drivers/watchdog/jz4740_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
   4  *  JZ4740 Watchdog driver
   5  */
   6
   7 #include <linux/mfd/ingenic-tcu.h>
   8 #include <linux/module.h>
   9 #include <linux/moduleparam.h>
  10 #include <linux/types.h>
  11 #include <linux/kernel.h>
  12 #include <linux/watchdog.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/io.h>
  15 #include <linux/device.h>
  16 #include <linux/clk.h>
  17 #include <linux/slab.h>
  18 #include <linux/err.h>
  19 #include <linux/of.h>
  20
  21 #include <asm/mach-jz4740/timer.h>
  22
  23 #define JZ_WDT_CLOCK_PCLK 0x1
  24 #define JZ_WDT_CLOCK_RTC  0x2
  25 #define JZ_WDT_CLOCK_EXT  0x4
  26
  27 #define JZ_WDT_CLOCK_DIV_1    (0 << TCU_TCSR_PRESCALE_LSB)
  28 #define JZ_WDT_CLOCK_DIV_4    (1 << TCU_TCSR_PRESCALE_LSB)
  29 #define JZ_WDT_CLOCK_DIV_16   (2 << TCU_TCSR_PRESCALE_LSB)
  30 #define JZ_WDT_CLOCK_DIV_64   (3 << TCU_TCSR_PRESCALE_LSB)
  31 #define JZ_WDT_CLOCK_DIV_256  (4 << TCU_TCSR_PRESCALE_LSB)
  32 #define JZ_WDT_CLOCK_DIV_1024 (5 << TCU_TCSR_PRESCALE_LSB)
  33
  34 #define DEFAULT_HEARTBEAT 5
  35 #define MAX_HEARTBEAT     2048
  36
  37 static bool nowayout = WATCHDOG_NOWAYOUT;
  38 module_param(nowayout, bool, 0);
  39 MODULE_PARM_DESC(nowayout,
  40                  "Watchdog cannot be stopped once started (default="
  41                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  42
  43 static unsigned int heartbeat = DEFAULT_HEARTBEAT;
  44 module_param(heartbeat, uint, 0);
  45 MODULE_PARM_DESC(heartbeat,
  46                 "Watchdog heartbeat period in seconds from 1 to "
  47                 __MODULE_STRING(MAX_HEARTBEAT) ", default "
  48                 __MODULE_STRING(DEFAULT_HEARTBEAT));
  49
  50 struct jz4740_wdt_drvdata {
  51         struct watchdog_device wdt;
  52         void __iomem *base;
  53         struct clk *rtc_clk;
  54 };
  55
  56 static int jz4740_wdt_ping(struct watchdog_device *wdt_dev)
  57 {
  58         struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
  59
  60         writew(0x0, drvdata->base + TCU_REG_WDT_TCNT);
  61         return 0;
  62 }
  63
  64 static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,
  65                                     unsigned int new_timeout)
  66 {
  67         struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
  68         unsigned int rtc_clk_rate;
  69         unsigned int timeout_value;
  70         unsigned short clock_div = JZ_WDT_CLOCK_DIV_1;
  71         u8 tcer;
  72
  73         rtc_clk_rate = clk_get_rate(drvdata->rtc_clk);
  74
  75         timeout_value = rtc_clk_rate * new_timeout;
  76         while (timeout_value > 0xffff) {
  77                 if (clock_div == JZ_WDT_CLOCK_DIV_1024) {
  78                         /* Requested timeout too high;
  79                         * use highest possible value. */
  80                         timeout_value = 0xffff;
  81                         break;
  82                 }
  83                 timeout_value >>= 2;
  84                 clock_div += (1 << TCU_TCSR_PRESCALE_LSB);
  85         }
  86
  87         tcer = readb(drvdata->base + TCU_REG_WDT_TCER);
  88         writeb(0x0, drvdata->base + TCU_REG_WDT_TCER);
  89         writew(clock_div, drvdata->base + TCU_REG_WDT_TCSR);
  90
  91         writew((u16)timeout_value, drvdata->base + TCU_REG_WDT_TDR);
  92         writew(0x0, drvdata->base + TCU_REG_WDT_TCNT);
  93         writew(clock_div | JZ_WDT_CLOCK_RTC, drvdata->base + TCU_REG_WDT_TCSR);
  94
  95         if (tcer & TCU_WDT_TCER_TCEN)
  96                 writeb(TCU_WDT_TCER_TCEN, drvdata->base + TCU_REG_WDT_TCER);
  97
  98         wdt_dev->timeout = new_timeout;
  99         return 0;
 100 }
 101
 102 static int jz4740_wdt_start(struct watchdog_device *wdt_dev)
 103 {
 104         struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 105         u8 tcer;
 106
 107         tcer = readb(drvdata->base + TCU_REG_WDT_TCER);
 108
 109         jz4740_timer_enable_watchdog();
 110         jz4740_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
 111
 112         /* Start watchdog if it wasn't started already */
 113         if (!(tcer & TCU_WDT_TCER_TCEN))
 114                 writeb(TCU_WDT_TCER_TCEN, drvdata->base + TCU_REG_WDT_TCER);
 115
 116         return 0;
 117 }
 118
 119 static int jz4740_wdt_stop(struct watchdog_device *wdt_dev)
 120 {
 121         struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 122
 123         writeb(0x0, drvdata->base + TCU_REG_WDT_TCER);
 124         jz4740_timer_disable_watchdog();
 125
 126         return 0;
 127 }
 128
 129 static int jz4740_wdt_restart(struct watchdog_device *wdt_dev,
 130                               unsigned long action, void *data)
 131 {
 132         wdt_dev->timeout = 0;
 133         jz4740_wdt_start(wdt_dev);
 134         return 0;
 135 }
 136
 137 static const struct watchdog_info jz4740_wdt_info = {
 138         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 139         .identity = "jz4740 Watchdog",
 140 };
 141
 142 static const struct watchdog_ops jz4740_wdt_ops = {
 143         .owner = THIS_MODULE,
 144         .start = jz4740_wdt_start,
 145         .stop = jz4740_wdt_stop,
 146         .ping = jz4740_wdt_ping,
 147         .set_timeout = jz4740_wdt_set_timeout,
 148         .restart = jz4740_wdt_restart,
 149 };
 150
 151 #ifdef CONFIG_OF
 152 static const struct of_device_id jz4740_wdt_of_matches[] = {
 153         { .compatible = "ingenic,jz4740-watchdog", },
 154         { .compatible = "ingenic,jz4780-watchdog", },
 155         { /* sentinel */ }
 156 };
 157 MODULE_DEVICE_TABLE(of, jz4740_wdt_of_matches);
 158 #endif
 159
 160 static int jz4740_wdt_probe(struct platform_device *pdev)
 161 {
 162         struct device *dev = &pdev->dev;
 163         struct jz4740_wdt_drvdata *drvdata;
 164         struct watchdog_device *jz4740_wdt;
 165         int ret;
 166
 167         drvdata = devm_kzalloc(dev, sizeof(struct jz4740_wdt_drvdata),
 168                                GFP_KERNEL);
 169         if (!drvdata)
 170                 return -ENOMEM;
 171
 172         if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
 173                 heartbeat = DEFAULT_HEARTBEAT;
 174
 175         jz4740_wdt = &drvdata->wdt;
 176         jz4740_wdt->info = &jz4740_wdt_info;
 177         jz4740_wdt->ops = &jz4740_wdt_ops;
 178         jz4740_wdt->timeout = heartbeat;
 179         jz4740_wdt->min_timeout = 1;
 180         jz4740_wdt->max_timeout = MAX_HEARTBEAT;
 181         jz4740_wdt->parent = dev;
 182         watchdog_set_nowayout(jz4740_wdt, nowayout);
 183         watchdog_set_drvdata(jz4740_wdt, drvdata);
 184
 185         drvdata->base = devm_platform_ioremap_resource(pdev, 0);
 186         if (IS_ERR(drvdata->base))
 187                 return PTR_ERR(drvdata->base);
 188
 189         drvdata->rtc_clk = devm_clk_get(dev, "rtc");
 190         if (IS_ERR(drvdata->rtc_clk)) {
 191                 dev_err(dev, "cannot find RTC clock\n");
 192                 return PTR_ERR(drvdata->rtc_clk);
 193         }
 194
 195         return devm_watchdog_register_device(dev, &drvdata->wdt);
 196 }
 197
 198 static struct platform_driver jz4740_wdt_driver = {
 199         .probe = jz4740_wdt_probe,
 200         .driver = {
 201                 .name = "jz4740-wdt",
 202                 .of_match_table = of_match_ptr(jz4740_wdt_of_matches),
 203         },
 204 };
 205
 206 module_platform_driver(jz4740_wdt_driver);
 207
 208 MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
 209 MODULE_DESCRIPTION("jz4740 Watchdog Driver");
 210 MODULE_LICENSE("GPL");
 211 MODULE_ALIAS("platform:jz4740-wdt");