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 struct meson_gxbb_wdt {
33 void __iomem *reg_base;
34 struct watchdog_device wdt_dev;
35 struct clk *clk;
36 };
37
meson_gxbb_wdt_start(struct watchdog_device * wdt_dev)38 static int meson_gxbb_wdt_start(struct watchdog_device *wdt_dev)
39 {
40 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
41
42 writel(readl(data->reg_base + GXBB_WDT_CTRL_REG) | GXBB_WDT_CTRL_EN,
43 data->reg_base + GXBB_WDT_CTRL_REG);
44
45 return 0;
46 }
47
meson_gxbb_wdt_stop(struct watchdog_device * wdt_dev)48 static int meson_gxbb_wdt_stop(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_ping(struct watchdog_device * wdt_dev)58 static int meson_gxbb_wdt_ping(struct watchdog_device *wdt_dev)
59 {
60 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
61
62 writel(0, data->reg_base + GXBB_WDT_RSET_REG);
63
64 return 0;
65 }
66
meson_gxbb_wdt_set_timeout(struct watchdog_device * wdt_dev,unsigned int timeout)67 static int meson_gxbb_wdt_set_timeout(struct watchdog_device *wdt_dev,
68 unsigned int timeout)
69 {
70 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
71 unsigned long tcnt = timeout * 1000;
72
73 if (tcnt > GXBB_WDT_TCNT_SETUP_MASK)
74 tcnt = GXBB_WDT_TCNT_SETUP_MASK;
75
76 wdt_dev->timeout = timeout;
77
78 meson_gxbb_wdt_ping(wdt_dev);
79
80 writel(tcnt, data->reg_base + GXBB_WDT_TCNT_REG);
81
82 return 0;
83 }
84
meson_gxbb_wdt_get_timeleft(struct watchdog_device * wdt_dev)85 static unsigned int meson_gxbb_wdt_get_timeleft(struct watchdog_device *wdt_dev)
86 {
87 struct meson_gxbb_wdt *data = watchdog_get_drvdata(wdt_dev);
88 unsigned long reg;
89
90 reg = readl(data->reg_base + GXBB_WDT_TCNT_REG);
91
92 return ((reg & GXBB_WDT_TCNT_SETUP_MASK) -
93 (reg >> GXBB_WDT_TCNT_CNT_SHIFT)) / 1000;
94 }
95
96 static const struct watchdog_ops meson_gxbb_wdt_ops = {
97 .start = meson_gxbb_wdt_start,
98 .stop = meson_gxbb_wdt_stop,
99 .ping = meson_gxbb_wdt_ping,
100 .set_timeout = meson_gxbb_wdt_set_timeout,
101 .get_timeleft = meson_gxbb_wdt_get_timeleft,
102 };
103
104 static const struct watchdog_info meson_gxbb_wdt_info = {
105 .identity = "Meson GXBB Watchdog",
106 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
107 };
108
meson_gxbb_wdt_resume(struct device * dev)109 static int __maybe_unused meson_gxbb_wdt_resume(struct device *dev)
110 {
111 struct meson_gxbb_wdt *data = dev_get_drvdata(dev);
112
113 if (watchdog_active(&data->wdt_dev))
114 meson_gxbb_wdt_start(&data->wdt_dev);
115
116 return 0;
117 }
118
meson_gxbb_wdt_suspend(struct device * dev)119 static int __maybe_unused meson_gxbb_wdt_suspend(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_stop(&data->wdt_dev);
125
126 return 0;
127 }
128
129 static const struct dev_pm_ops meson_gxbb_wdt_pm_ops = {
130 SET_SYSTEM_SLEEP_PM_OPS(meson_gxbb_wdt_suspend, meson_gxbb_wdt_resume)
131 };
132
133 static const struct of_device_id meson_gxbb_wdt_dt_ids[] = {
134 { .compatible = "amlogic,meson-gxbb-wdt", },
135 { /* sentinel */ },
136 };
137 MODULE_DEVICE_TABLE(of, meson_gxbb_wdt_dt_ids);
138
meson_clk_disable_unprepare(void * data)139 static void meson_clk_disable_unprepare(void *data)
140 {
141 clk_disable_unprepare(data);
142 }
143
meson_gxbb_wdt_probe(struct platform_device * pdev)144 static int meson_gxbb_wdt_probe(struct platform_device *pdev)
145 {
146 struct device *dev = &pdev->dev;
147 struct meson_gxbb_wdt *data;
148 int ret;
149
150 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
151 if (!data)
152 return -ENOMEM;
153
154 data->reg_base = devm_platform_ioremap_resource(pdev, 0);
155 if (IS_ERR(data->reg_base))
156 return PTR_ERR(data->reg_base);
157
158 data->clk = devm_clk_get(dev, NULL);
159 if (IS_ERR(data->clk))
160 return PTR_ERR(data->clk);
161
162 ret = clk_prepare_enable(data->clk);
163 if (ret)
164 return ret;
165 ret = devm_add_action_or_reset(dev, meson_clk_disable_unprepare,
166 data->clk);
167 if (ret)
168 return ret;
169
170 platform_set_drvdata(pdev, data);
171
172 data->wdt_dev.parent = dev;
173 data->wdt_dev.info = &meson_gxbb_wdt_info;
174 data->wdt_dev.ops = &meson_gxbb_wdt_ops;
175 data->wdt_dev.max_hw_heartbeat_ms = GXBB_WDT_TCNT_SETUP_MASK;
176 data->wdt_dev.min_timeout = 1;
177 data->wdt_dev.timeout = DEFAULT_TIMEOUT;
178 watchdog_set_drvdata(&data->wdt_dev, data);
179
180 /* Setup with 1ms timebase */
181 writel(((clk_get_rate(data->clk) / 1000) & GXBB_WDT_CTRL_DIV_MASK) |
182 GXBB_WDT_CTRL_EE_RESET |
183 GXBB_WDT_CTRL_CLK_EN |
184 GXBB_WDT_CTRL_CLKDIV_EN,
185 data->reg_base + GXBB_WDT_CTRL_REG);
186
187 meson_gxbb_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout);
188
189 watchdog_stop_on_reboot(&data->wdt_dev);
190 return devm_watchdog_register_device(dev, &data->wdt_dev);
191 }
192
193 static struct platform_driver meson_gxbb_wdt_driver = {
194 .probe = meson_gxbb_wdt_probe,
195 .driver = {
196 .name = "meson-gxbb-wdt",
197 .pm = &meson_gxbb_wdt_pm_ops,
198 .of_match_table = meson_gxbb_wdt_dt_ids,
199 },
200 };
201
202 module_platform_driver(meson_gxbb_wdt_driver);
203
204 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
205 MODULE_DESCRIPTION("Amlogic Meson GXBB Watchdog timer driver");
206 MODULE_LICENSE("Dual BSD/GPL");
207
