drivers/clocksource/timer-npcm7xx.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2014-2018 Nuvoton Technologies tomer.maimon@nuvoton.com
   4  * All rights reserved.
   5  *
   6  * Copyright 2017 Google, Inc.
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/sched.h>
  11 #include <linux/init.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/err.h>
  14 #include <linux/clk.h>
  15 #include <linux/io.h>
  16 #include <linux/clockchips.h>
  17 #include <linux/of_irq.h>
  18 #include <linux/of_address.h>
  19 #include "timer-of.h"
  20
  21 /* Timers registers */
  22 #define NPCM7XX_REG_TCSR0       0x0 /* Timer 0 Control and Status Register */
  23 #define NPCM7XX_REG_TICR0       0x8 /* Timer 0 Initial Count Register */
  24 #define NPCM7XX_REG_TCSR1       0x4 /* Timer 1 Control and Status Register */
  25 #define NPCM7XX_REG_TICR1       0xc /* Timer 1 Initial Count Register */
  26 #define NPCM7XX_REG_TDR1        0x14 /* Timer 1 Data Register */
  27 #define NPCM7XX_REG_TISR        0x18 /* Timer Interrupt Status Register */
  28
  29 /* Timers control */
  30 #define NPCM7XX_Tx_RESETINT             0x1f
  31 #define NPCM7XX_Tx_PERIOD               BIT(27)
  32 #define NPCM7XX_Tx_INTEN                BIT(29)
  33 #define NPCM7XX_Tx_COUNTEN              BIT(30)
  34 #define NPCM7XX_Tx_ONESHOT              0x0
  35 #define NPCM7XX_Tx_OPER                 GENMASK(27, 3)
  36 #define NPCM7XX_Tx_MIN_PRESCALE         0x1
  37 #define NPCM7XX_Tx_TDR_MASK_BITS        24
  38 #define NPCM7XX_Tx_MAX_CNT              0xFFFFFF
  39 #define NPCM7XX_T0_CLR_INT              0x1
  40 #define NPCM7XX_Tx_CLR_CSR              0x0
  41
  42 /* Timers operating mode */
  43 #define NPCM7XX_START_PERIODIC_Tx (NPCM7XX_Tx_PERIOD | NPCM7XX_Tx_COUNTEN | \
  44                                         NPCM7XX_Tx_INTEN | \
  45                                         NPCM7XX_Tx_MIN_PRESCALE)
  46
  47 #define NPCM7XX_START_ONESHOT_Tx (NPCM7XX_Tx_ONESHOT | NPCM7XX_Tx_COUNTEN | \
  48                                         NPCM7XX_Tx_INTEN | \
  49                                         NPCM7XX_Tx_MIN_PRESCALE)
  50
  51 #define NPCM7XX_START_Tx (NPCM7XX_Tx_COUNTEN | NPCM7XX_Tx_PERIOD | \
  52                                 NPCM7XX_Tx_MIN_PRESCALE)
  53
  54 #define NPCM7XX_DEFAULT_CSR (NPCM7XX_Tx_CLR_CSR | NPCM7XX_Tx_MIN_PRESCALE)
  55
  56 static int npcm7xx_timer_resume(struct clock_event_device *evt)
  57 {
  58         struct timer_of *to = to_timer_of(evt);
  59         u32 val;
  60
  61         val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
  62         val |= NPCM7XX_Tx_COUNTEN;
  63         writel(val, timer_of_base(to) + NPCM7XX_REG_TCSR0);
  64
  65         return 0;
  66 }
  67
  68 static int npcm7xx_timer_shutdown(struct clock_event_device *evt)
  69 {
  70         struct timer_of *to = to_timer_of(evt);
  71         u32 val;
  72
  73         val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
  74         val &= ~NPCM7XX_Tx_COUNTEN;
  75         writel(val, timer_of_base(to) + NPCM7XX_REG_TCSR0);
  76
  77         return 0;
  78 }
  79
  80 static int npcm7xx_timer_oneshot(struct clock_event_device *evt)
  81 {
  82         struct timer_of *to = to_timer_of(evt);
  83         u32 val;
  84
  85         val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
  86         val &= ~NPCM7XX_Tx_OPER;
  87
  88         val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
  89         val |= NPCM7XX_START_ONESHOT_Tx;
  90         writel(val, timer_of_base(to) + NPCM7XX_REG_TCSR0);
  91
  92         return 0;
  93 }
  94
  95 static int npcm7xx_timer_periodic(struct clock_event_device *evt)
  96 {
  97         struct timer_of *to = to_timer_of(evt);
  98         u32 val;
  99
 100         val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
 101         val &= ~NPCM7XX_Tx_OPER;
 102
 103         writel(timer_of_period(to), timer_of_base(to) + NPCM7XX_REG_TICR0);
 104         val |= NPCM7XX_START_PERIODIC_Tx;
 105
 106         writel(val, timer_of_base(to) + NPCM7XX_REG_TCSR0);
 107
 108         return 0;
 109 }
 110
 111 static int npcm7xx_clockevent_set_next_event(unsigned long evt,
 112                 struct clock_event_device *clk)
 113 {
 114         struct timer_of *to = to_timer_of(clk);
 115         u32 val;
 116
 117         writel(evt, timer_of_base(to) + NPCM7XX_REG_TICR0);
 118         val = readl(timer_of_base(to) + NPCM7XX_REG_TCSR0);
 119         val |= NPCM7XX_START_Tx;
 120         writel(val, timer_of_base(to) + NPCM7XX_REG_TCSR0);
 121
 122         return 0;
 123 }
 124
 125 static irqreturn_t npcm7xx_timer0_interrupt(int irq, void *dev_id)
 126 {
 127         struct clock_event_device *evt = (struct clock_event_device *)dev_id;
 128         struct timer_of *to = to_timer_of(evt);
 129
 130         writel(NPCM7XX_T0_CLR_INT, timer_of_base(to) + NPCM7XX_REG_TISR);
 131
 132         evt->event_handler(evt);
 133
 134         return IRQ_HANDLED;
 135 }
 136
 137 static struct timer_of npcm7xx_to = {
 138         .flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK,
 139
 140         .clkevt = {
 141                 .name               = "npcm7xx-timer0",
 142                 .features           = CLOCK_EVT_FEAT_PERIODIC |
 143                                       CLOCK_EVT_FEAT_ONESHOT,
 144                 .set_next_event     = npcm7xx_clockevent_set_next_event,
 145                 .set_state_shutdown = npcm7xx_timer_shutdown,
 146                 .set_state_periodic = npcm7xx_timer_periodic,
 147                 .set_state_oneshot  = npcm7xx_timer_oneshot,
 148                 .tick_resume        = npcm7xx_timer_resume,
 149                 .rating             = 300,
 150         },
 151
 152         .of_irq = {
 153                 .handler = npcm7xx_timer0_interrupt,
 154                 .flags = IRQF_TIMER | IRQF_IRQPOLL,
 155         },
 156 };
 157
 158 static void __init npcm7xx_clockevents_init(void)
 159 {
 160         writel(NPCM7XX_DEFAULT_CSR,
 161                 timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TCSR0);
 162
 163         writel(NPCM7XX_Tx_RESETINT,
 164                 timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TISR);
 165
 166         npcm7xx_to.clkevt.cpumask = cpumask_of(0);
 167         clockevents_config_and_register(&npcm7xx_to.clkevt,
 168                                         timer_of_rate(&npcm7xx_to),
 169                                         0x1, NPCM7XX_Tx_MAX_CNT);
 170 }
 171
 172 static void __init npcm7xx_clocksource_init(void)
 173 {
 174         u32 val;
 175
 176         writel(NPCM7XX_DEFAULT_CSR,
 177                 timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TCSR1);
 178         writel(NPCM7XX_Tx_MAX_CNT,
 179                 timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TICR1);
 180
 181         val = readl(timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TCSR1);
 182         val |= NPCM7XX_START_Tx;
 183         writel(val, timer_of_base(&npcm7xx_to) + NPCM7XX_REG_TCSR1);
 184
 185         clocksource_mmio_init(timer_of_base(&npcm7xx_to) +
 186                                 NPCM7XX_REG_TDR1,
 187                                 "npcm7xx-timer1", timer_of_rate(&npcm7xx_to),
 188                                 200, (unsigned int)NPCM7XX_Tx_TDR_MASK_BITS,
 189                                 clocksource_mmio_readl_down);
 190 }
 191
 192 static int __init npcm7xx_timer_init(struct device_node *np)
 193 {
 194         int ret;
 195
 196         ret = timer_of_init(np, &npcm7xx_to);
 197         if (ret)
 198                 return ret;
 199
 200         /* Clock input is divided by PRESCALE + 1 before it is fed */
 201         /* to the counter */
 202         npcm7xx_to.of_clk.rate = npcm7xx_to.of_clk.rate /
 203                 (NPCM7XX_Tx_MIN_PRESCALE + 1);
 204
 205         npcm7xx_clocksource_init();
 206         npcm7xx_clockevents_init();
 207
 208         pr_info("Enabling NPCM7xx clocksource timer base: %px, IRQ: %d ",
 209                 timer_of_base(&npcm7xx_to), timer_of_irq(&npcm7xx_to));
 210
 211         return 0;
 212 }
 213
 214 TIMER_OF_DECLARE(npcm7xx, "nuvoton,npcm750-timer", npcm7xx_timer_init);
 215