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7d831bf5 VB |
1 | /* |
2 | * drivers/char/watchdog/davinci_wdt.c | |
3 | * | |
4 | * Watchdog driver for DaVinci DM644x/DM646x processors | |
5 | * | |
6 | * Copyright (C) 2006 Texas Instruments. | |
7 | * | |
8 | * 2007 (c) MontaVista Software, Inc. This file is licensed under | |
9 | * the terms of the GNU General Public License version 2. This program | |
10 | * is licensed "as is" without any warranty of any kind, whether express | |
11 | * or implied. | |
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> | |
f78b0a8f AC |
25 | #include <linux/uaccess.h> |
26 | #include <linux/io.h> | |
a09e64fb | 27 | #include <mach/hardware.h> |
7d831bf5 VB |
28 | |
29 | #define MODULE_NAME "DAVINCI-WDT: " | |
30 | ||
31 | #define DEFAULT_HEARTBEAT 60 | |
32 | #define MAX_HEARTBEAT 600 /* really the max margin is 264/27MHz*/ | |
33 | ||
34 | /* Timer register set definition */ | |
35 | #define PID12 (0x0) | |
36 | #define EMUMGT (0x4) | |
37 | #define TIM12 (0x10) | |
38 | #define TIM34 (0x14) | |
39 | #define PRD12 (0x18) | |
40 | #define PRD34 (0x1C) | |
41 | #define TCR (0x20) | |
42 | #define TGCR (0x24) | |
43 | #define WDTCR (0x28) | |
44 | ||
45 | /* TCR bit definitions */ | |
46 | #define ENAMODE12_DISABLED (0 << 6) | |
47 | #define ENAMODE12_ONESHOT (1 << 6) | |
48 | #define ENAMODE12_PERIODIC (2 << 6) | |
49 | ||
50 | /* TGCR bit definitions */ | |
51 | #define TIM12RS_UNRESET (1 << 0) | |
52 | #define TIM34RS_UNRESET (1 << 1) | |
53 | #define TIMMODE_64BIT_WDOG (2 << 2) | |
54 | ||
55 | /* WDTCR bit definitions */ | |
56 | #define WDEN (1 << 14) | |
57 | #define WDFLAG (1 << 15) | |
58 | #define WDKEY_SEQ0 (0xa5c6 << 16) | |
59 | #define WDKEY_SEQ1 (0xda7e << 16) | |
60 | ||
61 | static int heartbeat = DEFAULT_HEARTBEAT; | |
62 | ||
c7dfd0cc | 63 | static DEFINE_SPINLOCK(io_lock); |
7d831bf5 VB |
64 | static unsigned long wdt_status; |
65 | #define WDT_IN_USE 0 | |
66 | #define WDT_OK_TO_CLOSE 1 | |
67 | #define WDT_REGION_INITED 2 | |
68 | #define WDT_DEVICE_INITED 3 | |
69 | ||
70 | static struct resource *wdt_mem; | |
71 | static void __iomem *wdt_base; | |
72 | ||
73 | static void wdt_service(void) | |
74 | { | |
75 | spin_lock(&io_lock); | |
76 | ||
77 | /* put watchdog in service state */ | |
78 | davinci_writel(WDKEY_SEQ0, wdt_base + WDTCR); | |
79 | /* put watchdog in active state */ | |
80 | davinci_writel(WDKEY_SEQ1, wdt_base + WDTCR); | |
81 | ||
82 | spin_unlock(&io_lock); | |
83 | } | |
84 | ||
85 | static void wdt_enable(void) | |
86 | { | |
87 | u32 tgcr; | |
88 | u32 timer_margin; | |
89 | ||
90 | spin_lock(&io_lock); | |
91 | ||
92 | /* disable, internal clock source */ | |
93 | davinci_writel(0, wdt_base + TCR); | |
94 | /* reset timer, set mode to 64-bit watchdog, and unreset */ | |
95 | davinci_writel(0, wdt_base + TGCR); | |
96 | tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET; | |
97 | davinci_writel(tgcr, wdt_base + TGCR); | |
98 | /* clear counter regs */ | |
99 | davinci_writel(0, wdt_base + TIM12); | |
100 | davinci_writel(0, wdt_base + TIM34); | |
101 | /* set timeout period */ | |
102 | timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) & 0xffffffff); | |
103 | davinci_writel(timer_margin, wdt_base + PRD12); | |
104 | timer_margin = (((u64)heartbeat * CLOCK_TICK_RATE) >> 32); | |
105 | davinci_writel(timer_margin, wdt_base + PRD34); | |
106 | /* enable run continuously */ | |
107 | davinci_writel(ENAMODE12_PERIODIC, wdt_base + TCR); | |
108 | /* Once the WDT is in pre-active state write to | |
109 | * TIM12, TIM34, PRD12, PRD34, TCR, TGCR, WDTCR are | |
110 | * write protected (except for the WDKEY field) | |
111 | */ | |
112 | /* put watchdog in pre-active state */ | |
113 | davinci_writel(WDKEY_SEQ0 | WDEN, wdt_base + WDTCR); | |
114 | /* put watchdog in active state */ | |
115 | davinci_writel(WDKEY_SEQ1 | WDEN, wdt_base + WDTCR); | |
116 | ||
117 | spin_unlock(&io_lock); | |
118 | } | |
119 | ||
120 | static int davinci_wdt_open(struct inode *inode, struct file *file) | |
121 | { | |
122 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) | |
123 | return -EBUSY; | |
124 | ||
125 | wdt_enable(); | |
126 | ||
127 | return nonseekable_open(inode, file); | |
128 | } | |
129 | ||
130 | static ssize_t | |
131 | davinci_wdt_write(struct file *file, const char *data, size_t len, | |
132 | loff_t *ppos) | |
133 | { | |
7d831bf5 VB |
134 | if (len) |
135 | wdt_service(); | |
136 | ||
137 | return len; | |
138 | } | |
139 | ||
140 | static struct watchdog_info ident = { | |
f1a08cc9 | 141 | .options = WDIOF_KEEPALIVEPING, |
7d831bf5 VB |
142 | .identity = "DaVinci Watchdog", |
143 | }; | |
144 | ||
f78b0a8f AC |
145 | static long davinci_wdt_ioctl(struct file *file, |
146 | unsigned int cmd, unsigned long arg) | |
7d831bf5 VB |
147 | { |
148 | int ret = -ENOTTY; | |
149 | ||
150 | switch (cmd) { | |
151 | case WDIOC_GETSUPPORT: | |
152 | ret = copy_to_user((struct watchdog_info *)arg, &ident, | |
153 | sizeof(ident)) ? -EFAULT : 0; | |
154 | break; | |
155 | ||
156 | case WDIOC_GETSTATUS: | |
f1a08cc9 | 157 | case WDIOC_GETBOOTSTATUS: |
7d831bf5 VB |
158 | ret = put_user(0, (int *)arg); |
159 | break; | |
160 | ||
7d831bf5 VB |
161 | case WDIOC_KEEPALIVE: |
162 | wdt_service(); | |
163 | ret = 0; | |
164 | break; | |
0c06090c WVS |
165 | |
166 | case WDIOC_GETTIMEOUT: | |
167 | ret = put_user(heartbeat, (int *)arg); | |
168 | break; | |
7d831bf5 VB |
169 | } |
170 | return ret; | |
171 | } | |
172 | ||
173 | static int davinci_wdt_release(struct inode *inode, struct file *file) | |
174 | { | |
175 | wdt_service(); | |
176 | clear_bit(WDT_IN_USE, &wdt_status); | |
177 | ||
178 | return 0; | |
179 | } | |
180 | ||
181 | static const struct file_operations davinci_wdt_fops = { | |
182 | .owner = THIS_MODULE, | |
183 | .llseek = no_llseek, | |
184 | .write = davinci_wdt_write, | |
f78b0a8f | 185 | .unlocked_ioctl = davinci_wdt_ioctl, |
7d831bf5 VB |
186 | .open = davinci_wdt_open, |
187 | .release = davinci_wdt_release, | |
188 | }; | |
189 | ||
190 | static struct miscdevice davinci_wdt_miscdev = { | |
191 | .minor = WATCHDOG_MINOR, | |
192 | .name = "watchdog", | |
193 | .fops = &davinci_wdt_fops, | |
194 | }; | |
195 | ||
196 | static int davinci_wdt_probe(struct platform_device *pdev) | |
197 | { | |
198 | int ret = 0, size; | |
199 | struct resource *res; | |
200 | ||
7d831bf5 VB |
201 | if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT) |
202 | heartbeat = DEFAULT_HEARTBEAT; | |
203 | ||
204 | printk(KERN_INFO MODULE_NAME | |
205 | "DaVinci Watchdog Timer: heartbeat %d sec\n", heartbeat); | |
206 | ||
207 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
208 | if (res == NULL) { | |
209 | printk(KERN_INFO MODULE_NAME | |
210 | "failed to get memory region resource\n"); | |
211 | return -ENOENT; | |
212 | } | |
213 | ||
214 | size = res->end - res->start + 1; | |
215 | wdt_mem = request_mem_region(res->start, size, pdev->name); | |
216 | ||
217 | if (wdt_mem == NULL) { | |
218 | printk(KERN_INFO MODULE_NAME "failed to get memory region\n"); | |
219 | return -ENOENT; | |
220 | } | |
221 | wdt_base = (void __iomem *)(res->start); | |
222 | ||
223 | ret = misc_register(&davinci_wdt_miscdev); | |
224 | if (ret < 0) { | |
225 | printk(KERN_ERR MODULE_NAME "cannot register misc device\n"); | |
226 | release_resource(wdt_mem); | |
227 | kfree(wdt_mem); | |
228 | } else { | |
229 | set_bit(WDT_DEVICE_INITED, &wdt_status); | |
230 | } | |
231 | ||
232 | return ret; | |
233 | } | |
234 | ||
235 | static int davinci_wdt_remove(struct platform_device *pdev) | |
236 | { | |
237 | misc_deregister(&davinci_wdt_miscdev); | |
238 | if (wdt_mem) { | |
239 | release_resource(wdt_mem); | |
240 | kfree(wdt_mem); | |
241 | wdt_mem = NULL; | |
242 | } | |
243 | return 0; | |
244 | } | |
245 | ||
246 | static struct platform_driver platform_wdt_driver = { | |
247 | .driver = { | |
248 | .name = "watchdog", | |
f37d193c | 249 | .owner = THIS_MODULE, |
7d831bf5 VB |
250 | }, |
251 | .probe = davinci_wdt_probe, | |
252 | .remove = davinci_wdt_remove, | |
253 | }; | |
254 | ||
255 | static int __init davinci_wdt_init(void) | |
256 | { | |
257 | return platform_driver_register(&platform_wdt_driver); | |
258 | } | |
259 | ||
260 | static void __exit davinci_wdt_exit(void) | |
261 | { | |
bb0a38d8 | 262 | platform_driver_unregister(&platform_wdt_driver); |
7d831bf5 VB |
263 | } |
264 | ||
265 | module_init(davinci_wdt_init); | |
266 | module_exit(davinci_wdt_exit); | |
267 | ||
268 | MODULE_AUTHOR("Texas Instruments"); | |
269 | MODULE_DESCRIPTION("DaVinci Watchdog Driver"); | |
270 | ||
271 | module_param(heartbeat, int, 0); | |
272 | MODULE_PARM_DESC(heartbeat, | |
273 | "Watchdog heartbeat period in seconds from 1 to " | |
274 | __MODULE_STRING(MAX_HEARTBEAT) ", default " | |
275 | __MODULE_STRING(DEFAULT_HEARTBEAT)); | |
276 | ||
277 | MODULE_LICENSE("GPL"); | |
278 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
f37d193c | 279 | MODULE_ALIAS("platform:watchdog"); |