1 // SPDX-License-Identifier: GPL-2.0
3 * Watchdog driver for the K3 RTI module
5 * (c) Copyright 2019-2020 Texas Instruments Inc.
10 #include <linux/device.h>
11 #include <linux/err.h>
13 #include <linux/kernel.h>
14 #include <linux/mod_devicetable.h>
15 #include <linux/module.h>
16 #include <linux/moduleparam.h>
17 #include <linux/platform_device.h>
18 #include <linux/pm_runtime.h>
19 #include <linux/types.h>
20 #include <linux/watchdog.h>
22 #define DEFAULT_HEARTBEAT 60
24 /* Max heartbeat is calculated at 32kHz source clock */
25 #define MAX_HEARTBEAT 1000
27 /* Timer register set definition */
28 #define RTIDWDCTRL 0x90
29 #define RTIDWDPRLD 0x94
30 #define RTIWDSTATUS 0x98
32 #define RTIDWDCNTR 0xa0
33 #define RTIWWDRXCTRL 0xa4
34 #define RTIWWDSIZECTRL 0xa8
36 #define RTIWWDRX_NMI 0xa
38 #define RTIWWDSIZE_50P 0x50
39 #define RTIWWDSIZE_25P 0x500
40 #define RTIWWDSIZE_12P5 0x5000
41 #define RTIWWDSIZE_6P25 0x50000
42 #define RTIWWDSIZE_3P125 0x500000
44 #define WDENABLE_KEY 0xa98559da
46 #define WDKEY_SEQ0 0xe51a
47 #define WDKEY_SEQ1 0xa35c
49 #define WDT_PRELOAD_SHIFT 13
51 #define WDT_PRELOAD_MAX 0xfff
55 static int heartbeat = DEFAULT_HEARTBEAT;
58 * struct to hold data for each WDT device
59 * @base - base io address of WD device
60 * @freq - source clock frequency of WDT
61 * @wdd - hold watchdog device as is in WDT core
63 struct rti_wdt_device {
66 struct watchdog_device wdd;
69 static int rti_wdt_start(struct watchdog_device *wdd)
72 struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
75 ret = pm_runtime_resume_and_get(wdd->parent);
79 /* set timeout period */
80 timer_margin = (u64)wdd->timeout * wdt->freq;
81 timer_margin >>= WDT_PRELOAD_SHIFT;
82 if (timer_margin > WDT_PRELOAD_MAX)
83 timer_margin = WDT_PRELOAD_MAX;
84 writel_relaxed(timer_margin, wdt->base + RTIDWDPRLD);
87 * RTI only supports a windowed mode, where the watchdog can only
88 * be petted during the open window; not too early or not too late.
89 * The HW configuration options only allow for the open window size
90 * to be 50% or less than that; we obviouly want to configure the open
91 * window as large as possible so we select the 50% option.
93 wdd->min_hw_heartbeat_ms = 500 * wdd->timeout;
95 /* Generate NMI when wdt expires */
96 writel_relaxed(RTIWWDRX_NMI, wdt->base + RTIWWDRXCTRL);
98 /* Open window size 50%; this is the largest window size available */
99 writel_relaxed(RTIWWDSIZE_50P, wdt->base + RTIWWDSIZECTRL);
101 readl_relaxed(wdt->base + RTIWWDSIZECTRL);
103 /* enable watchdog */
104 writel_relaxed(WDENABLE_KEY, wdt->base + RTIDWDCTRL);
108 static int rti_wdt_ping(struct watchdog_device *wdd)
110 struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
112 /* put watchdog in service state */
113 writel_relaxed(WDKEY_SEQ0, wdt->base + RTIWDKEY);
114 /* put watchdog in active state */
115 writel_relaxed(WDKEY_SEQ1, wdt->base + RTIWDKEY);
120 static int rti_wdt_setup_hw_hb(struct watchdog_device *wdd, u32 wsize)
123 * RTI only supports a windowed mode, where the watchdog can only
124 * be petted during the open window; not too early or not too late.
125 * The HW configuration options only allow for the open window size
126 * to be 50% or less than that.
130 /* 50% open window => 50% min heartbeat */
131 wdd->min_hw_heartbeat_ms = 500 * heartbeat;
135 /* 25% open window => 75% min heartbeat */
136 wdd->min_hw_heartbeat_ms = 750 * heartbeat;
139 case RTIWWDSIZE_12P5:
140 /* 12.5% open window => 87.5% min heartbeat */
141 wdd->min_hw_heartbeat_ms = 875 * heartbeat;
144 case RTIWWDSIZE_6P25:
145 /* 6.5% open window => 93.5% min heartbeat */
146 wdd->min_hw_heartbeat_ms = 935 * heartbeat;
149 case RTIWWDSIZE_3P125:
150 /* 3.125% open window => 96.9% min heartbeat */
151 wdd->min_hw_heartbeat_ms = 969 * heartbeat;
161 static unsigned int rti_wdt_get_timeleft_ms(struct watchdog_device *wdd)
165 struct rti_wdt_device *wdt = watchdog_get_drvdata(wdd);
167 /* if timeout has occurred then return 0 */
168 val = readl_relaxed(wdt->base + RTIWDSTATUS);
172 timer_counter = readl_relaxed(wdt->base + RTIDWDCNTR);
174 timer_counter *= 1000;
176 do_div(timer_counter, wdt->freq);
178 return timer_counter;
181 static unsigned int rti_wdt_get_timeleft(struct watchdog_device *wdd)
183 return rti_wdt_get_timeleft_ms(wdd) / 1000;
186 static const struct watchdog_info rti_wdt_info = {
187 .options = WDIOF_KEEPALIVEPING,
188 .identity = "K3 RTI Watchdog",
191 static const struct watchdog_ops rti_wdt_ops = {
192 .owner = THIS_MODULE,
193 .start = rti_wdt_start,
194 .ping = rti_wdt_ping,
195 .get_timeleft = rti_wdt_get_timeleft,
198 static int rti_wdt_probe(struct platform_device *pdev)
201 struct device *dev = &pdev->dev;
202 struct watchdog_device *wdd;
203 struct rti_wdt_device *wdt;
207 wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
211 clk = clk_get(dev, NULL);
213 return dev_err_probe(dev, PTR_ERR(clk), "failed to get clock\n");
215 wdt->freq = clk_get_rate(clk);
220 dev_err(dev, "Failed to get fck rate.\n");
225 * If watchdog is running at 32k clock, it is not accurate.
226 * Adjust frequency down in this case so that we don't pet
227 * the watchdog too often.
229 if (wdt->freq < 32768)
230 wdt->freq = wdt->freq * 9 / 10;
232 pm_runtime_enable(dev);
233 ret = pm_runtime_resume_and_get(dev);
235 pm_runtime_disable(&pdev->dev);
236 return dev_err_probe(dev, ret, "runtime pm failed\n");
239 platform_set_drvdata(pdev, wdt);
242 wdd->info = &rti_wdt_info;
243 wdd->ops = &rti_wdt_ops;
244 wdd->min_timeout = 1;
245 wdd->max_hw_heartbeat_ms = (WDT_PRELOAD_MAX << WDT_PRELOAD_SHIFT) /
249 watchdog_set_drvdata(wdd, wdt);
250 watchdog_set_nowayout(wdd, 1);
251 watchdog_set_restart_priority(wdd, 128);
253 wdt->base = devm_platform_ioremap_resource(pdev, 0);
254 if (IS_ERR(wdt->base)) {
255 ret = PTR_ERR(wdt->base);
259 if (readl(wdt->base + RTIDWDCTRL) == WDENABLE_KEY) {
260 int preset_heartbeat;
265 set_bit(WDOG_HW_RUNNING, &wdd->status);
266 time_left_ms = rti_wdt_get_timeleft_ms(wdd);
267 heartbeat_ms = readl(wdt->base + RTIDWDPRLD);
268 heartbeat_ms <<= WDT_PRELOAD_SHIFT;
269 heartbeat_ms *= 1000;
270 do_div(heartbeat_ms, wdt->freq);
271 preset_heartbeat = heartbeat_ms + 500;
272 preset_heartbeat /= 1000;
273 if (preset_heartbeat != heartbeat)
274 dev_warn(dev, "watchdog already running, ignoring heartbeat config!\n");
276 heartbeat = preset_heartbeat;
278 wsize = readl(wdt->base + RTIWWDSIZECTRL);
279 ret = rti_wdt_setup_hw_hb(wdd, wsize);
281 dev_err(dev, "bad window size.\n");
285 last_ping = heartbeat_ms - time_left_ms;
286 if (time_left_ms > heartbeat_ms) {
287 dev_warn(dev, "time_left > heartbeat? Assuming last ping just before now.\n");
292 watchdog_init_timeout(wdd, heartbeat, dev);
294 ret = watchdog_register_device(wdd);
296 dev_err(dev, "cannot register watchdog device\n");
301 watchdog_set_last_hw_keepalive(wdd, last_ping);
303 if (!watchdog_hw_running(wdd))
304 pm_runtime_put_sync(&pdev->dev);
309 pm_runtime_put_sync(&pdev->dev);
310 pm_runtime_disable(&pdev->dev);
315 static int rti_wdt_remove(struct platform_device *pdev)
317 struct rti_wdt_device *wdt = platform_get_drvdata(pdev);
319 watchdog_unregister_device(&wdt->wdd);
321 if (!pm_runtime_suspended(&pdev->dev))
322 pm_runtime_put(&pdev->dev);
324 pm_runtime_disable(&pdev->dev);
329 static const struct of_device_id rti_wdt_of_match[] = {
330 { .compatible = "ti,j7-rti-wdt", },
333 MODULE_DEVICE_TABLE(of, rti_wdt_of_match);
335 static struct platform_driver rti_wdt_driver = {
338 .of_match_table = rti_wdt_of_match,
340 .probe = rti_wdt_probe,
341 .remove = rti_wdt_remove,
344 module_platform_driver(rti_wdt_driver);
346 MODULE_AUTHOR("Tero Kristo <t-kristo@ti.com>");
347 MODULE_DESCRIPTION("K3 RTI Watchdog Driver");
349 module_param(heartbeat, int, 0);
350 MODULE_PARM_DESC(heartbeat,
351 "Watchdog heartbeat period in seconds from 1 to "
352 __MODULE_STRING(MAX_HEARTBEAT) ", default "
353 __MODULE_STRING(DEFAULT_HEARTBEAT));
355 MODULE_LICENSE("GPL");
356 MODULE_ALIAS("platform:rti-wdt");