drivers/watchdog/loongson1_wdt.c

   1 /*
   2  * Copyright (c) 2016 Yang Ling <gnaygnil@gmail.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License as published by the
   6  * Free Software Foundation; either version 2 of the License, or (at your
   7  * option) any later version.
   8  */
   9
  10 #include <linux/clk.h>
  11 #include <linux/module.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/watchdog.h>
  14 #include <loongson1.h>
  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 const struct watchdog_info ls1x_wdt_info = {
  74         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
  75         .identity = "Loongson1 Watchdog",
  76 };
  77
  78 static const struct watchdog_ops ls1x_wdt_ops = {
  79         .owner = THIS_MODULE,
  80         .start = ls1x_wdt_start,
  81         .stop = ls1x_wdt_stop,
  82         .ping = ls1x_wdt_ping,
  83         .set_timeout = ls1x_wdt_set_timeout,
  84 };
  85
  86 static int ls1x_wdt_probe(struct platform_device *pdev)
  87 {
  88         struct ls1x_wdt_drvdata *drvdata;
  89         struct watchdog_device *ls1x_wdt;
  90         unsigned long clk_rate;
  91         struct resource *res;
  92         int err;
  93
  94         drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
  95         if (!drvdata)
  96                 return -ENOMEM;
  97
  98         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  99         drvdata->base = devm_ioremap_resource(&pdev->dev, res);
 100         if (IS_ERR(drvdata->base))
 101                 return PTR_ERR(drvdata->base);
 102
 103         drvdata->clk = devm_clk_get(&pdev->dev, pdev->name);
 104         if (IS_ERR(drvdata->clk))
 105                 return PTR_ERR(drvdata->clk);
 106
 107         err = clk_prepare_enable(drvdata->clk);
 108         if (err) {
 109                 dev_err(&pdev->dev, "clk enable failed\n");
 110                 return err;
 111         }
 112
 113         clk_rate = clk_get_rate(drvdata->clk);
 114         if (!clk_rate) {
 115                 err = -EINVAL;
 116                 goto err0;
 117         }
 118         drvdata->clk_rate = clk_rate;
 119
 120         ls1x_wdt = &drvdata->wdt;
 121         ls1x_wdt->info = &ls1x_wdt_info;
 122         ls1x_wdt->ops = &ls1x_wdt_ops;
 123         ls1x_wdt->timeout = DEFAULT_HEARTBEAT;
 124         ls1x_wdt->min_timeout = 1;
 125         ls1x_wdt->max_hw_heartbeat_ms = U32_MAX / clk_rate * 1000;
 126         ls1x_wdt->parent = &pdev->dev;
 127
 128         watchdog_init_timeout(ls1x_wdt, heartbeat, &pdev->dev);
 129         watchdog_set_nowayout(ls1x_wdt, nowayout);
 130         watchdog_set_drvdata(ls1x_wdt, drvdata);
 131
 132         err = watchdog_register_device(&drvdata->wdt);
 133         if (err) {
 134                 dev_err(&pdev->dev, "failed to register watchdog device\n");
 135                 goto err0;
 136         }
 137
 138         platform_set_drvdata(pdev, drvdata);
 139
 140         dev_info(&pdev->dev, "Loongson1 Watchdog driver registered\n");
 141
 142         return 0;
 143 err0:
 144         clk_disable_unprepare(drvdata->clk);
 145         return err;
 146 }
 147
 148 static int ls1x_wdt_remove(struct platform_device *pdev)
 149 {
 150         struct ls1x_wdt_drvdata *drvdata = platform_get_drvdata(pdev);
 151
 152         watchdog_unregister_device(&drvdata->wdt);
 153         clk_disable_unprepare(drvdata->clk);
 154
 155         return 0;
 156 }
 157
 158 static struct platform_driver ls1x_wdt_driver = {
 159         .probe = ls1x_wdt_probe,
 160         .remove = ls1x_wdt_remove,
 161         .driver = {
 162                 .name = "ls1x-wdt",
 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");