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 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
 78static 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
 95static 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
105static 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
117static 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
138static 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
153static 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
163static 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
172static 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
178static 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
237register_device:
238	return devm_watchdog_register_device(dev, wdog);
239}
240
241static const struct of_device_id imx_sc_wdt_dt_ids[] = {
242	{ .compatible = "fsl,imx-sc-wdt", },
243	{ /* sentinel */ }
244};
245MODULE_DEVICE_TABLE(of, imx_sc_wdt_dt_ids);
246
247static 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};
254module_platform_driver(imx_sc_wdt_driver);
255
256MODULE_AUTHOR("Robin Gong <yibin.gong@nxp.com>");
257MODULE_DESCRIPTION("NXP i.MX system controller watchdog driver");
258MODULE_LICENSE("GPL v2");