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Viresh KUMAR4a370272010-08-04 11:44:14 +05301/*
2 * drivers/char/watchdog/sp805-wdt.c
3 *
4 * Watchdog driver for ARM SP805 watchdog module
5 *
6 * Copyright (C) 2010 ST Microelectronics
Viresh Kumar10d89352012-06-20 12:53:02 -07007 * Viresh Kumar <viresh.linux@gmail.com>
Viresh KUMAR4a370272010-08-04 11:44:14 +05308 *
9 * This file is licensed under the terms of the GNU General Public
10 * License version 2 or later. This program is licensed "as is" without any
11 * warranty of any kind, whether express or implied.
12 */
13
14#include <linux/device.h>
15#include <linux/resource.h>
16#include <linux/amba/bus.h>
17#include <linux/bitops.h>
18#include <linux/clk.h>
Viresh KUMAR4a370272010-08-04 11:44:14 +053019#include <linux/init.h>
20#include <linux/io.h>
21#include <linux/ioport.h>
22#include <linux/kernel.h>
23#include <linux/math64.h>
Viresh KUMAR4a370272010-08-04 11:44:14 +053024#include <linux/module.h>
25#include <linux/moduleparam.h>
Viresh Kumar16ac4ab2012-02-24 15:12:37 +053026#include <linux/pm.h>
Viresh KUMAR4a370272010-08-04 11:44:14 +053027#include <linux/slab.h>
28#include <linux/spinlock.h>
29#include <linux/types.h>
Viresh KUMAR4a370272010-08-04 11:44:14 +053030#include <linux/watchdog.h>
31
32/* default timeout in seconds */
33#define DEFAULT_TIMEOUT 60
34
35#define MODULE_NAME "sp805-wdt"
36
37/* watchdog register offsets and masks */
38#define WDTLOAD 0x000
39 #define LOAD_MIN 0x00000001
40 #define LOAD_MAX 0xFFFFFFFF
41#define WDTVALUE 0x004
42#define WDTCONTROL 0x008
43 /* control register masks */
44 #define INT_ENABLE (1 << 0)
45 #define RESET_ENABLE (1 << 1)
46#define WDTINTCLR 0x00C
47#define WDTRIS 0x010
48#define WDTMIS 0x014
49 #define INT_MASK (1 << 0)
50#define WDTLOCK 0xC00
51 #define UNLOCK 0x1ACCE551
52 #define LOCK 0x00000001
53
54/**
55 * struct sp805_wdt: sp805 wdt device structure
Viresh Kumar4a516532012-03-12 09:52:16 +053056 * @wdd: instance of struct watchdog_device
Viresh Kumarbfae14b2012-03-12 09:52:13 +053057 * @lock: spin lock protecting dev structure and io access
58 * @base: base address of wdt
59 * @clk: clock structure of wdt
60 * @adev: amba device structure of wdt
61 * @status: current status of wdt
62 * @load_val: load value to be set for current timeout
63 * @timeout: current programmed timeout
Viresh KUMAR4a370272010-08-04 11:44:14 +053064 */
65struct sp805_wdt {
Viresh Kumar4a516532012-03-12 09:52:16 +053066 struct watchdog_device wdd;
Viresh KUMAR4a370272010-08-04 11:44:14 +053067 spinlock_t lock;
68 void __iomem *base;
69 struct clk *clk;
70 struct amba_device *adev;
Viresh KUMAR4a370272010-08-04 11:44:14 +053071 unsigned int load_val;
72 unsigned int timeout;
73};
74
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010075static bool nowayout = WATCHDOG_NOWAYOUT;
Viresh Kumar4a516532012-03-12 09:52:16 +053076module_param(nowayout, bool, 0);
77MODULE_PARM_DESC(nowayout,
78 "Set to 1 to keep watchdog running after device release");
Viresh KUMAR4a370272010-08-04 11:44:14 +053079
80/* This routine finds load value that will reset system in required timout */
Viresh Kumar4a516532012-03-12 09:52:16 +053081static int wdt_setload(struct watchdog_device *wdd, unsigned int timeout)
Viresh KUMAR4a370272010-08-04 11:44:14 +053082{
Viresh Kumar4a516532012-03-12 09:52:16 +053083 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
Viresh KUMAR4a370272010-08-04 11:44:14 +053084 u64 load, rate;
85
86 rate = clk_get_rate(wdt->clk);
87
88 /*
89 * sp805 runs counter with given value twice, after the end of first
90 * counter it gives an interrupt and then starts counter again. If
Lucas De Marchi25985ed2011-03-30 22:57:33 -030091 * interrupt already occurred then it resets the system. This is why
Viresh KUMAR4a370272010-08-04 11:44:14 +053092 * load is half of what should be required.
93 */
94 load = div_u64(rate, 2) * timeout - 1;
95
96 load = (load > LOAD_MAX) ? LOAD_MAX : load;
97 load = (load < LOAD_MIN) ? LOAD_MIN : load;
98
99 spin_lock(&wdt->lock);
100 wdt->load_val = load;
101 /* roundup timeout to closest positive integer value */
102 wdt->timeout = div_u64((load + 1) * 2 + (rate / 2), rate);
103 spin_unlock(&wdt->lock);
Viresh Kumar4a516532012-03-12 09:52:16 +0530104
105 return 0;
Viresh KUMAR4a370272010-08-04 11:44:14 +0530106}
107
108/* returns number of seconds left for reset to occur */
Viresh Kumar4a516532012-03-12 09:52:16 +0530109static unsigned int wdt_timeleft(struct watchdog_device *wdd)
Viresh KUMAR4a370272010-08-04 11:44:14 +0530110{
Viresh Kumar4a516532012-03-12 09:52:16 +0530111 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530112 u64 load, rate;
113
114 rate = clk_get_rate(wdt->clk);
115
116 spin_lock(&wdt->lock);
Viresh Kumard2e89192012-03-12 09:52:14 +0530117 load = readl_relaxed(wdt->base + WDTVALUE);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530118
119 /*If the interrupt is inactive then time left is WDTValue + WDTLoad. */
Viresh Kumard2e89192012-03-12 09:52:14 +0530120 if (!(readl_relaxed(wdt->base + WDTRIS) & INT_MASK))
Viresh KUMAR4a370272010-08-04 11:44:14 +0530121 load += wdt->load_val + 1;
122 spin_unlock(&wdt->lock);
123
124 return div_u64(load, rate);
125}
126
Viresh Kumar4a516532012-03-12 09:52:16 +0530127static int wdt_config(struct watchdog_device *wdd, bool ping)
Viresh KUMAR4a370272010-08-04 11:44:14 +0530128{
Viresh Kumar4a516532012-03-12 09:52:16 +0530129 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
130 int ret;
131
132 if (!ping) {
Viresh Kumard9df0ef2012-03-12 09:52:17 +0530133
Julia Lawall63fbbc12012-08-26 18:01:02 +0200134 ret = clk_prepare_enable(wdt->clk);
Viresh Kumar4a516532012-03-12 09:52:16 +0530135 if (ret) {
136 dev_err(&wdt->adev->dev, "clock enable fail");
137 return ret;
138 }
139 }
140
Viresh KUMAR4a370272010-08-04 11:44:14 +0530141 spin_lock(&wdt->lock);
142
Viresh Kumard2e89192012-03-12 09:52:14 +0530143 writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
144 writel_relaxed(wdt->load_val, wdt->base + WDTLOAD);
Viresh Kumar4a516532012-03-12 09:52:16 +0530145
146 if (!ping) {
147 writel_relaxed(INT_MASK, wdt->base + WDTINTCLR);
148 writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base +
149 WDTCONTROL);
150 }
151
Viresh Kumard2e89192012-03-12 09:52:14 +0530152 writel_relaxed(LOCK, wdt->base + WDTLOCK);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530153
Nick Bowler081d83a2011-07-15 11:04:02 -0400154 /* Flush posted writes. */
Viresh Kumard2e89192012-03-12 09:52:14 +0530155 readl_relaxed(wdt->base + WDTLOCK);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530156 spin_unlock(&wdt->lock);
Viresh Kumar4a516532012-03-12 09:52:16 +0530157
158 return 0;
159}
160
161static int wdt_ping(struct watchdog_device *wdd)
162{
163 return wdt_config(wdd, true);
164}
165
166/* enables watchdog timers reset */
167static int wdt_enable(struct watchdog_device *wdd)
168{
169 return wdt_config(wdd, false);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530170}
171
172/* disables watchdog timers reset */
Viresh Kumar4a516532012-03-12 09:52:16 +0530173static int wdt_disable(struct watchdog_device *wdd)
Viresh KUMAR4a370272010-08-04 11:44:14 +0530174{
Viresh Kumar4a516532012-03-12 09:52:16 +0530175 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
176
Viresh KUMAR4a370272010-08-04 11:44:14 +0530177 spin_lock(&wdt->lock);
178
Viresh Kumard2e89192012-03-12 09:52:14 +0530179 writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
180 writel_relaxed(0, wdt->base + WDTCONTROL);
181 writel_relaxed(LOCK, wdt->base + WDTLOCK);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530182
Nick Bowler081d83a2011-07-15 11:04:02 -0400183 /* Flush posted writes. */
Viresh Kumard2e89192012-03-12 09:52:14 +0530184 readl_relaxed(wdt->base + WDTLOCK);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530185 spin_unlock(&wdt->lock);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530186
Julia Lawall63fbbc12012-08-26 18:01:02 +0200187 clk_disable_unprepare(wdt->clk);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530188
189 return 0;
190}
191
Viresh Kumar4a516532012-03-12 09:52:16 +0530192static const struct watchdog_info wdt_info = {
193 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
194 .identity = MODULE_NAME,
Viresh KUMAR4a370272010-08-04 11:44:14 +0530195};
196
Viresh Kumar4a516532012-03-12 09:52:16 +0530197static const struct watchdog_ops wdt_ops = {
198 .owner = THIS_MODULE,
199 .start = wdt_enable,
200 .stop = wdt_disable,
201 .ping = wdt_ping,
202 .set_timeout = wdt_setload,
203 .get_timeleft = wdt_timeleft,
Viresh KUMAR4a370272010-08-04 11:44:14 +0530204};
205
Bill Pemberton2d991a12012-11-19 13:21:41 -0500206static int
Russell Kingaa25afa2011-02-19 15:55:00 +0000207sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
Viresh KUMAR4a370272010-08-04 11:44:14 +0530208{
Viresh Kumar4a516532012-03-12 09:52:16 +0530209 struct sp805_wdt *wdt;
Viresh KUMAR4a370272010-08-04 11:44:14 +0530210 int ret = 0;
211
Viresh Kumarfb35a5a2012-03-12 09:52:15 +0530212 if (!devm_request_mem_region(&adev->dev, adev->res.start,
213 resource_size(&adev->res), "sp805_wdt")) {
Viresh KUMAR4a370272010-08-04 11:44:14 +0530214 dev_warn(&adev->dev, "Failed to get memory region resource\n");
215 ret = -ENOENT;
216 goto err;
217 }
218
Viresh Kumarfb35a5a2012-03-12 09:52:15 +0530219 wdt = devm_kzalloc(&adev->dev, sizeof(*wdt), GFP_KERNEL);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530220 if (!wdt) {
221 dev_warn(&adev->dev, "Kzalloc failed\n");
222 ret = -ENOMEM;
Viresh Kumarfb35a5a2012-03-12 09:52:15 +0530223 goto err;
224 }
225
226 wdt->base = devm_ioremap(&adev->dev, adev->res.start,
227 resource_size(&adev->res));
228 if (!wdt->base) {
229 ret = -ENOMEM;
230 dev_warn(&adev->dev, "ioremap fail\n");
231 goto err;
Viresh KUMAR4a370272010-08-04 11:44:14 +0530232 }
233
234 wdt->clk = clk_get(&adev->dev, NULL);
235 if (IS_ERR(wdt->clk)) {
236 dev_warn(&adev->dev, "Clock not found\n");
237 ret = PTR_ERR(wdt->clk);
Viresh Kumarfb35a5a2012-03-12 09:52:15 +0530238 goto err;
Viresh KUMAR4a370272010-08-04 11:44:14 +0530239 }
240
241 wdt->adev = adev;
Viresh Kumar4a516532012-03-12 09:52:16 +0530242 wdt->wdd.info = &wdt_info;
243 wdt->wdd.ops = &wdt_ops;
Viresh KUMAR4a370272010-08-04 11:44:14 +0530244
Viresh Kumar4a516532012-03-12 09:52:16 +0530245 spin_lock_init(&wdt->lock);
246 watchdog_set_nowayout(&wdt->wdd, nowayout);
247 watchdog_set_drvdata(&wdt->wdd, wdt);
248 wdt_setload(&wdt->wdd, DEFAULT_TIMEOUT);
249
250 ret = watchdog_register_device(&wdt->wdd);
251 if (ret) {
252 dev_err(&adev->dev, "watchdog_register_device() failed: %d\n",
253 ret);
254 goto err_register;
Viresh KUMAR4a370272010-08-04 11:44:14 +0530255 }
Viresh Kumar4a516532012-03-12 09:52:16 +0530256 amba_set_drvdata(adev, wdt);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530257
258 dev_info(&adev->dev, "registration successful\n");
259 return 0;
260
Viresh Kumar4a516532012-03-12 09:52:16 +0530261err_register:
Viresh KUMAR4a370272010-08-04 11:44:14 +0530262 clk_put(wdt->clk);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530263err:
264 dev_err(&adev->dev, "Probe Failed!!!\n");
265 return ret;
266}
267
Bill Pemberton4b12b892012-11-19 13:26:24 -0500268static int sp805_wdt_remove(struct amba_device *adev)
Viresh KUMAR4a370272010-08-04 11:44:14 +0530269{
Viresh Kumar4a516532012-03-12 09:52:16 +0530270 struct sp805_wdt *wdt = amba_get_drvdata(adev);
271
272 watchdog_unregister_device(&wdt->wdd);
273 amba_set_drvdata(adev, NULL);
274 watchdog_set_drvdata(&wdt->wdd, NULL);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530275 clk_put(wdt->clk);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530276
277 return 0;
278}
279
Russell King60d6dd52012-11-08 10:51:03 +0000280static int __maybe_unused sp805_wdt_suspend(struct device *dev)
Viresh Kumar16ac4ab2012-02-24 15:12:37 +0530281{
Viresh Kumar4a516532012-03-12 09:52:16 +0530282 struct sp805_wdt *wdt = dev_get_drvdata(dev);
283
284 if (watchdog_active(&wdt->wdd))
285 return wdt_disable(&wdt->wdd);
Viresh Kumar16ac4ab2012-02-24 15:12:37 +0530286
287 return 0;
288}
289
Russell King60d6dd52012-11-08 10:51:03 +0000290static int __maybe_unused sp805_wdt_resume(struct device *dev)
Viresh Kumar16ac4ab2012-02-24 15:12:37 +0530291{
Viresh Kumar4a516532012-03-12 09:52:16 +0530292 struct sp805_wdt *wdt = dev_get_drvdata(dev);
Viresh Kumar16ac4ab2012-02-24 15:12:37 +0530293
Viresh Kumar4a516532012-03-12 09:52:16 +0530294 if (watchdog_active(&wdt->wdd))
295 return wdt_enable(&wdt->wdd);
Viresh Kumar16ac4ab2012-02-24 15:12:37 +0530296
Viresh Kumar4a516532012-03-12 09:52:16 +0530297 return 0;
Viresh Kumar16ac4ab2012-02-24 15:12:37 +0530298}
Viresh Kumar16ac4ab2012-02-24 15:12:37 +0530299
300static SIMPLE_DEV_PM_OPS(sp805_wdt_dev_pm_ops, sp805_wdt_suspend,
301 sp805_wdt_resume);
302
Nick Bowlerbb558da2011-12-19 11:22:36 -0500303static struct amba_id sp805_wdt_ids[] = {
Viresh KUMAR4a370272010-08-04 11:44:14 +0530304 {
305 .id = 0x00141805,
306 .mask = 0x00ffffff,
307 },
308 { 0, 0 },
309};
310
Dave Martin17885b02011-10-05 15:15:23 +0100311MODULE_DEVICE_TABLE(amba, sp805_wdt_ids);
312
Viresh KUMAR4a370272010-08-04 11:44:14 +0530313static struct amba_driver sp805_wdt_driver = {
314 .drv = {
315 .name = MODULE_NAME,
Viresh Kumar16ac4ab2012-02-24 15:12:37 +0530316 .pm = &sp805_wdt_dev_pm_ops,
Viresh KUMAR4a370272010-08-04 11:44:14 +0530317 },
318 .id_table = sp805_wdt_ids,
319 .probe = sp805_wdt_probe,
Bill Pemberton82268712012-11-19 13:21:12 -0500320 .remove = sp805_wdt_remove,
Viresh KUMAR4a370272010-08-04 11:44:14 +0530321};
322
viresh kumar9e5ed092012-03-15 10:40:38 +0100323module_amba_driver(sp805_wdt_driver);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530324
Viresh Kumar10d89352012-06-20 12:53:02 -0700325MODULE_AUTHOR("Viresh Kumar <viresh.linux@gmail.com>");
Viresh KUMAR4a370272010-08-04 11:44:14 +0530326MODULE_DESCRIPTION("ARM SP805 Watchdog Driver");
327MODULE_LICENSE("GPL");