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3be10211 JC |
1 | /* |
2 | * mv64x60_wdt.c - MV64X60 (Marvell Discovery) watchdog userspace interface | |
3 | * | |
4 | * Author: James Chapman <jchapman@katalix.com> | |
5 | * | |
6 | * Platform-specific setup code should configure the dog to generate | |
7 | * interrupt or reset as required. This code only enables/disables | |
8 | * and services the watchdog. | |
9 | * | |
10 | * Derived from mpc8xx_wdt.c, with the following copyright. | |
11 | * | |
12 | * 2002 (c) Florian Schirmer <jolt@tuxbox.org> This file is licensed under | |
13 | * the terms of the GNU General Public License version 2. This program | |
14 | * is licensed "as is" without any warranty of any kind, whether express | |
15 | * or implied. | |
16 | */ | |
17 | ||
3be10211 JC |
18 | #include <linux/fs.h> |
19 | #include <linux/init.h> | |
20 | #include <linux/kernel.h> | |
21 | #include <linux/miscdevice.h> | |
22 | #include <linux/module.h> | |
23 | #include <linux/watchdog.h> | |
d052d1be RK |
24 | #include <linux/platform_device.h> |
25 | ||
7e07a159 | 26 | #include <linux/mv643xx.h> |
3be10211 JC |
27 | #include <asm/uaccess.h> |
28 | #include <asm/io.h> | |
29 | ||
8a5cfa64 DF |
30 | #define MV64x60_WDT_WDC_OFFSET 0 |
31 | ||
3be10211 JC |
32 | /* MV64x60 WDC (config) register access definitions */ |
33 | #define MV64x60_WDC_CTL1_MASK (3 << 24) | |
34 | #define MV64x60_WDC_CTL1(val) ((val & 3) << 24) | |
35 | #define MV64x60_WDC_CTL2_MASK (3 << 26) | |
36 | #define MV64x60_WDC_CTL2(val) ((val & 3) << 26) | |
37 | ||
38 | /* Flags bits */ | |
39 | #define MV64x60_WDOG_FLAG_OPENED 0 | |
40 | #define MV64x60_WDOG_FLAG_ENABLED 1 | |
41 | ||
42 | static unsigned long wdt_flags; | |
43 | static int wdt_status; | |
8a5cfa64 | 44 | static void __iomem *mv64x60_wdt_regs; |
3be10211 | 45 | static int mv64x60_wdt_timeout; |
94796f90 | 46 | static unsigned int bus_clk; |
bf2fc92c | 47 | static char expect_close; |
3be10211 | 48 | |
d37a5c3d DF |
49 | static int nowayout = WATCHDOG_NOWAYOUT; |
50 | module_param(nowayout, int, 0); | |
51 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
52 | ||
3be10211 JC |
53 | static void mv64x60_wdt_reg_write(u32 val) |
54 | { | |
55 | /* Allow write only to CTL1 / CTL2 fields, retaining values in | |
56 | * other fields. | |
57 | */ | |
8a5cfa64 | 58 | u32 data = readl(mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET); |
3be10211 JC |
59 | data &= ~(MV64x60_WDC_CTL1_MASK | MV64x60_WDC_CTL2_MASK); |
60 | data |= val; | |
8a5cfa64 | 61 | writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET); |
3be10211 JC |
62 | } |
63 | ||
64 | static void mv64x60_wdt_service(void) | |
65 | { | |
66 | /* Write 01 followed by 10 to CTL2 */ | |
67 | mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x01)); | |
68 | mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x02)); | |
69 | } | |
70 | ||
71 | static void mv64x60_wdt_handler_disable(void) | |
72 | { | |
73 | if (test_and_clear_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) { | |
74 | /* Write 01 followed by 10 to CTL1 */ | |
75 | mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01)); | |
76 | mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02)); | |
77 | printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n"); | |
78 | } | |
79 | } | |
80 | ||
81 | static void mv64x60_wdt_handler_enable(void) | |
82 | { | |
83 | if (!test_and_set_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) { | |
84 | /* Write 01 followed by 10 to CTL1 */ | |
85 | mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01)); | |
86 | mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02)); | |
87 | printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n"); | |
88 | } | |
89 | } | |
90 | ||
94796f90 DF |
91 | static void mv64x60_wdt_set_timeout(int timeout) |
92 | { | |
93 | /* maximum bus cycle count is 0xFFFFFFFF */ | |
94 | if (timeout > 0xFFFFFFFF / bus_clk) | |
95 | timeout = 0xFFFFFFFF / bus_clk; | |
96 | ||
97 | mv64x60_wdt_timeout = timeout; | |
98 | writel((timeout * bus_clk) >> 8, | |
99 | mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET); | |
100 | mv64x60_wdt_service(); | |
101 | } | |
102 | ||
3be10211 JC |
103 | static int mv64x60_wdt_open(struct inode *inode, struct file *file) |
104 | { | |
105 | if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags)) | |
106 | return -EBUSY; | |
107 | ||
d37a5c3d DF |
108 | if (nowayout) |
109 | __module_get(THIS_MODULE); | |
110 | ||
3be10211 JC |
111 | mv64x60_wdt_service(); |
112 | mv64x60_wdt_handler_enable(); | |
113 | ||
861e5137 | 114 | return nonseekable_open(inode, file); |
3be10211 JC |
115 | } |
116 | ||
117 | static int mv64x60_wdt_release(struct inode *inode, struct file *file) | |
118 | { | |
bf2fc92c | 119 | if (expect_close == 42) |
d37a5c3d | 120 | mv64x60_wdt_handler_disable(); |
bf2fc92c DF |
121 | else { |
122 | printk(KERN_CRIT | |
123 | "mv64x60_wdt: unexpected close, not stopping timer!\n"); | |
124 | mv64x60_wdt_service(); | |
125 | } | |
126 | expect_close = 0; | |
3be10211 JC |
127 | |
128 | clear_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags); | |
129 | ||
130 | return 0; | |
131 | } | |
132 | ||
b2846dfa | 133 | static ssize_t mv64x60_wdt_write(struct file *file, const char __user *data, |
3be10211 JC |
134 | size_t len, loff_t * ppos) |
135 | { | |
bf2fc92c DF |
136 | if (len) { |
137 | if (!nowayout) { | |
138 | size_t i; | |
139 | ||
140 | expect_close = 0; | |
141 | ||
142 | for (i = 0; i != len; i++) { | |
143 | char c; | |
144 | if(get_user(c, data + i)) | |
145 | return -EFAULT; | |
146 | if (c == 'V') | |
147 | expect_close = 42; | |
148 | } | |
149 | } | |
3be10211 | 150 | mv64x60_wdt_service(); |
bf2fc92c | 151 | } |
3be10211 JC |
152 | |
153 | return len; | |
154 | } | |
155 | ||
156 | static int mv64x60_wdt_ioctl(struct inode *inode, struct file *file, | |
157 | unsigned int cmd, unsigned long arg) | |
158 | { | |
94796f90 | 159 | int timeout; |
85d57238 | 160 | int options; |
b2846dfa | 161 | void __user *argp = (void __user *)arg; |
3be10211 | 162 | static struct watchdog_info info = { |
94796f90 | 163 | .options = WDIOF_SETTIMEOUT | |
bf2fc92c | 164 | WDIOF_MAGICCLOSE | |
94796f90 | 165 | WDIOF_KEEPALIVEPING, |
3be10211 JC |
166 | .firmware_version = 0, |
167 | .identity = "MV64x60 watchdog", | |
168 | }; | |
169 | ||
170 | switch (cmd) { | |
171 | case WDIOC_GETSUPPORT: | |
b2846dfa | 172 | if (copy_to_user(argp, &info, sizeof(info))) |
3be10211 JC |
173 | return -EFAULT; |
174 | break; | |
175 | ||
176 | case WDIOC_GETSTATUS: | |
177 | case WDIOC_GETBOOTSTATUS: | |
b2846dfa | 178 | if (put_user(wdt_status, (int __user *)argp)) |
3be10211 JC |
179 | return -EFAULT; |
180 | wdt_status &= ~WDIOF_KEEPALIVEPING; | |
181 | break; | |
182 | ||
183 | case WDIOC_GETTEMP: | |
184 | return -EOPNOTSUPP; | |
185 | ||
186 | case WDIOC_SETOPTIONS: | |
85d57238 DF |
187 | if (get_user(options, (int __user *)argp)) |
188 | return -EFAULT; | |
189 | ||
190 | if (options & WDIOS_DISABLECARD) | |
191 | mv64x60_wdt_handler_disable(); | |
192 | ||
193 | if (options & WDIOS_ENABLECARD) | |
194 | mv64x60_wdt_handler_enable(); | |
195 | break; | |
3be10211 JC |
196 | |
197 | case WDIOC_KEEPALIVE: | |
198 | mv64x60_wdt_service(); | |
199 | wdt_status |= WDIOF_KEEPALIVEPING; | |
200 | break; | |
201 | ||
202 | case WDIOC_SETTIMEOUT: | |
94796f90 DF |
203 | if (get_user(timeout, (int __user *)argp)) |
204 | return -EFAULT; | |
205 | mv64x60_wdt_set_timeout(timeout); | |
206 | /* Fall through */ | |
3be10211 JC |
207 | |
208 | case WDIOC_GETTIMEOUT: | |
264f0991 | 209 | if (put_user(mv64x60_wdt_timeout, (int __user *)argp)) |
3be10211 JC |
210 | return -EFAULT; |
211 | break; | |
212 | ||
213 | default: | |
795b89d2 | 214 | return -ENOTTY; |
3be10211 JC |
215 | } |
216 | ||
217 | return 0; | |
218 | } | |
219 | ||
62322d25 | 220 | static const struct file_operations mv64x60_wdt_fops = { |
3be10211 JC |
221 | .owner = THIS_MODULE, |
222 | .llseek = no_llseek, | |
223 | .write = mv64x60_wdt_write, | |
224 | .ioctl = mv64x60_wdt_ioctl, | |
225 | .open = mv64x60_wdt_open, | |
226 | .release = mv64x60_wdt_release, | |
227 | }; | |
228 | ||
229 | static struct miscdevice mv64x60_wdt_miscdev = { | |
230 | .minor = WATCHDOG_MINOR, | |
231 | .name = "watchdog", | |
232 | .fops = &mv64x60_wdt_fops, | |
233 | }; | |
234 | ||
3ae5eaec | 235 | static int __devinit mv64x60_wdt_probe(struct platform_device *dev) |
3be10211 | 236 | { |
3ae5eaec | 237 | struct mv64x60_wdt_pdata *pdata = dev->dev.platform_data; |
8a5cfa64 | 238 | struct resource *r; |
94796f90 | 239 | int timeout = 10; |
3be10211 | 240 | |
94796f90 | 241 | bus_clk = 133; /* in MHz */ |
3be10211 | 242 | if (pdata) { |
94796f90 | 243 | timeout = pdata->timeout; |
3be10211 JC |
244 | bus_clk = pdata->bus_clk; |
245 | } | |
246 | ||
94796f90 DF |
247 | /* Since bus_clk is truncated MHz, actual frequency could be |
248 | * up to 1MHz higher. Round up, since it's better to time out | |
249 | * too late than too soon. | |
250 | */ | |
251 | bus_clk++; | |
252 | bus_clk *= 1000000; /* convert to Hz */ | |
253 | ||
8a5cfa64 DF |
254 | r = platform_get_resource(dev, IORESOURCE_MEM, 0); |
255 | if (!r) | |
256 | return -ENODEV; | |
257 | ||
258 | mv64x60_wdt_regs = ioremap(r->start, r->end - r->start + 1); | |
259 | if (mv64x60_wdt_regs == NULL) | |
260 | return -ENOMEM; | |
3be10211 | 261 | |
94796f90 | 262 | mv64x60_wdt_set_timeout(timeout); |
3be10211 JC |
263 | |
264 | return misc_register(&mv64x60_wdt_miscdev); | |
265 | } | |
266 | ||
3ae5eaec | 267 | static int __devexit mv64x60_wdt_remove(struct platform_device *dev) |
3be10211 JC |
268 | { |
269 | misc_deregister(&mv64x60_wdt_miscdev); | |
270 | ||
271 | mv64x60_wdt_service(); | |
272 | mv64x60_wdt_handler_disable(); | |
273 | ||
8a5cfa64 DF |
274 | iounmap(mv64x60_wdt_regs); |
275 | ||
3be10211 JC |
276 | return 0; |
277 | } | |
278 | ||
3ae5eaec | 279 | static struct platform_driver mv64x60_wdt_driver = { |
3be10211 JC |
280 | .probe = mv64x60_wdt_probe, |
281 | .remove = __devexit_p(mv64x60_wdt_remove), | |
3ae5eaec RK |
282 | .driver = { |
283 | .owner = THIS_MODULE, | |
284 | .name = MV64x60_WDT_NAME, | |
285 | }, | |
3be10211 JC |
286 | }; |
287 | ||
3be10211 JC |
288 | static int __init mv64x60_wdt_init(void) |
289 | { | |
3be10211 JC |
290 | printk(KERN_INFO "MV64x60 watchdog driver\n"); |
291 | ||
422db8d2 | 292 | return platform_driver_register(&mv64x60_wdt_driver); |
3be10211 JC |
293 | } |
294 | ||
295 | static void __exit mv64x60_wdt_exit(void) | |
296 | { | |
3ae5eaec | 297 | platform_driver_unregister(&mv64x60_wdt_driver); |
3be10211 JC |
298 | } |
299 | ||
300 | module_init(mv64x60_wdt_init); | |
301 | module_exit(mv64x60_wdt_exit); | |
302 | ||
303 | MODULE_AUTHOR("James Chapman <jchapman@katalix.com>"); | |
304 | MODULE_DESCRIPTION("MV64x60 watchdog driver"); | |
305 | MODULE_LICENSE("GPL"); | |
306 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |