drivers/clocksource/mtk_timer.c

   1 /*
   2  * Mediatek SoCs General-Purpose Timer handling.
   3  *
   4  * Copyright (C) 2014 Matthias Brugger
   5  *
   6  * Matthias Brugger <matthias.bgg@gmail.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  */
  18
  19 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
  20
  21 #include <linux/clk.h>
  22 #include <linux/clockchips.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/irq.h>
  25 #include <linux/irqreturn.h>
  26 #include <linux/of.h>
  27 #include <linux/of_address.h>
  28 #include <linux/of_irq.h>
  29 #include <linux/sched_clock.h>
  30 #include <linux/slab.h>
  31
  32 #define GPT_IRQ_EN_REG          0x00
  33 #define GPT_IRQ_ENABLE(val)     BIT((val) - 1)
  34 #define GPT_IRQ_ACK_REG         0x08
  35 #define GPT_IRQ_ACK(val)        BIT((val) - 1)
  36
  37 #define TIMER_CTRL_REG(val)     (0x10 * (val))
  38 #define TIMER_CTRL_OP(val)      (((val) & 0x3) << 4)
  39 #define TIMER_CTRL_OP_ONESHOT   (0)
  40 #define TIMER_CTRL_OP_REPEAT    (1)
  41 #define TIMER_CTRL_OP_FREERUN   (3)
  42 #define TIMER_CTRL_CLEAR        (2)
  43 #define TIMER_CTRL_ENABLE       (1)
  44 #define TIMER_CTRL_DISABLE      (0)
  45
  46 #define TIMER_CLK_REG(val)      (0x04 + (0x10 * (val)))
  47 #define TIMER_CLK_SRC(val)      (((val) & 0x1) << 4)
  48 #define TIMER_CLK_SRC_SYS13M    (0)
  49 #define TIMER_CLK_SRC_RTC32K    (1)
  50 #define TIMER_CLK_DIV1          (0x0)
  51 #define TIMER_CLK_DIV2          (0x1)
  52
  53 #define TIMER_CNT_REG(val)      (0x08 + (0x10 * (val)))
  54 #define TIMER_CMP_REG(val)      (0x0C + (0x10 * (val)))
  55
  56 #define GPT_CLK_EVT     1
  57 #define GPT_CLK_SRC     2
  58
  59 struct mtk_clock_event_device {
  60         void __iomem *gpt_base;
  61         u32 ticks_per_jiffy;
  62         struct clock_event_device dev;
  63 };
  64
  65 static void __iomem *gpt_sched_reg __read_mostly;
  66
  67 static u64 notrace mtk_read_sched_clock(void)
  68 {
  69         return readl_relaxed(gpt_sched_reg);
  70 }
  71
  72 static inline struct mtk_clock_event_device *to_mtk_clk(
  73                                 struct clock_event_device *c)
  74 {
  75         return container_of(c, struct mtk_clock_event_device, dev);
  76 }
  77
  78 static void mtk_clkevt_time_stop(struct mtk_clock_event_device *evt, u8 timer)
  79 {
  80         u32 val;
  81
  82         val = readl(evt->gpt_base + TIMER_CTRL_REG(timer));
  83         writel(val & ~TIMER_CTRL_ENABLE, evt->gpt_base +
  84                         TIMER_CTRL_REG(timer));
  85 }
  86
  87 static void mtk_clkevt_time_setup(struct mtk_clock_event_device *evt,
  88                                 unsigned long delay, u8 timer)
  89 {
  90         writel(delay, evt->gpt_base + TIMER_CMP_REG(timer));
  91 }
  92
  93 static void mtk_clkevt_time_start(struct mtk_clock_event_device *evt,
  94                 bool periodic, u8 timer)
  95 {
  96         u32 val;
  97
  98         /* Acknowledge interrupt */
  99         writel(GPT_IRQ_ACK(timer), evt->gpt_base + GPT_IRQ_ACK_REG);
 100
 101         val = readl(evt->gpt_base + TIMER_CTRL_REG(timer));
 102
 103         /* Clear 2 bit timer operation mode field */
 104         val &= ~TIMER_CTRL_OP(0x3);
 105
 106         if (periodic)
 107                 val |= TIMER_CTRL_OP(TIMER_CTRL_OP_REPEAT);
 108         else
 109                 val |= TIMER_CTRL_OP(TIMER_CTRL_OP_ONESHOT);
 110
 111         writel(val | TIMER_CTRL_ENABLE | TIMER_CTRL_CLEAR,
 112                evt->gpt_base + TIMER_CTRL_REG(timer));
 113 }
 114
 115 static int mtk_clkevt_shutdown(struct clock_event_device *clk)
 116 {
 117         mtk_clkevt_time_stop(to_mtk_clk(clk), GPT_CLK_EVT);
 118         return 0;
 119 }
 120
 121 static int mtk_clkevt_set_periodic(struct clock_event_device *clk)
 122 {
 123         struct mtk_clock_event_device *evt = to_mtk_clk(clk);
 124
 125         mtk_clkevt_time_stop(evt, GPT_CLK_EVT);
 126         mtk_clkevt_time_setup(evt, evt->ticks_per_jiffy, GPT_CLK_EVT);
 127         mtk_clkevt_time_start(evt, true, GPT_CLK_EVT);
 128         return 0;
 129 }
 130
 131 static int mtk_clkevt_next_event(unsigned long event,
 132                                    struct clock_event_device *clk)
 133 {
 134         struct mtk_clock_event_device *evt = to_mtk_clk(clk);
 135
 136         mtk_clkevt_time_stop(evt, GPT_CLK_EVT);
 137         mtk_clkevt_time_setup(evt, event, GPT_CLK_EVT);
 138         mtk_clkevt_time_start(evt, false, GPT_CLK_EVT);
 139
 140         return 0;
 141 }
 142
 143 static irqreturn_t mtk_timer_interrupt(int irq, void *dev_id)
 144 {
 145         struct mtk_clock_event_device *evt = dev_id;
 146
 147         /* Acknowledge timer0 irq */
 148         writel(GPT_IRQ_ACK(GPT_CLK_EVT), evt->gpt_base + GPT_IRQ_ACK_REG);
 149         evt->dev.event_handler(&evt->dev);
 150
 151         return IRQ_HANDLED;
 152 }
 153
 154 static void
 155 mtk_timer_setup(struct mtk_clock_event_device *evt, u8 timer, u8 option)
 156 {
 157         writel(TIMER_CTRL_CLEAR | TIMER_CTRL_DISABLE,
 158                 evt->gpt_base + TIMER_CTRL_REG(timer));
 159
 160         writel(TIMER_CLK_SRC(TIMER_CLK_SRC_SYS13M) | TIMER_CLK_DIV1,
 161                         evt->gpt_base + TIMER_CLK_REG(timer));
 162
 163         writel(0x0, evt->gpt_base + TIMER_CMP_REG(timer));
 164
 165         writel(TIMER_CTRL_OP(option) | TIMER_CTRL_ENABLE,
 166                         evt->gpt_base + TIMER_CTRL_REG(timer));
 167 }
 168
 169 static void mtk_timer_enable_irq(struct mtk_clock_event_device *evt, u8 timer)
 170 {
 171         u32 val;
 172
 173         /* Disable all interrupts */
 174         writel(0x0, evt->gpt_base + GPT_IRQ_EN_REG);
 175
 176         /* Acknowledge all spurious pending interrupts */
 177         writel(0x3f, evt->gpt_base + GPT_IRQ_ACK_REG);
 178
 179         val = readl(evt->gpt_base + GPT_IRQ_EN_REG);
 180         writel(val | GPT_IRQ_ENABLE(timer),
 181                         evt->gpt_base + GPT_IRQ_EN_REG);
 182 }
 183
 184 static void __init mtk_timer_init(struct device_node *node)
 185 {
 186         struct mtk_clock_event_device *evt;
 187         struct resource res;
 188         unsigned long rate = 0;
 189         struct clk *clk;
 190
 191         evt = kzalloc(sizeof(*evt), GFP_KERNEL);
 192         if (!evt)
 193                 return;
 194
 195         evt->dev.name = "mtk_tick";
 196         evt->dev.rating = 300;
 197         evt->dev.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
 198         evt->dev.set_state_shutdown = mtk_clkevt_shutdown;
 199         evt->dev.set_state_periodic = mtk_clkevt_set_periodic;
 200         evt->dev.set_state_oneshot = mtk_clkevt_shutdown;
 201         evt->dev.tick_resume = mtk_clkevt_shutdown;
 202         evt->dev.set_next_event = mtk_clkevt_next_event;
 203         evt->dev.cpumask = cpu_possible_mask;
 204
 205         evt->gpt_base = of_io_request_and_map(node, 0, "mtk-timer");
 206         if (IS_ERR(evt->gpt_base)) {
 207                 pr_err("Can't get resource\n");
 208                 goto err_kzalloc;
 209         }
 210
 211         evt->dev.irq = irq_of_parse_and_map(node, 0);
 212         if (evt->dev.irq <= 0) {
 213                 pr_err("Can't parse IRQ\n");
 214                 goto err_mem;
 215         }
 216
 217         clk = of_clk_get(node, 0);
 218         if (IS_ERR(clk)) {
 219                 pr_err("Can't get timer clock\n");
 220                 goto err_irq;
 221         }
 222
 223         if (clk_prepare_enable(clk)) {
 224                 pr_err("Can't prepare clock\n");
 225                 goto err_clk_put;
 226         }
 227         rate = clk_get_rate(clk);
 228
 229         if (request_irq(evt->dev.irq, mtk_timer_interrupt,
 230                         IRQF_TIMER | IRQF_IRQPOLL, "mtk_timer", evt)) {
 231                 pr_err("failed to setup irq %d\n", evt->dev.irq);
 232                 goto err_clk_disable;
 233         }
 234
 235         evt->ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
 236
 237         /* Configure clock source */
 238         mtk_timer_setup(evt, GPT_CLK_SRC, TIMER_CTRL_OP_FREERUN);
 239         clocksource_mmio_init(evt->gpt_base + TIMER_CNT_REG(GPT_CLK_SRC),
 240                         node->name, rate, 300, 32, clocksource_mmio_readl_up);
 241         gpt_sched_reg = evt->gpt_base + TIMER_CNT_REG(GPT_CLK_SRC);
 242         sched_clock_register(mtk_read_sched_clock, 32, rate);
 243
 244         /* Configure clock event */
 245         mtk_timer_setup(evt, GPT_CLK_EVT, TIMER_CTRL_OP_REPEAT);
 246         clockevents_config_and_register(&evt->dev, rate, 0x3,
 247                                         0xffffffff);
 248
 249         mtk_timer_enable_irq(evt, GPT_CLK_EVT);
 250
 251         return;
 252
 253 err_clk_disable:
 254         clk_disable_unprepare(clk);
 255 err_clk_put:
 256         clk_put(clk);
 257 err_irq:
 258         irq_dispose_mapping(evt->dev.irq);
 259 err_mem:
 260         iounmap(evt->gpt_base);
 261         of_address_to_resource(node, 0, &res);
 262         release_mem_region(res.start, resource_size(&res));
 263 err_kzalloc:
 264         kfree(evt);
 265 }
 266 CLOCKSOURCE_OF_DECLARE(mtk_mt6577, "mediatek,mt6577-timer", mtk_timer_init);