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1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (C) 2013 Broadcom Corporation4 *5 */6 7#include <linux/debugfs.h>8#include <linux/delay.h>9#include <linux/err.h>10#include <linux/io.h>11#include <linux/module.h>12#include <linux/of_address.h>13#include <linux/platform_device.h>14#include <linux/watchdog.h>15 16#define SECWDOG_CTRL_REG 0x0000000017#define SECWDOG_COUNT_REG 0x0000000418 19#define SECWDOG_RESERVED_MASK 0x1dffffff20#define SECWDOG_WD_LOAD_FLAG 0x1000000021#define SECWDOG_EN_MASK 0x0800000022#define SECWDOG_SRSTEN_MASK 0x0400000023#define SECWDOG_RES_MASK 0x00f0000024#define SECWDOG_COUNT_MASK 0x000fffff25 26#define SECWDOG_MAX_COUNT SECWDOG_COUNT_MASK27#define SECWDOG_CLKS_SHIFT 2028#define SECWDOG_MAX_RES 1529#define SECWDOG_DEFAULT_RESOLUTION 430#define SECWDOG_MAX_TRY 100031 32#define SECS_TO_TICKS(x, w) ((x) << (w)->resolution)33#define TICKS_TO_SECS(x, w) ((x) >> (w)->resolution)34 35#define BCM_KONA_WDT_NAME "bcm_kona_wdt"36 37struct bcm_kona_wdt {38 void __iomem *base;39 /*40 * One watchdog tick is 1/(2^resolution) seconds. Resolution can take41 * the values 0-15, meaning one tick can be 1s to 30.52us. Our default42 * resolution of 4 means one tick is 62.5ms.43 *44 * The watchdog counter is 20 bits. Depending on resolution, the maximum45 * counter value of 0xfffff expires after about 12 days (resolution 0)46 * down to only 32s (resolution 15). The default resolution of 4 gives47 * us a maximum of about 18 hours and 12 minutes before the watchdog48 * times out.49 */50 int resolution;51 spinlock_t lock;52#ifdef CONFIG_BCM_KONA_WDT_DEBUG53 unsigned long busy_count;54 struct dentry *debugfs;55#endif56};57 58static int secure_register_read(struct bcm_kona_wdt *wdt, uint32_t offset)59{60 uint32_t val;61 unsigned count = 0;62 63 /*64 * If the WD_LOAD_FLAG is set, the watchdog counter field is being65 * updated in hardware. Once the WD timer is updated in hardware, it66 * gets cleared.67 */68 do {69 if (unlikely(count > 1))70 udelay(5);71 val = readl_relaxed(wdt->base + offset);72 count++;73 } while ((val & SECWDOG_WD_LOAD_FLAG) && count < SECWDOG_MAX_TRY);74 75#ifdef CONFIG_BCM_KONA_WDT_DEBUG76 /* Remember the maximum number iterations due to WD_LOAD_FLAG */77 if (count > wdt->busy_count)78 wdt->busy_count = count;79#endif80 81 /* This is the only place we return a negative value. */82 if (val & SECWDOG_WD_LOAD_FLAG)83 return -ETIMEDOUT;84 85 /* We always mask out reserved bits. */86 val &= SECWDOG_RESERVED_MASK;87 88 return val;89}90 91#ifdef CONFIG_BCM_KONA_WDT_DEBUG92 93static int bcm_kona_show(struct seq_file *s, void *data)94{95 int ctl_val, cur_val;96 unsigned long flags;97 struct bcm_kona_wdt *wdt = s->private;98 99 if (!wdt) {100 seq_puts(s, "No device pointer\n");101 return 0;102 }103 104 spin_lock_irqsave(&wdt->lock, flags);105 ctl_val = secure_register_read(wdt, SECWDOG_CTRL_REG);106 cur_val = secure_register_read(wdt, SECWDOG_COUNT_REG);107 spin_unlock_irqrestore(&wdt->lock, flags);108 109 if (ctl_val < 0 || cur_val < 0) {110 seq_puts(s, "Error accessing hardware\n");111 } else {112 int ctl, cur, ctl_sec, cur_sec, res;113 114 ctl = ctl_val & SECWDOG_COUNT_MASK;115 res = (ctl_val & SECWDOG_RES_MASK) >> SECWDOG_CLKS_SHIFT;116 cur = cur_val & SECWDOG_COUNT_MASK;117 ctl_sec = TICKS_TO_SECS(ctl, wdt);118 cur_sec = TICKS_TO_SECS(cur, wdt);119 seq_printf(s,120 "Resolution: %d / %d\n"121 "Control: %d s / %d (%#x) ticks\n"122 "Current: %d s / %d (%#x) ticks\n"123 "Busy count: %lu\n",124 res, wdt->resolution,125 ctl_sec, ctl, ctl,126 cur_sec, cur, cur,127 wdt->busy_count);128 }129 130 return 0;131}132 133DEFINE_SHOW_ATTRIBUTE(bcm_kona);134 135static void bcm_kona_wdt_debug_init(struct platform_device *pdev)136{137 struct dentry *dir;138 struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);139 140 if (!wdt)141 return;142 143 wdt->debugfs = NULL;144 145 dir = debugfs_create_dir(BCM_KONA_WDT_NAME, NULL);146 147 debugfs_create_file("info", S_IFREG | S_IRUGO, dir, wdt,148 &bcm_kona_fops);149 wdt->debugfs = dir;150}151 152static void bcm_kona_wdt_debug_exit(struct platform_device *pdev)153{154 struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);155 156 if (wdt)157 debugfs_remove_recursive(wdt->debugfs);158}159 160#else161 162static void bcm_kona_wdt_debug_init(struct platform_device *pdev) {}163static void bcm_kona_wdt_debug_exit(struct platform_device *pdev) {}164 165#endif /* CONFIG_BCM_KONA_WDT_DEBUG */166 167static int bcm_kona_wdt_ctrl_reg_modify(struct bcm_kona_wdt *wdt,168 unsigned mask, unsigned newval)169{170 int val;171 unsigned long flags;172 int ret = 0;173 174 spin_lock_irqsave(&wdt->lock, flags);175 176 val = secure_register_read(wdt, SECWDOG_CTRL_REG);177 if (val < 0) {178 ret = val;179 } else {180 val &= ~mask;181 val |= newval;182 writel_relaxed(val, wdt->base + SECWDOG_CTRL_REG);183 }184 185 spin_unlock_irqrestore(&wdt->lock, flags);186 187 return ret;188}189 190static int bcm_kona_wdt_set_resolution_reg(struct bcm_kona_wdt *wdt)191{192 if (wdt->resolution > SECWDOG_MAX_RES)193 return -EINVAL;194 195 return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_RES_MASK,196 wdt->resolution << SECWDOG_CLKS_SHIFT);197}198 199static int bcm_kona_wdt_set_timeout_reg(struct watchdog_device *wdog,200 unsigned watchdog_flags)201{202 struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);203 204 return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_COUNT_MASK,205 SECS_TO_TICKS(wdog->timeout, wdt) |206 watchdog_flags);207}208 209static int bcm_kona_wdt_set_timeout(struct watchdog_device *wdog,210 unsigned int t)211{212 wdog->timeout = t;213 return 0;214}215 216static unsigned int bcm_kona_wdt_get_timeleft(struct watchdog_device *wdog)217{218 struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);219 int val;220 unsigned long flags;221 222 spin_lock_irqsave(&wdt->lock, flags);223 val = secure_register_read(wdt, SECWDOG_COUNT_REG);224 spin_unlock_irqrestore(&wdt->lock, flags);225 226 if (val < 0)227 return val;228 229 return TICKS_TO_SECS(val & SECWDOG_COUNT_MASK, wdt);230}231 232static int bcm_kona_wdt_start(struct watchdog_device *wdog)233{234 return bcm_kona_wdt_set_timeout_reg(wdog,235 SECWDOG_EN_MASK | SECWDOG_SRSTEN_MASK);236}237 238static int bcm_kona_wdt_stop(struct watchdog_device *wdog)239{240 struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);241 242 return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_EN_MASK |243 SECWDOG_SRSTEN_MASK, 0);244}245 246static const struct watchdog_ops bcm_kona_wdt_ops = {247 .owner = THIS_MODULE,248 .start = bcm_kona_wdt_start,249 .stop = bcm_kona_wdt_stop,250 .set_timeout = bcm_kona_wdt_set_timeout,251 .get_timeleft = bcm_kona_wdt_get_timeleft,252};253 254static const struct watchdog_info bcm_kona_wdt_info = {255 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |256 WDIOF_KEEPALIVEPING,257 .identity = "Broadcom Kona Watchdog Timer",258};259 260static struct watchdog_device bcm_kona_wdt_wdd = {261 .info = &bcm_kona_wdt_info,262 .ops = &bcm_kona_wdt_ops,263 .min_timeout = 1,264 .max_timeout = SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,265 .timeout = SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,266};267 268static int bcm_kona_wdt_probe(struct platform_device *pdev)269{270 struct device *dev = &pdev->dev;271 struct bcm_kona_wdt *wdt;272 int ret;273 274 wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);275 if (!wdt)276 return -ENOMEM;277 278 spin_lock_init(&wdt->lock);279 280 wdt->base = devm_platform_ioremap_resource(pdev, 0);281 if (IS_ERR(wdt->base))282 return PTR_ERR(wdt->base);283 284 wdt->resolution = SECWDOG_DEFAULT_RESOLUTION;285 ret = bcm_kona_wdt_set_resolution_reg(wdt);286 if (ret) {287 dev_err(dev, "Failed to set resolution (error: %d)", ret);288 return ret;289 }290 291 platform_set_drvdata(pdev, wdt);292 watchdog_set_drvdata(&bcm_kona_wdt_wdd, wdt);293 bcm_kona_wdt_wdd.parent = dev;294 295 ret = bcm_kona_wdt_set_timeout_reg(&bcm_kona_wdt_wdd, 0);296 if (ret) {297 dev_err(dev, "Failed set watchdog timeout");298 return ret;299 }300 301 watchdog_stop_on_reboot(&bcm_kona_wdt_wdd);302 watchdog_stop_on_unregister(&bcm_kona_wdt_wdd);303 ret = devm_watchdog_register_device(dev, &bcm_kona_wdt_wdd);304 if (ret)305 return ret;306 307 bcm_kona_wdt_debug_init(pdev);308 dev_dbg(dev, "Broadcom Kona Watchdog Timer");309 310 return 0;311}312 313static void bcm_kona_wdt_remove(struct platform_device *pdev)314{315 bcm_kona_wdt_debug_exit(pdev);316 dev_dbg(&pdev->dev, "Watchdog driver disabled");317}318 319static const struct of_device_id bcm_kona_wdt_of_match[] = {320 { .compatible = "brcm,kona-wdt", },321 {},322};323MODULE_DEVICE_TABLE(of, bcm_kona_wdt_of_match);324 325static struct platform_driver bcm_kona_wdt_driver = {326 .driver = {327 .name = BCM_KONA_WDT_NAME,328 .of_match_table = bcm_kona_wdt_of_match,329 },330 .probe = bcm_kona_wdt_probe,331 .remove_new = bcm_kona_wdt_remove,332};333 334module_platform_driver(bcm_kona_wdt_driver);335 336MODULE_ALIAS("platform:" BCM_KONA_WDT_NAME);337MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");338MODULE_DESCRIPTION("Broadcom Kona Watchdog Driver");339MODULE_LICENSE("GPL v2");340