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 #include <linux/clk.h>
  20 #include <linux/clockchips.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/irq.h>
  23 #include <linux/irqreturn.h>
  24 #include <linux/of.h>
  25 #include <linux/of_address.h>
  26 #include <linux/of_irq.h>
  27 #include <linux/slab.h>
  28
  29 #define GPT_IRQ_EN_REG          0x00
  30 #define GPT_IRQ_ENABLE(val)     BIT((val) - 1)
  31 #define GPT_IRQ_ACK_REG         0x08
  32 #define GPT_IRQ_ACK(val)        BIT((val) - 1)
  33
  34 #define TIMER_CTRL_REG(val)     (0x10 * (val))
  35 #define TIMER_CTRL_OP(val)      (((val) & 0x3) << 4)
  36 #define TIMER_CTRL_OP_ONESHOT   (0)
  37 #define TIMER_CTRL_OP_REPEAT    (1)
  38 #define TIMER_CTRL_OP_FREERUN   (3)
  39 #define TIMER_CTRL_CLEAR        (2)
  40 #define TIMER_CTRL_ENABLE       (1)
  41 #define TIMER_CTRL_DISABLE      (0)
  42
  43 #define TIMER_CLK_REG(val)      (0x04 + (0x10 * (val)))
  44 #define TIMER_CLK_SRC(val)      (((val) & 0x1) << 4)
  45 #define TIMER_CLK_SRC_SYS13M    (0)
  46 #define TIMER_CLK_SRC_RTC32K    (1)
  47 #define TIMER_CLK_DIV1          (0x0)
  48 #define TIMER_CLK_DIV2          (0x1)
  49
  50 #define TIMER_CNT_REG(val)      (0x08 + (0x10 * (val)))
  51 #define TIMER_CMP_REG(val)      (0x0C + (0x10 * (val)))
  52
  53 #define GPT_CLK_EVT     1
  54 #define GPT_CLK_SRC     2
  55
  56 struct mtk_clock_event_device {
  57         void __iomem *gpt_base;
  58         u32 ticks_per_jiffy;
  59         struct clock_event_device dev;
  60 };
  61
  62 static inline struct mtk_clock_event_device *to_mtk_clk(
  63                                 struct clock_event_device *c)
  64 {
  65         return container_of(c, struct mtk_clock_event_device, dev);
  66 }
  67
  68 static void mtk_clkevt_time_stop(struct mtk_clock_event_device *evt, u8 timer)
  69 {
  70         u32 val;
  71
  72         val = readl(evt->gpt_base + TIMER_CTRL_REG(timer));
  73         writel(val & ~TIMER_CTRL_ENABLE, evt->gpt_base +
  74                         TIMER_CTRL_REG(timer));
  75 }
  76
  77 static void mtk_clkevt_time_setup(struct mtk_clock_event_device *evt,
  78                                 unsigned long delay, u8 timer)
  79 {
  80         writel(delay, evt->gpt_base + TIMER_CMP_REG(timer));
  81 }
  82
  83 static void mtk_clkevt_time_start(struct mtk_clock_event_device *evt,
  84                 bool periodic, u8 timer)
  85 {
  86         u32 val;
  87
  88         /* Acknowledge interrupt */
  89         writel(GPT_IRQ_ACK(timer), evt->gpt_base + GPT_IRQ_ACK_REG);
  90
  91         val = readl(evt->gpt_base + TIMER_CTRL_REG(timer));
  92
  93         /* Clear 2 bit timer operation mode field */
  94         val &= ~TIMER_CTRL_OP(0x3);
  95
  96         if (periodic)
  97                 val |= TIMER_CTRL_OP(TIMER_CTRL_OP_REPEAT);
  98         else
  99                 val |= TIMER_CTRL_OP(TIMER_CTRL_OP_ONESHOT);
 100
 101         writel(val | TIMER_CTRL_ENABLE | TIMER_CTRL_CLEAR,
 102                evt->gpt_base + TIMER_CTRL_REG(timer));
 103 }
 104
 105 static void mtk_clkevt_mode(enum clock_event_mode mode,
 106                                 struct clock_event_device *clk)
 107 {
 108         struct mtk_clock_event_device *evt = to_mtk_clk(clk);
 109
 110         mtk_clkevt_time_stop(evt, GPT_CLK_EVT);
 111
 112         switch (mode) {
 113         case CLOCK_EVT_MODE_PERIODIC:
 114                 mtk_clkevt_time_setup(evt, evt->ticks_per_jiffy, GPT_CLK_EVT);
 115                 mtk_clkevt_time_start(evt, true, GPT_CLK_EVT);
 116                 break;
 117         case CLOCK_EVT_MODE_ONESHOT:
 118                 /* Timer is enabled in set_next_event */
 119                 break;
 120         case CLOCK_EVT_MODE_UNUSED:
 121         case CLOCK_EVT_MODE_SHUTDOWN:
 122         default:
 123                 /* No more interrupts will occur as source is disabled */
 124                 break;
 125         }
 126 }
 127
 128 static int mtk_clkevt_next_event(unsigned long event,
 129                                    struct clock_event_device *clk)
 130 {
 131         struct mtk_clock_event_device *evt = to_mtk_clk(clk);
 132
 133         mtk_clkevt_time_stop(evt, GPT_CLK_EVT);
 134         mtk_clkevt_time_setup(evt, event, GPT_CLK_EVT);
 135         mtk_clkevt_time_start(evt, false, GPT_CLK_EVT);
 136
 137         return 0;
 138 }
 139
 140 static irqreturn_t mtk_timer_interrupt(int irq, void *dev_id)
 141 {
 142         struct mtk_clock_event_device *evt = dev_id;
 143
 144         /* Acknowledge timer0 irq */
 145         writel(GPT_IRQ_ACK(GPT_CLK_EVT), evt->gpt_base + GPT_IRQ_ACK_REG);
 146         evt->dev.event_handler(&evt->dev);
 147
 148         return IRQ_HANDLED;
 149 }
 150
 151 static void mtk_timer_global_reset(struct mtk_clock_event_device *evt)
 152 {
 153         /* Disable all interrupts */
 154         writel(0x0, evt->gpt_base + GPT_IRQ_EN_REG);
 155         /* Acknowledge all interrupts */
 156         writel(0x3f, evt->gpt_base + GPT_IRQ_ACK_REG);
 157 }
 158
 159 static void
 160 mtk_timer_setup(struct mtk_clock_event_device *evt, u8 timer, u8 option)
 161 {
 162         writel(TIMER_CTRL_CLEAR | TIMER_CTRL_DISABLE,
 163                 evt->gpt_base + TIMER_CTRL_REG(timer));
 164
 165         writel(TIMER_CLK_SRC(TIMER_CLK_SRC_SYS13M) | TIMER_CLK_DIV1,
 166                         evt->gpt_base + TIMER_CLK_REG(timer));
 167
 168         writel(0x0, evt->gpt_base + TIMER_CMP_REG(timer));
 169
 170         writel(TIMER_CTRL_OP(option) | TIMER_CTRL_ENABLE,
 171                         evt->gpt_base + TIMER_CTRL_REG(timer));
 172 }
 173
 174 static void mtk_timer_enable_irq(struct mtk_clock_event_device *evt, u8 timer)
 175 {
 176         u32 val;
 177
 178         val = readl(evt->gpt_base + GPT_IRQ_EN_REG);
 179         writel(val | GPT_IRQ_ENABLE(timer),
 180                         evt->gpt_base + GPT_IRQ_EN_REG);
 181 }
 182
 183 static void __init mtk_timer_init(struct device_node *node)
 184 {
 185         struct mtk_clock_event_device *evt;
 186         struct resource res;
 187         unsigned long rate = 0;
 188         struct clk *clk;
 189
 190         evt = kzalloc(sizeof(*evt), GFP_KERNEL);
 191         if (!evt) {
 192                 pr_warn("Can't allocate mtk clock event driver struct");
 193                 return;
 194         }
 195
 196         evt->dev.name = "mtk_tick";
 197         evt->dev.rating = 300;
 198         evt->dev.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
 199         evt->dev.set_mode = mtk_clkevt_mode;
 200         evt->dev.set_next_event = mtk_clkevt_next_event;
 201         evt->dev.cpumask = cpu_possible_mask;
 202
 203         evt->gpt_base = of_io_request_and_map(node, 0, "mtk-timer");
 204         if (IS_ERR(evt->gpt_base)) {
 205                 pr_warn("Can't get resource\n");
 206                 return;
 207         }
 208
 209         evt->dev.irq = irq_of_parse_and_map(node, 0);
 210         if (evt->dev.irq <= 0) {
 211                 pr_warn("Can't parse IRQ");
 212                 goto err_mem;
 213         }
 214
 215         clk = of_clk_get(node, 0);
 216         if (IS_ERR(clk)) {
 217                 pr_warn("Can't get timer clock");
 218                 goto err_irq;
 219         }
 220
 221         if (clk_prepare_enable(clk)) {
 222                 pr_warn("Can't prepare clock");
 223                 goto err_clk_put;
 224         }
 225         rate = clk_get_rate(clk);
 226
 227         if (request_irq(evt->dev.irq, mtk_timer_interrupt,
 228                         IRQF_TIMER | IRQF_IRQPOLL, "mtk_timer", evt)) {
 229                 pr_warn("failed to setup irq %d\n", evt->dev.irq);
 230                 goto err_clk_disable;
 231         }
 232
 233         evt->ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
 234
 235         mtk_timer_global_reset(evt);
 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
 242         /* Configure clock event */
 243         mtk_timer_setup(evt, GPT_CLK_EVT, TIMER_CTRL_OP_REPEAT);
 244         mtk_timer_enable_irq(evt, GPT_CLK_EVT);
 245
 246         clockevents_config_and_register(&evt->dev, rate, 0x3,
 247                                         0xffffffff);
 248         return;
 249
 250 err_clk_disable:
 251         clk_disable_unprepare(clk);
 252 err_clk_put:
 253         clk_put(clk);
 254 err_irq:
 255         irq_dispose_mapping(evt->dev.irq);
 256 err_mem:
 257         iounmap(evt->gpt_base);
 258         of_address_to_resource(node, 0, &res);
 259         release_mem_region(res.start, resource_size(&res));
 260 }
 261 CLOCKSOURCE_OF_DECLARE(mtk_mt6577, "mediatek,mt6577-timer", mtk_timer_init);