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