1 /*
2 * drivers/char/watchdog/pnx4008_wdt.c
3 *
4 * Watchdog driver for PNX4008 board
5 *
6 * Authors: Dmitry Chigirev <source@mvista.com>,
7 * Vitaly Wool <vitalywool@gmail.com>
8 * Based on sa1100 driver,
9 * Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
10 *
11 * 2005-2006 (c) MontaVista Software, Inc.
12 *
13 * (C) 2012 Wolfram Sang, Pengutronix
14 *
15 * This file is licensed under the terms of the GNU General Public License
16 * version 2. This program is licensed "as is" without any warranty of any
17 * kind, whether express or implied.
18 */
19
20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21
22 #include <linux/module.h>
23 #include <linux/moduleparam.h>
24 #include <linux/types.h>
25 #include <linux/kernel.h>
26 #include <linux/watchdog.h>
27 #include <linux/platform_device.h>
28 #include <linux/clk.h>
29 #include <linux/spinlock.h>
30 #include <linux/io.h>
31 #include <linux/slab.h>
32 #include <linux/err.h>
33 #include <linux/of.h>
34 #include <linux/delay.h>
35 #include <linux/reboot.h>
36 #include <mach/hardware.h>
37
38 /* WatchDog Timer - Chapter 23 Page 207 */
39
40 #define DEFAULT_HEARTBEAT 19
41 #define MAX_HEARTBEAT 60
42
43 /* Watchdog timer register set definition */
44 #define WDTIM_INT(p) ((p) + 0x0)
45 #define WDTIM_CTRL(p) ((p) + 0x4)
46 #define WDTIM_COUNTER(p) ((p) + 0x8)
47 #define WDTIM_MCTRL(p) ((p) + 0xC)
48 #define WDTIM_MATCH0(p) ((p) + 0x10)
49 #define WDTIM_EMR(p) ((p) + 0x14)
50 #define WDTIM_PULSE(p) ((p) + 0x18)
51 #define WDTIM_RES(p) ((p) + 0x1C)
52
53 /* WDTIM_INT bit definitions */
54 #define MATCH_INT 1
55
56 /* WDTIM_CTRL bit definitions */
57 #define COUNT_ENAB 1
58 #define RESET_COUNT (1 << 1)
59 #define DEBUG_EN (1 << 2)
60
61 /* WDTIM_MCTRL bit definitions */
62 #define MR0_INT 1
63 #undef RESET_COUNT0
64 #define RESET_COUNT0 (1 << 2)
65 #define STOP_COUNT0 (1 << 2)
66 #define M_RES1 (1 << 3)
67 #define M_RES2 (1 << 4)
68 #define RESFRC1 (1 << 5)
69 #define RESFRC2 (1 << 6)
70
71 /* WDTIM_EMR bit definitions */
72 #define EXT_MATCH0 1
73 #define MATCH_OUTPUT_HIGH (2 << 4) /*a MATCH_CTRL setting */
74
75 /* WDTIM_RES bit definitions */
76 #define WDOG_RESET 1 /* read only */
77
78 #define WDOG_COUNTER_RATE 13000000 /*the counter clock is 13 MHz fixed */
79
80 static bool nowayout = WATCHDOG_NOWAYOUT;
81 static unsigned int heartbeat;
82
83 static DEFINE_SPINLOCK(io_lock);
84 static void __iomem *wdt_base;
85 static struct clk *wdt_clk;
86
pnx4008_wdt_start(struct watchdog_device * wdd)87 static int pnx4008_wdt_start(struct watchdog_device *wdd)
88 {
89 spin_lock(&io_lock);
90
91 /* stop counter, initiate counter reset */
92 writel(RESET_COUNT, WDTIM_CTRL(wdt_base));
93 /*wait for reset to complete. 100% guarantee event */
94 while (readl(WDTIM_COUNTER(wdt_base)))
95 cpu_relax();
96 /* internal and external reset, stop after that */
97 writel(M_RES2 | STOP_COUNT0 | RESET_COUNT0, WDTIM_MCTRL(wdt_base));
98 /* configure match output */
99 writel(MATCH_OUTPUT_HIGH, WDTIM_EMR(wdt_base));
100 /* clear interrupt, just in case */
101 writel(MATCH_INT, WDTIM_INT(wdt_base));
102 /* the longest pulse period 65541/(13*10^6) seconds ~ 5 ms. */
103 writel(0xFFFF, WDTIM_PULSE(wdt_base));
104 writel(wdd->timeout * WDOG_COUNTER_RATE, WDTIM_MATCH0(wdt_base));
105 /*enable counter, stop when debugger active */
106 writel(COUNT_ENAB | DEBUG_EN, WDTIM_CTRL(wdt_base));
107
108 spin_unlock(&io_lock);
109 return 0;
110 }
111
pnx4008_wdt_stop(struct watchdog_device * wdd)112 static int pnx4008_wdt_stop(struct watchdog_device *wdd)
113 {
114 spin_lock(&io_lock);
115
116 writel(0, WDTIM_CTRL(wdt_base)); /*stop counter */
117
118 spin_unlock(&io_lock);
119 return 0;
120 }
121
pnx4008_wdt_set_timeout(struct watchdog_device * wdd,unsigned int new_timeout)122 static int pnx4008_wdt_set_timeout(struct watchdog_device *wdd,
123 unsigned int new_timeout)
124 {
125 wdd->timeout = new_timeout;
126 return 0;
127 }
128
pnx4008_restart_handler(struct watchdog_device * wdd,unsigned long mode,void * cmd)129 static int pnx4008_restart_handler(struct watchdog_device *wdd,
130 unsigned long mode, void *cmd)
131 {
132 const char *boot_cmd = cmd;
133
134 /*
135 * Verify if a "cmd" passed from the userspace program rebooting
136 * the system; if available, handle it.
137 * - For details, see the 'reboot' syscall in kernel/reboot.c
138 * - If the received "cmd" is not supported, use the default mode.
139 */
140 if (boot_cmd) {
141 if (boot_cmd[0] == 'h')
142 mode = REBOOT_HARD;
143 else if (boot_cmd[0] == 's')
144 mode = REBOOT_SOFT;
145 }
146
147 if (mode == REBOOT_SOFT) {
148 /* Force match output active */
149 writel(EXT_MATCH0, WDTIM_EMR(wdt_base));
150 /* Internal reset on match output (RESOUT_N not asserted) */
151 writel(M_RES1, WDTIM_MCTRL(wdt_base));
152 } else {
153 /* Instant assert of RESETOUT_N with pulse length 1mS */
154 writel(13000, WDTIM_PULSE(wdt_base));
155 writel(M_RES2 | RESFRC1 | RESFRC2, WDTIM_MCTRL(wdt_base));
156 }
157
158 /* Wait for watchdog to reset system */
159 mdelay(1000);
160
161 return NOTIFY_DONE;
162 }
163
164 static const struct watchdog_info pnx4008_wdt_ident = {
165 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
166 WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
167 .identity = "PNX4008 Watchdog",
168 };
169
170 static const struct watchdog_ops pnx4008_wdt_ops = {
171 .owner = THIS_MODULE,
172 .start = pnx4008_wdt_start,
173 .stop = pnx4008_wdt_stop,
174 .set_timeout = pnx4008_wdt_set_timeout,
175 .restart = pnx4008_restart_handler,
176 };
177
178 static struct watchdog_device pnx4008_wdd = {
179 .info = &pnx4008_wdt_ident,
180 .ops = &pnx4008_wdt_ops,
181 .timeout = DEFAULT_HEARTBEAT,
182 .min_timeout = 1,
183 .max_timeout = MAX_HEARTBEAT,
184 };
185
pnx4008_wdt_probe(struct platform_device * pdev)186 static int pnx4008_wdt_probe(struct platform_device *pdev)
187 {
188 struct resource *r;
189 int ret = 0;
190
191 watchdog_init_timeout(&pnx4008_wdd, heartbeat, &pdev->dev);
192
193 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
194 wdt_base = devm_ioremap_resource(&pdev->dev, r);
195 if (IS_ERR(wdt_base))
196 return PTR_ERR(wdt_base);
197
198 wdt_clk = devm_clk_get(&pdev->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
206 pnx4008_wdd.bootstatus = (readl(WDTIM_RES(wdt_base)) & WDOG_RESET) ?
207 WDIOF_CARDRESET : 0;
208 pnx4008_wdd.parent = &pdev->dev;
209 watchdog_set_nowayout(&pnx4008_wdd, nowayout);
210 watchdog_set_restart_priority(&pnx4008_wdd, 128);
211
212 pnx4008_wdt_stop(&pnx4008_wdd); /* disable for now */
213
214 ret = watchdog_register_device(&pnx4008_wdd);
215 if (ret < 0) {
216 dev_err(&pdev->dev, "cannot register watchdog device\n");
217 goto disable_clk;
218 }
219
220 dev_info(&pdev->dev, "heartbeat %d sec\n", pnx4008_wdd.timeout);
221
222 return 0;
223
224 disable_clk:
225 clk_disable_unprepare(wdt_clk);
226 return ret;
227 }
228
pnx4008_wdt_remove(struct platform_device * pdev)229 static int pnx4008_wdt_remove(struct platform_device *pdev)
230 {
231 watchdog_unregister_device(&pnx4008_wdd);
232
233 clk_disable_unprepare(wdt_clk);
234
235 return 0;
236 }
237
238 #ifdef CONFIG_OF
239 static const struct of_device_id pnx4008_wdt_match[] = {
240 { .compatible = "nxp,pnx4008-wdt" },
241 { }
242 };
243 MODULE_DEVICE_TABLE(of, pnx4008_wdt_match);
244 #endif
245
246 static struct platform_driver platform_wdt_driver = {
247 .driver = {
248 .name = "pnx4008-watchdog",
249 .of_match_table = of_match_ptr(pnx4008_wdt_match),
250 },
251 .probe = pnx4008_wdt_probe,
252 .remove = pnx4008_wdt_remove,
253 };
254
255 module_platform_driver(platform_wdt_driver);
256
257 MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
258 MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
259 MODULE_DESCRIPTION("PNX4008 Watchdog Driver");
260
261 module_param(heartbeat, uint, 0);
262 MODULE_PARM_DESC(heartbeat,
263 "Watchdog heartbeat period in seconds from 1 to "
264 __MODULE_STRING(MAX_HEARTBEAT) ", default "
265 __MODULE_STRING(DEFAULT_HEARTBEAT));
266
267 module_param(nowayout, bool, 0);
268 MODULE_PARM_DESC(nowayout,
269 "Set to 1 to keep watchdog running after device release");
270
271 MODULE_LICENSE("GPL");
272 MODULE_ALIAS("platform:pnx4008-watchdog");
273
