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
39static bool nowayout = WATCHDOG_NOWAYOUT;
40module_param(nowayout, bool, 0000);
41MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
42		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
43
44struct imx_sc_wdt_device {
45	struct watchdog_device wdd;
46	struct notifier_block wdt_notifier;
47};
48
49static 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
59static int imx_sc_wdt_start(struct watchdog_device *wdog)
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	/* Ignore if already enabled(SC_TIMER_ERR_BUSY) */
67	if (res.a0 && res.a0 != SC_TIMER_ERR_BUSY)
68		return -EACCES;
69
70	arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_WDOG_ACT,
71		      SC_TIMER_WDOG_ACTION_PARTITION,
72		      0, 0, 0, 0, 0, &res);
73	return res.a0 ? -EACCES : 0;
74}
75
76static int imx_sc_wdt_stop(struct watchdog_device *wdog)
77{
78	struct arm_smccc_res res;
79
80	arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_STOP_WDOG,
81		      0, 0, 0, 0, 0, 0, &res);
82
83	return res.a0 ? -EACCES : 0;
84}
85
86static int imx_sc_wdt_set_timeout(struct watchdog_device *wdog,
87				unsigned int timeout)
88{
89	struct arm_smccc_res res;
90
91	wdog->timeout = timeout;
92	arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_TIMEOUT_WDOG,
93		      timeout * 1000, 0, 0, 0, 0, 0, &res);
94
95	return res.a0 ? -EACCES : 0;
96}
97
98static int imx_sc_wdt_set_pretimeout(struct watchdog_device *wdog,
99				     unsigned int pretimeout)
100{
101	struct arm_smccc_res res;
102
103	/*
104	 * SCU firmware calculates pretimeout based on current time
105	 * stamp instead of watchdog timeout stamp, need to convert
106	 * the pretimeout to SCU firmware's timeout value.
107	 */
108	arm_smccc_smc(IMX_SIP_TIMER, IMX_SIP_TIMER_SET_PRETIME_WDOG,
109		      (wdog->timeout - pretimeout) * 1000, 0, 0, 0,
110		      0, 0, &res);
111	if (res.a0)
112		return -EACCES;
113
114	wdog->pretimeout = pretimeout;
115
116	return 0;
117}
118
119static int imx_sc_wdt_notify(struct notifier_block *nb,
120			     unsigned long event, void *group)
121{
122	struct imx_sc_wdt_device *imx_sc_wdd =
123				 container_of(nb,
124					      struct imx_sc_wdt_device,
125					      wdt_notifier);
126
127	if (event & SC_IRQ_WDOG &&
128	    *(u8 *)group == SC_IRQ_GROUP_WDOG)
129		watchdog_notify_pretimeout(&imx_sc_wdd->wdd);
130
131	return 0;
132}
133
134static void imx_sc_wdt_action(void *data)
135{
136	struct notifier_block *wdt_notifier = data;
137
138	imx_scu_irq_unregister_notifier(wdt_notifier);
139	imx_scu_irq_group_enable(SC_IRQ_GROUP_WDOG,
140				 SC_IRQ_WDOG,
141				 false);
142}
143
144static const struct watchdog_ops imx_sc_wdt_ops = {
145	.owner = THIS_MODULE,
146	.start = imx_sc_wdt_start,
147	.stop  = imx_sc_wdt_stop,
148	.ping  = imx_sc_wdt_ping,
149	.set_timeout = imx_sc_wdt_set_timeout,
150	.set_pretimeout = imx_sc_wdt_set_pretimeout,
151};
152
153static struct watchdog_info imx_sc_wdt_info = {
154	.identity	= "i.MX SC watchdog timer",
155	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
156			  WDIOF_MAGICCLOSE,
157};
158
159static int imx_sc_wdt_probe(struct platform_device *pdev)
160{
161	struct imx_sc_wdt_device *imx_sc_wdd;
162	struct watchdog_device *wdog;
163	struct device *dev = &pdev->dev;
164	int ret;
165
166	imx_sc_wdd = devm_kzalloc(dev, sizeof(*imx_sc_wdd), GFP_KERNEL);
167	if (!imx_sc_wdd)
168		return -ENOMEM;
169
170	platform_set_drvdata(pdev, imx_sc_wdd);
171
172	wdog = &imx_sc_wdd->wdd;
173	wdog->info = &imx_sc_wdt_info;
174	wdog->ops = &imx_sc_wdt_ops;
175	wdog->min_timeout = 1;
176	wdog->max_timeout = MAX_TIMEOUT;
177	wdog->parent = dev;
178	wdog->timeout = DEFAULT_TIMEOUT;
179
180	watchdog_init_timeout(wdog, 0, dev);
181
182	ret = imx_sc_wdt_set_timeout(wdog, wdog->timeout);
183	if (ret)
184		return ret;
185
186	watchdog_stop_on_reboot(wdog);
187	watchdog_stop_on_unregister(wdog);
188
189	ret = imx_scu_irq_group_enable(SC_IRQ_GROUP_WDOG,
190				       SC_IRQ_WDOG,
191				       true);
192	if (ret) {
193		dev_warn(dev, "Enable irq failed, pretimeout NOT supported\n");
194		goto register_device;
195	}
196
197	imx_sc_wdd->wdt_notifier.notifier_call = imx_sc_wdt_notify;
198	ret = imx_scu_irq_register_notifier(&imx_sc_wdd->wdt_notifier);
199	if (ret) {
200		imx_scu_irq_group_enable(SC_IRQ_GROUP_WDOG,
201					 SC_IRQ_WDOG,
202					 false);
203		dev_warn(dev,
204			 "Register irq notifier failed, pretimeout NOT supported\n");
205		goto register_device;
206	}
207
208	ret = devm_add_action_or_reset(dev, imx_sc_wdt_action,
209				       &imx_sc_wdd->wdt_notifier);
210	if (!ret)
211		imx_sc_wdt_info.options |= WDIOF_PRETIMEOUT;
212	else
213		dev_warn(dev, "Add action failed, pretimeout NOT supported\n");
214
215register_device:
216	return devm_watchdog_register_device(dev, wdog);
217}
218
219static int __maybe_unused imx_sc_wdt_suspend(struct device *dev)
220{
221	struct imx_sc_wdt_device *imx_sc_wdd = dev_get_drvdata(dev);
222
223	if (watchdog_active(&imx_sc_wdd->wdd))
224		imx_sc_wdt_stop(&imx_sc_wdd->wdd);
225
226	return 0;
227}
228
229static int __maybe_unused imx_sc_wdt_resume(struct device *dev)
230{
231	struct imx_sc_wdt_device *imx_sc_wdd = dev_get_drvdata(dev);
232
233	if (watchdog_active(&imx_sc_wdd->wdd))
234		imx_sc_wdt_start(&imx_sc_wdd->wdd);
235
236	return 0;
237}
238
239static SIMPLE_DEV_PM_OPS(imx_sc_wdt_pm_ops,
240			 imx_sc_wdt_suspend, imx_sc_wdt_resume);
241
242static const struct of_device_id imx_sc_wdt_dt_ids[] = {
243	{ .compatible = "fsl,imx-sc-wdt", },
244	{ /* sentinel */ }
245};
246MODULE_DEVICE_TABLE(of, imx_sc_wdt_dt_ids);
247
248static struct platform_driver imx_sc_wdt_driver = {
249	.probe		= imx_sc_wdt_probe,
250	.driver		= {
251		.name	= "imx-sc-wdt",
252		.of_match_table = imx_sc_wdt_dt_ids,
253		.pm	= &imx_sc_wdt_pm_ops,
254	},
255};
256module_platform_driver(imx_sc_wdt_driver);
257
258MODULE_AUTHOR("Robin Gong <yibin.gong@nxp.com>");
259MODULE_DESCRIPTION("NXP i.MX system controller watchdog driver");
260MODULE_LICENSE("GPL v2");
261