1
2
3
4
5
6
7
8
9
10
11
12
13
14#include <linux/debugfs.h>
15#include <linux/delay.h>
16#include <linux/err.h>
17#include <linux/io.h>
18#include <linux/module.h>
19#include <linux/of_address.h>
20#include <linux/platform_device.h>
21#include <linux/watchdog.h>
22
23#define SECWDOG_CTRL_REG 0x00000000
24#define SECWDOG_COUNT_REG 0x00000004
25
26#define SECWDOG_RESERVED_MASK 0x1dffffff
27#define SECWDOG_WD_LOAD_FLAG 0x10000000
28#define SECWDOG_EN_MASK 0x08000000
29#define SECWDOG_SRSTEN_MASK 0x04000000
30#define SECWDOG_RES_MASK 0x00f00000
31#define SECWDOG_COUNT_MASK 0x000fffff
32
33#define SECWDOG_MAX_COUNT SECWDOG_COUNT_MASK
34#define SECWDOG_CLKS_SHIFT 20
35#define SECWDOG_MAX_RES 15
36#define SECWDOG_DEFAULT_RESOLUTION 4
37#define SECWDOG_MAX_TRY 1000
38
39#define SECS_TO_TICKS(x, w) ((x) << (w)->resolution)
40#define TICKS_TO_SECS(x, w) ((x) >> (w)->resolution)
41
42#define BCM_KONA_WDT_NAME "bcm_kona_wdt"
43
44struct bcm_kona_wdt {
45 void __iomem *base;
46
47
48
49
50
51
52
53
54
55
56
57 int resolution;
58 spinlock_t lock;
59#ifdef CONFIG_BCM_KONA_WDT_DEBUG
60 unsigned long busy_count;
61 struct dentry *debugfs;
62#endif
63};
64
65static int secure_register_read(struct bcm_kona_wdt *wdt, uint32_t offset)
66{
67 uint32_t val;
68 unsigned count = 0;
69
70
71
72
73
74
75 do {
76 if (unlikely(count > 1))
77 udelay(5);
78 val = readl_relaxed(wdt->base + offset);
79 count++;
80 } while ((val & SECWDOG_WD_LOAD_FLAG) && count < SECWDOG_MAX_TRY);
81
82#ifdef CONFIG_BCM_KONA_WDT_DEBUG
83
84 if (count > wdt->busy_count)
85 wdt->busy_count = count;
86#endif
87
88
89 if (val & SECWDOG_WD_LOAD_FLAG)
90 return -ETIMEDOUT;
91
92
93 val &= SECWDOG_RESERVED_MASK;
94
95 return val;
96}
97
98#ifdef CONFIG_BCM_KONA_WDT_DEBUG
99
100static int bcm_kona_wdt_dbg_show(struct seq_file *s, void *data)
101{
102 int ctl_val, cur_val;
103 unsigned long flags;
104 struct bcm_kona_wdt *wdt = s->private;
105
106 if (!wdt) {
107 seq_puts(s, "No device pointer\n");
108 return 0;
109 }
110
111 spin_lock_irqsave(&wdt->lock, flags);
112 ctl_val = secure_register_read(wdt, SECWDOG_CTRL_REG);
113 cur_val = secure_register_read(wdt, SECWDOG_COUNT_REG);
114 spin_unlock_irqrestore(&wdt->lock, flags);
115
116 if (ctl_val < 0 || cur_val < 0) {
117 seq_puts(s, "Error accessing hardware\n");
118 } else {
119 int ctl, cur, ctl_sec, cur_sec, res;
120
121 ctl = ctl_val & SECWDOG_COUNT_MASK;
122 res = (ctl_val & SECWDOG_RES_MASK) >> SECWDOG_CLKS_SHIFT;
123 cur = cur_val & SECWDOG_COUNT_MASK;
124 ctl_sec = TICKS_TO_SECS(ctl, wdt);
125 cur_sec = TICKS_TO_SECS(cur, wdt);
126 seq_printf(s,
127 "Resolution: %d / %d\n"
128 "Control: %d s / %d (%#x) ticks\n"
129 "Current: %d s / %d (%#x) ticks\n"
130 "Busy count: %lu\n",
131 res, wdt->resolution,
132 ctl_sec, ctl, ctl,
133 cur_sec, cur, cur,
134 wdt->busy_count);
135 }
136
137 return 0;
138}
139
140static int bcm_kona_dbg_open(struct inode *inode, struct file *file)
141{
142 return single_open(file, bcm_kona_wdt_dbg_show, inode->i_private);
143}
144
145static const struct file_operations bcm_kona_dbg_operations = {
146 .open = bcm_kona_dbg_open,
147 .read = seq_read,
148 .llseek = seq_lseek,
149 .release = single_release,
150};
151
152static void bcm_kona_wdt_debug_init(struct platform_device *pdev)
153{
154 struct dentry *dir;
155 struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);
156
157 if (!wdt)
158 return;
159
160 wdt->debugfs = NULL;
161
162 dir = debugfs_create_dir(BCM_KONA_WDT_NAME, NULL);
163 if (IS_ERR_OR_NULL(dir))
164 return;
165
166 if (debugfs_create_file("info", S_IFREG | S_IRUGO, dir, wdt,
167 &bcm_kona_dbg_operations))
168 wdt->debugfs = dir;
169 else
170 debugfs_remove_recursive(dir);
171}
172
173static void bcm_kona_wdt_debug_exit(struct platform_device *pdev)
174{
175 struct bcm_kona_wdt *wdt = platform_get_drvdata(pdev);
176
177 if (wdt && wdt->debugfs) {
178 debugfs_remove_recursive(wdt->debugfs);
179 wdt->debugfs = NULL;
180 }
181}
182
183#else
184
185static void bcm_kona_wdt_debug_init(struct platform_device *pdev) {}
186static void bcm_kona_wdt_debug_exit(struct platform_device *pdev) {}
187
188#endif
189
190static int bcm_kona_wdt_ctrl_reg_modify(struct bcm_kona_wdt *wdt,
191 unsigned mask, unsigned newval)
192{
193 int val;
194 unsigned long flags;
195 int ret = 0;
196
197 spin_lock_irqsave(&wdt->lock, flags);
198
199 val = secure_register_read(wdt, SECWDOG_CTRL_REG);
200 if (val < 0) {
201 ret = val;
202 } else {
203 val &= ~mask;
204 val |= newval;
205 writel_relaxed(val, wdt->base + SECWDOG_CTRL_REG);
206 }
207
208 spin_unlock_irqrestore(&wdt->lock, flags);
209
210 return ret;
211}
212
213static int bcm_kona_wdt_set_resolution_reg(struct bcm_kona_wdt *wdt)
214{
215 if (wdt->resolution > SECWDOG_MAX_RES)
216 return -EINVAL;
217
218 return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_RES_MASK,
219 wdt->resolution << SECWDOG_CLKS_SHIFT);
220}
221
222static int bcm_kona_wdt_set_timeout_reg(struct watchdog_device *wdog,
223 unsigned watchdog_flags)
224{
225 struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
226
227 return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_COUNT_MASK,
228 SECS_TO_TICKS(wdog->timeout, wdt) |
229 watchdog_flags);
230}
231
232static int bcm_kona_wdt_set_timeout(struct watchdog_device *wdog,
233 unsigned int t)
234{
235 wdog->timeout = t;
236 return 0;
237}
238
239static unsigned int bcm_kona_wdt_get_timeleft(struct watchdog_device *wdog)
240{
241 struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
242 int val;
243 unsigned long flags;
244
245 spin_lock_irqsave(&wdt->lock, flags);
246 val = secure_register_read(wdt, SECWDOG_COUNT_REG);
247 spin_unlock_irqrestore(&wdt->lock, flags);
248
249 if (val < 0)
250 return val;
251
252 return TICKS_TO_SECS(val & SECWDOG_COUNT_MASK, wdt);
253}
254
255static int bcm_kona_wdt_start(struct watchdog_device *wdog)
256{
257 return bcm_kona_wdt_set_timeout_reg(wdog,
258 SECWDOG_EN_MASK | SECWDOG_SRSTEN_MASK);
259}
260
261static int bcm_kona_wdt_stop(struct watchdog_device *wdog)
262{
263 struct bcm_kona_wdt *wdt = watchdog_get_drvdata(wdog);
264
265 return bcm_kona_wdt_ctrl_reg_modify(wdt, SECWDOG_EN_MASK |
266 SECWDOG_SRSTEN_MASK, 0);
267}
268
269static const struct watchdog_ops bcm_kona_wdt_ops = {
270 .owner = THIS_MODULE,
271 .start = bcm_kona_wdt_start,
272 .stop = bcm_kona_wdt_stop,
273 .set_timeout = bcm_kona_wdt_set_timeout,
274 .get_timeleft = bcm_kona_wdt_get_timeleft,
275};
276
277static const struct watchdog_info bcm_kona_wdt_info = {
278 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
279 WDIOF_KEEPALIVEPING,
280 .identity = "Broadcom Kona Watchdog Timer",
281};
282
283static struct watchdog_device bcm_kona_wdt_wdd = {
284 .info = &bcm_kona_wdt_info,
285 .ops = &bcm_kona_wdt_ops,
286 .min_timeout = 1,
287 .max_timeout = SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,
288 .timeout = SECWDOG_MAX_COUNT >> SECWDOG_DEFAULT_RESOLUTION,
289};
290
291static void bcm_kona_wdt_shutdown(struct platform_device *pdev)
292{
293 bcm_kona_wdt_stop(&bcm_kona_wdt_wdd);
294}
295
296static int bcm_kona_wdt_probe(struct platform_device *pdev)
297{
298 struct device *dev = &pdev->dev;
299 struct bcm_kona_wdt *wdt;
300 struct resource *res;
301 int ret;
302
303 wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
304 if (!wdt)
305 return -ENOMEM;
306
307 spin_lock_init(&wdt->lock);
308
309 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
310 wdt->base = devm_ioremap_resource(dev, res);
311 if (IS_ERR(wdt->base))
312 return -ENODEV;
313
314 wdt->resolution = SECWDOG_DEFAULT_RESOLUTION;
315 ret = bcm_kona_wdt_set_resolution_reg(wdt);
316 if (ret) {
317 dev_err(dev, "Failed to set resolution (error: %d)", ret);
318 return ret;
319 }
320
321 platform_set_drvdata(pdev, wdt);
322 watchdog_set_drvdata(&bcm_kona_wdt_wdd, wdt);
323 bcm_kona_wdt_wdd.parent = &pdev->dev;
324
325 ret = bcm_kona_wdt_set_timeout_reg(&bcm_kona_wdt_wdd, 0);
326 if (ret) {
327 dev_err(dev, "Failed set watchdog timeout");
328 return ret;
329 }
330
331 ret = watchdog_register_device(&bcm_kona_wdt_wdd);
332 if (ret) {
333 dev_err(dev, "Failed to register watchdog device");
334 return ret;
335 }
336
337 bcm_kona_wdt_debug_init(pdev);
338 dev_dbg(dev, "Broadcom Kona Watchdog Timer");
339
340 return 0;
341}
342
343static int bcm_kona_wdt_remove(struct platform_device *pdev)
344{
345 bcm_kona_wdt_debug_exit(pdev);
346 bcm_kona_wdt_shutdown(pdev);
347 watchdog_unregister_device(&bcm_kona_wdt_wdd);
348 dev_dbg(&pdev->dev, "Watchdog driver disabled");
349
350 return 0;
351}
352
353static const struct of_device_id bcm_kona_wdt_of_match[] = {
354 { .compatible = "brcm,kona-wdt", },
355 {},
356};
357MODULE_DEVICE_TABLE(of, bcm_kona_wdt_of_match);
358
359static struct platform_driver bcm_kona_wdt_driver = {
360 .driver = {
361 .name = BCM_KONA_WDT_NAME,
362 .of_match_table = bcm_kona_wdt_of_match,
363 },
364 .probe = bcm_kona_wdt_probe,
365 .remove = bcm_kona_wdt_remove,
366 .shutdown = bcm_kona_wdt_shutdown,
367};
368
369module_platform_driver(bcm_kona_wdt_driver);
370
371MODULE_ALIAS("platform:" BCM_KONA_WDT_NAME);
372MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");
373MODULE_DESCRIPTION("Broadcom Kona Watchdog Driver");
374MODULE_LICENSE("GPL v2");
375
