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