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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/io.h>
20#include <linux/ioport.h>
21#include <linux/kernel.h>
22#include <linux/math64.h>
Viresh KUMAR4a370272010-08-04 11:44:14 +053023#include <linux/module.h>
24#include <linux/moduleparam.h>
Viresh Kumar16ac4ab2012-02-24 15:12:37 +053025#include <linux/pm.h>
Viresh KUMAR4a370272010-08-04 11:44:14 +053026#include <linux/slab.h>
27#include <linux/spinlock.h>
28#include <linux/types.h>
Viresh KUMAR4a370272010-08-04 11:44:14 +053029#include <linux/watchdog.h>
30
31/* default timeout in seconds */
32#define DEFAULT_TIMEOUT 60
33
34#define MODULE_NAME "sp805-wdt"
35
36/* watchdog register offsets and masks */
37#define WDTLOAD 0x000
38 #define LOAD_MIN 0x00000001
39 #define LOAD_MAX 0xFFFFFFFF
40#define WDTVALUE 0x004
41#define WDTCONTROL 0x008
42 /* control register masks */
43 #define INT_ENABLE (1 << 0)
44 #define RESET_ENABLE (1 << 1)
45#define WDTINTCLR 0x00C
46#define WDTRIS 0x010
47#define WDTMIS 0x014
48 #define INT_MASK (1 << 0)
49#define WDTLOCK 0xC00
50 #define UNLOCK 0x1ACCE551
51 #define LOCK 0x00000001
52
53/**
54 * struct sp805_wdt: sp805 wdt device structure
Viresh Kumar4a516532012-03-12 09:52:16 +053055 * @wdd: instance of struct watchdog_device
Viresh Kumarbfae14b2012-03-12 09:52:13 +053056 * @lock: spin lock protecting dev structure and io access
57 * @base: base address of wdt
58 * @clk: clock structure of wdt
59 * @adev: amba device structure of wdt
60 * @status: current status of wdt
61 * @load_val: load value to be set for current timeout
62 * @timeout: current programmed timeout
Viresh KUMAR4a370272010-08-04 11:44:14 +053063 */
64struct sp805_wdt {
Viresh Kumar4a516532012-03-12 09:52:16 +053065 struct watchdog_device wdd;
Viresh KUMAR4a370272010-08-04 11:44:14 +053066 spinlock_t lock;
67 void __iomem *base;
68 struct clk *clk;
69 struct amba_device *adev;
Viresh KUMAR4a370272010-08-04 11:44:14 +053070 unsigned int load_val;
71 unsigned int timeout;
72};
73
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010074static bool nowayout = WATCHDOG_NOWAYOUT;
Viresh Kumar4a516532012-03-12 09:52:16 +053075module_param(nowayout, bool, 0);
76MODULE_PARM_DESC(nowayout,
77 "Set to 1 to keep watchdog running after device release");
Viresh KUMAR4a370272010-08-04 11:44:14 +053078
79/* This routine finds load value that will reset system in required timout */
Viresh Kumar4a516532012-03-12 09:52:16 +053080static int wdt_setload(struct watchdog_device *wdd, unsigned int timeout)
Viresh KUMAR4a370272010-08-04 11:44:14 +053081{
Viresh Kumar4a516532012-03-12 09:52:16 +053082 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
Viresh KUMAR4a370272010-08-04 11:44:14 +053083 u64 load, rate;
84
85 rate = clk_get_rate(wdt->clk);
86
87 /*
88 * sp805 runs counter with given value twice, after the end of first
89 * counter it gives an interrupt and then starts counter again. If
Lucas De Marchi25985ed2011-03-30 22:57:33 -030090 * interrupt already occurred then it resets the system. This is why
Viresh KUMAR4a370272010-08-04 11:44:14 +053091 * load is half of what should be required.
92 */
93 load = div_u64(rate, 2) * timeout - 1;
94
95 load = (load > LOAD_MAX) ? LOAD_MAX : load;
96 load = (load < LOAD_MIN) ? LOAD_MIN : load;
97
98 spin_lock(&wdt->lock);
99 wdt->load_val = load;
100 /* roundup timeout to closest positive integer value */
101 wdt->timeout = div_u64((load + 1) * 2 + (rate / 2), rate);
102 spin_unlock(&wdt->lock);
Viresh Kumar4a516532012-03-12 09:52:16 +0530103
104 return 0;
Viresh KUMAR4a370272010-08-04 11:44:14 +0530105}
106
107/* returns number of seconds left for reset to occur */
Viresh Kumar4a516532012-03-12 09:52:16 +0530108static unsigned int wdt_timeleft(struct watchdog_device *wdd)
Viresh KUMAR4a370272010-08-04 11:44:14 +0530109{
Viresh Kumar4a516532012-03-12 09:52:16 +0530110 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530111 u64 load, rate;
112
113 rate = clk_get_rate(wdt->clk);
114
115 spin_lock(&wdt->lock);
Viresh Kumard2e89192012-03-12 09:52:14 +0530116 load = readl_relaxed(wdt->base + WDTVALUE);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530117
118 /*If the interrupt is inactive then time left is WDTValue + WDTLoad. */
Viresh Kumard2e89192012-03-12 09:52:14 +0530119 if (!(readl_relaxed(wdt->base + WDTRIS) & INT_MASK))
Viresh KUMAR4a370272010-08-04 11:44:14 +0530120 load += wdt->load_val + 1;
121 spin_unlock(&wdt->lock);
122
123 return div_u64(load, rate);
124}
125
Viresh Kumar4a516532012-03-12 09:52:16 +0530126static int wdt_config(struct watchdog_device *wdd, bool ping)
Viresh KUMAR4a370272010-08-04 11:44:14 +0530127{
Viresh Kumar4a516532012-03-12 09:52:16 +0530128 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
129 int ret;
130
131 if (!ping) {
Viresh Kumard9df0ef2012-03-12 09:52:17 +0530132
Julia Lawall63fbbc12012-08-26 18:01:02 +0200133 ret = clk_prepare_enable(wdt->clk);
Viresh Kumar4a516532012-03-12 09:52:16 +0530134 if (ret) {
135 dev_err(&wdt->adev->dev, "clock enable fail");
136 return ret;
137 }
138 }
139
Viresh KUMAR4a370272010-08-04 11:44:14 +0530140 spin_lock(&wdt->lock);
141
Viresh Kumard2e89192012-03-12 09:52:14 +0530142 writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
143 writel_relaxed(wdt->load_val, wdt->base + WDTLOAD);
Viresh Kumar4a516532012-03-12 09:52:16 +0530144
145 if (!ping) {
146 writel_relaxed(INT_MASK, wdt->base + WDTINTCLR);
147 writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base +
148 WDTCONTROL);
149 }
150
Viresh Kumard2e89192012-03-12 09:52:14 +0530151 writel_relaxed(LOCK, wdt->base + WDTLOCK);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530152
Nick Bowler081d83a2011-07-15 11:04:02 -0400153 /* Flush posted writes. */
Viresh Kumard2e89192012-03-12 09:52:14 +0530154 readl_relaxed(wdt->base + WDTLOCK);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530155 spin_unlock(&wdt->lock);
Viresh Kumar4a516532012-03-12 09:52:16 +0530156
157 return 0;
158}
159
160static int wdt_ping(struct watchdog_device *wdd)
161{
162 return wdt_config(wdd, true);
163}
164
165/* enables watchdog timers reset */
166static int wdt_enable(struct watchdog_device *wdd)
167{
168 return wdt_config(wdd, false);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530169}
170
171/* disables watchdog timers reset */
Viresh Kumar4a516532012-03-12 09:52:16 +0530172static int wdt_disable(struct watchdog_device *wdd)
Viresh KUMAR4a370272010-08-04 11:44:14 +0530173{
Viresh Kumar4a516532012-03-12 09:52:16 +0530174 struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
175
Viresh KUMAR4a370272010-08-04 11:44:14 +0530176 spin_lock(&wdt->lock);
177
Viresh Kumard2e89192012-03-12 09:52:14 +0530178 writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
179 writel_relaxed(0, wdt->base + WDTCONTROL);
180 writel_relaxed(LOCK, wdt->base + WDTLOCK);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530181
Nick Bowler081d83a2011-07-15 11:04:02 -0400182 /* Flush posted writes. */
Viresh Kumard2e89192012-03-12 09:52:14 +0530183 readl_relaxed(wdt->base + WDTLOCK);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530184 spin_unlock(&wdt->lock);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530185
Julia Lawall63fbbc12012-08-26 18:01:02 +0200186 clk_disable_unprepare(wdt->clk);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530187
188 return 0;
189}
190
Viresh Kumar4a516532012-03-12 09:52:16 +0530191static const struct watchdog_info wdt_info = {
192 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
193 .identity = MODULE_NAME,
Viresh KUMAR4a370272010-08-04 11:44:14 +0530194};
195
Viresh Kumar4a516532012-03-12 09:52:16 +0530196static const struct watchdog_ops wdt_ops = {
197 .owner = THIS_MODULE,
198 .start = wdt_enable,
199 .stop = wdt_disable,
200 .ping = wdt_ping,
201 .set_timeout = wdt_setload,
202 .get_timeleft = wdt_timeleft,
Viresh KUMAR4a370272010-08-04 11:44:14 +0530203};
204
Bill Pemberton2d991a12012-11-19 13:21:41 -0500205static int
Russell Kingaa25afa2011-02-19 15:55:00 +0000206sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
Viresh KUMAR4a370272010-08-04 11:44:14 +0530207{
Viresh Kumar4a516532012-03-12 09:52:16 +0530208 struct sp805_wdt *wdt;
Viresh KUMAR4a370272010-08-04 11:44:14 +0530209 int ret = 0;
210
Viresh Kumarfb35a5a2012-03-12 09:52:15 +0530211 wdt = devm_kzalloc(&adev->dev, sizeof(*wdt), GFP_KERNEL);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530212 if (!wdt) {
Viresh KUMAR4a370272010-08-04 11:44:14 +0530213 ret = -ENOMEM;
Viresh Kumarfb35a5a2012-03-12 09:52:15 +0530214 goto err;
215 }
216
Jingoo Han9d11e4f2014-02-11 21:45:56 +0900217 wdt->base = devm_ioremap_resource(&adev->dev, &adev->res);
218 if (IS_ERR(wdt->base))
219 return PTR_ERR(wdt->base);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530220
Jingoo Han07bf9712013-04-29 18:16:49 +0900221 wdt->clk = devm_clk_get(&adev->dev, NULL);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530222 if (IS_ERR(wdt->clk)) {
223 dev_warn(&adev->dev, "Clock not found\n");
224 ret = PTR_ERR(wdt->clk);
Viresh Kumarfb35a5a2012-03-12 09:52:15 +0530225 goto err;
Viresh KUMAR4a370272010-08-04 11:44:14 +0530226 }
227
228 wdt->adev = adev;
Viresh Kumar4a516532012-03-12 09:52:16 +0530229 wdt->wdd.info = &wdt_info;
230 wdt->wdd.ops = &wdt_ops;
Viresh KUMAR4a370272010-08-04 11:44:14 +0530231
Viresh Kumar4a516532012-03-12 09:52:16 +0530232 spin_lock_init(&wdt->lock);
233 watchdog_set_nowayout(&wdt->wdd, nowayout);
234 watchdog_set_drvdata(&wdt->wdd, wdt);
235 wdt_setload(&wdt->wdd, DEFAULT_TIMEOUT);
236
237 ret = watchdog_register_device(&wdt->wdd);
238 if (ret) {
239 dev_err(&adev->dev, "watchdog_register_device() failed: %d\n",
240 ret);
Jingoo Han07bf9712013-04-29 18:16:49 +0900241 goto err;
Viresh KUMAR4a370272010-08-04 11:44:14 +0530242 }
Viresh Kumar4a516532012-03-12 09:52:16 +0530243 amba_set_drvdata(adev, wdt);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530244
245 dev_info(&adev->dev, "registration successful\n");
246 return 0;
247
Viresh KUMAR4a370272010-08-04 11:44:14 +0530248err:
249 dev_err(&adev->dev, "Probe Failed!!!\n");
250 return ret;
251}
252
Bill Pemberton4b12b892012-11-19 13:26:24 -0500253static int sp805_wdt_remove(struct amba_device *adev)
Viresh KUMAR4a370272010-08-04 11:44:14 +0530254{
Viresh Kumar4a516532012-03-12 09:52:16 +0530255 struct sp805_wdt *wdt = amba_get_drvdata(adev);
256
257 watchdog_unregister_device(&wdt->wdd);
Viresh Kumar4a516532012-03-12 09:52:16 +0530258 watchdog_set_drvdata(&wdt->wdd, NULL);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530259
260 return 0;
261}
262
Russell King60d6dd52012-11-08 10:51:03 +0000263static int __maybe_unused sp805_wdt_suspend(struct device *dev)
Viresh Kumar16ac4ab2012-02-24 15:12:37 +0530264{
Viresh Kumar4a516532012-03-12 09:52:16 +0530265 struct sp805_wdt *wdt = dev_get_drvdata(dev);
266
267 if (watchdog_active(&wdt->wdd))
268 return wdt_disable(&wdt->wdd);
Viresh Kumar16ac4ab2012-02-24 15:12:37 +0530269
270 return 0;
271}
272
Russell King60d6dd52012-11-08 10:51:03 +0000273static int __maybe_unused sp805_wdt_resume(struct device *dev)
Viresh Kumar16ac4ab2012-02-24 15:12:37 +0530274{
Viresh Kumar4a516532012-03-12 09:52:16 +0530275 struct sp805_wdt *wdt = dev_get_drvdata(dev);
Viresh Kumar16ac4ab2012-02-24 15:12:37 +0530276
Viresh Kumar4a516532012-03-12 09:52:16 +0530277 if (watchdog_active(&wdt->wdd))
278 return wdt_enable(&wdt->wdd);
Viresh Kumar16ac4ab2012-02-24 15:12:37 +0530279
Viresh Kumar4a516532012-03-12 09:52:16 +0530280 return 0;
Viresh Kumar16ac4ab2012-02-24 15:12:37 +0530281}
Viresh Kumar16ac4ab2012-02-24 15:12:37 +0530282
283static SIMPLE_DEV_PM_OPS(sp805_wdt_dev_pm_ops, sp805_wdt_suspend,
284 sp805_wdt_resume);
285
Nick Bowlerbb558da2011-12-19 11:22:36 -0500286static struct amba_id sp805_wdt_ids[] = {
Viresh KUMAR4a370272010-08-04 11:44:14 +0530287 {
288 .id = 0x00141805,
289 .mask = 0x00ffffff,
290 },
291 { 0, 0 },
292};
293
Dave Martin17885b02011-10-05 15:15:23 +0100294MODULE_DEVICE_TABLE(amba, sp805_wdt_ids);
295
Viresh KUMAR4a370272010-08-04 11:44:14 +0530296static struct amba_driver sp805_wdt_driver = {
297 .drv = {
298 .name = MODULE_NAME,
Viresh Kumar16ac4ab2012-02-24 15:12:37 +0530299 .pm = &sp805_wdt_dev_pm_ops,
Viresh KUMAR4a370272010-08-04 11:44:14 +0530300 },
301 .id_table = sp805_wdt_ids,
302 .probe = sp805_wdt_probe,
Bill Pemberton82268712012-11-19 13:21:12 -0500303 .remove = sp805_wdt_remove,
Viresh KUMAR4a370272010-08-04 11:44:14 +0530304};
305
viresh kumar9e5ed092012-03-15 10:40:38 +0100306module_amba_driver(sp805_wdt_driver);
Viresh KUMAR4a370272010-08-04 11:44:14 +0530307
Viresh Kumar10d89352012-06-20 12:53:02 -0700308MODULE_AUTHOR("Viresh Kumar <viresh.linux@gmail.com>");
Viresh KUMAR4a370272010-08-04 11:44:14 +0530309MODULE_DESCRIPTION("ARM SP805 Watchdog Driver");
310MODULE_LICENSE("GPL");