1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2013 Broadcom Corporation
7 #include <linux/debugfs.h>
8 #include <linux/delay.h>
11 #include <linux/module.h>
12 #include <linux/of_address.h>
13 #include <linux/platform_device.h>
14 #include <linux/watchdog.h>
16 #define SECWDOG_CTRL_REG 0x00000000
17 #define SECWDOG_COUNT_REG 0x00000004
19 #define SECWDOG_RESERVED_MASK 0x1dffffff
20 #define SECWDOG_WD_LOAD_FLAG 0x10000000
21 #define SECWDOG_EN_MASK 0x08000000
22 #define SECWDOG_SRSTEN_MASK 0x04000000
23 #define SECWDOG_RES_MASK 0x00f00000
24 #define SECWDOG_COUNT_MASK 0x000fffff
26 #define SECWDOG_MAX_COUNT SECWDOG_COUNT_MASK
27 #define SECWDOG_CLKS_SHIFT 20
28 #define SECWDOG_MAX_RES 15
29 #define SECWDOG_DEFAULT_RESOLUTION 4
30 #define SECWDOG_MAX_TRY 1000
32 #define SECS_TO_TICKS(x, w) ((x) << (w)->resolution)
33 #define TICKS_TO_SECS(x, w) ((x) >> (w)->resolution)
35 #define BCM_KONA_WDT_NAME "bcm_kona_wdt"
40 * One watchdog tick is 1/(2^resolution) seconds. Resolution can take
41 * the values 0-15, meaning one tick can be 1s to 30.52us. Our default
42 * resolution of 4 means one tick is 62.5ms.
44 * The watchdog counter is 20 bits. Depending on resolution, the maximum
45 * counter value of 0xfffff expires after about 12 days (resolution 0)
46 * down to only 32s (resolution 15). The default resolution of 4 gives
47 * us a maximum of about 18 hours and 12 minutes before the watchdog
52 #ifdef CONFIG_BCM_KONA_WDT_DEBUG
53 unsigned long busy_count;
54 struct dentry *debugfs;
58 static int secure_register_read(struct bcm_kona_wdt *wdt, uint32_t offset)
64 * If the WD_LOAD_FLAG is set, the watchdog counter field is being
65 * updated in hardware. Once the WD timer is updated in hardware, it
69 if (unlikely(count > 1))
71 val = readl_relaxed(wdt->base + offset);
73 } while ((val & SECWDOG_WD_LOAD_FLAG) && count < SECWDOG_MAX_TRY);
75 #ifdef CONFIG_BCM_KONA_WDT_DEBUG
76 /* Remember the maximum number iterations due to WD_LOAD_FLAG */
77 if (count > wdt->busy_count)
78 wdt->busy_count = count;
81 /* This is the only place we return a negative value. */
82 if (val & SECWDOG_WD_LOAD_FLAG)
85 /* We always mask out reserved bits. */
86 val &= SECWDOG_RESERVED_MASK;
91 #ifdef CONFIG_BCM_KONA_WDT_DEBUG
93 static int bcm_kona_show(struct seq_file *s, void *data)
97 struct bcm_kona_wdt *wdt = s->private;
100 seq_puts(s, "No device pointer\n");
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);
109 if (ctl_val < 0 || cur_val < 0) {
110 seq_puts(s, "Error accessing hardware\n");
112 int ctl, cur, ctl_sec, cur_sec, res;
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);
120 "Resolution: %d / %d\n"
121 "Control: %d s / %d (%#x) ticks\n"
122 "Current: %d s / %d (%#x) ticks\n"
124 res, wdt->resolution,
133 DEFINE_SHOW_ATTRIBUTE(bcm_kona);
135 static void bcm_kona_wdt_debug_init(struct platform_device *pdev)
138 struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);
145 dir = debugfs_create_dir(BCM_KONA_WDT_NAME, NULL);
146 if (IS_ERR_OR_NULL(dir))
149 if (debugfs_create_file("info", S_IFREG | S_IRUGO, dir, wdt,
153 debugfs_remove_recursive(dir);
156 static void bcm_kona_wdt_debug_exit(struct platform_device *pdev)
158 struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);
160 if (wdt && wdt->debugfs) {
161 debugfs_remove_recursive(wdt->debugfs);
168 static void bcm_kona_wdt_debug_init(struct platform_device *pdev) {}
169 static void bcm_kona_wdt_debug_exit(struct platform_device *pdev) {}
171 #endif /* CONFIG_BCM_KONA_WDT_DEBUG */
173 static int bcm_kona_wdt_ctrl_reg_modify(struct bcm_kona_wdt *wdt,
174 unsigned mask, unsigned newval)
180 spin_lock_irqsave(&wdt->lock, flags);
182 val = secure_register_read(wdt, SECWDOG_CTRL_REG);
188 writel_relaxed(val, wdt->base + SECWDOG_CTRL_REG);
191 spin_unlock_irqrestore(&wdt->lock, flags);
196 static int bcm_kona_wdt_set_resolution_reg(struct bcm_kona_wdt *wdt)
198 if (wdt->resolution > SECWDOG_MAX_RES)
201 return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_RES_MASK,
202 wdt->resolution << SECWDOG_CLKS_SHIFT);
205 static int bcm_kona_wdt_set_timeout_reg(struct watchdog_device *wdog,
206 unsigned watchdog_flags)
208 struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
210 return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_COUNT_MASK,
211 SECS_TO_TICKS(wdog->timeout, wdt) |
215 static int bcm_kona_wdt_set_timeout(struct watchdog_device *wdog,
222 static unsigned int bcm_kona_wdt_get_timeleft(struct watchdog_device *wdog)
224 struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
228 spin_lock_irqsave(&wdt->lock, flags);
229 val = secure_register_read(wdt, SECWDOG_COUNT_REG);
230 spin_unlock_irqrestore(&wdt->lock, flags);
235 return TICKS_TO_SECS(val & SECWDOG_COUNT_MASK, wdt);
238 static int bcm_kona_wdt_start(struct watchdog_device *wdog)
240 return bcm_kona_wdt_set_timeout_reg(wdog,
241 SECWDOG_EN_MASK | SECWDOG_SRSTEN_MASK);
244 static int bcm_kona_wdt_stop(struct watchdog_device *wdog)
246 struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
248 return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_EN_MASK |
249 SECWDOG_SRSTEN_MASK, 0);
252 static const struct watchdog_ops bcm_kona_wdt_ops = {
253 .owner = THIS_MODULE,
254 .start = bcm_kona_wdt_start,
255 .stop = bcm_kona_wdt_stop,
256 .set_timeout = bcm_kona_wdt_set_timeout,
257 .get_timeleft = bcm_kona_wdt_get_timeleft,
260 static const struct watchdog_info bcm_kona_wdt_info = {
261 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
263 .identity = "Broadcom Kona Watchdog Timer",
266 static struct watchdog_device bcm_kona_wdt_wdd = {
267 .info = &bcm_kona_wdt_info,
268 .ops = &bcm_kona_wdt_ops,
270 .max_timeout = SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,
271 .timeout = SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,
274 static void bcm_kona_wdt_shutdown(struct platform_device *pdev)
276 bcm_kona_wdt_stop(&bcm_kona_wdt_wdd);
279 static int bcm_kona_wdt_probe(struct platform_device *pdev)
281 struct device *dev = &pdev->dev;
282 struct bcm_kona_wdt *wdt;
285 wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
289 spin_lock_init(&wdt->lock);
291 wdt->base = devm_platform_ioremap_resource(pdev, 0);
292 if (IS_ERR(wdt->base))
295 wdt->resolution = SECWDOG_DEFAULT_RESOLUTION;
296 ret = bcm_kona_wdt_set_resolution_reg(wdt);
298 dev_err(dev, "Failed to set resolution (error: %d)", ret);
302 platform_set_drvdata(pdev, wdt);
303 watchdog_set_drvdata(&bcm_kona_wdt_wdd, wdt);
304 bcm_kona_wdt_wdd.parent = &pdev->dev;
306 ret = bcm_kona_wdt_set_timeout_reg(&bcm_kona_wdt_wdd, 0);
308 dev_err(dev, "Failed set watchdog timeout");
312 ret = watchdog_register_device(&bcm_kona_wdt_wdd);
314 dev_err(dev, "Failed to register watchdog device");
318 bcm_kona_wdt_debug_init(pdev);
319 dev_dbg(dev, "Broadcom Kona Watchdog Timer");
324 static int bcm_kona_wdt_remove(struct platform_device *pdev)
326 bcm_kona_wdt_debug_exit(pdev);
327 bcm_kona_wdt_shutdown(pdev);
328 watchdog_unregister_device(&bcm_kona_wdt_wdd);
329 dev_dbg(&pdev->dev, "Watchdog driver disabled");
334 static const struct of_device_id bcm_kona_wdt_of_match[] = {
335 { .compatible = "brcm,kona-wdt", },
338 MODULE_DEVICE_TABLE(of, bcm_kona_wdt_of_match);
340 static struct platform_driver bcm_kona_wdt_driver = {
342 .name = BCM_KONA_WDT_NAME,
343 .of_match_table = bcm_kona_wdt_of_match,
345 .probe = bcm_kona_wdt_probe,
346 .remove = bcm_kona_wdt_remove,
347 .shutdown = bcm_kona_wdt_shutdown,
350 module_platform_driver(bcm_kona_wdt_driver);
352 MODULE_ALIAS("platform:" BCM_KONA_WDT_NAME);
353 MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");
354 MODULE_DESCRIPTION("Broadcom Kona Watchdog Driver");
355 MODULE_LICENSE("GPL v2");