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/of_platform.h>
12#include <linux/platform_device.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
62struct gti_match_data {
63	u32 gti_num_timers;
64};
65
66static const struct gti_match_data match_data_octeontx2 = {
67	.gti_num_timers = 54,
68};
69
70static const struct gti_match_data match_data_cn10k = {
71	.gti_num_timers = 64,
72};
73
74struct 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
84static 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
98static 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
108static 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
134static 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
151static 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
187static 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	/* pretimeout should 1/3 of max_timeout */
194	if (timeout * 3 <= wdog_dev->max_timeout)
195		return gti_wdt_settimeout(wdev, timeout * 3);
196
197	return -EINVAL;
198}
199
200static void gti_clk_disable_unprepare(void *data)
201{
202	clk_disable_unprepare(data);
203}
204
205static int gti_wdt_get_cntfrq(struct platform_device *pdev,
206			      struct gti_wdt_priv *priv)
207{
208	int err;
209
210	priv->sclk = devm_clk_get_enabled(&pdev->dev, NULL);
211	if (IS_ERR(priv->sclk))
212		return PTR_ERR(priv->sclk);
213
214	err = devm_add_action_or_reset(&pdev->dev,
215				       gti_clk_disable_unprepare, priv->sclk);
216	if (err)
217		return err;
218
219	priv->clock_freq = clk_get_rate(priv->sclk);
220	if (!priv->clock_freq)
221		return -EINVAL;
222
223	return 0;
224}
225
226static const struct watchdog_info gti_wdt_ident = {
227	.identity = "Marvell GTI watchdog",
228	.options = WDIOF_SETTIMEOUT | WDIOF_PRETIMEOUT | WDIOF_KEEPALIVEPING |
229		   WDIOF_MAGICCLOSE | WDIOF_CARDRESET,
230};
231
232static const struct watchdog_ops gti_wdt_ops = {
233	.owner = THIS_MODULE,
234	.start = gti_wdt_start,
235	.stop = gti_wdt_stop,
236	.ping = gti_wdt_ping,
237	.set_timeout = gti_wdt_settimeout,
238	.set_pretimeout = gti_wdt_set_pretimeout,
239};
240
241static int gti_wdt_probe(struct platform_device *pdev)
242{
243	struct gti_wdt_priv *priv;
244	struct device *dev = &pdev->dev;
245	struct watchdog_device *wdog_dev;
246	u64 max_pretimeout;
247	u32 wdt_idx;
248	int irq;
249	int err;
250
251	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
252	if (!priv)
253		return -ENOMEM;
254
255	priv->base = devm_platform_ioremap_resource(pdev, 0);
256	if (IS_ERR(priv->base))
257		return dev_err_probe(&pdev->dev, PTR_ERR(priv->base),
258			      "reg property not valid/found\n");
259
260	err = gti_wdt_get_cntfrq(pdev, priv);
261	if (err)
262		return dev_err_probe(&pdev->dev, err,
263				     "GTI clock frequency not valid/found");
264
265	priv->data = of_device_get_match_data(dev);
266
267	/* default use last timer for watchdog */
268	priv->wdt_timer_idx = priv->data->gti_num_timers - 1;
269
270	err = of_property_read_u32(dev->of_node, "marvell,wdt-timer-index",
271				   &wdt_idx);
272	if (!err) {
273		if (wdt_idx >= priv->data->gti_num_timers)
274			return dev_err_probe(&pdev->dev, -EINVAL,
275				"GTI wdog timer index not valid");
276
277		priv->wdt_timer_idx = wdt_idx;
278	}
279
280	wdog_dev = &priv->wdev;
281	wdog_dev->info = &gti_wdt_ident,
282	wdog_dev->ops = &gti_wdt_ops,
283	wdog_dev->parent = dev;
284	/*
285	 * Watchdog counter is 24 bit where lower 8 bits are zeros
286	 * This counter decrements every 1024 clock cycles.
287	 */
288	max_pretimeout = (GTI_CWD_WDOG_CNT_MASK >> GTI_CWD_WDOG_CNT_SHIFT);
289	max_pretimeout &= ~0xFFUL;
290	max_pretimeout = (max_pretimeout * 1024) / priv->clock_freq;
291	wdog_dev->pretimeout = max_pretimeout;
292
293	/* Maximum timeout is 3 times the pretimeout */
294	wdog_dev->max_timeout = max_pretimeout * 3;
295	/* Minimum first timeout (pretimeout) is 1, so min_timeout as 3 */
296	wdog_dev->min_timeout = 3;
297	wdog_dev->timeout = wdog_dev->pretimeout;
298
299	watchdog_set_drvdata(wdog_dev, priv);
300	platform_set_drvdata(pdev, priv);
301	gti_wdt_settimeout(wdog_dev, wdog_dev->timeout);
302	watchdog_stop_on_reboot(wdog_dev);
303	watchdog_stop_on_unregister(wdog_dev);
304
305	err = devm_watchdog_register_device(dev, wdog_dev);
306	if (err)
307		return err;
308
309	irq = platform_get_irq(pdev, 0);
310	if (irq < 0)
311		return dev_err_probe(&pdev->dev, irq, "IRQ resource not found\n");
312
313	err = devm_request_irq(dev, irq, gti_wdt_interrupt, 0,
314			       pdev->name, &priv->wdev);
315	if (err)
316		return dev_err_probe(dev, err, "Failed to register interrupt handler\n");
317
318	dev_info(dev, "Watchdog enabled (timeout=%d sec)\n", wdog_dev->timeout);
319	return 0;
320}
321
322static const struct of_device_id gti_wdt_of_match[] = {
323	{ .compatible = "marvell,cn9670-wdt", .data = &match_data_octeontx2},
324	{ .compatible = "marvell,cn10624-wdt", .data = &match_data_cn10k},
325	{ },
326};
327MODULE_DEVICE_TABLE(of, gti_wdt_of_match);
328
329static struct platform_driver gti_wdt_driver = {
330	.driver = {
331		.name = "gti-wdt",
332		.of_match_table = gti_wdt_of_match,
333	},
334	.probe = gti_wdt_probe,
335};
336module_platform_driver(gti_wdt_driver);
337
338MODULE_AUTHOR("Bharat Bhushan <bbhushan2@marvell.com>");
339MODULE_DESCRIPTION("Marvell GTI watchdog driver");
340MODULE_LICENSE("GPL");
341