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Thomas Gleixner2874c5f2019-05-27 08:55:01 +02001// SPDX-License-Identifier: GPL-2.0-or-later
Martyn Welch3268b562008-11-10 12:31:26 +00002/*
Martyn Welchcda61c92010-03-01 17:06:20 +00003 * GE watchdog userspace interface
Martyn Welch3268b562008-11-10 12:31:26 +00004 *
Martyn Welchcda61c92010-03-01 17:06:20 +00005 * Author: Martyn Welch <martyn.welch@ge.com>
Martyn Welch3268b562008-11-10 12:31:26 +00006 *
Martyn Welchcda61c92010-03-01 17:06:20 +00007 * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc.
Martyn Welch3268b562008-11-10 12:31:26 +00008 *
Martyn Welch3268b562008-11-10 12:31:26 +00009 * Based on: mv64x60_wdt.c (MV64X60 watchdog userspace interface)
10 * Author: James Chapman <jchapman@katalix.com>
11 */
12
13/* TODO:
14 * This driver does not provide support for the hardwares capability of sending
15 * an interrupt at a programmable threshold.
16 *
17 * This driver currently can only support 1 watchdog - there are 2 in the
18 * hardware that this driver supports. Thus one could be configured as a
19 * process-based watchdog (via /dev/watchdog), the second (using the interrupt
20 * capabilities) a kernel-based watchdog.
21 */
22
Joe Perches27c766a2012-02-15 15:06:19 -080023#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24
Martyn Welch3268b562008-11-10 12:31:26 +000025#include <linux/kernel.h>
26#include <linux/compiler.h>
27#include <linux/init.h>
28#include <linux/module.h>
29#include <linux/miscdevice.h>
30#include <linux/watchdog.h>
Wolfram Sang & Martyn Welchf6e07222010-12-02 00:11:16 +010031#include <linux/fs.h>
Martyn Welch3268b562008-11-10 12:31:26 +000032#include <linux/of.h>
Rob Herring5af50732013-09-17 14:28:33 -050033#include <linux/of_address.h>
Rob Herringcc85f872023-07-26 17:33:00 -060034#include <linux/platform_device.h>
Martyn Welch3268b562008-11-10 12:31:26 +000035#include <linux/io.h>
36#include <linux/uaccess.h>
37
38#include <sysdev/fsl_soc.h>
39
40/*
41 * The watchdog configuration register contains a pair of 2-bit fields,
42 * 1. a reload field, bits 27-26, which triggers a reload of
43 * the countdown register, and
44 * 2. an enable field, bits 25-24, which toggles between
45 * enabling and disabling the watchdog timer.
46 * Bit 31 is a read-only field which indicates whether the
47 * watchdog timer is currently enabled.
48 *
49 * The low 24 bits contain the timer reload value.
50 */
51#define GEF_WDC_ENABLE_SHIFT 24
52#define GEF_WDC_SERVICE_SHIFT 26
53#define GEF_WDC_ENABLED_SHIFT 31
54
55#define GEF_WDC_ENABLED_TRUE 1
56#define GEF_WDC_ENABLED_FALSE 0
57
58/* Flags bits */
59#define GEF_WDOG_FLAG_OPENED 0
60
61static unsigned long wdt_flags;
62static int wdt_status;
63static void __iomem *gef_wdt_regs;
64static int gef_wdt_timeout;
65static int gef_wdt_count;
66static unsigned int bus_clk;
67static char expect_close;
68static DEFINE_SPINLOCK(gef_wdt_spinlock);
69
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010070static bool nowayout = WATCHDOG_NOWAYOUT;
71module_param(nowayout, bool, 0);
Martyn Welch3268b562008-11-10 12:31:26 +000072MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
73 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
74
75
76static int gef_wdt_toggle_wdc(int enabled_predicate, int field_shift)
77{
78 u32 data;
79 u32 enabled;
80 int ret = 0;
81
82 spin_lock(&gef_wdt_spinlock);
83 data = ioread32be(gef_wdt_regs);
84 enabled = (data >> GEF_WDC_ENABLED_SHIFT) & 1;
85
86 /* only toggle the requested field if enabled state matches predicate */
87 if ((enabled ^ enabled_predicate) == 0) {
88 /* We write a 1, then a 2 -- to the appropriate field */
89 data = (1 << field_shift) | gef_wdt_count;
90 iowrite32be(data, gef_wdt_regs);
91
92 data = (2 << field_shift) | gef_wdt_count;
93 iowrite32be(data, gef_wdt_regs);
94 ret = 1;
95 }
96 spin_unlock(&gef_wdt_spinlock);
97
98 return ret;
99}
100
101static void gef_wdt_service(void)
102{
103 gef_wdt_toggle_wdc(GEF_WDC_ENABLED_TRUE,
104 GEF_WDC_SERVICE_SHIFT);
105}
106
107static void gef_wdt_handler_enable(void)
108{
109 if (gef_wdt_toggle_wdc(GEF_WDC_ENABLED_FALSE,
110 GEF_WDC_ENABLE_SHIFT)) {
111 gef_wdt_service();
Joe Perches27c766a2012-02-15 15:06:19 -0800112 pr_notice("watchdog activated\n");
Martyn Welch3268b562008-11-10 12:31:26 +0000113 }
114}
115
116static void gef_wdt_handler_disable(void)
117{
118 if (gef_wdt_toggle_wdc(GEF_WDC_ENABLED_TRUE,
119 GEF_WDC_ENABLE_SHIFT))
Joe Perches27c766a2012-02-15 15:06:19 -0800120 pr_notice("watchdog deactivated\n");
Martyn Welch3268b562008-11-10 12:31:26 +0000121}
122
123static void gef_wdt_set_timeout(unsigned int timeout)
124{
125 /* maximum bus cycle count is 0xFFFFFFFF */
126 if (timeout > 0xFFFFFFFF / bus_clk)
127 timeout = 0xFFFFFFFF / bus_clk;
128
129 /* Register only holds upper 24 bits, bit shifted into lower 24 */
130 gef_wdt_count = (timeout * bus_clk) >> 8;
131 gef_wdt_timeout = timeout;
132}
133
134
135static ssize_t gef_wdt_write(struct file *file, const char __user *data,
136 size_t len, loff_t *ppos)
137{
138 if (len) {
139 if (!nowayout) {
140 size_t i;
141
142 expect_close = 0;
143
144 for (i = 0; i != len; i++) {
145 char c;
146 if (get_user(c, data + i))
147 return -EFAULT;
148 if (c == 'V')
149 expect_close = 42;
150 }
151 }
152 gef_wdt_service();
153 }
154
155 return len;
156}
157
158static long gef_wdt_ioctl(struct file *file, unsigned int cmd,
159 unsigned long arg)
160{
161 int timeout;
162 int options;
163 void __user *argp = (void __user *)arg;
Wim Van Sebroeck42747d72009-12-26 18:55:22 +0000164 static const struct watchdog_info info = {
Martyn Welch3268b562008-11-10 12:31:26 +0000165 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
166 WDIOF_KEEPALIVEPING,
167 .firmware_version = 0,
Martyn Welchcda61c92010-03-01 17:06:20 +0000168 .identity = "GE watchdog",
Martyn Welch3268b562008-11-10 12:31:26 +0000169 };
170
171 switch (cmd) {
172 case WDIOC_GETSUPPORT:
173 if (copy_to_user(argp, &info, sizeof(info)))
174 return -EFAULT;
175 break;
176
177 case WDIOC_GETSTATUS:
178 case WDIOC_GETBOOTSTATUS:
179 if (put_user(wdt_status, (int __user *)argp))
180 return -EFAULT;
181 wdt_status &= ~WDIOF_KEEPALIVEPING;
182 break;
183
184 case WDIOC_SETOPTIONS:
185 if (get_user(options, (int __user *)argp))
186 return -EFAULT;
187
188 if (options & WDIOS_DISABLECARD)
189 gef_wdt_handler_disable();
190
191 if (options & WDIOS_ENABLECARD)
192 gef_wdt_handler_enable();
193 break;
194
195 case WDIOC_KEEPALIVE:
196 gef_wdt_service();
197 wdt_status |= WDIOF_KEEPALIVEPING;
198 break;
199
200 case WDIOC_SETTIMEOUT:
201 if (get_user(timeout, (int __user *)argp))
202 return -EFAULT;
203 gef_wdt_set_timeout(timeout);
Gustavo A. R. Silvabd490f82020-07-07 12:11:21 -0500204 fallthrough;
Martyn Welch3268b562008-11-10 12:31:26 +0000205
206 case WDIOC_GETTIMEOUT:
207 if (put_user(gef_wdt_timeout, (int __user *)argp))
208 return -EFAULT;
209 break;
210
211 default:
212 return -ENOTTY;
213 }
214
215 return 0;
216}
217
218static int gef_wdt_open(struct inode *inode, struct file *file)
219{
220 if (test_and_set_bit(GEF_WDOG_FLAG_OPENED, &wdt_flags))
221 return -EBUSY;
222
223 if (nowayout)
224 __module_get(THIS_MODULE);
225
226 gef_wdt_handler_enable();
227
Kirill Smelkovc5bf68f2019-03-26 23:51:19 +0300228 return stream_open(inode, file);
Martyn Welch3268b562008-11-10 12:31:26 +0000229}
230
231static int gef_wdt_release(struct inode *inode, struct file *file)
232{
233 if (expect_close == 42)
234 gef_wdt_handler_disable();
235 else {
Joe Perches27c766a2012-02-15 15:06:19 -0800236 pr_crit("unexpected close, not stopping timer!\n");
Martyn Welch3268b562008-11-10 12:31:26 +0000237 gef_wdt_service();
238 }
239 expect_close = 0;
240
241 clear_bit(GEF_WDOG_FLAG_OPENED, &wdt_flags);
242
243 return 0;
244}
245
246static const struct file_operations gef_wdt_fops = {
247 .owner = THIS_MODULE,
Martyn Welch3268b562008-11-10 12:31:26 +0000248 .write = gef_wdt_write,
249 .unlocked_ioctl = gef_wdt_ioctl,
Arnd Bergmannb6dfb242019-06-03 14:23:09 +0200250 .compat_ioctl = compat_ptr_ioctl,
Martyn Welch3268b562008-11-10 12:31:26 +0000251 .open = gef_wdt_open,
252 .release = gef_wdt_release,
253};
254
255static struct miscdevice gef_wdt_miscdev = {
256 .minor = WATCHDOG_MINOR,
257 .name = "watchdog",
258 .fops = &gef_wdt_fops,
259};
260
261
Bill Pemberton2d991a12012-11-19 13:21:41 -0500262static int gef_wdt_probe(struct platform_device *dev)
Martyn Welch3268b562008-11-10 12:31:26 +0000263{
264 int timeout = 10;
265 u32 freq;
266
267 bus_clk = 133; /* in MHz */
268
269 freq = fsl_get_sys_freq();
Roel Kluin26952662009-03-03 15:10:05 +0100270 if (freq != -1)
Martyn Welch3268b562008-11-10 12:31:26 +0000271 bus_clk = freq;
272
273 /* Map devices registers into memory */
Anatolij Gustschinb74dbf22010-06-03 03:30:31 +0200274 gef_wdt_regs = of_iomap(dev->dev.of_node, 0);
Martyn Welch3268b562008-11-10 12:31:26 +0000275 if (gef_wdt_regs == NULL)
276 return -ENOMEM;
277
278 gef_wdt_set_timeout(timeout);
279
280 gef_wdt_handler_disable(); /* in case timer was already running */
281
282 return misc_register(&gef_wdt_miscdev);
283}
284
Uwe Kleine-Königb5f2e362023-03-03 22:36:54 +0100285static void gef_wdt_remove(struct platform_device *dev)
Martyn Welch3268b562008-11-10 12:31:26 +0000286{
287 misc_deregister(&gef_wdt_miscdev);
288
289 gef_wdt_handler_disable();
290
291 iounmap(gef_wdt_regs);
Martyn Welch3268b562008-11-10 12:31:26 +0000292}
293
294static const struct of_device_id gef_wdt_ids[] = {
295 {
296 .compatible = "gef,fpga-wdt",
297 },
298 {},
299};
Luis de Bethencourtc73318f2015-09-03 13:06:09 +0200300MODULE_DEVICE_TABLE(of, gef_wdt_ids);
Martyn Welch3268b562008-11-10 12:31:26 +0000301
Grant Likely1c48a5c2011-02-17 02:43:24 -0700302static struct platform_driver gef_wdt_driver = {
Grant Likely40182942010-04-13 16:13:02 -0700303 .driver = {
304 .name = "gef_wdt",
Grant Likely40182942010-04-13 16:13:02 -0700305 .of_match_table = gef_wdt_ids,
306 },
Martyn Welch3268b562008-11-10 12:31:26 +0000307 .probe = gef_wdt_probe,
Uwe Kleine-Königb5f2e362023-03-03 22:36:54 +0100308 .remove_new = gef_wdt_remove,
Martyn Welch3268b562008-11-10 12:31:26 +0000309};
310
311static int __init gef_wdt_init(void)
312{
Joe Perches27c766a2012-02-15 15:06:19 -0800313 pr_info("GE watchdog driver\n");
Grant Likely1c48a5c2011-02-17 02:43:24 -0700314 return platform_driver_register(&gef_wdt_driver);
Martyn Welch3268b562008-11-10 12:31:26 +0000315}
316
317static void __exit gef_wdt_exit(void)
318{
Grant Likely1c48a5c2011-02-17 02:43:24 -0700319 platform_driver_unregister(&gef_wdt_driver);
Martyn Welch3268b562008-11-10 12:31:26 +0000320}
321
322module_init(gef_wdt_init);
323module_exit(gef_wdt_exit);
324
Martyn Welchcda61c92010-03-01 17:06:20 +0000325MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>");
326MODULE_DESCRIPTION("GE watchdog driver");
Martyn Welch3268b562008-11-10 12:31:26 +0000327MODULE_LICENSE("GPL");
Axel Linae2a0062011-06-27 22:37:16 +0800328MODULE_ALIAS("platform:gef_wdt");