Merge tag 'v3.10.81' into update
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / watchdog / ar7_wdt.c
CommitLineData
c283cf2c
MC
1/*
2 * drivers/watchdog/ar7_wdt.c
3 *
4 * Copyright (C) 2007 Nicolas Thill <nico@openwrt.org>
5 * Copyright (c) 2005 Enrik Berkhan <Enrik.Berkhan@akk.org>
6 *
7 * Some code taken from:
8 * National Semiconductor SCx200 Watchdog support
9 * Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
24 */
25
27c766aa
JP
26#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27
c283cf2c
MC
28#include <linux/module.h>
29#include <linux/moduleparam.h>
30#include <linux/errno.h>
31#include <linux/init.h>
32#include <linux/miscdevice.h>
64d4062a 33#include <linux/platform_device.h>
c283cf2c 34#include <linux/watchdog.h>
c283cf2c
MC
35#include <linux/fs.h>
36#include <linux/ioport.h>
37#include <linux/io.h>
38#include <linux/uaccess.h>
780019dd 39#include <linux/clk.h>
c283cf2c
MC
40
41#include <asm/addrspace.h>
c5e7f5a3 42#include <asm/mach-ar7/ar7.h>
c283cf2c 43
c283cf2c
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44#define LONGNAME "TI AR7 Watchdog Timer"
45
46MODULE_AUTHOR("Nicolas Thill <nico@openwrt.org>");
47MODULE_DESCRIPTION(LONGNAME);
48MODULE_LICENSE("GPL");
49MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
50
51static int margin = 60;
52module_param(margin, int, 0);
53MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
54
86a1e189
WVS
55static bool nowayout = WATCHDOG_NOWAYOUT;
56module_param(nowayout, bool, 0);
c283cf2c
MC
57MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
58
59#define READ_REG(x) readl((void __iomem *)&(x))
60#define WRITE_REG(x, v) writel((v), (void __iomem *)&(x))
61
62struct ar7_wdt {
63 u32 kick_lock;
64 u32 kick;
65 u32 change_lock;
66 u32 change;
67 u32 disable_lock;
68 u32 disable;
69 u32 prescale_lock;
70 u32 prescale;
71};
72
670d59c0 73static unsigned long wdt_is_open;
c283cf2c 74static unsigned expect_close;
1334f329 75static DEFINE_SPINLOCK(wdt_lock);
c283cf2c
MC
76
77/* XXX currently fixed, allows max margin ~68.72 secs */
78#define prescale_value 0xffff
79
64d4062a
FF
80/* Resource of the WDT registers */
81static struct resource *ar7_regs_wdt;
c283cf2c
MC
82/* Pointer to the remapped WDT IO space */
83static struct ar7_wdt *ar7_wdt;
c283cf2c 84
780019dd
FF
85static struct clk *vbus_clk;
86
c283cf2c
MC
87static void ar7_wdt_kick(u32 value)
88{
89 WRITE_REG(ar7_wdt->kick_lock, 0x5555);
90 if ((READ_REG(ar7_wdt->kick_lock) & 3) == 1) {
91 WRITE_REG(ar7_wdt->kick_lock, 0xaaaa);
92 if ((READ_REG(ar7_wdt->kick_lock) & 3) == 3) {
93 WRITE_REG(ar7_wdt->kick, value);
94 return;
95 }
96 }
27c766aa 97 pr_err("failed to unlock WDT kick reg\n");
c283cf2c
MC
98}
99
100static void ar7_wdt_prescale(u32 value)
101{
102 WRITE_REG(ar7_wdt->prescale_lock, 0x5a5a);
103 if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 1) {
104 WRITE_REG(ar7_wdt->prescale_lock, 0xa5a5);
105 if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 3) {
106 WRITE_REG(ar7_wdt->prescale, value);
107 return;
108 }
109 }
27c766aa 110 pr_err("failed to unlock WDT prescale reg\n");
c283cf2c
MC
111}
112
113static void ar7_wdt_change(u32 value)
114{
115 WRITE_REG(ar7_wdt->change_lock, 0x6666);
116 if ((READ_REG(ar7_wdt->change_lock) & 3) == 1) {
117 WRITE_REG(ar7_wdt->change_lock, 0xbbbb);
118 if ((READ_REG(ar7_wdt->change_lock) & 3) == 3) {
119 WRITE_REG(ar7_wdt->change, value);
120 return;
121 }
122 }
27c766aa 123 pr_err("failed to unlock WDT change reg\n");
c283cf2c
MC
124}
125
126static void ar7_wdt_disable(u32 value)
127{
128 WRITE_REG(ar7_wdt->disable_lock, 0x7777);
129 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 1) {
130 WRITE_REG(ar7_wdt->disable_lock, 0xcccc);
131 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 2) {
132 WRITE_REG(ar7_wdt->disable_lock, 0xdddd);
133 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 3) {
134 WRITE_REG(ar7_wdt->disable, value);
135 return;
136 }
137 }
138 }
27c766aa 139 pr_err("failed to unlock WDT disable reg\n");
c283cf2c
MC
140}
141
142static void ar7_wdt_update_margin(int new_margin)
143{
144 u32 change;
780019dd 145 u32 vbus_rate;
c283cf2c 146
780019dd
FF
147 vbus_rate = clk_get_rate(vbus_clk);
148 change = new_margin * (vbus_rate / prescale_value);
670d59c0
AC
149 if (change < 1)
150 change = 1;
151 if (change > 0xffff)
152 change = 0xffff;
c283cf2c 153 ar7_wdt_change(change);
780019dd 154 margin = change * prescale_value / vbus_rate;
27c766aa
JP
155 pr_info("timer margin %d seconds (prescale %d, change %d, freq %d)\n",
156 margin, prescale_value, change, vbus_rate);
c283cf2c
MC
157}
158
159static void ar7_wdt_enable_wdt(void)
160{
27c766aa 161 pr_debug("enabling watchdog timer\n");
c283cf2c
MC
162 ar7_wdt_disable(1);
163 ar7_wdt_kick(1);
164}
165
166static void ar7_wdt_disable_wdt(void)
167{
27c766aa 168 pr_debug("disabling watchdog timer\n");
c283cf2c
MC
169 ar7_wdt_disable(0);
170}
171
172static int ar7_wdt_open(struct inode *inode, struct file *file)
173{
174 /* only allow one at a time */
670d59c0 175 if (test_and_set_bit(0, &wdt_is_open))
c283cf2c
MC
176 return -EBUSY;
177 ar7_wdt_enable_wdt();
178 expect_close = 0;
179
180 return nonseekable_open(inode, file);
181}
182
183static int ar7_wdt_release(struct inode *inode, struct file *file)
184{
185 if (!expect_close)
27c766aa 186 pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
c283cf2c
MC
187 else if (!nowayout)
188 ar7_wdt_disable_wdt();
670d59c0 189 clear_bit(0, &wdt_is_open);
c283cf2c
MC
190 return 0;
191}
192
c283cf2c
MC
193static ssize_t ar7_wdt_write(struct file *file, const char *data,
194 size_t len, loff_t *ppos)
195{
196 /* check for a magic close character */
197 if (len) {
198 size_t i;
199
670d59c0 200 spin_lock(&wdt_lock);
c283cf2c 201 ar7_wdt_kick(1);
670d59c0 202 spin_unlock(&wdt_lock);
c283cf2c
MC
203
204 expect_close = 0;
205 for (i = 0; i < len; ++i) {
206 char c;
7944d3a5 207 if (get_user(c, data + i))
c283cf2c
MC
208 return -EFAULT;
209 if (c == 'V')
210 expect_close = 1;
211 }
212
213 }
214 return len;
215}
216
670d59c0
AC
217static long ar7_wdt_ioctl(struct file *file,
218 unsigned int cmd, unsigned long arg)
c283cf2c 219{
42747d71 220 static const struct watchdog_info ident = {
c283cf2c
MC
221 .identity = LONGNAME,
222 .firmware_version = 1,
e73a7802
WVS
223 .options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
224 WDIOF_MAGICCLOSE),
c283cf2c
MC
225 };
226 int new_margin;
227
228 switch (cmd) {
c283cf2c
MC
229 case WDIOC_GETSUPPORT:
230 if (copy_to_user((struct watchdog_info *)arg, &ident,
231 sizeof(ident)))
232 return -EFAULT;
233 return 0;
234 case WDIOC_GETSTATUS:
235 case WDIOC_GETBOOTSTATUS:
236 if (put_user(0, (int *)arg))
237 return -EFAULT;
238 return 0;
239 case WDIOC_KEEPALIVE:
240 ar7_wdt_kick(1);
241 return 0;
242 case WDIOC_SETTIMEOUT:
243 if (get_user(new_margin, (int *)arg))
244 return -EFAULT;
245 if (new_margin < 1)
246 return -EINVAL;
247
670d59c0 248 spin_lock(&wdt_lock);
c283cf2c
MC
249 ar7_wdt_update_margin(new_margin);
250 ar7_wdt_kick(1);
670d59c0 251 spin_unlock(&wdt_lock);
c283cf2c
MC
252
253 case WDIOC_GETTIMEOUT:
254 if (put_user(margin, (int *)arg))
255 return -EFAULT;
256 return 0;
0c06090c
WVS
257 default:
258 return -ENOTTY;
c283cf2c
MC
259 }
260}
261
b47a166e 262static const struct file_operations ar7_wdt_fops = {
c283cf2c
MC
263 .owner = THIS_MODULE,
264 .write = ar7_wdt_write,
670d59c0 265 .unlocked_ioctl = ar7_wdt_ioctl,
c283cf2c
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266 .open = ar7_wdt_open,
267 .release = ar7_wdt_release,
6038f373 268 .llseek = no_llseek,
c283cf2c
MC
269};
270
271static struct miscdevice ar7_wdt_miscdev = {
272 .minor = WATCHDOG_MINOR,
273 .name = "watchdog",
274 .fops = &ar7_wdt_fops,
275};
276
2d991a16 277static int ar7_wdt_probe(struct platform_device *pdev)
c283cf2c
MC
278{
279 int rc;
280
64d4062a
FF
281 ar7_regs_wdt =
282 platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
283 if (!ar7_regs_wdt) {
27c766aa 284 pr_err("could not get registers resource\n");
ae21cc20 285 return -ENODEV;
c283cf2c
MC
286 }
287
4c271bb6
TR
288 ar7_wdt = devm_ioremap_resource(&pdev->dev, ar7_regs_wdt);
289 if (IS_ERR(ar7_wdt))
290 return PTR_ERR(ar7_wdt);
c283cf2c 291
780019dd
FF
292 vbus_clk = clk_get(NULL, "vbus");
293 if (IS_ERR(vbus_clk)) {
27c766aa 294 pr_err("could not get vbus clock\n");
ae21cc20 295 return PTR_ERR(vbus_clk);
780019dd
FF
296 }
297
c283cf2c
MC
298 ar7_wdt_disable_wdt();
299 ar7_wdt_prescale(prescale_value);
300 ar7_wdt_update_margin(margin);
301
c283cf2c
MC
302 rc = misc_register(&ar7_wdt_miscdev);
303 if (rc) {
27c766aa 304 pr_err("unable to register misc device\n");
ae21cc20 305 goto out;
c283cf2c 306 }
ae21cc20 307 return 0;
c283cf2c 308
c283cf2c 309out:
ae21cc20
JL
310 clk_put(vbus_clk);
311 vbus_clk = NULL;
c283cf2c
MC
312 return rc;
313}
314
4b12b896 315static int ar7_wdt_remove(struct platform_device *pdev)
c283cf2c
MC
316{
317 misc_deregister(&ar7_wdt_miscdev);
ae21cc20
JL
318 clk_put(vbus_clk);
319 vbus_clk = NULL;
64d4062a
FF
320 return 0;
321}
322
323static void ar7_wdt_shutdown(struct platform_device *pdev)
324{
325 if (!nowayout)
326 ar7_wdt_disable_wdt();
327}
328
329static struct platform_driver ar7_wdt_driver = {
330 .probe = ar7_wdt_probe,
82268714 331 .remove = ar7_wdt_remove,
64d4062a
FF
332 .shutdown = ar7_wdt_shutdown,
333 .driver = {
334 .owner = THIS_MODULE,
335 .name = "ar7_wdt",
336 },
337};
338
b8ec6118 339module_platform_driver(ar7_wdt_driver);