1
2
3
4
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 0x00000000
17#define SECWDOG_COUNT_REG 0x00000004
18
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
25
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
31
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
41
42
43
44
45
46
47
48
49
50 int resolution;
51 spinlock_t lock;
52#ifdef CONFIG_BCM_KONA_WDT_DEBUG
53 unsigned long busy_count;
54 struct dentry *debugfs;
55#endif
56};
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
65
66
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_DEBUG
76
77 if (count > wdt->busy_count)
78 wdt->busy_count = count;
79#endif
80
81
82 if (val & SECWDOG_WD_LOAD_FLAG)
83 return -ETIMEDOUT;
84
85
86 val &= SECWDOG_RESERVED_MASK;
87
88 return val;
89}
90
91#ifdef CONFIG_BCM_KONA_WDT_DEBUG
92
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#else
161
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
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 -ENODEV;
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 int 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 return 0;
319}
320
321static const struct of_device_id bcm_kona_wdt_of_match[] = {
322 { .compatible = "brcm,kona-wdt", },
323 {},
324};
325MODULE_DEVICE_TABLE(of, bcm_kona_wdt_of_match);
326
327static struct platform_driver bcm_kona_wdt_driver = {
328 .driver = {
329 .name = BCM_KONA_WDT_NAME,
330 .of_match_table = bcm_kona_wdt_of_match,
331 },
332 .probe = bcm_kona_wdt_probe,
333 .remove = bcm_kona_wdt_remove,
334};
335
336module_platform_driver(bcm_kona_wdt_driver);
337
338MODULE_ALIAS("platform:" BCM_KONA_WDT_NAME);
339MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");
340MODULE_DESCRIPTION("Broadcom Kona Watchdog Driver");
341MODULE_LICENSE("GPL v2");
342
