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 #define SC_TIMER_ERR_BUSY 10
38
39 static bool nowayout = WATCHDOG_NOWAYOUT;
40 module_param(nowayout, bool, 0000);
41 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
42 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
43
44 struct imx_sc_wdt_device {
45 struct watchdog_device wdd;
46 struct notifier_block wdt_notifier;
47 };
48
imx_sc_wdt_ping(struct watchdog_device * wdog)49 static int imx_sc_wdt_ping(struct watchdog_device *wdog)
50 {
51 struct arm_smccc_res res;
52
53 arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_PING_WDOG,
54 0, 0, 0, 0, 0, 0, &res);
55
56 return 0;
57 }
58
imx_sc_wdt_is_running(void)59 static bool imx_sc_wdt_is_running(void)
60 {
61 struct arm_smccc_res res;
62
63 arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_START_WDOG,
64 0, 0, 0, 0, 0, 0, &res);
65
66 /* Already enabled (SC_TIMER_ERR_BUSY)? */
67 if (res.a0 == SC_TIMER_ERR_BUSY)
68 return true;
69
70 /* Undo only if that was us who has (successfully) enabled the WDT */
71 if (!res.a0)
72 arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_STOP_WDOG,
73 0, 0, 0, 0, 0, 0, &res);
74
75 return false;
76 }
77
imx_sc_wdt_start(struct watchdog_device * wdog)78 static int imx_sc_wdt_start(struct watchdog_device *wdog)
79 {
80 struct arm_smccc_res res;
81
82 arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_START_WDOG,
83 0, 0, 0, 0, 0, 0, &res);
84
85 /* Ignore if already enabled(SC_TIMER_ERR_BUSY) */
86 if (res.a0 && res.a0 != SC_TIMER_ERR_BUSY)
87 return -EACCES;
88
89 arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_WDOG_ACT,
90 SC_TIMER_WDOG_ACTION_PARTITION,
91 0, 0, 0, 0, 0, &res);
92 return res.a0 ? -EACCES : 0;
93 }
94
imx_sc_wdt_stop(struct watchdog_device * wdog)95 static int imx_sc_wdt_stop(struct watchdog_device *wdog)
96 {
97 struct arm_smccc_res res;
98
99 arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_STOP_WDOG,
100 0, 0, 0, 0, 0, 0, &res);
101
102 return res.a0 ? -EACCES : 0;
103 }
104
imx_sc_wdt_set_timeout(struct watchdog_device * wdog,unsigned int timeout)105 static int imx_sc_wdt_set_timeout(struct watchdog_device *wdog,
106 unsigned int timeout)
107 {
108 struct arm_smccc_res res;
109
110 wdog->timeout = timeout;
111 arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_TIMEOUT_WDOG,
112 timeout * 1000, 0, 0, 0, 0, 0, &res);
113
114 return res.a0 ? -EACCES : 0;
115 }
116
imx_sc_wdt_set_pretimeout(struct watchdog_device * wdog,unsigned int pretimeout)117 static int imx_sc_wdt_set_pretimeout(struct watchdog_device *wdog,
118 unsigned int pretimeout)
119 {
120 struct arm_smccc_res res;
121
122 /*
123 * SCU firmware calculates pretimeout based on current time
124 * stamp instead of watchdog timeout stamp, need to convert
125 * the pretimeout to SCU firmware's timeout value.
126 */
127 arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_PRETIME_WDOG,
128 (wdog->timeout - pretimeout) * 1000, 0, 0, 0,
129 0, 0, &res);
130 if (res.a0)
131 return -EACCES;
132
133 wdog->pretimeout = pretimeout;
134
135 return 0;
136 }
137
imx_sc_wdt_notify(struct notifier_block * nb,unsigned long event,void * group)138 static int imx_sc_wdt_notify(struct notifier_block *nb,
139 unsigned long event, void *group)
140 {
141 struct imx_sc_wdt_device *imx_sc_wdd =
142 container_of(nb,
143 struct imx_sc_wdt_device,
144 wdt_notifier);
145
146 if (event & SC_IRQ_WDOG &&
147 *(u8 *)group == SC_IRQ_GROUP_WDOG)
148 watchdog_notify_pretimeout(&imx_sc_wdd->wdd);
149
150 return 0;
151 }
152
imx_sc_wdt_action(void * data)153 static void imx_sc_wdt_action(void *data)
154 {
155 struct notifier_block *wdt_notifier = data;
156
157 imx_scu_irq_unregister_notifier(wdt_notifier);
158 imx_scu_irq_group_enable(SC_IRQ_GROUP_WDOG,
159 SC_IRQ_WDOG,
160 false);
161 }
162
163 static const struct watchdog_ops imx_sc_wdt_ops = {
164 .owner = THIS_MODULE,
165 .start = imx_sc_wdt_start,
166 .stop = imx_sc_wdt_stop,
167 .ping = imx_sc_wdt_ping,
168 .set_timeout = imx_sc_wdt_set_timeout,
169 .set_pretimeout = imx_sc_wdt_set_pretimeout,
170 };
171
172 static struct watchdog_info imx_sc_wdt_info = {
173 .identity = "i.MX SC watchdog timer",
174 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
175 WDIOF_MAGICCLOSE,
176 };
177
imx_sc_wdt_probe(struct platform_device * pdev)178 static int imx_sc_wdt_probe(struct platform_device *pdev)
179 {
180 struct imx_sc_wdt_device *imx_sc_wdd;
181 struct watchdog_device *wdog;
182 struct device *dev = &pdev->dev;
183 int ret;
184
185 imx_sc_wdd = devm_kzalloc(dev, sizeof(*imx_sc_wdd), GFP_KERNEL);
186 if (!imx_sc_wdd)
187 return -ENOMEM;
188
189 platform_set_drvdata(pdev, imx_sc_wdd);
190
191 wdog = &imx_sc_wdd->wdd;
192 wdog->info = &imx_sc_wdt_info;
193 wdog->ops = &imx_sc_wdt_ops;
194 wdog->min_timeout = 1;
195 wdog->max_timeout = MAX_TIMEOUT;
196 wdog->parent = dev;
197 wdog->timeout = DEFAULT_TIMEOUT;
198
199 watchdog_init_timeout(wdog, 0, dev);
200
201 ret = imx_sc_wdt_set_timeout(wdog, wdog->timeout);
202 if (ret)
203 return ret;
204
205 if (imx_sc_wdt_is_running())
206 set_bit(WDOG_HW_RUNNING, &wdog->status);
207
208 watchdog_stop_on_reboot(wdog);
209 watchdog_stop_on_unregister(wdog);
210
211 ret = imx_scu_irq_group_enable(SC_IRQ_GROUP_WDOG,
212 SC_IRQ_WDOG,
213 true);
214 if (ret) {
215 dev_warn(dev, "Enable irq failed, pretimeout NOT supported\n");
216 goto register_device;
217 }
218
219 imx_sc_wdd->wdt_notifier.notifier_call = imx_sc_wdt_notify;
220 ret = imx_scu_irq_register_notifier(&imx_sc_wdd->wdt_notifier);
221 if (ret) {
222 imx_scu_irq_group_enable(SC_IRQ_GROUP_WDOG,
223 SC_IRQ_WDOG,
224 false);
225 dev_warn(dev,
226 "Register irq notifier failed, pretimeout NOT supported\n");
227 goto register_device;
228 }
229
230 ret = devm_add_action_or_reset(dev, imx_sc_wdt_action,
231 &imx_sc_wdd->wdt_notifier);
232 if (!ret)
233 imx_sc_wdt_info.options |= WDIOF_PRETIMEOUT;
234 else
235 dev_warn(dev, "Add action failed, pretimeout NOT supported\n");
236
237 register_device:
238 return devm_watchdog_register_device(dev, wdog);
239 }
240
241 static const struct of_device_id imx_sc_wdt_dt_ids[] = {
242 { .compatible = "fsl,imx-sc-wdt", },
243 { /* sentinel */ }
244 };
245 MODULE_DEVICE_TABLE(of, imx_sc_wdt_dt_ids);
246
247 static struct platform_driver imx_sc_wdt_driver = {
248 .probe = imx_sc_wdt_probe,
249 .driver = {
250 .name = "imx-sc-wdt",
251 .of_match_table = imx_sc_wdt_dt_ids,
252 },
253 };
254 module_platform_driver(imx_sc_wdt_driver);
255
256 MODULE_AUTHOR("Robin Gong <yibin.gong@nxp.com>");
257 MODULE_DESCRIPTION("NXP i.MX system controller watchdog driver");
258 MODULE_LICENSE("GPL v2");
259