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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_wdt_dbg_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
133static int bcm_kona_dbg_open(struct inode *inode, struct file *file)
134{
135 return single_open(file, bcm_kona_wdt_dbg_show, inode->i_private);
136}
137
138static const struct file_operations bcm_kona_dbg_operations = {
139 .open = bcm_kona_dbg_open,
140 .read = seq_read,
141 .llseek = seq_lseek,
142 .release = single_release,
143};
144
145static void bcm_kona_wdt_debug_init(struct platform_device *pdev)
146{
147 struct dentry *dir;
148 struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);
149
150 if (!wdt)
151 return;
152
153 wdt->debugfs = NULL;
154
155 dir = debugfs_create_dir(BCM_KONA_WDT_NAME, NULL);
156 if (IS_ERR_OR_NULL(dir))
157 return;
158
159 if (debugfs_create_file("info", S_IFREG | S_IRUGO, dir, wdt,
160 &bcm_kona_dbg_operations))
161 wdt->debugfs = dir;
162 else
163 debugfs_remove_recursive(dir);
164}
165
166static void bcm_kona_wdt_debug_exit(struct platform_device *pdev)
167{
168 struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);
169
170 if (wdt && wdt->debugfs) {
171 debugfs_remove_recursive(wdt->debugfs);
172 wdt->debugfs = NULL;
173 }
174}
175
176#else
177
178static void bcm_kona_wdt_debug_init(struct platform_device *pdev) {}
179static void bcm_kona_wdt_debug_exit(struct platform_device *pdev) {}
180
181#endif
182
183static int bcm_kona_wdt_ctrl_reg_modify(struct bcm_kona_wdt *wdt,
184 unsigned mask, unsigned newval)
185{
186 int val;
187 unsigned long flags;
188 int ret = 0;
189
190 spin_lock_irqsave(&wdt->lock, flags);
191
192 val = secure_register_read(wdt, SECWDOG_CTRL_REG);
193 if (val < 0) {
194 ret = val;
195 } else {
196 val &= ~mask;
197 val |= newval;
198 writel_relaxed(val, wdt->base + SECWDOG_CTRL_REG);
199 }
200
201 spin_unlock_irqrestore(&wdt->lock, flags);
202
203 return ret;
204}
205
206static int bcm_kona_wdt_set_resolution_reg(struct bcm_kona_wdt *wdt)
207{
208 if (wdt->resolution > SECWDOG_MAX_RES)
209 return -EINVAL;
210
211 return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_RES_MASK,
212 wdt->resolution << SECWDOG_CLKS_SHIFT);
213}
214
215static int bcm_kona_wdt_set_timeout_reg(struct watchdog_device *wdog,
216 unsigned watchdog_flags)
217{
218 struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
219
220 return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_COUNT_MASK,
221 SECS_TO_TICKS(wdog->timeout, wdt) |
222 watchdog_flags);
223}
224
225static int bcm_kona_wdt_set_timeout(struct watchdog_device *wdog,
226 unsigned int t)
227{
228 wdog->timeout = t;
229 return 0;
230}
231
232static unsigned int bcm_kona_wdt_get_timeleft(struct watchdog_device *wdog)
233{
234 struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
235 int val;
236 unsigned long flags;
237
238 spin_lock_irqsave(&wdt->lock, flags);
239 val = secure_register_read(wdt, SECWDOG_COUNT_REG);
240 spin_unlock_irqrestore(&wdt->lock, flags);
241
242 if (val < 0)
243 return val;
244
245 return TICKS_TO_SECS(val & SECWDOG_COUNT_MASK, wdt);
246}
247
248static int bcm_kona_wdt_start(struct watchdog_device *wdog)
249{
250 return bcm_kona_wdt_set_timeout_reg(wdog,
251 SECWDOG_EN_MASK | SECWDOG_SRSTEN_MASK);
252}
253
254static int bcm_kona_wdt_stop(struct watchdog_device *wdog)
255{
256 struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
257
258 return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_EN_MASK |
259 SECWDOG_SRSTEN_MASK, 0);
260}
261
262static const struct watchdog_ops bcm_kona_wdt_ops = {
263 .owner = THIS_MODULE,
264 .start = bcm_kona_wdt_start,
265 .stop = bcm_kona_wdt_stop,
266 .set_timeout = bcm_kona_wdt_set_timeout,
267 .get_timeleft = bcm_kona_wdt_get_timeleft,
268};
269
270static const struct watchdog_info bcm_kona_wdt_info = {
271 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
272 WDIOF_KEEPALIVEPING,
273 .identity = "Broadcom Kona Watchdog Timer",
274};
275
276static struct watchdog_device bcm_kona_wdt_wdd = {
277 .info = &bcm_kona_wdt_info,
278 .ops = &bcm_kona_wdt_ops,
279 .min_timeout = 1,
280 .max_timeout = SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,
281 .timeout = SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,
282};
283
284static void bcm_kona_wdt_shutdown(struct platform_device *pdev)
285{
286 bcm_kona_wdt_stop(&bcm_kona_wdt_wdd);
287}
288
289static int bcm_kona_wdt_probe(struct platform_device *pdev)
290{
291 struct device *dev = &pdev->dev;
292 struct bcm_kona_wdt *wdt;
293 struct resource *res;
294 int ret;
295
296 wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
297 if (!wdt)
298 return -ENOMEM;
299
300 spin_lock_init(&wdt->lock);
301
302 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
303 wdt->base = devm_ioremap_resource(dev, res);
304 if (IS_ERR(wdt->base))
305 return -ENODEV;
306
307 wdt->resolution = SECWDOG_DEFAULT_RESOLUTION;
308 ret = bcm_kona_wdt_set_resolution_reg(wdt);
309 if (ret) {
310 dev_err(dev, "Failed to set resolution (error: %d)", ret);
311 return ret;
312 }
313
314 platform_set_drvdata(pdev, wdt);
315 watchdog_set_drvdata(&bcm_kona_wdt_wdd, wdt);
316 bcm_kona_wdt_wdd.parent = &pdev->dev;
317
318 ret = bcm_kona_wdt_set_timeout_reg(&bcm_kona_wdt_wdd, 0);
319 if (ret) {
320 dev_err(dev, "Failed set watchdog timeout");
321 return ret;
322 }
323
324 ret = watchdog_register_device(&bcm_kona_wdt_wdd);
325 if (ret) {
326 dev_err(dev, "Failed to register watchdog device");
327 return ret;
328 }
329
330 bcm_kona_wdt_debug_init(pdev);
331 dev_dbg(dev, "Broadcom Kona Watchdog Timer");
332
333 return 0;
334}
335
336static int bcm_kona_wdt_remove(struct platform_device *pdev)
337{
338 bcm_kona_wdt_debug_exit(pdev);
339 bcm_kona_wdt_shutdown(pdev);
340 watchdog_unregister_device(&bcm_kona_wdt_wdd);
341 dev_dbg(&pdev->dev, "Watchdog driver disabled");
342
343 return 0;
344}
345
346static const struct of_device_id bcm_kona_wdt_of_match[] = {
347 { .compatible = "brcm,kona-wdt", },
348 {},
349};
350MODULE_DEVICE_TABLE(of, bcm_kona_wdt_of_match);
351
352static struct platform_driver bcm_kona_wdt_driver = {
353 .driver = {
354 .name = BCM_KONA_WDT_NAME,
355 .of_match_table = bcm_kona_wdt_of_match,
356 },
357 .probe = bcm_kona_wdt_probe,
358 .remove = bcm_kona_wdt_remove,
359 .shutdown = bcm_kona_wdt_shutdown,
360};
361
362module_platform_driver(bcm_kona_wdt_driver);
363
364MODULE_ALIAS("platform:" BCM_KONA_WDT_NAME);
365MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");
366MODULE_DESCRIPTION("Broadcom Kona Watchdog Driver");
367MODULE_LICENSE("GPL v2");
368
