drivers/watchdog/loongson1_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (c) 2016 Yang Ling <gnaygnil@gmail.com>
   4  */
   5
   6 #include <linux/clk.h>
   7 #include <linux/io.h>
   8 #include <linux/module.h>
   9 #include <linux/of.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/watchdog.h>
  12
  13 /* Loongson 1 Watchdog Register Definitions */
  14 #define WDT_EN                  0x0
  15 #define WDT_TIMER               0x4
  16 #define WDT_SET                 0x8
  17
  18 #define DEFAULT_HEARTBEAT       30
  19
  20 static bool nowayout = WATCHDOG_NOWAYOUT;
  21 module_param(nowayout, bool, 0444);
  22
  23 static unsigned int heartbeat;
  24 module_param(heartbeat, uint, 0444);
  25
  26 struct ls1x_wdt_drvdata {
  27         void __iomem *base;
  28         struct clk *clk;
  29         unsigned long clk_rate;
  30         struct watchdog_device wdt;
  31 };
  32
  33 static int ls1x_wdt_ping(struct watchdog_device *wdt_dev)
  34 {
  35         struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
  36
  37         writel(0x1, drvdata->base + WDT_SET);
  38
  39         return 0;
  40 }
  41
  42 static int ls1x_wdt_set_timeout(struct watchdog_device *wdt_dev,
  43                                 unsigned int timeout)
  44 {
  45         struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
  46         unsigned int max_hw_heartbeat = wdt_dev->max_hw_heartbeat_ms / 1000;
  47         unsigned int counts;
  48
  49         wdt_dev->timeout = timeout;
  50
  51         counts = drvdata->clk_rate * min(timeout, max_hw_heartbeat);
  52         writel(counts, drvdata->base + WDT_TIMER);
  53
  54         return 0;
  55 }
  56
  57 static int ls1x_wdt_start(struct watchdog_device *wdt_dev)
  58 {
  59         struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
  60
  61         writel(0x1, drvdata->base + WDT_EN);
  62
  63         return 0;
  64 }
  65
  66 static int ls1x_wdt_stop(struct watchdog_device *wdt_dev)
  67 {
  68         struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
  69
  70         writel(0x0, drvdata->base + WDT_EN);
  71
  72         return 0;
  73 }
  74
  75 static int ls1x_wdt_restart(struct watchdog_device *wdt_dev,
  76                             unsigned long action, void *data)
  77 {
  78         struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
  79
  80         writel(0x1, drvdata->base + WDT_EN);
  81         writel(0x1, drvdata->base + WDT_TIMER);
  82         writel(0x1, drvdata->base + WDT_SET);
  83
  84         return 0;
  85 }
  86
  87 static const struct watchdog_info ls1x_wdt_info = {
  88         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
  89         .identity = "Loongson1 Watchdog",
  90 };
  91
  92 static const struct watchdog_ops ls1x_wdt_ops = {
  93         .owner = THIS_MODULE,
  94         .start = ls1x_wdt_start,
  95         .stop = ls1x_wdt_stop,
  96         .ping = ls1x_wdt_ping,
  97         .set_timeout = ls1x_wdt_set_timeout,
  98         .restart = ls1x_wdt_restart,
  99 };
 100
 101 static int ls1x_wdt_probe(struct platform_device *pdev)
 102 {
 103         struct device *dev = &pdev->dev;
 104         struct ls1x_wdt_drvdata *drvdata;
 105         struct watchdog_device *ls1x_wdt;
 106         unsigned long clk_rate;
 107         int err;
 108
 109         drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
 110         if (!drvdata)
 111                 return -ENOMEM;
 112
 113         drvdata->base = devm_platform_ioremap_resource(pdev, 0);
 114         if (IS_ERR(drvdata->base))
 115                 return PTR_ERR(drvdata->base);
 116
 117         drvdata->clk = devm_clk_get_enabled(dev, NULL);
 118         if (IS_ERR(drvdata->clk))
 119                 return PTR_ERR(drvdata->clk);
 120
 121         clk_rate = clk_get_rate(drvdata->clk);
 122         if (!clk_rate)
 123                 return -EINVAL;
 124         drvdata->clk_rate = clk_rate;
 125
 126         ls1x_wdt = &drvdata->wdt;
 127         ls1x_wdt->info = &ls1x_wdt_info;
 128         ls1x_wdt->ops = &ls1x_wdt_ops;
 129         ls1x_wdt->timeout = DEFAULT_HEARTBEAT;
 130         ls1x_wdt->min_timeout = 1;
 131         ls1x_wdt->max_hw_heartbeat_ms = U32_MAX / clk_rate * 1000;
 132         ls1x_wdt->parent = dev;
 133
 134         watchdog_init_timeout(ls1x_wdt, heartbeat, dev);
 135         watchdog_set_nowayout(ls1x_wdt, nowayout);
 136         watchdog_set_drvdata(ls1x_wdt, drvdata);
 137
 138         err = devm_watchdog_register_device(dev, &drvdata->wdt);
 139         if (err)
 140                 return err;
 141
 142         platform_set_drvdata(pdev, drvdata);
 143
 144         dev_info(dev, "Loongson1 Watchdog driver registered\n");
 145
 146         return 0;
 147 }
 148
 149 #ifdef CONFIG_OF
 150 static const struct of_device_id ls1x_wdt_dt_ids[] = {
 151         { .compatible = "loongson,ls1b-wdt", },
 152         { .compatible = "loongson,ls1c-wdt", },
 153         { /* sentinel */ }
 154 };
 155 MODULE_DEVICE_TABLE(of, ls1x_wdt_dt_ids);
 156 #endif
 157
 158 static struct platform_driver ls1x_wdt_driver = {
 159         .probe = ls1x_wdt_probe,
 160         .driver = {
 161                 .name = "ls1x-wdt",
 162                 .of_match_table = of_match_ptr(ls1x_wdt_dt_ids),
 163         },
 164 };
 165
 166 module_platform_driver(ls1x_wdt_driver);
 167
 168 MODULE_AUTHOR("Yang Ling <gnaygnil@gmail.com>");
 169 MODULE_DESCRIPTION("Loongson1 Watchdog Driver");
 170 MODULE_LICENSE("GPL");