drivers/watchdog/uniphier_wdt.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Watchdog driver for the UniPhier watchdog timer
0004  *
0005  * (c) Copyright 2014 Panasonic Corporation
0006  * (c) Copyright 2016 Socionext Inc.
0007  * All rights reserved.
0008  */
0009
0010 #include <linux/bitops.h>
0011 #include <linux/mfd/syscon.h>
0012 #include <linux/module.h>
0013 #include <linux/of.h>
0014 #include <linux/platform_device.h>
0015 #include <linux/regmap.h>
0016 #include <linux/watchdog.h>
0017
0018 /* WDT timer setting register */
0019 #define WDTTIMSET           0x3004
0020 #define   WDTTIMSET_PERIOD_MASK     (0xf << 0)
0021 #define   WDTTIMSET_PERIOD_1_SEC    (0x3 << 0)
0022
0023 /* WDT reset selection register */
0024 #define WDTRSTSEL           0x3008
0025 #define   WDTRSTSEL_RSTSEL_MASK     (0x3 << 0)
0026 #define   WDTRSTSEL_RSTSEL_BOTH     (0x0 << 0)
0027 #define   WDTRSTSEL_RSTSEL_IRQ_ONLY (0x2 << 0)
0028
0029 /* WDT control register */
0030 #define WDTCTRL             0x300c
0031 #define   WDTCTRL_STATUS        BIT(8)
0032 #define   WDTCTRL_CLEAR         BIT(1)
0033 #define   WDTCTRL_ENABLE        BIT(0)
0034
0035 #define SEC_TO_WDTTIMSET_PRD(sec) \
0036         (ilog2(sec) + WDTTIMSET_PERIOD_1_SEC)
0037
0038 #define WDTST_TIMEOUT           1000 /* usec */
0039
0040 #define WDT_DEFAULT_TIMEOUT     64   /* Default is 64 seconds */
0041 #define WDT_PERIOD_MIN          1
0042 #define WDT_PERIOD_MAX          128
0043
0044 static unsigned int timeout = 0;
0045 static bool nowayout = WATCHDOG_NOWAYOUT;
0046
0047 struct uniphier_wdt_dev {
0048     struct watchdog_device wdt_dev;
0049     struct regmap   *regmap;
0050 };
0051
0052 /*
0053  * UniPhier Watchdog operations
0054  */
0055 static int uniphier_watchdog_ping(struct watchdog_device *w)
0056 {
0057     struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
0058     unsigned int val;
0059     int ret;
0060
0061     /* Clear counter */
0062     ret = regmap_write_bits(wdev->regmap, WDTCTRL,
0063                 WDTCTRL_CLEAR, WDTCTRL_CLEAR);
0064     if (!ret)
0065         /*
0066          * As SoC specification, after clear counter,
0067          * it needs to wait until counter status is 1.
0068          */
0069         ret = regmap_read_poll_timeout(wdev->regmap, WDTCTRL, val,
0070                            (val & WDTCTRL_STATUS),
0071                            0, WDTST_TIMEOUT);
0072
0073     return ret;
0074 }
0075
0076 static int __uniphier_watchdog_start(struct regmap *regmap, unsigned int sec)
0077 {
0078     unsigned int val;
0079     int ret;
0080
0081     ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
0082                        !(val & WDTCTRL_STATUS),
0083                        0, WDTST_TIMEOUT);
0084     if (ret)
0085         return ret;
0086
0087     /* Setup period */
0088     ret = regmap_write(regmap, WDTTIMSET,
0089                SEC_TO_WDTTIMSET_PRD(sec));
0090     if (ret)
0091         return ret;
0092
0093     /* Enable and clear watchdog */
0094     ret = regmap_write(regmap, WDTCTRL, WDTCTRL_ENABLE | WDTCTRL_CLEAR);
0095     if (!ret)
0096         /*
0097          * As SoC specification, after clear counter,
0098          * it needs to wait until counter status is 1.
0099          */
0100         ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
0101                            (val & WDTCTRL_STATUS),
0102                            0, WDTST_TIMEOUT);
0103
0104     return ret;
0105 }
0106
0107 static int __uniphier_watchdog_stop(struct regmap *regmap)
0108 {
0109     /* Disable and stop watchdog */
0110     return regmap_write_bits(regmap, WDTCTRL, WDTCTRL_ENABLE, 0);
0111 }
0112
0113 static int __uniphier_watchdog_restart(struct regmap *regmap, unsigned int sec)
0114 {
0115     int ret;
0116
0117     ret = __uniphier_watchdog_stop(regmap);
0118     if (ret)
0119         return ret;
0120
0121     return __uniphier_watchdog_start(regmap, sec);
0122 }
0123
0124 static int uniphier_watchdog_start(struct watchdog_device *w)
0125 {
0126     struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
0127     unsigned int tmp_timeout;
0128
0129     tmp_timeout = roundup_pow_of_two(w->timeout);
0130
0131     return __uniphier_watchdog_start(wdev->regmap, tmp_timeout);
0132 }
0133
0134 static int uniphier_watchdog_stop(struct watchdog_device *w)
0135 {
0136     struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
0137
0138     return __uniphier_watchdog_stop(wdev->regmap);
0139 }
0140
0141 static int uniphier_watchdog_set_timeout(struct watchdog_device *w,
0142                      unsigned int t)
0143 {
0144     struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
0145     unsigned int tmp_timeout;
0146     int ret;
0147
0148     tmp_timeout = roundup_pow_of_two(t);
0149     if (tmp_timeout == w->timeout)
0150         return 0;
0151
0152     if (watchdog_active(w)) {
0153         ret = __uniphier_watchdog_restart(wdev->regmap, tmp_timeout);
0154         if (ret)
0155             return ret;
0156     }
0157
0158     w->timeout = tmp_timeout;
0159
0160     return 0;
0161 }
0162
0163 /*
0164  * Kernel Interfaces
0165  */
0166 static const struct watchdog_info uniphier_wdt_info = {
0167     .identity   = "uniphier-wdt",
0168     .options    = WDIOF_SETTIMEOUT |
0169               WDIOF_KEEPALIVEPING |
0170               WDIOF_MAGICCLOSE |
0171               WDIOF_OVERHEAT,
0172 };
0173
0174 static const struct watchdog_ops uniphier_wdt_ops = {
0175     .owner      = THIS_MODULE,
0176     .start      = uniphier_watchdog_start,
0177     .stop       = uniphier_watchdog_stop,
0178     .ping       = uniphier_watchdog_ping,
0179     .set_timeout    = uniphier_watchdog_set_timeout,
0180 };
0181
0182 static int uniphier_wdt_probe(struct platform_device *pdev)
0183 {
0184     struct device *dev = &pdev->dev;
0185     struct uniphier_wdt_dev *wdev;
0186     struct regmap *regmap;
0187     struct device_node *parent;
0188     int ret;
0189
0190     wdev = devm_kzalloc(dev, sizeof(*wdev), GFP_KERNEL);
0191     if (!wdev)
0192         return -ENOMEM;
0193
0194     parent = of_get_parent(dev->of_node); /* parent should be syscon node */
0195     regmap = syscon_node_to_regmap(parent);
0196     of_node_put(parent);
0197     if (IS_ERR(regmap))
0198         return PTR_ERR(regmap);
0199
0200     wdev->regmap = regmap;
0201     wdev->wdt_dev.info = &uniphier_wdt_info;
0202     wdev->wdt_dev.ops = &uniphier_wdt_ops;
0203     wdev->wdt_dev.max_timeout = WDT_PERIOD_MAX;
0204     wdev->wdt_dev.min_timeout = WDT_PERIOD_MIN;
0205     wdev->wdt_dev.timeout = WDT_DEFAULT_TIMEOUT;
0206     wdev->wdt_dev.parent = dev;
0207
0208     watchdog_init_timeout(&wdev->wdt_dev, timeout, dev);
0209     watchdog_set_nowayout(&wdev->wdt_dev, nowayout);
0210     watchdog_stop_on_reboot(&wdev->wdt_dev);
0211
0212     watchdog_set_drvdata(&wdev->wdt_dev, wdev);
0213
0214     uniphier_watchdog_stop(&wdev->wdt_dev);
0215     ret = regmap_write(wdev->regmap, WDTRSTSEL, WDTRSTSEL_RSTSEL_BOTH);
0216     if (ret)
0217         return ret;
0218
0219     ret = devm_watchdog_register_device(dev, &wdev->wdt_dev);
0220     if (ret)
0221         return ret;
0222
0223     dev_info(dev, "watchdog driver (timeout=%d sec, nowayout=%d)\n",
0224          wdev->wdt_dev.timeout, nowayout);
0225
0226     return 0;
0227 }
0228
0229 static const struct of_device_id uniphier_wdt_dt_ids[] = {
0230     { .compatible = "socionext,uniphier-wdt" },
0231     { /* sentinel */ }
0232 };
0233 MODULE_DEVICE_TABLE(of, uniphier_wdt_dt_ids);
0234
0235 static struct platform_driver uniphier_wdt_driver = {
0236     .probe      = uniphier_wdt_probe,
0237     .driver     = {
0238         .name       = "uniphier-wdt",
0239         .of_match_table = uniphier_wdt_dt_ids,
0240     },
0241 };
0242
0243 module_platform_driver(uniphier_wdt_driver);
0244
0245 module_param(timeout, uint, 0000);
0246 MODULE_PARM_DESC(timeout,
0247     "Watchdog timeout seconds in power of 2. (0 < timeout < 128, default="
0248                 __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
0249
0250 module_param(nowayout, bool, 0000);
0251 MODULE_PARM_DESC(nowayout,
0252     "Watchdog cannot be stopped once started (default="
0253                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
0254
0255 MODULE_AUTHOR("Keiji Hayashibara <hayashibara.keiji@socionext.com>");
0256 MODULE_DESCRIPTION("UniPhier Watchdog Device Driver");
0257 MODULE_LICENSE("GPL v2");