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/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/moduleparam.h>
  12 #include <linux/of.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/watchdog.h>
  15
  16 #define DEFAULT_TIMEOUT 60
  17 /*
  18  * Software timer tick implemented in scfw side, support 10ms to 0xffffffff ms
  19  * in theory, but for normal case, 1s~128s is enough, you can change this max
  20  * value in case it's not enough.
  21  */
  22 #define MAX_TIMEOUT 128
  23
  24 #define IMX_SIP_TIMER                   0xC2000002
  25 #define IMX_SIP_TIMER_START_WDOG                0x01
  26 #define IMX_SIP_TIMER_STOP_WDOG         0x02
  27 #define IMX_SIP_TIMER_SET_WDOG_ACT      0x03
  28 #define IMX_SIP_TIMER_PING_WDOG         0x04
  29 #define IMX_SIP_TIMER_SET_TIMEOUT_WDOG  0x05
  30 #define IMX_SIP_TIMER_GET_WDOG_STAT     0x06
  31 #define IMX_SIP_TIMER_SET_PRETIME_WDOG  0x07
  32
  33 #define SC_TIMER_WDOG_ACTION_PARTITION  0
  34
  35 #define SC_IRQ_WDOG                     1
  36 #define SC_IRQ_GROUP_WDOG               1
  37
  38 static bool nowayout = WATCHDOG_NOWAYOUT;
  39 module_param(nowayout, bool, 0000);
  40 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  41                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  42
  43 struct imx_sc_wdt_device {
  44         struct watchdog_device wdd;
  45         struct notifier_block wdt_notifier;
  46 };
  47
  48 static int imx_sc_wdt_ping(struct watchdog_device *wdog)
  49 {
  50         struct arm_smccc_res res;
  51
  52         arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_PING_WDOG,
  53                       0, 0, 0, 0, 0, 0, &res);
  54
  55         return 0;
  56 }
  57
  58 static int imx_sc_wdt_start(struct watchdog_device *wdog)
  59 {
  60         struct arm_smccc_res res;
  61
  62         arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_START_WDOG,
  63                       0, 0, 0, 0, 0, 0, &res);
  64         if (res.a0)
  65                 return -EACCES;
  66
  67         arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_WDOG_ACT,
  68                       SC_TIMER_WDOG_ACTION_PARTITION,
  69                       0, 0, 0, 0, 0, &res);
  70         return res.a0 ? -EACCES : 0;
  71 }
  72
  73 static int imx_sc_wdt_stop(struct watchdog_device *wdog)
  74 {
  75         struct arm_smccc_res res;
  76
  77         arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_STOP_WDOG,
  78                       0, 0, 0, 0, 0, 0, &res);
  79
  80         return res.a0 ? -EACCES : 0;
  81 }
  82
  83 static int imx_sc_wdt_set_timeout(struct watchdog_device *wdog,
  84                                 unsigned int timeout)
  85 {
  86         struct arm_smccc_res res;
  87
  88         wdog->timeout = timeout;
  89         arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_TIMEOUT_WDOG,
  90                       timeout * 1000, 0, 0, 0, 0, 0, &res);
  91
  92         return res.a0 ? -EACCES : 0;
  93 }
  94
  95 static int imx_sc_wdt_set_pretimeout(struct watchdog_device *wdog,
  96                                      unsigned int pretimeout)
  97 {
  98         struct arm_smccc_res res;
  99
 100         /*
 101          * SCU firmware calculates pretimeout based on current time
 102          * stamp instead of watchdog timeout stamp, need to convert
 103          * the pretimeout to SCU firmware's timeout value.
 104          */
 105         arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_PRETIME_WDOG,
 106                       (wdog->timeout - pretimeout) * 1000, 0, 0, 0,
 107                       0, 0, &res);
 108         if (res.a0)
 109                 return -EACCES;
 110
 111         wdog->pretimeout = pretimeout;
 112
 113         return 0;
 114 }
 115
 116 static int imx_sc_wdt_notify(struct notifier_block *nb,
 117                              unsigned long event, void *group)
 118 {
 119         struct imx_sc_wdt_device *imx_sc_wdd =
 120                                  container_of(nb,
 121                                               struct imx_sc_wdt_device,
 122                                               wdt_notifier);
 123
 124         if (event & SC_IRQ_WDOG &&
 125             *(u8 *)group == SC_IRQ_GROUP_WDOG)
 126                 watchdog_notify_pretimeout(&imx_sc_wdd->wdd);
 127
 128         return 0;
 129 }
 130
 131 static void imx_sc_wdt_action(void *data)
 132 {
 133         struct notifier_block *wdt_notifier = data;
 134
 135         imx_scu_irq_unregister_notifier(wdt_notifier);
 136         imx_scu_irq_group_enable(SC_IRQ_GROUP_WDOG,
 137                                  SC_IRQ_WDOG,
 138                                  false);
 139 }
 140
 141 static const struct watchdog_ops imx_sc_wdt_ops = {
 142         .owner = THIS_MODULE,
 143         .start = imx_sc_wdt_start,
 144         .stop  = imx_sc_wdt_stop,
 145         .ping  = imx_sc_wdt_ping,
 146         .set_timeout = imx_sc_wdt_set_timeout,
 147         .set_pretimeout = imx_sc_wdt_set_pretimeout,
 148 };
 149
 150 static struct watchdog_info imx_sc_wdt_info = {
 151         .identity       = "i.MX SC watchdog timer",
 152         .options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
 153                           WDIOF_MAGICCLOSE,
 154 };
 155
 156 static int imx_sc_wdt_probe(struct platform_device *pdev)
 157 {
 158         struct imx_sc_wdt_device *imx_sc_wdd;
 159         struct watchdog_device *wdog;
 160         struct device *dev = &pdev->dev;
 161         int ret;
 162
 163         imx_sc_wdd = devm_kzalloc(dev, sizeof(*imx_sc_wdd), GFP_KERNEL);
 164         if (!imx_sc_wdd)
 165                 return -ENOMEM;
 166
 167         platform_set_drvdata(pdev, imx_sc_wdd);
 168
 169         wdog = &imx_sc_wdd->wdd;
 170         wdog->info = &imx_sc_wdt_info;
 171         wdog->ops = &imx_sc_wdt_ops;
 172         wdog->min_timeout = 1;
 173         wdog->max_timeout = MAX_TIMEOUT;
 174         wdog->parent = dev;
 175         wdog->timeout = DEFAULT_TIMEOUT;
 176
 177         watchdog_init_timeout(wdog, 0, dev);
 178
 179         ret = imx_sc_wdt_set_timeout(wdog, wdog->timeout);
 180         if (ret)
 181                 return ret;
 182
 183         watchdog_stop_on_reboot(wdog);
 184         watchdog_stop_on_unregister(wdog);
 185
 186         ret = imx_scu_irq_group_enable(SC_IRQ_GROUP_WDOG,
 187                                        SC_IRQ_WDOG,
 188                                        true);
 189         if (ret) {
 190                 dev_warn(dev, "Enable irq failed, pretimeout NOT supported\n");
 191                 goto register_device;
 192         }
 193
 194         imx_sc_wdd->wdt_notifier.notifier_call = imx_sc_wdt_notify;
 195         ret = imx_scu_irq_register_notifier(&imx_sc_wdd->wdt_notifier);
 196         if (ret) {
 197                 imx_scu_irq_group_enable(SC_IRQ_GROUP_WDOG,
 198                                          SC_IRQ_WDOG,
 199                                          false);
 200                 dev_warn(dev,
 201                          "Register irq notifier failed, pretimeout NOT supported\n");
 202                 goto register_device;
 203         }
 204
 205         ret = devm_add_action_or_reset(dev, imx_sc_wdt_action,
 206                                        &imx_sc_wdd->wdt_notifier);
 207         if (!ret)
 208                 imx_sc_wdt_info.options |= WDIOF_PRETIMEOUT;
 209         else
 210                 dev_warn(dev, "Add action failed, pretimeout NOT supported\n");
 211
 212 register_device:
 213         return devm_watchdog_register_device(dev, wdog);
 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");