1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright 2018-2019 NXP.
4 */
5
6 #include <linux/arm-smccc.h>
7 #include <linux/firmware/imx/sci.h>
8 #include <linux/io.h>
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/moduleparam.h>
12 #include <linux/of.h>
13 #include <linux/platform_device.h>
14 #include <linux/watchdog.h>
15
16 #define DEFAULT_TIMEOUT 60
17 /*
18 * Software timer tick implemented in scfw side, support 10ms to 0xffffffff ms
19 * in theory, but for normal case, 1s~128s is enough, you can change this max
20 * value in case it's not enough.
21 */
22 #define MAX_TIMEOUT 128
23
24 #define IMX_SIP_TIMER 0xC2000002
25 #define IMX_SIP_TIMER_START_WDOG 0x01
26 #define IMX_SIP_TIMER_STOP_WDOG 0x02
27 #define IMX_SIP_TIMER_SET_WDOG_ACT 0x03
28 #define IMX_SIP_TIMER_PING_WDOG 0x04
29 #define IMX_SIP_TIMER_SET_TIMEOUT_WDOG 0x05
30 #define IMX_SIP_TIMER_GET_WDOG_STAT 0x06
31 #define IMX_SIP_TIMER_SET_PRETIME_WDOG 0x07
32
33 #define SC_TIMER_WDOG_ACTION_PARTITION 0
34
35 #define SC_IRQ_WDOG 1
36 #define SC_IRQ_GROUP_WDOG 1
37
38 static bool nowayout = WATCHDOG_NOWAYOUT;
39 module_param(nowayout, bool, 0000);
40 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
41 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
42
43 struct imx_sc_wdt_device {
44 struct watchdog_device wdd;
45 struct notifier_block wdt_notifier;
46 };
47
imx_sc_wdt_ping(struct watchdog_device * wdog)48 static int imx_sc_wdt_ping(struct watchdog_device *wdog)
49 {
50 struct arm_smccc_res res;
51
52 arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_PING_WDOG,
53 0, 0, 0, 0, 0, 0, &res);
54
55 return 0;
56 }
57
imx_sc_wdt_start(struct watchdog_device * wdog)58 static int imx_sc_wdt_start(struct watchdog_device *wdog)
59 {
60 struct arm_smccc_res res;
61
62 arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_START_WDOG,
63 0, 0, 0, 0, 0, 0, &res);
64 if (res.a0)
65 return -EACCES;
66
67 arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_WDOG_ACT,
68 SC_TIMER_WDOG_ACTION_PARTITION,
69 0, 0, 0, 0, 0, &res);
70 return res.a0 ? -EACCES : 0;
71 }
72
imx_sc_wdt_stop(struct watchdog_device * wdog)73 static int imx_sc_wdt_stop(struct watchdog_device *wdog)
74 {
75 struct arm_smccc_res res;
76
77 arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_STOP_WDOG,
78 0, 0, 0, 0, 0, 0, &res);
79
80 return res.a0 ? -EACCES : 0;
81 }
82
imx_sc_wdt_set_timeout(struct watchdog_device * wdog,unsigned int timeout)83 static int imx_sc_wdt_set_timeout(struct watchdog_device *wdog,
84 unsigned int timeout)
85 {
86 struct arm_smccc_res res;
87
88 wdog->timeout = timeout;
89 arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_TIMEOUT_WDOG,
90 timeout * 1000, 0, 0, 0, 0, 0, &res);
91
92 return res.a0 ? -EACCES : 0;
93 }
94
imx_sc_wdt_set_pretimeout(struct watchdog_device * wdog,unsigned int pretimeout)95 static int imx_sc_wdt_set_pretimeout(struct watchdog_device *wdog,
96 unsigned int pretimeout)
97 {
98 struct arm_smccc_res res;
99
100 /*
101 * SCU firmware calculates pretimeout based on current time
102 * stamp instead of watchdog timeout stamp, need to convert
103 * the pretimeout to SCU firmware's timeout value.
104 */
105 arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_PRETIME_WDOG,
106 (wdog->timeout - pretimeout) * 1000, 0, 0, 0,
107 0, 0, &res);
108 if (res.a0)
109 return -EACCES;
110
111 wdog->pretimeout = pretimeout;
112
113 return 0;
114 }
115
imx_sc_wdt_notify(struct notifier_block * nb,unsigned long event,void * group)116 static int imx_sc_wdt_notify(struct notifier_block *nb,
117 unsigned long event, void *group)
118 {
119 struct imx_sc_wdt_device *imx_sc_wdd =
120 container_of(nb,
121 struct imx_sc_wdt_device,
122 wdt_notifier);
123
124 if (event & SC_IRQ_WDOG &&
125 *(u8 *)group == SC_IRQ_GROUP_WDOG)
126 watchdog_notify_pretimeout(&imx_sc_wdd->wdd);
127
128 return 0;
129 }
130
imx_sc_wdt_action(void * data)131 static void imx_sc_wdt_action(void *data)
132 {
133 struct notifier_block *wdt_notifier = data;
134
135 imx_scu_irq_unregister_notifier(wdt_notifier);
136 imx_scu_irq_group_enable(SC_IRQ_GROUP_WDOG,
137 SC_IRQ_WDOG,
138 false);
139 }
140
141 static const struct watchdog_ops imx_sc_wdt_ops = {
142 .owner = THIS_MODULE,
143 .start = imx_sc_wdt_start,
144 .stop = imx_sc_wdt_stop,
145 .ping = imx_sc_wdt_ping,
146 .set_timeout = imx_sc_wdt_set_timeout,
147 .set_pretimeout = imx_sc_wdt_set_pretimeout,
148 };
149
150 static struct watchdog_info imx_sc_wdt_info = {
151 .identity = "i.MX SC watchdog timer",
152 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
153 WDIOF_MAGICCLOSE,
154 };
155
imx_sc_wdt_probe(struct platform_device * pdev)156 static int imx_sc_wdt_probe(struct platform_device *pdev)
157 {
158 struct imx_sc_wdt_device *imx_sc_wdd;
159 struct watchdog_device *wdog;
160 struct device *dev = &pdev->dev;
161 int ret;
162
163 imx_sc_wdd = devm_kzalloc(dev, sizeof(*imx_sc_wdd), GFP_KERNEL);
164 if (!imx_sc_wdd)
165 return -ENOMEM;
166
167 platform_set_drvdata(pdev, imx_sc_wdd);
168
169 wdog = &imx_sc_wdd->wdd;
170 wdog->info = &imx_sc_wdt_info;
171 wdog->ops = &imx_sc_wdt_ops;
172 wdog->min_timeout = 1;
173 wdog->max_timeout = MAX_TIMEOUT;
174 wdog->parent = dev;
175 wdog->timeout = DEFAULT_TIMEOUT;
176
177 watchdog_init_timeout(wdog, 0, dev);
178
179 ret = imx_sc_wdt_set_timeout(wdog, wdog->timeout);
180 if (ret)
181 return ret;
182
183 watchdog_stop_on_reboot(wdog);
184 watchdog_stop_on_unregister(wdog);
185
186 ret = imx_scu_irq_group_enable(SC_IRQ_GROUP_WDOG,
187 SC_IRQ_WDOG,
188 true);
189 if (ret) {
190 dev_warn(dev, "Enable irq failed, pretimeout NOT supported\n");
191 goto register_device;
192 }
193
194 imx_sc_wdd->wdt_notifier.notifier_call = imx_sc_wdt_notify;
195 ret = imx_scu_irq_register_notifier(&imx_sc_wdd->wdt_notifier);
196 if (ret) {
197 imx_scu_irq_group_enable(SC_IRQ_GROUP_WDOG,
198 SC_IRQ_WDOG,
199 false);
200 dev_warn(dev,
201 "Register irq notifier failed, pretimeout NOT supported\n");
202 goto register_device;
203 }
204
205 ret = devm_add_action_or_reset(dev, imx_sc_wdt_action,
206 &imx_sc_wdd->wdt_notifier);
207 if (!ret)
208 imx_sc_wdt_info.options |= WDIOF_PRETIMEOUT;
209 else
210 dev_warn(dev, "Add action failed, pretimeout NOT supported\n");
211
212 register_device:
213 return devm_watchdog_register_device(dev, wdog);
214 }
215
imx_sc_wdt_suspend(struct device * dev)216 static int __maybe_unused imx_sc_wdt_suspend(struct device *dev)
217 {
218 struct imx_sc_wdt_device *imx_sc_wdd = dev_get_drvdata(dev);
219
220 if (watchdog_active(&imx_sc_wdd->wdd))
221 imx_sc_wdt_stop(&imx_sc_wdd->wdd);
222
223 return 0;
224 }
225
imx_sc_wdt_resume(struct device * dev)226 static int __maybe_unused imx_sc_wdt_resume(struct device *dev)
227 {
228 struct imx_sc_wdt_device *imx_sc_wdd = dev_get_drvdata(dev);
229
230 if (watchdog_active(&imx_sc_wdd->wdd))
231 imx_sc_wdt_start(&imx_sc_wdd->wdd);
232
233 return 0;
234 }
235
236 static SIMPLE_DEV_PM_OPS(imx_sc_wdt_pm_ops,
237 imx_sc_wdt_suspend, imx_sc_wdt_resume);
238
239 static const struct of_device_id imx_sc_wdt_dt_ids[] = {
240 { .compatible = "fsl,imx-sc-wdt", },
241 { /* sentinel */ }
242 };
243 MODULE_DEVICE_TABLE(of, imx_sc_wdt_dt_ids);
244
245 static struct platform_driver imx_sc_wdt_driver = {
246 .probe = imx_sc_wdt_probe,
247 .driver = {
248 .name = "imx-sc-wdt",
249 .of_match_table = imx_sc_wdt_dt_ids,
250 .pm = &imx_sc_wdt_pm_ops,
251 },
252 };
253 module_platform_driver(imx_sc_wdt_driver);
254
255 MODULE_AUTHOR("Robin Gong <yibin.gong@nxp.com>");
256 MODULE_DESCRIPTION("NXP i.MX system controller watchdog driver");
257 MODULE_LICENSE("GPL v2");
258