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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
26#include <asm/hardware.h>
27#include <asm/uaccess.h>
28#include <asm/io.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;
73
74static void wdt_service(void)
75{
76 spin_lock(&io_lock);
77
78
79 davinci_writel(WDKEY_SEQ0, wdt_base + WDTCR);
80
81 davinci_writel(WDKEY_SEQ1, wdt_base + WDTCR);
82
83 spin_unlock(&io_lock);
84}
85
86static void wdt_enable(void)
87{
88 u32 tgcr;
89 u32 timer_margin;
90
91 spin_lock(&io_lock);
92
93
94 davinci_writel(0, wdt_base + TCR);
95
96 davinci_writel(0, wdt_base + TGCR);
97 tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET;
98 davinci_writel(tgcr, wdt_base + TGCR);
99
100 davinci_writel(0, wdt_base + TIM12);
101 davinci_writel(0, wdt_base + TIM34);
102
103 timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) & 0xffffffff);
104 davinci_writel(timer_margin, wdt_base + PRD12);
105 timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) >> 32);
106 davinci_writel(timer_margin, wdt_base + PRD34);
107
108 davinci_writel(ENAMODE12_PERIODIC, wdt_base + TCR);
109
110
111
112
113
114 davinci_writel(WDKEY_SEQ0 | WDEN, wdt_base + WDTCR);
115
116 davinci_writel(WDKEY_SEQ1 | WDEN, wdt_base + WDTCR);
117
118 spin_unlock(&io_lock);
119}
120
121static int davinci_wdt_open(struct inode *inode, struct file *file)
122{
123 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
124 return -EBUSY;
125
126 wdt_enable();
127
128 return nonseekable_open(inode, file);
129}
130
131static ssize_t
132davinci_wdt_write(struct file *file, const char *data, size_t len,
133 loff_t *ppos)
134{
135 if (len)
136 wdt_service();
137
138 return len;
139}
140
141static struct watchdog_info ident = {
142 .options = WDIOF_KEEPALIVEPING,
143 .identity = "DaVinci Watchdog",
144};
145
146static int
147davinci_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
148 unsigned long arg)
149{
150 int ret = -ENOTTY;
151
152 switch (cmd) {
153 case WDIOC_GETSUPPORT:
154 ret = copy_to_user((struct watchdog_info *)arg, &ident,
155 sizeof(ident)) ? -EFAULT : 0;
156 break;
157
158 case WDIOC_GETSTATUS:
159 case WDIOC_GETBOOTSTATUS:
160 ret = put_user(0, (int *)arg);
161 break;
162
163 case WDIOC_GETTIMEOUT:
164 ret = put_user(heartbeat, (int *)arg);
165 break;
166
167 case WDIOC_KEEPALIVE:
168 wdt_service();
169 ret = 0;
170 break;
171 }
172 return ret;
173}
174
175static int davinci_wdt_release(struct inode *inode, struct file *file)
176{
177 wdt_service();
178 clear_bit(WDT_IN_USE, &wdt_status);
179
180 return 0;
181}
182
183static const struct file_operations davinci_wdt_fops = {
184 .owner = THIS_MODULE,
185 .llseek = no_llseek,
186 .write = davinci_wdt_write,
187 .ioctl = davinci_wdt_ioctl,
188 .open = davinci_wdt_open,
189 .release = davinci_wdt_release,
190};
191
192static struct miscdevice davinci_wdt_miscdev = {
193 .minor = WATCHDOG_MINOR,
194 .name = "watchdog",
195 .fops = &davinci_wdt_fops,
196};
197
198static int davinci_wdt_probe(struct platform_device *pdev)
199{
200 int ret = 0, size;
201 struct resource *res;
202
203 if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
204 heartbeat = DEFAULT_HEARTBEAT;
205
206 printk(KERN_INFO MODULE_NAME
207 "DaVinci Watchdog Timer: heartbeat %d sec\n", heartbeat);
208
209 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
210 if (res == NULL) {
211 printk(KERN_INFO MODULE_NAME
212 "failed to get memory region resource\n");
213 return -ENOENT;
214 }
215
216 size = res->end - res->start + 1;
217 wdt_mem = request_mem_region(res->start, size, pdev->name);
218
219 if (wdt_mem == NULL) {
220 printk(KERN_INFO MODULE_NAME "failed to get memory region\n");
221 return -ENOENT;
222 }
223 wdt_base = (void __iomem *)(res->start);
224
225 ret = misc_register(&davinci_wdt_miscdev);
226 if (ret < 0) {
227 printk(KERN_ERR MODULE_NAME "cannot register misc device\n");
228 release_resource(wdt_mem);
229 kfree(wdt_mem);
230 } else {
231 set_bit(WDT_DEVICE_INITED, &wdt_status);
232 }
233
234 return ret;
235}
236
237static int davinci_wdt_remove(struct platform_device *pdev)
238{
239 misc_deregister(&davinci_wdt_miscdev);
240 if (wdt_mem) {
241 release_resource(wdt_mem);
242 kfree(wdt_mem);
243 wdt_mem = NULL;
244 }
245 return 0;
246}
247
248static struct platform_driver platform_wdt_driver = {
249 .driver = {
250 .name = "watchdog",
251 },
252 .probe = davinci_wdt_probe,
253 .remove = davinci_wdt_remove,
254};
255
256static int __init davinci_wdt_init(void)
257{
258 return platform_driver_register(&platform_wdt_driver);
259}
260
261static void __exit davinci_wdt_exit(void)
262{
263 platform_driver_unregister(&platform_wdt_driver);
264}
265
266module_init(davinci_wdt_init);
267module_exit(davinci_wdt_exit);
268
269MODULE_AUTHOR("Texas Instruments");
270MODULE_DESCRIPTION("DaVinci Watchdog Driver");
271
272module_param(heartbeat, int, 0);
273MODULE_PARM_DESC(heartbeat,
274 "Watchdog heartbeat period in seconds from 1 to "
275 __MODULE_STRING(MAX_HEARTBEAT) ", default "
276 __MODULE_STRING(DEFAULT_HEARTBEAT));
277
278MODULE_LICENSE("GPL");
279MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
280
