1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * mpc8xxx_wdt.c - MPC8xx/MPC83xx/MPC86xx watchdog userspace interface
4 *
5 * Authors: Dave Updegraff <dave@cray.org>
6 * Kumar Gala <galak@kernel.crashing.org>
7 * Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org>
8 * ..and from sc520_wdt
9 * Copyright (c) 2008 MontaVista Software, Inc.
10 * Anton Vorontsov <avorontsov@ru.mvista.com>
11 *
12 * Note: it appears that you can only actually ENABLE or DISABLE the thing
13 * once after POR. Once enabled, you cannot disable, and vice versa.
14 */
15
16 #include <linux/fs.h>
17 #include <linux/init.h>
18 #include <linux/kernel.h>
19 #include <linux/of.h>
20 #include <linux/platform_device.h>
21 #include <linux/module.h>
22 #include <linux/watchdog.h>
23 #include <linux/io.h>
24 #include <linux/uaccess.h>
25 #include <sysdev/fsl_soc.h>
26
27 #define WATCHDOG_TIMEOUT 10
28
29 struct mpc8xxx_wdt {
30 __be32 res0;
31 __be32 swcrr; /* System watchdog control register */
32 #define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */
33 #define SWCRR_SWF 0x00000008 /* Software Watchdog Freeze (mpc8xx). */
34 #define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */
35 #define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/
36 #define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */
37 __be32 swcnr; /* System watchdog count register */
38 u8 res1[2];
39 __be16 swsrr; /* System watchdog service register */
40 u8 res2[0xF0];
41 };
42
43 struct mpc8xxx_wdt_type {
44 int prescaler;
45 bool hw_enabled;
46 u32 rsr_mask;
47 };
48
49 struct mpc8xxx_wdt_ddata {
50 struct mpc8xxx_wdt __iomem *base;
51 struct watchdog_device wdd;
52 spinlock_t lock;
53 u16 swtc;
54 };
55
56 static u16 timeout;
57 module_param(timeout, ushort, 0);
58 MODULE_PARM_DESC(timeout,
59 "Watchdog timeout in seconds. (1<timeout<65535, default="
60 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
61
62 static bool reset = 1;
63 module_param(reset, bool, 0);
64 MODULE_PARM_DESC(reset,
65 "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");
66
67 static bool nowayout = WATCHDOG_NOWAYOUT;
68 module_param(nowayout, bool, 0);
69 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
70 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
71
mpc8xxx_wdt_keepalive(struct mpc8xxx_wdt_ddata * ddata)72 static void mpc8xxx_wdt_keepalive(struct mpc8xxx_wdt_ddata *ddata)
73 {
74 /* Ping the WDT */
75 spin_lock(&ddata->lock);
76 out_be16(&ddata->base->swsrr, 0x556c);
77 out_be16(&ddata->base->swsrr, 0xaa39);
78 spin_unlock(&ddata->lock);
79 }
80
mpc8xxx_wdt_start(struct watchdog_device * w)81 static int mpc8xxx_wdt_start(struct watchdog_device *w)
82 {
83 struct mpc8xxx_wdt_ddata *ddata =
84 container_of(w, struct mpc8xxx_wdt_ddata, wdd);
85 u32 tmp = in_be32(&ddata->base->swcrr);
86
87 /* Good, fire up the show */
88 tmp &= ~(SWCRR_SWTC | SWCRR_SWF | SWCRR_SWEN | SWCRR_SWRI | SWCRR_SWPR);
89 tmp |= SWCRR_SWEN | SWCRR_SWPR | (ddata->swtc << 16);
90
91 if (reset)
92 tmp |= SWCRR_SWRI;
93
94 out_be32(&ddata->base->swcrr, tmp);
95
96 tmp = in_be32(&ddata->base->swcrr);
97 if (!(tmp & SWCRR_SWEN))
98 return -EOPNOTSUPP;
99
100 ddata->swtc = tmp >> 16;
101 set_bit(WDOG_HW_RUNNING, &ddata->wdd.status);
102
103 return 0;
104 }
105
mpc8xxx_wdt_ping(struct watchdog_device * w)106 static int mpc8xxx_wdt_ping(struct watchdog_device *w)
107 {
108 struct mpc8xxx_wdt_ddata *ddata =
109 container_of(w, struct mpc8xxx_wdt_ddata, wdd);
110
111 mpc8xxx_wdt_keepalive(ddata);
112 return 0;
113 }
114
115 static struct watchdog_info mpc8xxx_wdt_info = {
116 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT,
117 .firmware_version = 1,
118 .identity = "MPC8xxx",
119 };
120
121 static const struct watchdog_ops mpc8xxx_wdt_ops = {
122 .owner = THIS_MODULE,
123 .start = mpc8xxx_wdt_start,
124 .ping = mpc8xxx_wdt_ping,
125 };
126
mpc8xxx_wdt_probe(struct platform_device * ofdev)127 static int mpc8xxx_wdt_probe(struct platform_device *ofdev)
128 {
129 int ret;
130 struct resource *res;
131 const struct mpc8xxx_wdt_type *wdt_type;
132 struct mpc8xxx_wdt_ddata *ddata;
133 u32 freq = fsl_get_sys_freq();
134 bool enabled;
135 struct device *dev = &ofdev->dev;
136
137 wdt_type = of_device_get_match_data(dev);
138 if (!wdt_type)
139 return -EINVAL;
140
141 if (!freq || freq == -1)
142 return -EINVAL;
143
144 ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
145 if (!ddata)
146 return -ENOMEM;
147
148 ddata->base = devm_platform_ioremap_resource(ofdev, 0);
149 if (IS_ERR(ddata->base))
150 return PTR_ERR(ddata->base);
151
152 enabled = in_be32(&ddata->base->swcrr) & SWCRR_SWEN;
153 if (!enabled && wdt_type->hw_enabled) {
154 dev_info(dev, "could not be enabled in software\n");
155 return -ENODEV;
156 }
157
158 res = platform_get_resource(ofdev, IORESOURCE_MEM, 1);
159 if (res) {
160 bool status;
161 u32 __iomem *rsr = ioremap(res->start, resource_size(res));
162
163 if (!rsr)
164 return -ENOMEM;
165
166 status = in_be32(rsr) & wdt_type->rsr_mask;
167 ddata->wdd.bootstatus = status ? WDIOF_CARDRESET : 0;
168 /* clear reset status bits related to watchdog timer */
169 out_be32(rsr, wdt_type->rsr_mask);
170 iounmap(rsr);
171
172 dev_info(dev, "Last boot was %scaused by watchdog\n",
173 status ? "" : "not ");
174 }
175
176 spin_lock_init(&ddata->lock);
177
178 ddata->wdd.info = &mpc8xxx_wdt_info;
179 ddata->wdd.ops = &mpc8xxx_wdt_ops;
180
181 ddata->wdd.timeout = WATCHDOG_TIMEOUT;
182 watchdog_init_timeout(&ddata->wdd, timeout, dev);
183
184 watchdog_set_nowayout(&ddata->wdd, nowayout);
185
186 ddata->swtc = min(ddata->wdd.timeout * freq / wdt_type->prescaler,
187 0xffffU);
188
189 /*
190 * If the watchdog was previously enabled or we're running on
191 * MPC8xxx, we should ping the wdt from the kernel until the
192 * userspace handles it.
193 */
194 if (enabled)
195 mpc8xxx_wdt_start(&ddata->wdd);
196
197 ddata->wdd.max_hw_heartbeat_ms = (ddata->swtc * wdt_type->prescaler) /
198 (freq / 1000);
199 ddata->wdd.min_timeout = ddata->wdd.max_hw_heartbeat_ms / 1000;
200 if (ddata->wdd.timeout < ddata->wdd.min_timeout)
201 ddata->wdd.timeout = ddata->wdd.min_timeout;
202
203 ret = devm_watchdog_register_device(dev, &ddata->wdd);
204 if (ret)
205 return ret;
206
207 dev_info(dev,
208 "WDT driver for MPC8xxx initialized. mode:%s timeout=%d sec\n",
209 reset ? "reset" : "interrupt", ddata->wdd.timeout);
210
211 platform_set_drvdata(ofdev, ddata);
212 return 0;
213 }
214
215 static const struct of_device_id mpc8xxx_wdt_match[] = {
216 {
217 .compatible = "mpc83xx_wdt",
218 .data = &(struct mpc8xxx_wdt_type) {
219 .prescaler = 0x10000,
220 .rsr_mask = BIT(3), /* RSR Bit SWRS */
221 },
222 },
223 {
224 .compatible = "fsl,mpc8610-wdt",
225 .data = &(struct mpc8xxx_wdt_type) {
226 .prescaler = 0x10000,
227 .hw_enabled = true,
228 .rsr_mask = BIT(20), /* RSTRSCR Bit WDT_RR */
229 },
230 },
231 {
232 .compatible = "fsl,mpc823-wdt",
233 .data = &(struct mpc8xxx_wdt_type) {
234 .prescaler = 0x800,
235 .hw_enabled = true,
236 .rsr_mask = BIT(28), /* RSR Bit SWRS */
237 },
238 },
239 {},
240 };
241 MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match);
242
243 static struct platform_driver mpc8xxx_wdt_driver = {
244 .probe = mpc8xxx_wdt_probe,
245 .driver = {
246 .name = "mpc8xxx_wdt",
247 .of_match_table = mpc8xxx_wdt_match,
248 },
249 };
250
mpc8xxx_wdt_init(void)251 static int __init mpc8xxx_wdt_init(void)
252 {
253 return platform_driver_register(&mpc8xxx_wdt_driver);
254 }
255 arch_initcall(mpc8xxx_wdt_init);
256
mpc8xxx_wdt_exit(void)257 static void __exit mpc8xxx_wdt_exit(void)
258 {
259 platform_driver_unregister(&mpc8xxx_wdt_driver);
260 }
261 module_exit(mpc8xxx_wdt_exit);
262
263 MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
264 MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx "
265 "uProcessors");
266 MODULE_LICENSE("GPL");
267