1
2
3
4
5
6
7
8
9
10
11
12
13
14#include <linux/module.h>
15#include <linux/moduleparam.h>
16#include <linux/types.h>
17#include <linux/kernel.h>
18#include <linux/fs.h>
19#include <linux/miscdevice.h>
20#include <linux/watchdog.h>
21#include <linux/init.h>
22#include <linux/bitops.h>
23#include <linux/platform_device.h>
24#include <linux/spinlock.h>
25#include <linux/uaccess.h>
26#include <linux/io.h>
27#include <linux/device.h>
28#include <linux/clk.h>
29
30#define MODULE_NAME "DAVINCI-WDT: "
31
32#define DEFAULT_HEARTBEAT 60
33#define MAX_HEARTBEAT 600
34
35
36#define PID12 (0x0)
37#define EMUMGT (0x4)
38#define TIM12 (0x10)
39#define TIM34 (0x14)
40#define PRD12 (0x18)
41#define PRD34 (0x1C)
42#define TCR (0x20)
43#define TGCR (0x24)
44#define WDTCR (0x28)
45
46
47#define ENAMODE12_DISABLED (0 << 6)
48#define ENAMODE12_ONESHOT (1 << 6)
49#define ENAMODE12_PERIODIC (2 << 6)
50
51
52#define TIM12RS_UNRESET (1 << 0)
53#define TIM34RS_UNRESET (1 << 1)
54#define TIMMODE_64BIT_WDOG (2 << 2)
55
56
57#define WDEN (1 << 14)
58#define WDFLAG (1 << 15)
59#define WDKEY_SEQ0 (0xa5c6 << 16)
60#define WDKEY_SEQ1 (0xda7e << 16)
61
62static int heartbeat = DEFAULT_HEARTBEAT;
63
64static DEFINE_SPINLOCK(io_lock);
65static unsigned long wdt_status;
66#define WDT_IN_USE 0
67#define WDT_OK_TO_CLOSE 1
68#define WDT_REGION_INITED 2
69#define WDT_DEVICE_INITED 3
70
71static struct resource *wdt_mem;
72static void __iomem *wdt_base;
73struct clk *wdt_clk;
74
75static void wdt_service(void)
76{
77 spin_lock(&io_lock);
78
79
80 iowrite32(WDKEY_SEQ0, wdt_base + WDTCR);
81
82 iowrite32(WDKEY_SEQ1, wdt_base + WDTCR);
83
84 spin_unlock(&io_lock);
85}
86
87static void wdt_enable(void)
88{
89 u32 tgcr;
90 u32 timer_margin;
91 unsigned long wdt_freq;
92
93 wdt_freq = clk_get_rate(wdt_clk);
94
95 spin_lock(&io_lock);
96
97
98 iowrite32(0, wdt_base + TCR);
99
100 iowrite32(0, wdt_base + TGCR);
101 tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET;
102 iowrite32(tgcr, wdt_base + TGCR);
103
104 iowrite32(0, wdt_base + TIM12);
105 iowrite32(0, wdt_base + TIM34);
106
107 timer_margin = (((u64)heartbeat * wdt_freq) & 0xffffffff);
108 iowrite32(timer_margin, wdt_base + PRD12);
109 timer_margin = (((u64)heartbeat * wdt_freq) >> 32);
110 iowrite32(timer_margin, wdt_base + PRD34);
111
112 iowrite32(ENAMODE12_PERIODIC, wdt_base + TCR);
113
114
115
116
117
118 iowrite32(WDKEY_SEQ0 | WDEN, wdt_base + WDTCR);
119
120 iowrite32(WDKEY_SEQ1 | WDEN, wdt_base + WDTCR);
121
122 spin_unlock(&io_lock);
123}
124
125static int davinci_wdt_open(struct inode *inode, struct file *file)
126{
127 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
128 return -EBUSY;
129
130 wdt_enable();
131
132 return nonseekable_open(inode, file);
133}
134
135static ssize_t
136davinci_wdt_write(struct file *file, const char *data, size_t len,
137 loff_t *ppos)
138{
139 if (len)
140 wdt_service();
141
142 return len;
143}
144
145static struct watchdog_info ident = {
146 .options = WDIOF_KEEPALIVEPING,
147 .identity = "DaVinci Watchdog",
148};
149
150static long davinci_wdt_ioctl(struct file *file,
151 unsigned int cmd, unsigned long arg)
152{
153 int ret = -ENOTTY;
154
155 switch (cmd) {
156 case WDIOC_GETSUPPORT:
157 ret = copy_to_user((struct watchdog_info *)arg, &ident,
158 sizeof(ident)) ? -EFAULT : 0;
159 break;
160
161 case WDIOC_GETSTATUS:
162 case WDIOC_GETBOOTSTATUS:
163 ret = put_user(0, (int *)arg);
164 break;
165
166 case WDIOC_KEEPALIVE:
167 wdt_service();
168 ret = 0;
169 break;
170
171 case WDIOC_GETTIMEOUT:
172 ret = put_user(heartbeat, (int *)arg);
173 break;
174 }
175 return ret;
176}
177
178static int davinci_wdt_release(struct inode *inode, struct file *file)
179{
180 wdt_service();
181 clear_bit(WDT_IN_USE, &wdt_status);
182
183 return 0;
184}
185
186static const struct file_operations davinci_wdt_fops = {
187 .owner = THIS_MODULE,
188 .llseek = no_llseek,
189 .write = davinci_wdt_write,
190 .unlocked_ioctl = davinci_wdt_ioctl,
191 .open = davinci_wdt_open,
192 .release = davinci_wdt_release,
193};
194
195static struct miscdevice davinci_wdt_miscdev = {
196 .minor = WATCHDOG_MINOR,
197 .name = "watchdog",
198 .fops = &davinci_wdt_fops,
199};
200
201static int __devinit davinci_wdt_probe(struct platform_device *pdev)
202{
203 int ret = 0, size;
204 struct resource *res;
205 struct device *dev = &pdev->dev;
206
207 wdt_clk = clk_get(dev, NULL);
208 if (WARN_ON(IS_ERR(wdt_clk)))
209 return PTR_ERR(wdt_clk);
210
211 clk_enable(wdt_clk);
212
213 if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
214 heartbeat = DEFAULT_HEARTBEAT;
215
216 dev_info(dev, "heartbeat %d sec\n", heartbeat);
217
218 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
219 if (res == NULL) {
220 dev_err(dev, "failed to get memory region resource\n");
221 return -ENOENT;
222 }
223
224 size = res->end - res->start + 1;
225 wdt_mem = request_mem_region(res->start, size, pdev->name);
226
227 if (wdt_mem == NULL) {
228 dev_err(dev, "failed to get memory region\n");
229 return -ENOENT;
230 }
231
232 wdt_base = ioremap(res->start, size);
233 if (!wdt_base) {
234 dev_err(dev, "failed to map memory region\n");
235 return -ENOMEM;
236 }
237
238 ret = misc_register(&davinci_wdt_miscdev);
239 if (ret < 0) {
240 dev_err(dev, "cannot register misc device\n");
241 release_resource(wdt_mem);
242 kfree(wdt_mem);
243 } else {
244 set_bit(WDT_DEVICE_INITED, &wdt_status);
245 }
246
247 iounmap(wdt_base);
248 return ret;
249}
250
251static int __devexit davinci_wdt_remove(struct platform_device *pdev)
252{
253 misc_deregister(&davinci_wdt_miscdev);
254 if (wdt_mem) {
255 release_resource(wdt_mem);
256 kfree(wdt_mem);
257 wdt_mem = NULL;
258 }
259
260 clk_disable(wdt_clk);
261 clk_put(wdt_clk);
262
263 return 0;
264}
265
266static struct platform_driver platform_wdt_driver = {
267 .driver = {
268 .name = "watchdog",
269 .owner = THIS_MODULE,
270 },
271 .probe = davinci_wdt_probe,
272 .remove = __devexit_p(davinci_wdt_remove),
273};
274
275static int __init davinci_wdt_init(void)
276{
277 return platform_driver_register(&platform_wdt_driver);
278}
279
280static void __exit davinci_wdt_exit(void)
281{
282 platform_driver_unregister(&platform_wdt_driver);
283}
284
285module_init(davinci_wdt_init);
286module_exit(davinci_wdt_exit);
287
288MODULE_AUTHOR("Texas Instruments");
289MODULE_DESCRIPTION("DaVinci Watchdog Driver");
290
291module_param(heartbeat, int, 0);
292MODULE_PARM_DESC(heartbeat,
293 "Watchdog heartbeat period in seconds from 1 to "
294 __MODULE_STRING(MAX_HEARTBEAT) ", default "
295 __MODULE_STRING(DEFAULT_HEARTBEAT));
296
297MODULE_LICENSE("GPL");
298MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
299MODULE_ALIAS("platform:watchdog");
300
