                 .tick_resume = rda_ostimer_tick_resume,
 141                 .set_next_event = rda_ostimer_set_next_event,
 142         },
 143
 144         .of_base = {
 145                 .name = "rda-timer",
 146                 .index = 0,
 147         },
 148
 149         .of_irq = {
 150                 .name = "ostimer",
 151                 .handler = rda_ostimer_interrupt,
 152                 .flags = IRQF_TIMER,
 153         },
 154 };
 155
 156 static u64 rda_hwtimer_read(struct clocksource *cs)
 157 {
 158         void __iomem *base = timer_of_base(&rda_ostimer_of);
 159         u32 lo, hi;
 160
 161         /* Always read low 32 bits first */
 162         do {
 163                 lo = readl_relaxed(base + RDA_HWTIMER_LOCKVAL_L);
 164                 hi = readl_relaxed(base + RDA_HWTIMER_LOCKVAL_H);
 165         } while (hi != readl_relaxed(base + RDA_HWTIMER_LOCKVAL_H));
 166
 167         return ((u64)hi << 32) | lo;
 168 }
 169
 170 static struct clocksource rda_hwtimer_clocksource = {
 171         .name           = "rda-timer",
 172         .rating         = 400,
 173         .read           = rda_hwtimer_read,
 174         .mask           = CLOCKSOURCE_MASK(64),
 175         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 176 };
 177
 178 static int __init rda_timer_init(struct device_node *np)
 179 {
 180         unsigned long rate = 2000000;
 181         int ret;
 182
 183         ret = timer_of_init(np, &rda_ostimer_of);
 184         if (ret)
 185                 return ret;
 186
 187         clocksource_register_hz(&rda_hwtimer_clocksource, rate);
 188
 189         clockevents_config_and_register(&rda_ostimer_of.clkevt, rate,
 190                                         0x2, UINT_MAX);
 191
 192         return 0;
 193 }
 194
 195 TIMER_OF_DECLARE(rda8810pl, "rda,8810pl-timer", rda_timer_init);