1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * drivers/char/watchdog/pnx4008_wdt.c
4 *
5 * Watchdog driver for PNX4008 board
6 *
7 * Authors: Dmitry Chigirev <source@mvista.com>,
8 * Vitaly Wool <vitalywool@gmail.com>
9 * Based on sa1100 driver,
10 * Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
11 *
12 * 2005-2006 (c) MontaVista Software, Inc.
13 *
14 * (C) 2012 Wolfram Sang, Pengutronix
15 */
16
17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19 #include <linux/module.h>
20 #include <linux/moduleparam.h>
21 #include <linux/types.h>
22 #include <linux/kernel.h>
23 #include <linux/watchdog.h>
24 #include <linux/platform_device.h>
25 #include <linux/clk.h>
26 #include <linux/spinlock.h>
27 #include <linux/io.h>
28 #include <linux/slab.h>
29 #include <linux/err.h>
30 #include <linux/of.h>
31 #include <linux/delay.h>
32 #include <linux/reboot.h>
33
34 /* WatchDog Timer - Chapter 23 Page 207 */
35
36 #define DEFAULT_HEARTBEAT 19
37 #define MAX_HEARTBEAT 60
38
39 /* Watchdog timer register set definition */
40 #define WDTIM_INT(p) ((p) + 0x0)
41 #define WDTIM_CTRL(p) ((p) + 0x4)
42 #define WDTIM_COUNTER(p) ((p) + 0x8)
43 #define WDTIM_MCTRL(p) ((p) + 0xC)
44 #define WDTIM_MATCH0(p) ((p) + 0x10)
45 #define WDTIM_EMR(p) ((p) + 0x14)
46 #define WDTIM_PULSE(p) ((p) + 0x18)
47 #define WDTIM_RES(p) ((p) + 0x1C)
48
49 /* WDTIM_INT bit definitions */
50 #define MATCH_INT 1
51
52 /* WDTIM_CTRL bit definitions */
53 #define COUNT_ENAB 1
54 #define RESET_COUNT (1 << 1)
55 #define DEBUG_EN (1 << 2)
56
57 /* WDTIM_MCTRL bit definitions */
58 #define MR0_INT 1
59 #undef RESET_COUNT0
60 #define RESET_COUNT0 (1 << 2)
61 #define STOP_COUNT0 (1 << 2)
62 #define M_RES1 (1 << 3)
63 #define M_RES2 (1 << 4)
64 #define RESFRC1 (1 << 5)
65 #define RESFRC2 (1 << 6)
66
67 /* WDTIM_EMR bit definitions */
68 #define EXT_MATCH0 1
69 #define MATCH_OUTPUT_HIGH (2 << 4) /*a MATCH_CTRL setting */
70
71 /* WDTIM_RES bit definitions */
72 #define WDOG_RESET 1 /* read only */
73
74 #define WDOG_COUNTER_RATE 13000000 /*the counter clock is 13 MHz fixed */
75
76 static bool nowayout = WATCHDOG_NOWAYOUT;
77 static unsigned int heartbeat;
78
79 static DEFINE_SPINLOCK(io_lock);
80 static void __iomem *wdt_base;
81 static struct clk *wdt_clk;
82
pnx4008_wdt_start(struct watchdog_device * wdd)83 static int pnx4008_wdt_start(struct watchdog_device *wdd)
84 {
85 spin_lock(&io_lock);
86
87 /* stop counter, initiate counter reset */
88 writel(RESET_COUNT, WDTIM_CTRL(wdt_base));
89 /*wait for reset to complete. 100% guarantee event */
90 while (readl(WDTIM_COUNTER(wdt_base)))
91 cpu_relax();
92 /* internal and external reset, stop after that */
93 writel(M_RES2 | STOP_COUNT0 | RESET_COUNT0, WDTIM_MCTRL(wdt_base));
94 /* configure match output */
95 writel(MATCH_OUTPUT_HIGH, WDTIM_EMR(wdt_base));
96 /* clear interrupt, just in case */
97 writel(MATCH_INT, WDTIM_INT(wdt_base));
98 /* the longest pulse period 65541/(13*10^6) seconds ~ 5 ms. */
99 writel(0xFFFF, WDTIM_PULSE(wdt_base));
100 writel(wdd->timeout * WDOG_COUNTER_RATE, WDTIM_MATCH0(wdt_base));
101 /*enable counter, stop when debugger active */
102 writel(COUNT_ENAB | DEBUG_EN, WDTIM_CTRL(wdt_base));
103
104 spin_unlock(&io_lock);
105 return 0;
106 }
107
pnx4008_wdt_stop(struct watchdog_device * wdd)108 static int pnx4008_wdt_stop(struct watchdog_device *wdd)
109 {
110 spin_lock(&io_lock);
111
112 writel(0, WDTIM_CTRL(wdt_base)); /*stop counter */
113
114 spin_unlock(&io_lock);
115 return 0;
116 }
117
pnx4008_wdt_set_timeout(struct watchdog_device * wdd,unsigned int new_timeout)118 static int pnx4008_wdt_set_timeout(struct watchdog_device *wdd,
119 unsigned int new_timeout)
120 {
121 wdd->timeout = new_timeout;
122 return 0;
123 }
124
pnx4008_restart_handler(struct watchdog_device * wdd,unsigned long mode,void * cmd)125 static int pnx4008_restart_handler(struct watchdog_device *wdd,
126 unsigned long mode, void *cmd)
127 {
128 const char *boot_cmd = cmd;
129
130 /*
131 * Verify if a "cmd" passed from the userspace program rebooting
132 * the system; if available, handle it.
133 * - For details, see the 'reboot' syscall in kernel/reboot.c
134 * - If the received "cmd" is not supported, use the default mode.
135 */
136 if (boot_cmd) {
137 if (boot_cmd[0] == 'h')
138 mode = REBOOT_HARD;
139 else if (boot_cmd[0] == 's')
140 mode = REBOOT_SOFT;
141 }
142
143 if (mode == REBOOT_SOFT) {
144 /* Force match output active */
145 writel(EXT_MATCH0, WDTIM_EMR(wdt_base));
146 /* Internal reset on match output (RESOUT_N not asserted) */
147 writel(M_RES1, WDTIM_MCTRL(wdt_base));
148 } else {
149 /* Instant assert of RESETOUT_N with pulse length 1mS */
150 writel(13000, WDTIM_PULSE(wdt_base));
151 writel(M_RES2 | RESFRC1 | RESFRC2, WDTIM_MCTRL(wdt_base));
152 }
153
154 /* Wait for watchdog to reset system */
155 mdelay(1000);
156
157 return NOTIFY_DONE;
158 }
159
160 static const struct watchdog_info pnx4008_wdt_ident = {
161 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
162 WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
163 .identity = "PNX4008 Watchdog",
164 };
165
166 static const struct watchdog_ops pnx4008_wdt_ops = {
167 .owner = THIS_MODULE,
168 .start = pnx4008_wdt_start,
169 .stop = pnx4008_wdt_stop,
170 .set_timeout = pnx4008_wdt_set_timeout,
171 .restart = pnx4008_restart_handler,
172 };
173
174 static struct watchdog_device pnx4008_wdd = {
175 .info = &pnx4008_wdt_ident,
176 .ops = &pnx4008_wdt_ops,
177 .timeout = DEFAULT_HEARTBEAT,
178 .min_timeout = 1,
179 .max_timeout = MAX_HEARTBEAT,
180 };
181
pnx4008_clk_disable_unprepare(void * data)182 static void pnx4008_clk_disable_unprepare(void *data)
183 {
184 clk_disable_unprepare(data);
185 }
186
pnx4008_wdt_probe(struct platform_device * pdev)187 static int pnx4008_wdt_probe(struct platform_device *pdev)
188 {
189 struct device *dev = &pdev->dev;
190 int ret = 0;
191
192 watchdog_init_timeout(&pnx4008_wdd, heartbeat, dev);
193
194 wdt_base = devm_platform_ioremap_resource(pdev, 0);
195 if (IS_ERR(wdt_base))
196 return PTR_ERR(wdt_base);
197
198 wdt_clk = devm_clk_get(dev, NULL);
199 if (IS_ERR(wdt_clk))
200 return PTR_ERR(wdt_clk);
201
202 ret = clk_prepare_enable(wdt_clk);
203 if (ret)
204 return ret;
205 ret = devm_add_action_or_reset(dev, pnx4008_clk_disable_unprepare,
206 wdt_clk);
207 if (ret)
208 return ret;
209
210 pnx4008_wdd.bootstatus = (readl(WDTIM_RES(wdt_base)) & WDOG_RESET) ?
211 WDIOF_CARDRESET : 0;
212 pnx4008_wdd.parent = dev;
213 watchdog_set_nowayout(&pnx4008_wdd, nowayout);
214 watchdog_set_restart_priority(&pnx4008_wdd, 128);
215
216 if (readl(WDTIM_CTRL(wdt_base)) & COUNT_ENAB)
217 set_bit(WDOG_HW_RUNNING, &pnx4008_wdd.status);
218
219 ret = devm_watchdog_register_device(dev, &pnx4008_wdd);
220 if (ret < 0)
221 return ret;
222
223 dev_info(dev, "heartbeat %d sec\n", pnx4008_wdd.timeout);
224
225 return 0;
226 }
227
228 #ifdef CONFIG_OF
229 static const struct of_device_id pnx4008_wdt_match[] = {
230 { .compatible = "nxp,pnx4008-wdt" },
231 { }
232 };
233 MODULE_DEVICE_TABLE(of, pnx4008_wdt_match);
234 #endif
235
236 static struct platform_driver platform_wdt_driver = {
237 .driver = {
238 .name = "pnx4008-watchdog",
239 .of_match_table = of_match_ptr(pnx4008_wdt_match),
240 },
241 .probe = pnx4008_wdt_probe,
242 };
243
244 module_platform_driver(platform_wdt_driver);
245
246 MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
247 MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
248 MODULE_DESCRIPTION("PNX4008 Watchdog Driver");
249
250 module_param(heartbeat, uint, 0);
251 MODULE_PARM_DESC(heartbeat,
252 "Watchdog heartbeat period in seconds from 1 to "
253 __MODULE_STRING(MAX_HEARTBEAT) ", default "
254 __MODULE_STRING(DEFAULT_HEARTBEAT));
255
256 module_param(nowayout, bool, 0);
257 MODULE_PARM_DESC(nowayout,
258 "Set to 1 to keep watchdog running after device release");
259
260 MODULE_LICENSE("GPL");
261 MODULE_ALIAS("platform:pnx4008-watchdog");
262