1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
2 /*
3 * Copyright (c) 2016 BayLibre, SAS.
4 * Author: Neil Armstrong <narmstrong@baylibre.com>
5 *
6 */
7 #include <linux/clk.h>
8 #include <linux/err.h>
9 #include <linux/io.h>
10 #include <linux/module.h>
11 #include <linux/of.h>
12 #include <linux/platform_device.h>
13 #include <linux/slab.h>
14 #include <linux/types.h>
15 #include <linux/watchdog.h>
16
17 #define DEFAULT_TIMEOUT 30 /* seconds */
18
19 #define GXBB_WDT_CTRL_REG 0x0
20 #define GXBB_WDT_TCNT_REG 0x8
21 #define GXBB_WDT_RSET_REG 0xc
22
23 #define GXBB_WDT_CTRL_CLKDIV_EN BIT(25)
24 #define GXBB_WDT_CTRL_CLK_EN BIT(24)
25 #define GXBB_WDT_CTRL_EE_RESET BIT(21)
26 #define GXBB_WDT_CTRL_EN BIT(18)
27 #define GXBB_WDT_CTRL_DIV_MASK (BIT(18) - 1)
28
29 #define GXBB_WDT_TCNT_SETUP_MASK (BIT(16) - 1)
30 #define GXBB_WDT_TCNT_CNT_SHIFT 16
31
32 static bool nowayout = WATCHDOG_NOWAYOUT;
33 module_param(nowayout, bool, 0);
34 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started default="
35 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
36
37 static unsigned int timeout;
38 module_param(timeout, uint, 0);
39 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds="
40 __MODULE_STRING(DEFAULT_TIMEOUT) ")");
41
42 struct meson_gxbb_wdt {
43 void __iomem *reg_base;
44 struct watchdog_device wdt_dev;
45 struct clk *clk;
46 };
47
meson_gxbb_wdt_start(struct watchdog_device * wdt_dev)48 static int meson_gxbb_wdt_start(struct watchdog_device *wdt_dev)
49 {
50 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
51
52 writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) | GXBB_WDT_CTRL_EN,
53 data->reg_base + GXBB_WDT_CTRL_REG);
54
55 return 0;
56 }
57
meson_gxbb_wdt_stop(struct watchdog_device * wdt_dev)58 static int meson_gxbb_wdt_stop(struct watchdog_device *wdt_dev)
59 {
60 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
61
62 writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) & ~GXBB_WDT_CTRL_EN,
63 data->reg_base + GXBB_WDT_CTRL_REG);
64
65 return 0;
66 }
67
meson_gxbb_wdt_ping(struct watchdog_device * wdt_dev)68 static int meson_gxbb_wdt_ping(struct watchdog_device *wdt_dev)
69 {
70 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
71
72 writel(0, data->reg_base + GXBB_WDT_RSET_REG);
73
74 return 0;
75 }
76
meson_gxbb_wdt_set_timeout(struct watchdog_device * wdt_dev,unsigned int timeout)77 static int meson_gxbb_wdt_set_timeout(struct watchdog_device *wdt_dev,
78 unsigned int timeout)
79 {
80 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
81 unsigned long tcnt = timeout * 1000;
82
83 if (tcnt > GXBB_WDT_TCNT_SETUP_MASK)
84 tcnt = GXBB_WDT_TCNT_SETUP_MASK;
85
86 wdt_dev->timeout = timeout;
87
88 meson_gxbb_wdt_ping(wdt_dev);
89
90 writel(tcnt, data->reg_base + GXBB_WDT_TCNT_REG);
91
92 return 0;
93 }
94
meson_gxbb_wdt_get_timeleft(struct watchdog_device * wdt_dev)95 static unsigned int meson_gxbb_wdt_get_timeleft(struct watchdog_device *wdt_dev)
96 {
97 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
98 unsigned long reg;
99
100 reg = readl(data->reg_base + GXBB_WDT_TCNT_REG);
101
102 return ((reg & GXBB_WDT_TCNT_SETUP_MASK) -
103 (reg >> GXBB_WDT_TCNT_CNT_SHIFT)) / 1000;
104 }
105
106 static const struct watchdog_ops meson_gxbb_wdt_ops = {
107 .start = meson_gxbb_wdt_start,
108 .stop = meson_gxbb_wdt_stop,
109 .ping = meson_gxbb_wdt_ping,
110 .set_timeout = meson_gxbb_wdt_set_timeout,
111 .get_timeleft = meson_gxbb_wdt_get_timeleft,
112 };
113
114 static const struct watchdog_info meson_gxbb_wdt_info = {
115 .identity = "Meson GXBB Watchdog",
116 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
117 };
118
meson_gxbb_wdt_resume(struct device * dev)119 static int __maybe_unused meson_gxbb_wdt_resume(struct device *dev)
120 {
121 struct meson_gxbb_wdt *data = dev_get_drvdata(dev);
122
123 if (watchdog_active(&data->wdt_dev))
124 meson_gxbb_wdt_start(&data->wdt_dev);
125
126 return 0;
127 }
128
meson_gxbb_wdt_suspend(struct device * dev)129 static int __maybe_unused meson_gxbb_wdt_suspend(struct device *dev)
130 {
131 struct meson_gxbb_wdt *data = dev_get_drvdata(dev);
132
133 if (watchdog_active(&data->wdt_dev))
134 meson_gxbb_wdt_stop(&data->wdt_dev);
135
136 return 0;
137 }
138
139 static const struct dev_pm_ops meson_gxbb_wdt_pm_ops = {
140 SET_SYSTEM_SLEEP_PM_OPS(meson_gxbb_wdt_suspend, meson_gxbb_wdt_resume)
141 };
142
143 static const struct of_device_id meson_gxbb_wdt_dt_ids[] = {
144 { .compatible = "amlogic,meson-gxbb-wdt", },
145 { /* sentinel */ },
146 };
147 MODULE_DEVICE_TABLE(of, meson_gxbb_wdt_dt_ids);
148
meson_clk_disable_unprepare(void * data)149 static void meson_clk_disable_unprepare(void *data)
150 {
151 clk_disable_unprepare(data);
152 }
153
meson_gxbb_wdt_probe(struct platform_device * pdev)154 static int meson_gxbb_wdt_probe(struct platform_device *pdev)
155 {
156 struct device *dev = &pdev->dev;
157 struct meson_gxbb_wdt *data;
158 int ret;
159
160 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
161 if (!data)
162 return -ENOMEM;
163
164 data->reg_base = devm_platform_ioremap_resource(pdev, 0);
165 if (IS_ERR(data->reg_base))
166 return PTR_ERR(data->reg_base);
167
168 data->clk = devm_clk_get(dev, NULL);
169 if (IS_ERR(data->clk))
170 return PTR_ERR(data->clk);
171
172 ret = clk_prepare_enable(data->clk);
173 if (ret)
174 return ret;
175 ret = devm_add_action_or_reset(dev, meson_clk_disable_unprepare,
176 data->clk);
177 if (ret)
178 return ret;
179
180 platform_set_drvdata(pdev, data);
181
182 data->wdt_dev.parent = dev;
183 data->wdt_dev.info = &meson_gxbb_wdt_info;
184 data->wdt_dev.ops = &meson_gxbb_wdt_ops;
185 data->wdt_dev.max_hw_heartbeat_ms = GXBB_WDT_TCNT_SETUP_MASK;
186 data->wdt_dev.min_timeout = 1;
187 data->wdt_dev.timeout = DEFAULT_TIMEOUT;
188 watchdog_init_timeout(&data->wdt_dev, timeout, dev);
189 watchdog_set_nowayout(&data->wdt_dev, nowayout);
190 watchdog_set_drvdata(&data->wdt_dev, data);
191
192 /* Setup with 1ms timebase */
193 writel(((clk_get_rate(data->clk) / 1000) & GXBB_WDT_CTRL_DIV_MASK) |
194 GXBB_WDT_CTRL_EE_RESET |
195 GXBB_WDT_CTRL_CLK_EN |
196 GXBB_WDT_CTRL_CLKDIV_EN,
197 data->reg_base + GXBB_WDT_CTRL_REG);
198
199 meson_gxbb_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout);
200
201 watchdog_stop_on_reboot(&data->wdt_dev);
202 return devm_watchdog_register_device(dev, &data->wdt_dev);
203 }
204
205 static struct platform_driver meson_gxbb_wdt_driver = {
206 .probe = meson_gxbb_wdt_probe,
207 .driver = {
208 .name = "meson-gxbb-wdt",
209 .pm = &meson_gxbb_wdt_pm_ops,
210 .of_match_table = meson_gxbb_wdt_dt_ids,
211 },
212 };
213
214 module_platform_driver(meson_gxbb_wdt_driver);
215
216 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
217 MODULE_DESCRIPTION("Amlogic Meson GXBB Watchdog timer driver");
218 MODULE_LICENSE("Dual BSD/GPL");
219