1 // SPDX-License-Identifier: GPL-2.0
2 /* Marvell GTI Watchdog driver
3 *
4 * Copyright (C) 2023 Marvell.
5 */
6
7 #include <linux/clk.h>
8 #include <linux/interrupt.h>
9 #include <linux/io.h>
10 #include <linux/module.h>
11 #include <linux/platform_device.h>
12 #include <linux/of.h>
13 #include <linux/watchdog.h>
14
15 /*
16 * Hardware supports following mode of operation:
17 * 1) Interrupt Only:
18 * This will generate the interrupt to arm core whenever timeout happens.
19 *
20 * 2) Interrupt + del3t (Interrupt to firmware (SCP processor)).
21 * This will generate interrupt to arm core on 1st timeout happens
22 * This will generate interrupt to SCP processor on 2nd timeout happens
23 *
24 * 3) Interrupt + Interrupt to SCP processor (called delt3t) + reboot.
25 * This will generate interrupt to arm core on 1st timeout happens
26 * Will generate interrupt to SCP processor on 2nd timeout happens,
27 * if interrupt is configured.
28 * Reboot on 3rd timeout.
29 *
30 * Driver will use hardware in mode-3 above so that system can reboot in case
31 * a hardware hang. Also h/w is configured not to generate SCP interrupt, so
32 * effectively 2nd timeout is ignored within hardware.
33 *
34 * First timeout is effectively watchdog pretimeout.
35 */
36
37 /* GTI CWD Watchdog (GTI_CWD_WDOG) Register */
38 #define GTI_CWD_WDOG(reg_offset) (0x8 * (reg_offset))
39 #define GTI_CWD_WDOG_MODE_INT_DEL3T_RST 0x3
40 #define GTI_CWD_WDOG_MODE_MASK GENMASK_ULL(1, 0)
41 #define GTI_CWD_WDOG_LEN_SHIFT 4
42 #define GTI_CWD_WDOG_LEN_MASK GENMASK_ULL(19, 4)
43 #define GTI_CWD_WDOG_CNT_SHIFT 20
44 #define GTI_CWD_WDOG_CNT_MASK GENMASK_ULL(43, 20)
45
46 /* GTI CWD Watchdog Interrupt (GTI_CWD_INT) Register */
47 #define GTI_CWD_INT 0x200
48 #define GTI_CWD_INT_PENDING_STATUS(bit) BIT_ULL(bit)
49
50 /* GTI CWD Watchdog Interrupt Enable Clear (GTI_CWD_INT_ENA_CLR) Register */
51 #define GTI_CWD_INT_ENA_CLR 0x210
52 #define GTI_CWD_INT_ENA_CLR_VAL(bit) BIT_ULL(bit)
53
54 /* GTI CWD Watchdog Interrupt Enable Set (GTI_CWD_INT_ENA_SET) Register */
55 #define GTI_CWD_INT_ENA_SET 0x218
56 #define GTI_CWD_INT_ENA_SET_VAL(bit) BIT_ULL(bit)
57
58 /* GTI CWD Watchdog Poke (GTI_CWD_POKE) Registers */
59 #define GTI_CWD_POKE(reg_offset) (0x10000 + 0x8 * (reg_offset))
60 #define GTI_CWD_POKE_VAL 1
61
62 struct gti_match_data {
63 u32 gti_num_timers;
64 };
65
66 static const struct gti_match_data match_data_octeontx2 = {
67 .gti_num_timers = 54,
68 };
69
70 static const struct gti_match_data match_data_cn10k = {
71 .gti_num_timers = 64,
72 };
73
74 struct gti_wdt_priv {
75 struct watchdog_device wdev;
76 void __iomem *base;
77 u32 clock_freq;
78 struct clk *sclk;
79 /* wdt_timer_idx used for timer to be used for system watchdog */
80 u32 wdt_timer_idx;
81 const struct gti_match_data *data;
82 };
83
gti_wdt_interrupt(int irq,void * data)84 static irqreturn_t gti_wdt_interrupt(int irq, void *data)
85 {
86 struct watchdog_device *wdev = data;
87 struct gti_wdt_priv *priv = watchdog_get_drvdata(wdev);
88
89 /* Clear Interrupt Pending Status */
90 writeq(GTI_CWD_INT_PENDING_STATUS(priv->wdt_timer_idx),
91 priv->base + GTI_CWD_INT);
92
93 watchdog_notify_pretimeout(wdev);
94
95 return IRQ_HANDLED;
96 }
97
gti_wdt_ping(struct watchdog_device * wdev)98 static int gti_wdt_ping(struct watchdog_device *wdev)
99 {
100 struct gti_wdt_priv *priv = watchdog_get_drvdata(wdev);
101
102 writeq(GTI_CWD_POKE_VAL,
103 priv->base + GTI_CWD_POKE(priv->wdt_timer_idx));
104
105 return 0;
106 }
107
gti_wdt_start(struct watchdog_device * wdev)108 static int gti_wdt_start(struct watchdog_device *wdev)
109 {
110 struct gti_wdt_priv *priv = watchdog_get_drvdata(wdev);
111 u64 regval;
112
113 if (!wdev->pretimeout)
114 return -EINVAL;
115
116 set_bit(WDOG_HW_RUNNING, &wdev->status);
117
118 /* Clear any pending interrupt */
119 writeq(GTI_CWD_INT_PENDING_STATUS(priv->wdt_timer_idx),
120 priv->base + GTI_CWD_INT);
121
122 /* Enable Interrupt */
123 writeq(GTI_CWD_INT_ENA_SET_VAL(priv->wdt_timer_idx),
124 priv->base + GTI_CWD_INT_ENA_SET);
125
126 /* Set (Interrupt + SCP interrupt (DEL3T) + core domain reset) Mode */
127 regval = readq(priv->base + GTI_CWD_WDOG(priv->wdt_timer_idx));
128 regval |= GTI_CWD_WDOG_MODE_INT_DEL3T_RST;
129 writeq(regval, priv->base + GTI_CWD_WDOG(priv->wdt_timer_idx));
130
131 return 0;
132 }
133
gti_wdt_stop(struct watchdog_device * wdev)134 static int gti_wdt_stop(struct watchdog_device *wdev)
135 {
136 struct gti_wdt_priv *priv = watchdog_get_drvdata(wdev);
137 u64 regval;
138
139 /* Disable Interrupt */
140 writeq(GTI_CWD_INT_ENA_CLR_VAL(priv->wdt_timer_idx),
141 priv->base + GTI_CWD_INT_ENA_CLR);
142
143 /* Set GTI_CWD_WDOG.Mode = 0 to stop the timer */
144 regval = readq(priv->base + GTI_CWD_WDOG(priv->wdt_timer_idx));
145 regval &= ~GTI_CWD_WDOG_MODE_MASK;
146 writeq(regval, priv->base + GTI_CWD_WDOG(priv->wdt_timer_idx));
147
148 return 0;
149 }
150
gti_wdt_settimeout(struct watchdog_device * wdev,unsigned int timeout)151 static int gti_wdt_settimeout(struct watchdog_device *wdev,
152 unsigned int timeout)
153 {
154 struct gti_wdt_priv *priv = watchdog_get_drvdata(wdev);
155 u64 timeout_wdog, regval;
156
157 /* Update new timeout */
158 wdev->timeout = timeout;
159
160 /* Pretimeout is 1/3 of timeout */
161 wdev->pretimeout = timeout / 3;
162
163 /* Get clock cycles from pretimeout */
164 timeout_wdog = (u64)priv->clock_freq * wdev->pretimeout;
165
166 /* Watchdog counts in 1024 cycle steps */
167 timeout_wdog = timeout_wdog >> 10;
168
169 /* GTI_CWD_WDOG.CNT: reload counter is 16-bit */
170 timeout_wdog = (timeout_wdog + 0xff) >> 8;
171 if (timeout_wdog >= 0x10000)
172 timeout_wdog = 0xffff;
173
174 /*
175 * GTI_CWD_WDOG.LEN is 24bit, lower 8-bits should be zero and
176 * upper 16-bits are same as GTI_CWD_WDOG.CNT
177 */
178 regval = readq(priv->base + GTI_CWD_WDOG(priv->wdt_timer_idx));
179 regval &= GTI_CWD_WDOG_MODE_MASK;
180 regval |= (timeout_wdog << (GTI_CWD_WDOG_CNT_SHIFT + 8)) |
181 (timeout_wdog << GTI_CWD_WDOG_LEN_SHIFT);
182 writeq(regval, priv->base + GTI_CWD_WDOG(priv->wdt_timer_idx));
183
184 return 0;
185 }
186
gti_wdt_set_pretimeout(struct watchdog_device * wdev,unsigned int timeout)187 static int gti_wdt_set_pretimeout(struct watchdog_device *wdev,
188 unsigned int timeout)
189 {
190 struct gti_wdt_priv *priv = watchdog_get_drvdata(wdev);
191 struct watchdog_device *wdog_dev = &priv->wdev;
192
193 if (!timeout) {
194 /* Disable Interrupt */
195 writeq(GTI_CWD_INT_ENA_CLR_VAL(priv->wdt_timer_idx),
196 priv->base + GTI_CWD_INT_ENA_CLR);
197 return 0;
198 }
199
200 /* pretimeout should 1/3 of max_timeout */
201 if (timeout * 3 <= wdog_dev->max_timeout)
202 return gti_wdt_settimeout(wdev, timeout * 3);
203
204 return -EINVAL;
205 }
206
gti_clk_disable_unprepare(void * data)207 static void gti_clk_disable_unprepare(void *data)
208 {
209 clk_disable_unprepare(data);
210 }
211
gti_wdt_get_cntfrq(struct platform_device * pdev,struct gti_wdt_priv * priv)212 static int gti_wdt_get_cntfrq(struct platform_device *pdev,
213 struct gti_wdt_priv *priv)
214 {
215 int err;
216
217 priv->sclk = devm_clk_get_enabled(&pdev->dev, NULL);
218 if (IS_ERR(priv->sclk))
219 return PTR_ERR(priv->sclk);
220
221 err = devm_add_action_or_reset(&pdev->dev,
222 gti_clk_disable_unprepare, priv->sclk);
223 if (err)
224 return err;
225
226 priv->clock_freq = clk_get_rate(priv->sclk);
227 if (!priv->clock_freq)
228 return -EINVAL;
229
230 return 0;
231 }
232
233 static const struct watchdog_info gti_wdt_ident = {
234 .identity = "Marvell GTI watchdog",
235 .options = WDIOF_SETTIMEOUT | WDIOF_PRETIMEOUT | WDIOF_KEEPALIVEPING |
236 WDIOF_MAGICCLOSE | WDIOF_CARDRESET,
237 };
238
239 static const struct watchdog_ops gti_wdt_ops = {
240 .owner = THIS_MODULE,
241 .start = gti_wdt_start,
242 .stop = gti_wdt_stop,
243 .ping = gti_wdt_ping,
244 .set_timeout = gti_wdt_settimeout,
245 .set_pretimeout = gti_wdt_set_pretimeout,
246 };
247
gti_wdt_probe(struct platform_device * pdev)248 static int gti_wdt_probe(struct platform_device *pdev)
249 {
250 struct gti_wdt_priv *priv;
251 struct device *dev = &pdev->dev;
252 struct watchdog_device *wdog_dev;
253 u64 max_pretimeout;
254 u32 wdt_idx;
255 int irq;
256 int err;
257
258 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
259 if (!priv)
260 return -ENOMEM;
261
262 priv->base = devm_platform_ioremap_resource(pdev, 0);
263 if (IS_ERR(priv->base))
264 return dev_err_probe(&pdev->dev, PTR_ERR(priv->base),
265 "reg property not valid/found\n");
266
267 err = gti_wdt_get_cntfrq(pdev, priv);
268 if (err)
269 return dev_err_probe(&pdev->dev, err,
270 "GTI clock frequency not valid/found");
271
272 priv->data = of_device_get_match_data(dev);
273
274 /* default use last timer for watchdog */
275 priv->wdt_timer_idx = priv->data->gti_num_timers - 1;
276
277 err = of_property_read_u32(dev->of_node, "marvell,wdt-timer-index",
278 &wdt_idx);
279 if (!err) {
280 if (wdt_idx >= priv->data->gti_num_timers)
281 return dev_err_probe(&pdev->dev, -EINVAL,
282 "GTI wdog timer index not valid");
283
284 priv->wdt_timer_idx = wdt_idx;
285 }
286
287 wdog_dev = &priv->wdev;
288 wdog_dev->info = >i_wdt_ident;
289 wdog_dev->ops = >i_wdt_ops;
290 wdog_dev->parent = dev;
291 /*
292 * Watchdog counter is 24 bit where lower 8 bits are zeros
293 * This counter decrements every 1024 clock cycles.
294 */
295 max_pretimeout = (GTI_CWD_WDOG_CNT_MASK >> GTI_CWD_WDOG_CNT_SHIFT);
296 max_pretimeout &= ~0xFFUL;
297 max_pretimeout = (max_pretimeout * 1024) / priv->clock_freq;
298 wdog_dev->pretimeout = max_pretimeout;
299
300 /* Maximum timeout is 3 times the pretimeout */
301 wdog_dev->max_timeout = max_pretimeout * 3;
302 wdog_dev->max_hw_heartbeat_ms = max_pretimeout * 1000;
303 /* Minimum first timeout (pretimeout) is 1, so min_timeout as 3 */
304 wdog_dev->min_timeout = 3;
305 wdog_dev->timeout = wdog_dev->pretimeout;
306
307 watchdog_set_drvdata(wdog_dev, priv);
308 platform_set_drvdata(pdev, priv);
309 gti_wdt_settimeout(wdog_dev, wdog_dev->timeout);
310 watchdog_stop_on_reboot(wdog_dev);
311 watchdog_stop_on_unregister(wdog_dev);
312
313 err = devm_watchdog_register_device(dev, wdog_dev);
314 if (err)
315 return err;
316
317 irq = platform_get_irq(pdev, 0);
318 if (irq < 0)
319 return irq;
320
321 err = devm_request_irq(dev, irq, gti_wdt_interrupt, 0,
322 pdev->name, &priv->wdev);
323 if (err)
324 return dev_err_probe(dev, err, "Failed to register interrupt handler\n");
325
326 dev_info(dev, "Watchdog enabled (timeout=%d sec)\n", wdog_dev->timeout);
327 return 0;
328 }
329
330 static const struct of_device_id gti_wdt_of_match[] = {
331 { .compatible = "marvell,cn9670-wdt", .data = &match_data_octeontx2},
332 { .compatible = "marvell,cn10624-wdt", .data = &match_data_cn10k},
333 { },
334 };
335 MODULE_DEVICE_TABLE(of, gti_wdt_of_match);
336
337 static struct platform_driver gti_wdt_driver = {
338 .driver = {
339 .name = "gti-wdt",
340 .of_match_table = gti_wdt_of_match,
341 },
342 .probe = gti_wdt_probe,
343 };
344 module_platform_driver(gti_wdt_driver);
345
346 MODULE_AUTHOR("Bharat Bhushan <bbhushan2@marvell.com>");
347 MODULE_DESCRIPTION("Marvell GTI watchdog driver");
348 MODULE_LICENSE("GPL");
349