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
 38static bool nowayout = WATCHDOG_NOWAYOUT;
 39module_param(nowayout, bool, 0000);
 40MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 41		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 42
 43struct imx_sc_wdt_device {
 44	struct watchdog_device wdd;
 45	struct notifier_block wdt_notifier;
 46};
 47
 48static 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
 58static 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
 73static 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
 83static 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
 95static 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
116static 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
131static 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
141static 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
150static 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
156static 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
212register_device:
213	return devm_watchdog_register_device(dev, wdog);
214}
215
216static 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
226static 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
236static SIMPLE_DEV_PM_OPS(imx_sc_wdt_pm_ops,
237			 imx_sc_wdt_suspend, imx_sc_wdt_resume);
238
239static const struct of_device_id imx_sc_wdt_dt_ids[] = {
240	{ .compatible = "fsl,imx-sc-wdt", },
241	{ /* sentinel */ }
242};
243MODULE_DEVICE_TABLE(of, imx_sc_wdt_dt_ids);
244
245static 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};
253module_platform_driver(imx_sc_wdt_driver);
254
255MODULE_AUTHOR("Robin Gong <yibin.gong@nxp.com>");
256MODULE_DESCRIPTION("NXP i.MX system controller watchdog driver");
257MODULE_LICENSE("GPL v2");