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