Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[linux-2.6-block.git] / drivers / watchdog / renesas_wdt.c
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3bed02a2 1// SPDX-License-Identifier: GPL-2.0
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2/*
3 * Watchdog driver for Renesas WDT watchdog
4 *
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5 * Copyright (C) 2015-17 Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
6 * Copyright (C) 2015-17 Renesas Electronics Corporation
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7 */
8#include <linux/bitops.h>
9#include <linux/clk.h>
10#include <linux/io.h>
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/of.h>
14#include <linux/platform_device.h>
15#include <linux/pm_runtime.h>
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16#include <linux/smp.h>
17#include <linux/sys_soc.h>
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18#include <linux/watchdog.h>
19
20#define RWTCNT 0
21#define RWTCSRA 4
22#define RWTCSRA_WOVF BIT(4)
23#define RWTCSRA_WRFLG BIT(5)
24#define RWTCSRA_TME BIT(7)
03a196f2 25#define RWTCSRB 8
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26
27#define RWDT_DEFAULT_TIMEOUT 60U
28
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29/*
30 * In probe, clk_rate is checked to be not more than 16 bit * biggest clock
03a196f2 31 * divider (12 bits). d is only a factor to fully utilize the WDT counter and
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32 * will not exceed its 16 bits. Thus, no overflow, we stay below 32 bits.
33 */
34#define MUL_BY_CLKS_PER_SEC(p, d) \
35 DIV_ROUND_UP((d) * (p)->clk_rate, clk_divs[(p)->cks])
36
03a196f2 37/* d is 16 bit, clk_divs 12 bit -> no 32 bit overflow */
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38#define DIV_BY_CLKS_PER_SEC(p, d) ((d) * clk_divs[(p)->cks] / (p)->clk_rate)
39
03a196f2 40static const unsigned int clk_divs[] = { 1, 4, 16, 32, 64, 128, 1024, 4096 };
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41
42static bool nowayout = WATCHDOG_NOWAYOUT;
43module_param(nowayout, bool, 0);
44MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
45 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
46
47struct rwdt_priv {
48 void __iomem *base;
49 struct watchdog_device wdev;
82f64cd2 50 unsigned long clk_rate;
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51 u8 cks;
52};
53
54static void rwdt_write(struct rwdt_priv *priv, u32 val, unsigned int reg)
55{
56 if (reg == RWTCNT)
57 val |= 0x5a5a0000;
58 else
59 val |= 0xa5a5a500;
60
61 writel_relaxed(val, priv->base + reg);
62}
63
64static int rwdt_init_timeout(struct watchdog_device *wdev)
65{
66 struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
67
82f64cd2 68 rwdt_write(priv, 65536 - MUL_BY_CLKS_PER_SEC(priv, wdev->timeout), RWTCNT);
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69
70 return 0;
71}
72
73static int rwdt_start(struct watchdog_device *wdev)
74{
75 struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
e990e127 76 u8 val;
bd99b68e 77
3be42941 78 pm_runtime_get_sync(wdev->parent);
bd99b68e 79
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80 /* Stop the timer before we modify any register */
81 val = readb_relaxed(priv->base + RWTCSRA) & ~RWTCSRA_TME;
82 rwdt_write(priv, val, RWTCSRA);
83
bd99b68e 84 rwdt_init_timeout(wdev);
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85 rwdt_write(priv, priv->cks, RWTCSRA);
86 rwdt_write(priv, 0, RWTCSRB);
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87
88 while (readb_relaxed(priv->base + RWTCSRA) & RWTCSRA_WRFLG)
89 cpu_relax();
90
91 rwdt_write(priv, priv->cks | RWTCSRA_TME, RWTCSRA);
92
93 return 0;
94}
95
96static int rwdt_stop(struct watchdog_device *wdev)
97{
98 struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
99
100 rwdt_write(priv, priv->cks, RWTCSRA);
3be42941 101 pm_runtime_put(wdev->parent);
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102
103 return 0;
104}
105
106static unsigned int rwdt_get_timeleft(struct watchdog_device *wdev)
107{
108 struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
109 u16 val = readw_relaxed(priv->base + RWTCNT);
110
82f64cd2 111 return DIV_BY_CLKS_PER_SEC(priv, 65536 - val);
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112}
113
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114static int rwdt_restart(struct watchdog_device *wdev, unsigned long action,
115 void *data)
116{
117 struct rwdt_priv *priv = watchdog_get_drvdata(wdev);
118
119 rwdt_start(wdev);
120 rwdt_write(priv, 0xffff, RWTCNT);
121 return 0;
122}
123
bd99b68e 124static const struct watchdog_info rwdt_ident = {
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125 .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
126 WDIOF_CARDRESET,
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127 .identity = "Renesas WDT Watchdog",
128};
129
130static const struct watchdog_ops rwdt_ops = {
131 .owner = THIS_MODULE,
132 .start = rwdt_start,
133 .stop = rwdt_stop,
134 .ping = rwdt_init_timeout,
135 .get_timeleft = rwdt_get_timeleft,
089bcaa8 136 .restart = rwdt_restart,
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137};
138
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139#if defined(CONFIG_ARCH_RCAR_GEN2) && defined(CONFIG_SMP)
140/*
141 * Watchdog-reset integration is broken on early revisions of R-Car Gen2 SoCs
142 */
143static const struct soc_device_attribute rwdt_quirks_match[] = {
144 {
145 .soc_id = "r8a7790",
146 .revision = "ES1.*",
147 .data = (void *)1, /* needs single CPU */
148 }, {
149 .soc_id = "r8a7791",
665f9442 150 .revision = "ES1.*",
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151 .data = (void *)1, /* needs single CPU */
152 }, {
153 .soc_id = "r8a7792",
154 .revision = "*",
155 .data = (void *)0, /* needs SMP disabled */
156 },
157 { /* sentinel */ }
158};
159
160static bool rwdt_blacklisted(struct device *dev)
161{
162 const struct soc_device_attribute *attr;
163
164 attr = soc_device_match(rwdt_quirks_match);
165 if (attr && setup_max_cpus > (uintptr_t)attr->data) {
166 dev_info(dev, "Watchdog blacklisted on %s %s\n", attr->soc_id,
167 attr->revision);
168 return true;
169 }
170
171 return false;
172}
173#else /* !CONFIG_ARCH_RCAR_GEN2 || !CONFIG_SMP */
174static inline bool rwdt_blacklisted(struct device *dev) { return false; }
175#endif /* !CONFIG_ARCH_RCAR_GEN2 || !CONFIG_SMP */
176
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177static int rwdt_probe(struct platform_device *pdev)
178{
179 struct rwdt_priv *priv;
180 struct resource *res;
9c22b6d3 181 struct clk *clk;
82f64cd2 182 unsigned long clks_per_sec;
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183 int ret, i;
184
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185 if (rwdt_blacklisted(&pdev->dev))
186 return -ENODEV;
187
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188 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
189 if (!priv)
190 return -ENOMEM;
191
192 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
193 priv->base = devm_ioremap_resource(&pdev->dev, res);
194 if (IS_ERR(priv->base))
195 return PTR_ERR(priv->base);
196
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197 clk = devm_clk_get(&pdev->dev, NULL);
198 if (IS_ERR(clk))
199 return PTR_ERR(clk);
bd99b68e 200
3be42941 201 pm_runtime_enable(&pdev->dev);
3be42941 202 pm_runtime_get_sync(&pdev->dev);
9c22b6d3 203 priv->clk_rate = clk_get_rate(clk);
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204 priv->wdev.bootstatus = (readb_relaxed(priv->base + RWTCSRA) &
205 RWTCSRA_WOVF) ? WDIOF_CARDRESET : 0;
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206 pm_runtime_put(&pdev->dev);
207
208 if (!priv->clk_rate) {
209 ret = -ENOENT;
210 goto out_pm_disable;
211 }
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212
213 for (i = ARRAY_SIZE(clk_divs) - 1; i >= 0; i--) {
82f64cd2 214 clks_per_sec = priv->clk_rate / clk_divs[i];
b51247c8 215 if (clks_per_sec && clks_per_sec < 65536) {
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216 priv->cks = i;
217 break;
218 }
219 }
220
b51247c8 221 if (i < 0) {
bd99b68e 222 dev_err(&pdev->dev, "Can't find suitable clock divider\n");
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223 ret = -ERANGE;
224 goto out_pm_disable;
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225 }
226
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227 priv->wdev.info = &rwdt_ident;
228 priv->wdev.ops = &rwdt_ops;
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229 priv->wdev.parent = &pdev->dev;
230 priv->wdev.min_timeout = 1;
82f64cd2 231 priv->wdev.max_timeout = DIV_BY_CLKS_PER_SEC(priv, 65536);
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232 priv->wdev.timeout = min(priv->wdev.max_timeout, RWDT_DEFAULT_TIMEOUT);
233
234 platform_set_drvdata(pdev, priv);
235 watchdog_set_drvdata(&priv->wdev, priv);
236 watchdog_set_nowayout(&priv->wdev, nowayout);
089bcaa8 237 watchdog_set_restart_priority(&priv->wdev, 0);
14de99b4 238 watchdog_stop_on_unregister(&priv->wdev);
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239
240 /* This overrides the default timeout only if DT configuration was found */
241 ret = watchdog_init_timeout(&priv->wdev, 0, &pdev->dev);
242 if (ret)
243 dev_warn(&pdev->dev, "Specified timeout value invalid, using default\n");
244
245 ret = watchdog_register_device(&priv->wdev);
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246 if (ret < 0)
247 goto out_pm_disable;
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248
249 return 0;
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250
251 out_pm_disable:
252 pm_runtime_disable(&pdev->dev);
253 return ret;
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254}
255
256static int rwdt_remove(struct platform_device *pdev)
257{
258 struct rwdt_priv *priv = platform_get_drvdata(pdev);
259
260 watchdog_unregister_device(&priv->wdev);
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261 pm_runtime_disable(&pdev->dev);
262
263 return 0;
264}
265
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266static int __maybe_unused rwdt_suspend(struct device *dev)
267{
268 struct rwdt_priv *priv = dev_get_drvdata(dev);
269
9077123c 270 if (watchdog_active(&priv->wdev))
07278ca1 271 rwdt_stop(&priv->wdev);
9077123c 272
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273 return 0;
274}
275
276static int __maybe_unused rwdt_resume(struct device *dev)
277{
278 struct rwdt_priv *priv = dev_get_drvdata(dev);
279
9077123c 280 if (watchdog_active(&priv->wdev))
07278ca1 281 rwdt_start(&priv->wdev);
9077123c 282
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283 return 0;
284}
285
286static SIMPLE_DEV_PM_OPS(rwdt_pm_ops, rwdt_suspend, rwdt_resume);
287
bd99b68e 288static const struct of_device_id rwdt_ids[] = {
3fe95e6c 289 { .compatible = "renesas,rcar-gen2-wdt", },
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290 { .compatible = "renesas,rcar-gen3-wdt", },
291 { /* sentinel */ }
292};
293MODULE_DEVICE_TABLE(of, rwdt_ids);
294
295static struct platform_driver rwdt_driver = {
296 .driver = {
297 .name = "renesas_wdt",
298 .of_match_table = rwdt_ids,
07278ca1 299 .pm = &rwdt_pm_ops,
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300 },
301 .probe = rwdt_probe,
302 .remove = rwdt_remove,
303};
304module_platform_driver(rwdt_driver);
305
306MODULE_DESCRIPTION("Renesas WDT Watchdog Driver");
307MODULE_LICENSE("GPL v2");
308MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");