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40#include <linux/clk.h>
41#include <linux/io.h>
42#include <linux/log2.h>
43#include <linux/module.h>
44#include <linux/mod_devicetable.h>
45#include <linux/platform_device.h>
46#include <linux/slab.h>
47#include <linux/watchdog.h>
48
49
50#define PDC_WDT_SOFT_RESET 0x00
51#define PDC_WDT_CONFIG 0x04
52 #define PDC_WDT_CONFIG_ENABLE BIT(31)
53 #define PDC_WDT_CONFIG_DELAY_MASK 0x1f
54
55#define PDC_WDT_TICKLE1 0x08
56#define PDC_WDT_TICKLE1_MAGIC 0xabcd1234
57#define PDC_WDT_TICKLE2 0x0c
58#define PDC_WDT_TICKLE2_MAGIC 0x4321dcba
59
60#define PDC_WDT_TICKLE_STATUS_MASK 0x7
61#define PDC_WDT_TICKLE_STATUS_SHIFT 0
62#define PDC_WDT_TICKLE_STATUS_HRESET 0x0
63#define PDC_WDT_TICKLE_STATUS_TIMEOUT 0x1
64#define PDC_WDT_TICKLE_STATUS_TICKLE 0x2
65#define PDC_WDT_TICKLE_STATUS_SRESET 0x3
66#define PDC_WDT_TICKLE_STATUS_USER 0x4
67
68
69#define PDC_WDT_MIN_TIMEOUT 1
70#define PDC_WDT_DEF_TIMEOUT 64
71
72static int heartbeat;
73module_param(heartbeat, int, 0);
74MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds "
75 "(default=" __MODULE_STRING(PDC_WDT_DEF_TIMEOUT) ")");
76
77static bool nowayout = WATCHDOG_NOWAYOUT;
78module_param(nowayout, bool, 0);
79MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
80 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
81
82struct pdc_wdt_dev {
83 struct watchdog_device wdt_dev;
84 struct clk *wdt_clk;
85 struct clk *sys_clk;
86 void __iomem *base;
87};
88
89static int pdc_wdt_keepalive(struct watchdog_device *wdt_dev)
90{
91 struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
92
93 writel(PDC_WDT_TICKLE1_MAGIC, wdt->base + PDC_WDT_TICKLE1);
94 writel(PDC_WDT_TICKLE2_MAGIC, wdt->base + PDC_WDT_TICKLE2);
95
96 return 0;
97}
98
99static int pdc_wdt_stop(struct watchdog_device *wdt_dev)
100{
101 unsigned int val;
102 struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
103
104 val = readl(wdt->base + PDC_WDT_CONFIG);
105 val &= ~PDC_WDT_CONFIG_ENABLE;
106 writel(val, wdt->base + PDC_WDT_CONFIG);
107
108
109 pdc_wdt_keepalive(wdt_dev);
110
111 return 0;
112}
113
114static void __pdc_wdt_set_timeout(struct pdc_wdt_dev *wdt)
115{
116 unsigned long clk_rate = clk_get_rate(wdt->wdt_clk);
117 unsigned int val;
118
119 val = readl(wdt->base + PDC_WDT_CONFIG) & ~PDC_WDT_CONFIG_DELAY_MASK;
120 val |= order_base_2(wdt->wdt_dev.timeout * clk_rate) - 1;
121 writel(val, wdt->base + PDC_WDT_CONFIG);
122}
123
124static int pdc_wdt_set_timeout(struct watchdog_device *wdt_dev,
125 unsigned int new_timeout)
126{
127 struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
128
129 wdt->wdt_dev.timeout = new_timeout;
130
131 __pdc_wdt_set_timeout(wdt);
132
133 return 0;
134}
135
136
137static int pdc_wdt_start(struct watchdog_device *wdt_dev)
138{
139 unsigned int val;
140 struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
141
142 __pdc_wdt_set_timeout(wdt);
143
144 val = readl(wdt->base + PDC_WDT_CONFIG);
145 val |= PDC_WDT_CONFIG_ENABLE;
146 writel(val, wdt->base + PDC_WDT_CONFIG);
147
148 return 0;
149}
150
151static int pdc_wdt_restart(struct watchdog_device *wdt_dev,
152 unsigned long action, void *data)
153{
154 struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
155
156
157 writel(0x1, wdt->base + PDC_WDT_SOFT_RESET);
158
159 return 0;
160}
161
162static const struct watchdog_info pdc_wdt_info = {
163 .identity = "IMG PDC Watchdog",
164 .options = WDIOF_SETTIMEOUT |
165 WDIOF_KEEPALIVEPING |
166 WDIOF_MAGICCLOSE,
167};
168
169static const struct watchdog_ops pdc_wdt_ops = {
170 .owner = THIS_MODULE,
171 .start = pdc_wdt_start,
172 .stop = pdc_wdt_stop,
173 .ping = pdc_wdt_keepalive,
174 .set_timeout = pdc_wdt_set_timeout,
175 .restart = pdc_wdt_restart,
176};
177
178static void pdc_clk_disable_unprepare(void *data)
179{
180 clk_disable_unprepare(data);
181}
182
183static int pdc_wdt_probe(struct platform_device *pdev)
184{
185 struct device *dev = &pdev->dev;
186 u64 div;
187 int ret, val;
188 unsigned long clk_rate;
189 struct pdc_wdt_dev *pdc_wdt;
190
191 pdc_wdt = devm_kzalloc(dev, sizeof(*pdc_wdt), GFP_KERNEL);
192 if (!pdc_wdt)
193 return -ENOMEM;
194
195 pdc_wdt->base = devm_platform_ioremap_resource(pdev, 0);
196 if (IS_ERR(pdc_wdt->base))
197 return PTR_ERR(pdc_wdt->base);
198
199 pdc_wdt->sys_clk = devm_clk_get(dev, "sys");
200 if (IS_ERR(pdc_wdt->sys_clk)) {
201 dev_err(dev, "failed to get the sys clock\n");
202 return PTR_ERR(pdc_wdt->sys_clk);
203 }
204
205 pdc_wdt->wdt_clk = devm_clk_get(dev, "wdt");
206 if (IS_ERR(pdc_wdt->wdt_clk)) {
207 dev_err(dev, "failed to get the wdt clock\n");
208 return PTR_ERR(pdc_wdt->wdt_clk);
209 }
210
211 ret = clk_prepare_enable(pdc_wdt->sys_clk);
212 if (ret) {
213 dev_err(dev, "could not prepare or enable sys clock\n");
214 return ret;
215 }
216 ret = devm_add_action_or_reset(dev, pdc_clk_disable_unprepare,
217 pdc_wdt->sys_clk);
218 if (ret)
219 return ret;
220
221 ret = clk_prepare_enable(pdc_wdt->wdt_clk);
222 if (ret) {
223 dev_err(dev, "could not prepare or enable wdt clock\n");
224 return ret;
225 }
226 ret = devm_add_action_or_reset(dev, pdc_clk_disable_unprepare,
227 pdc_wdt->wdt_clk);
228 if (ret)
229 return ret;
230
231
232 clk_rate = clk_get_rate(pdc_wdt->wdt_clk);
233 if (clk_rate == 0) {
234 dev_err(dev, "failed to get clock rate\n");
235 return -EINVAL;
236 }
237
238 if (order_base_2(clk_rate) > PDC_WDT_CONFIG_DELAY_MASK + 1) {
239 dev_err(dev, "invalid clock rate\n");
240 return -EINVAL;
241 }
242
243 if (order_base_2(clk_rate) == 0)
244 pdc_wdt->wdt_dev.min_timeout = PDC_WDT_MIN_TIMEOUT + 1;
245 else
246 pdc_wdt->wdt_dev.min_timeout = PDC_WDT_MIN_TIMEOUT;
247
248 pdc_wdt->wdt_dev.info = &pdc_wdt_info;
249 pdc_wdt->wdt_dev.ops = &pdc_wdt_ops;
250
251 div = 1ULL << (PDC_WDT_CONFIG_DELAY_MASK + 1);
252 do_div(div, clk_rate);
253 pdc_wdt->wdt_dev.max_timeout = div;
254 pdc_wdt->wdt_dev.timeout = PDC_WDT_DEF_TIMEOUT;
255 pdc_wdt->wdt_dev.parent = dev;
256 watchdog_set_drvdata(&pdc_wdt->wdt_dev, pdc_wdt);
257
258 watchdog_init_timeout(&pdc_wdt->wdt_dev, heartbeat, dev);
259
260 pdc_wdt_stop(&pdc_wdt->wdt_dev);
261
262
263 val = readl(pdc_wdt->base + PDC_WDT_TICKLE1);
264 val = (val & PDC_WDT_TICKLE_STATUS_MASK) >> PDC_WDT_TICKLE_STATUS_SHIFT;
265 switch (val) {
266 case PDC_WDT_TICKLE_STATUS_TICKLE:
267 case PDC_WDT_TICKLE_STATUS_TIMEOUT:
268 pdc_wdt->wdt_dev.bootstatus |= WDIOF_CARDRESET;
269 dev_info(dev, "watchdog module last reset due to timeout\n");
270 break;
271 case PDC_WDT_TICKLE_STATUS_HRESET:
272 dev_info(dev,
273 "watchdog module last reset due to hard reset\n");
274 break;
275 case PDC_WDT_TICKLE_STATUS_SRESET:
276 dev_info(dev,
277 "watchdog module last reset due to soft reset\n");
278 break;
279 case PDC_WDT_TICKLE_STATUS_USER:
280 dev_info(dev,
281 "watchdog module last reset due to user reset\n");
282 break;
283 default:
284 dev_info(dev, "contains an illegal status code (%08x)\n", val);
285 break;
286 }
287
288 watchdog_set_nowayout(&pdc_wdt->wdt_dev, nowayout);
289 watchdog_set_restart_priority(&pdc_wdt->wdt_dev, 128);
290
291 platform_set_drvdata(pdev, pdc_wdt);
292
293 watchdog_stop_on_reboot(&pdc_wdt->wdt_dev);
294 watchdog_stop_on_unregister(&pdc_wdt->wdt_dev);
295 return devm_watchdog_register_device(dev, &pdc_wdt->wdt_dev);
296}
297
298static const struct of_device_id pdc_wdt_match[] = {
299 { .compatible = "img,pdc-wdt" },
300 {}
301};
302MODULE_DEVICE_TABLE(of, pdc_wdt_match);
303
304static struct platform_driver pdc_wdt_driver = {
305 .driver = {
306 .name = "imgpdc-wdt",
307 .of_match_table = pdc_wdt_match,
308 },
309 .probe = pdc_wdt_probe,
310};
311module_platform_driver(pdc_wdt_driver);
312
313MODULE_AUTHOR("Jude Abraham <Jude.Abraham@imgtec.com>");
314MODULE_AUTHOR("Naidu Tellapati <Naidu.Tellapati@imgtec.com>");
315MODULE_DESCRIPTION("Imagination Technologies PDC Watchdog Timer Driver");
316MODULE_LICENSE("GPL v2");
317
