1 // SPDX-License-Identifier: GPL-2.0
5  * Copyright (C) 2015-17 Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
6  * Copyright (C) 2015-17 Renesas Electronics Corporation
9 #include <linux/clk.h>
10 #include <linux/delay.h>
36 	DIV_ROUND_UP((d) * (p)->clk_rate, clk_divs[(p)->cks])
38 /* d is 16 bit, clk_divs 12 bit -> no 32 bit overflow */
39 #define DIV_BY_CLKS_PER_SEC(p, d) ((d) * clk_divs[(p)->cks] / (p)->clk_rate)
62 	writel_relaxed(val, priv->base + reg);  in rwdt_write()
69 	rwdt_write(priv, 65536 - MUL_BY_CLKS_PER_SEC(priv, wdev->timeout), RWTCNT);  in rwdt_init_timeout()
74 static void rwdt_wait_cycles(struct rwdt_priv *priv, unsigned int cycles)  in rwdt_wait_cycles()  argument
76 	unsigned int delay;  in rwdt_wait_cycles()  local
78 	delay = DIV_ROUND_UP(cycles * 1000000, priv->clk_rate);  in rwdt_wait_cycles()
80 	usleep_range(delay, 2 * delay);  in rwdt_wait_cycles()
88 	pm_runtime_get_sync(wdev->parent);  in rwdt_start()
91 	val = readb_relaxed(priv->base + RWTCSRA) & ~RWTCSRA_TME;  in rwdt_start()
93 	/* Delay 2 cycles before setting watchdog counter */  in rwdt_start()
97 	rwdt_write(priv, priv->cks, RWTCSRA);  in rwdt_start()
100 	while (readb_relaxed(priv->base + RWTCSRA) & RWTCSRA_WRFLG)  in rwdt_start()
103 	rwdt_write(priv, priv->cks | RWTCSRA_TME, RWTCSRA);  in rwdt_start()
112 	rwdt_write(priv, priv->cks, RWTCSRA);  in rwdt_stop()
113 	/* Delay 3 cycles before disabling module clock */  in rwdt_stop()
115 	pm_runtime_put(wdev->parent);  in rwdt_stop()
123 	u16 val = readw_relaxed(priv->base + RWTCNT);  in rwdt_get_timeleft()
125 	return DIV_BY_CLKS_PER_SEC(priv, 65536 - val);  in rwdt_get_timeleft()
155  * Watchdog-reset integration is broken on early revisions of R-Car Gen2 SoCs
178 	if (attr && setup_max_cpus > (uintptr_t)attr->data) {  in rwdt_blacklisted()
179 		dev_info(dev, "Watchdog blacklisted on %s %s\n", attr->soc_id,  in rwdt_blacklisted()
180 			 attr->revision);  in rwdt_blacklisted()
192 	struct device *dev = &pdev->dev;  in rwdt_probe()
194 	struct clk *clk;  in rwdt_probe()  local
200 		return -ENODEV;  in rwdt_probe()
204 		return -ENOMEM;  in rwdt_probe()
206 	priv->base = devm_platform_ioremap_resource(pdev, 0);  in rwdt_probe()
207 	if (IS_ERR(priv->base))  in rwdt_probe()
208 		return PTR_ERR(priv->base);  in rwdt_probe()
210 	clk = devm_clk_get(dev, NULL);  in rwdt_probe()
211 	if (IS_ERR(clk))  in rwdt_probe()
212 		return PTR_ERR(clk);  in rwdt_probe()
216 	priv->clk_rate = clk_get_rate(clk);  in rwdt_probe()
217 	csra = readb_relaxed(priv->base + RWTCSRA);  in rwdt_probe()
218 	priv->wdev.bootstatus = csra & RWTCSRA_WOVF ? WDIOF_CARDRESET : 0;  in rwdt_probe()
221 	if (!priv->clk_rate) {  in rwdt_probe()
222 		ret = -ENOENT;  in rwdt_probe()
226 	for (i = ARRAY_SIZE(clk_divs) - 1; i >= 0; i--) {  in rwdt_probe()
227 		clks_per_sec = priv->clk_rate / clk_divs[i];  in rwdt_probe()
229 			priv->cks = i;  in rwdt_probe()
236 		ret = -ERANGE;  in rwdt_probe()
240 	priv->wdev.info = &rwdt_ident;  in rwdt_probe()
241 	priv->wdev.ops = &rwdt_ops;  in rwdt_probe()
242 	priv->wdev.parent = dev;  in rwdt_probe()
243 	priv->wdev.min_timeout = 1;  in rwdt_probe()
244 	priv->wdev.max_timeout = DIV_BY_CLKS_PER_SEC(priv, 65536);  in rwdt_probe()
245 	priv->wdev.timeout = min(priv->wdev.max_timeout, RWDT_DEFAULT_TIMEOUT);  in rwdt_probe()
248 	watchdog_set_drvdata(&priv->wdev, priv);  in rwdt_probe()
249 	watchdog_set_nowayout(&priv->wdev, nowayout);  in rwdt_probe()
250 	watchdog_set_restart_priority(&priv->wdev, 0);  in rwdt_probe()
251 	watchdog_stop_on_unregister(&priv->wdev);  in rwdt_probe()
254 	watchdog_init_timeout(&priv->wdev, 0, dev);  in rwdt_probe()
259 		rwdt_start(&priv->wdev);  in rwdt_probe()
260 		set_bit(WDOG_HW_RUNNING, &priv->wdev.status);  in rwdt_probe()
263 	ret = watchdog_register_device(&priv->wdev);  in rwdt_probe()
278 	watchdog_unregister_device(&priv->wdev);  in rwdt_remove()
279 	pm_runtime_disable(&pdev->dev);  in rwdt_remove()
288 	if (watchdog_active(&priv->wdev))  in rwdt_suspend()
289 		rwdt_stop(&priv->wdev);  in rwdt_suspend()
298 	if (watchdog_active(&priv->wdev))  in rwdt_resume()
299 		rwdt_start(&priv->wdev);  in rwdt_resume()
307 	{ .compatible = "renesas,rcar-gen2-wdt", },
308 	{ .compatible = "renesas,rcar-gen3-wdt", },
326 MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");