linux/drivers/watchdog/imx_sc_wdt.c
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   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
  38static bool nowayout = WATCHDOG_NOWAYOUT;
  39module_param(nowayout, bool, 0000);
  40MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  41                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  42
  43struct imx_sc_wdt_device {
  44        struct watchdog_device wdd;
  45        struct notifier_block wdt_notifier;
  46};
  47
  48static 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
  58static 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
  73static 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
  83static 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
  95static 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
 116static 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
 131static 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
 141static 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
 150static 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
 156static 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
 212register_device:
 213        return devm_watchdog_register_device(dev, wdog);
 214}
 215
 216static 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
 226static 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
 236static SIMPLE_DEV_PM_OPS(imx_sc_wdt_pm_ops,
 237                         imx_sc_wdt_suspend, imx_sc_wdt_resume);
 238
 239static const struct of_device_id imx_sc_wdt_dt_ids[] = {
 240        { .compatible = "fsl,imx-sc-wdt", },
 241        { /* sentinel */ }
 242};
 243MODULE_DEVICE_TABLE(of, imx_sc_wdt_dt_ids);
 244
 245static 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};
 253module_platform_driver(imx_sc_wdt_driver);
 254
 255MODULE_AUTHOR("Robin Gong <yibin.gong@nxp.com>");
 256MODULE_DESCRIPTION("NXP i.MX system controller watchdog driver");
 257MODULE_LICENSE("GPL v2");
 258