drivers/watchdog/imx_sc_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright 2018-2019 NXP.
   4  */
   5
   6 #include <linux/arm-smccc.h>
   7 #include <linux/firmware/imx/sci.h>
   8 #include <linux/io.h>
   9 #include <linux/init.h>
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/moduleparam.h>
  13 #include <linux/of.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/reboot.h>
  16 #include <linux/watchdog.h>
  17
  18 #define DEFAULT_TIMEOUT 60
  19 /*
  20  * Software timer tick implemented in scfw side, support 10ms to 0xffffffff ms
  21  * in theory, but for normal case, 1s~128s is enough, you can change this max
  22  * value in case it's not enough.
  23  */
  24 #define MAX_TIMEOUT 128
  25
  26 #define IMX_SIP_TIMER                   0xC2000002
  27 #define IMX_SIP_TIMER_START_WDOG                0x01
  28 #define IMX_SIP_TIMER_STOP_WDOG         0x02
  29 #define IMX_SIP_TIMER_SET_WDOG_ACT      0x03
  30 #define IMX_SIP_TIMER_PING_WDOG         0x04
  31 #define IMX_SIP_TIMER_SET_TIMEOUT_WDOG  0x05
  32 #define IMX_SIP_TIMER_GET_WDOG_STAT     0x06
  33 #define IMX_SIP_TIMER_SET_PRETIME_WDOG  0x07
  34
  35 #define SC_TIMER_WDOG_ACTION_PARTITION  0
  36
  37 #define SC_IRQ_WDOG                     1
  38 #define SC_IRQ_GROUP_WDOG               1
  39
  40 static bool nowayout = WATCHDOG_NOWAYOUT;
  41 module_param(nowayout, bool, 0000);
  42 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  43                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  44
  45 struct imx_sc_wdt_device {
  46         struct watchdog_device wdd;
  47         struct notifier_block wdt_notifier;
  48 };
  49
  50 static int imx_sc_wdt_ping(struct watchdog_device *wdog)
  51 {
  52         struct arm_smccc_res res;
  53
  54         arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_PING_WDOG,
  55                       0, 0, 0, 0, 0, 0, &res);
  56
  57         return 0;
  58 }
  59
  60 static int imx_sc_wdt_start(struct watchdog_device *wdog)
  61 {
  62         struct arm_smccc_res res;
  63
  64         arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_START_WDOG,
  65                       0, 0, 0, 0, 0, 0, &res);
  66         if (res.a0)
  67                 return -EACCES;
  68
  69         arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_WDOG_ACT,
  70                       SC_TIMER_WDOG_ACTION_PARTITION,
  71                       0, 0, 0, 0, 0, &res);
  72         return res.a0 ? -EACCES : 0;
  73 }
  74
  75 static int imx_sc_wdt_stop(struct watchdog_device *wdog)
  76 {
  77         struct arm_smccc_res res;
  78
  79         arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_STOP_WDOG,
  80                       0, 0, 0, 0, 0, 0, &res);
  81
  82         return res.a0 ? -EACCES : 0;
  83 }
  84
  85 static int imx_sc_wdt_set_timeout(struct watchdog_device *wdog,
  86                                 unsigned int timeout)
  87 {
  88         struct arm_smccc_res res;
  89
  90         wdog->timeout = timeout;
  91         arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_TIMEOUT_WDOG,
  92                       timeout * 1000, 0, 0, 0, 0, 0, &res);
  93
  94         return res.a0 ? -EACCES : 0;
  95 }
  96
  97 static int imx_sc_wdt_set_pretimeout(struct watchdog_device *wdog,
  98                                      unsigned int pretimeout)
  99 {
 100         struct arm_smccc_res res;
 101
 102         /*
 103          * SCU firmware calculates pretimeout based on current time
 104          * stamp instead of watchdog timeout stamp, need to convert
 105          * the pretimeout to SCU firmware's timeout value.
 106          */
 107         arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_PRETIME_WDOG,
 108                       (wdog->timeout - pretimeout) * 1000, 0, 0, 0,
 109                       0, 0, &res);
 110         if (res.a0)
 111                 return -EACCES;
 112
 113         wdog->pretimeout = pretimeout;
 114
 115         return 0;
 116 }
 117
 118 static int imx_sc_wdt_notify(struct notifier_block *nb,
 119                              unsigned long event, void *group)
 120 {
 121         struct imx_sc_wdt_device *imx_sc_wdd =
 122                                  container_of(nb,
 123                                               struct imx_sc_wdt_device,
 124                                               wdt_notifier);
 125
 126         if (event & SC_IRQ_WDOG &&
 127             *(u8 *)group == SC_IRQ_GROUP_WDOG)
 128                 watchdog_notify_pretimeout(&imx_sc_wdd->wdd);
 129
 130         return 0;
 131 }
 132
 133 static void imx_sc_wdt_action(void *data)
 134 {
 135         struct notifier_block *wdt_notifier = data;
 136
 137         imx_scu_irq_unregister_notifier(wdt_notifier);
 138         imx_scu_irq_group_enable(SC_IRQ_GROUP_WDOG,
 139                                  SC_IRQ_WDOG,
 140                                  false);
 141 }
 142
 143 static const struct watchdog_ops imx_sc_wdt_ops = {
 144         .owner = THIS_MODULE,
 145         .start = imx_sc_wdt_start,
 146         .stop  = imx_sc_wdt_stop,
 147         .ping  = imx_sc_wdt_ping,
 148         .set_timeout = imx_sc_wdt_set_timeout,
 149         .set_pretimeout = imx_sc_wdt_set_pretimeout,
 150 };
 151
 152 static struct watchdog_info imx_sc_wdt_info = {
 153         .identity       = "i.MX SC watchdog timer",
 154         .options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
 155                           WDIOF_MAGICCLOSE,
 156 };
 157
 158 static int imx_sc_wdt_probe(struct platform_device *pdev)
 159 {
 160         struct imx_sc_wdt_device *imx_sc_wdd;
 161         struct watchdog_device *wdog;
 162         struct device *dev = &pdev->dev;
 163         int ret;
 164
 165         imx_sc_wdd = devm_kzalloc(dev, sizeof(*imx_sc_wdd), GFP_KERNEL);
 166         if (!imx_sc_wdd)
 167                 return -ENOMEM;
 168
 169         platform_set_drvdata(pdev, imx_sc_wdd);
 170
 171         wdog = &imx_sc_wdd->wdd;
 172         wdog->info = &imx_sc_wdt_info;
 173         wdog->ops = &imx_sc_wdt_ops;
 174         wdog->min_timeout = 1;
 175         wdog->max_timeout = MAX_TIMEOUT;
 176         wdog->parent = dev;
 177         wdog->timeout = DEFAULT_TIMEOUT;
 178
 179         watchdog_init_timeout(wdog, 0, dev);
 180         watchdog_stop_on_reboot(wdog);
 181         watchdog_stop_on_unregister(wdog);
 182
 183         ret = devm_watchdog_register_device(dev, wdog);
 184         if (ret)
 185                 return ret;
 186
 187         ret = imx_scu_irq_group_enable(SC_IRQ_GROUP_WDOG,
 188                                        SC_IRQ_WDOG,
 189                                        true);
 190         if (ret) {
 191                 dev_warn(dev, "Enable irq failed, pretimeout NOT supported\n");
 192                 return 0;
 193         }
 194
 195         imx_sc_wdd->wdt_notifier.notifier_call = imx_sc_wdt_notify;
 196         ret = imx_scu_irq_register_notifier(&imx_sc_wdd->wdt_notifier);
 197         if (ret) {
 198                 imx_scu_irq_group_enable(SC_IRQ_GROUP_WDOG,
 199                                          SC_IRQ_WDOG,
 200                                          false);
 201                 dev_warn(dev,
 202                          "Register irq notifier failed, pretimeout NOT supported\n");
 203                 return 0;
 204         }
 205
 206         ret = devm_add_action_or_reset(dev, imx_sc_wdt_action,
 207                                        &imx_sc_wdd->wdt_notifier);
 208         if (!ret)
 209                 imx_sc_wdt_info.options |= WDIOF_PRETIMEOUT;
 210         else
 211                 dev_warn(dev, "Add action failed, pretimeout NOT supported\n");
 212
 213         return 0;
 214 }
 215
 216 static int __maybe_unused imx_sc_wdt_suspend(struct device *dev)
 217 {
 218         struct imx_sc_wdt_device *imx_sc_wdd = dev_get_drvdata(dev);
 219
 220         if (watchdog_active(&imx_sc_wdd->wdd))
 221                 imx_sc_wdt_stop(&imx_sc_wdd->wdd);
 222
 223         return 0;
 224 }
 225
 226 static int __maybe_unused imx_sc_wdt_resume(struct device *dev)
 227 {
 228         struct imx_sc_wdt_device *imx_sc_wdd = dev_get_drvdata(dev);
 229
 230         if (watchdog_active(&imx_sc_wdd->wdd))
 231                 imx_sc_wdt_start(&imx_sc_wdd->wdd);
 232
 233         return 0;
 234 }
 235
 236 static SIMPLE_DEV_PM_OPS(imx_sc_wdt_pm_ops,
 237                          imx_sc_wdt_suspend, imx_sc_wdt_resume);
 238
 239 static const struct of_device_id imx_sc_wdt_dt_ids[] = {
 240         { .compatible = "fsl,imx-sc-wdt", },
 241         { /* sentinel */ }
 242 };
 243 MODULE_DEVICE_TABLE(of, imx_sc_wdt_dt_ids);
 244
 245 static struct platform_driver imx_sc_wdt_driver = {
 246         .probe          = imx_sc_wdt_probe,
 247         .driver         = {
 248                 .name   = "imx-sc-wdt",
 249                 .of_match_table = imx_sc_wdt_dt_ids,
 250                 .pm     = &imx_sc_wdt_pm_ops,
 251         },
 252 };
 253 module_platform_driver(imx_sc_wdt_driver);
 254
 255 MODULE_AUTHOR("Robin Gong <yibin.gong@nxp.com>");
 256 MODULE_DESCRIPTION("NXP i.MX system controller watchdog driver");
 257 MODULE_LICENSE("GPL v2");