1 // SPDX-License-Identifier: GPL-2.0-or-later
7  * Copyright (C) 2001 - 2012  Paul Mundt <lethal@linux-sh.org>
9  * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
12  * 19-Apr-2002 Rob Radez <rob@osinvestor.com>
31 #include <linux/clk.h>
35 #define DRV_NAME "sh-wdt"
39  * values, consult the asm-sh/watchdog.h. Overload this at module load
43  * something quite higher than 100 (or we need a proper high-res timer
46  * the SH-4 and SH-5, this isn't necessarily that big of a problem, though
47  * for the SH-2 and SH-3, this isn't recommended unless the WDT is absolutely
65 #define next_ping_period(cks)	(jiffies + msecs_to_jiffies(cks - 4))
75 	struct clk		*clk;  member
85 	u8 csr;  in sh_wdt_start()  local
87 	pm_runtime_get_sync(wdt->dev);  in sh_wdt_start()
88 	clk_enable(wdt->clk);  in sh_wdt_start()
90 	spin_lock_irqsave(&wdt->lock, flags);  in sh_wdt_start()
93 	mod_timer(&wdt->timer, next_ping_period(clock_division_ratio));  in sh_wdt_start()
95 	csr = sh_wdt_read_csr();  in sh_wdt_start()
96 	csr |= WTCSR_WT | clock_division_ratio;  in sh_wdt_start()
97 	sh_wdt_write_csr(csr);  in sh_wdt_start()
103 	 * process.. starting with SH-3, RSTS was moved to WTCSR, and the  in sh_wdt_start()
106 	 * On the SH-2 however, in addition with bits being in different  in sh_wdt_start()
109 	csr = sh_wdt_read_csr();  in sh_wdt_start()
110 	csr |= WTCSR_TME;  in sh_wdt_start()
111 	csr &= ~WTCSR_RSTS;  in sh_wdt_start()
112 	sh_wdt_write_csr(csr);  in sh_wdt_start()
115 	csr = sh_wdt_read_rstcsr();  in sh_wdt_start()
116 	csr &= ~RSTCSR_RSTS;  in sh_wdt_start()
117 	sh_wdt_write_rstcsr(csr);  in sh_wdt_start()
119 	spin_unlock_irqrestore(&wdt->lock, flags);  in sh_wdt_start()
128 	u8 csr;  in sh_wdt_stop()  local
130 	spin_lock_irqsave(&wdt->lock, flags);  in sh_wdt_stop()
132 	del_timer(&wdt->timer);  in sh_wdt_stop()
134 	csr = sh_wdt_read_csr();  in sh_wdt_stop()
135 	csr &= ~WTCSR_TME;  in sh_wdt_stop()
136 	sh_wdt_write_csr(csr);  in sh_wdt_stop()
138 	spin_unlock_irqrestore(&wdt->lock, flags);  in sh_wdt_stop()
140 	clk_disable(wdt->clk);  in sh_wdt_stop()
141 	pm_runtime_put_sync(wdt->dev);  in sh_wdt_stop()
151 	spin_lock_irqsave(&wdt->lock, flags);  in sh_wdt_keepalive()
153 	spin_unlock_irqrestore(&wdt->lock, flags);  in sh_wdt_keepalive()
164 		return -EINVAL;  in sh_wdt_set_heartbeat()
166 	spin_lock_irqsave(&wdt->lock, flags);  in sh_wdt_set_heartbeat()
168 	wdt_dev->timeout = t;  in sh_wdt_set_heartbeat()
169 	spin_unlock_irqrestore(&wdt->lock, flags);  in sh_wdt_set_heartbeat()
179 	spin_lock_irqsave(&wdt->lock, flags);  in sh_wdt_ping()
181 		u8 csr;  in sh_wdt_ping()  local
183 		csr = sh_wdt_read_csr();  in sh_wdt_ping()
184 		csr &= ~WTCSR_IOVF;  in sh_wdt_ping()
185 		sh_wdt_write_csr(csr);  in sh_wdt_ping()
189 		mod_timer(&wdt->timer, next_ping_period(clock_division_ratio));  in sh_wdt_ping()
191 		dev_warn(wdt->dev, "Heartbeat lost! Will not ping "  in sh_wdt_ping()
193 	spin_unlock_irqrestore(&wdt->lock, flags);  in sh_wdt_ping()
223 	 * any attempts to register per-CPU watchdogs.  in sh_wdt_probe()
225 	if (pdev->id != -1)  in sh_wdt_probe()
226 		return -EINVAL;  in sh_wdt_probe()
228 	wdt = devm_kzalloc(&pdev->dev, sizeof(struct sh_wdt), GFP_KERNEL);  in sh_wdt_probe()
230 		return -ENOMEM;  in sh_wdt_probe()
232 	wdt->dev = &pdev->dev;  in sh_wdt_probe()
234 	wdt->clk = devm_clk_get(&pdev->dev, NULL);  in sh_wdt_probe()
235 	if (IS_ERR(wdt->clk)) {  in sh_wdt_probe()
240 		wdt->clk = NULL;  in sh_wdt_probe()
243 	wdt->base = devm_platform_ioremap_resource(pdev, 0);  in sh_wdt_probe()
244 	if (IS_ERR(wdt->base))  in sh_wdt_probe()
245 		return PTR_ERR(wdt->base);  in sh_wdt_probe()
249 	sh_wdt_dev.parent = &pdev->dev;  in sh_wdt_probe()
251 	spin_lock_init(&wdt->lock);  in sh_wdt_probe()
258 		dev_warn(&pdev->dev,  in sh_wdt_probe()
263 	dev_info(&pdev->dev, "configured with heartbeat=%d sec (nowayout=%d)\n",  in sh_wdt_probe()
268 		dev_err(&pdev->dev, "Can't register watchdog (err=%d)\n", rc);  in sh_wdt_probe()
272 	timer_setup(&wdt->timer, sh_wdt_ping, 0);  in sh_wdt_probe()
273 	wdt->timer.expires	= next_ping_period(clock_division_ratio);  in sh_wdt_probe()
275 	dev_info(&pdev->dev, "initialized.\n");  in sh_wdt_probe()
277 	pm_runtime_enable(&pdev->dev);  in sh_wdt_probe()
286 	pm_runtime_disable(&pdev->dev);  in sh_wdt_remove()
324 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");