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