1 // SPDX-License-Identifier: GPL-2.0-only
3 * intel-mid_wdt: generic Intel MID SCU watchdog driver
5 * Platforms supported so far:
8 * Copyright (C) 2014 Intel Corporation. All rights reserved.
9 * Contact: David Cohen <david.a.cohen@linux.intel.com>
12 #include <linux/interrupt.h>
13 #include <linux/module.h>
14 #include <linux/nmi.h>
15 #include <linux/platform_device.h>
16 #include <linux/watchdog.h>
17 #include <linux/platform_data/intel-mid_wdt.h>
19 #include <asm/intel_scu_ipc.h>
20 #include <asm/intel-mid.h>
22 #define IPC_WATCHDOG 0xf8
24 #define MID_WDT_PRETIMEOUT 15
25 #define MID_WDT_TIMEOUT_MIN (1 + MID_WDT_PRETIMEOUT)
26 #define MID_WDT_TIMEOUT_MAX 170
27 #define MID_WDT_DEFAULT_TIMEOUT 90
29 /* SCU watchdog messages */
31 SCU_WATCHDOG_START = 0,
33 SCU_WATCHDOG_KEEPALIVE,
36 static inline int wdt_command(int sub, u32 *in, int inlen)
38 return intel_scu_ipc_command(IPC_WATCHDOG, sub, in, inlen, NULL, 0);
41 static int wdt_start(struct watchdog_device *wd)
43 struct device *dev = watchdog_get_drvdata(wd);
45 int timeout = wd->timeout;
49 } ipc_wd_start = { timeout - MID_WDT_PRETIMEOUT, timeout };
52 * SCU expects the input size for watchdog IPC to
55 in_size = DIV_ROUND_UP(sizeof(ipc_wd_start), 4);
57 ret = wdt_command(SCU_WATCHDOG_START, (u32 *)&ipc_wd_start, in_size);
59 dev_crit(dev, "error starting watchdog: %d\n", ret);
64 static int wdt_ping(struct watchdog_device *wd)
66 struct device *dev = watchdog_get_drvdata(wd);
69 ret = wdt_command(SCU_WATCHDOG_KEEPALIVE, NULL, 0);
71 dev_crit(dev, "Error executing keepalive: %d\n", ret);
76 static int wdt_stop(struct watchdog_device *wd)
78 struct device *dev = watchdog_get_drvdata(wd);
81 ret = wdt_command(SCU_WATCHDOG_STOP, NULL, 0);
83 dev_crit(dev, "Error stopping watchdog: %d\n", ret);
88 static irqreturn_t mid_wdt_irq(int irq, void *dev_id)
90 panic("Kernel Watchdog");
92 /* This code should not be reached */
96 static const struct watchdog_info mid_wdt_info = {
97 .identity = "Intel MID SCU watchdog",
98 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
101 static const struct watchdog_ops mid_wdt_ops = {
102 .owner = THIS_MODULE,
108 static int mid_wdt_probe(struct platform_device *pdev)
110 struct device *dev = &pdev->dev;
111 struct watchdog_device *wdt_dev;
112 struct intel_mid_wdt_pdata *pdata = dev->platform_data;
116 dev_err(dev, "missing platform data\n");
121 ret = pdata->probe(pdev);
126 wdt_dev = devm_kzalloc(dev, sizeof(*wdt_dev), GFP_KERNEL);
130 wdt_dev->info = &mid_wdt_info;
131 wdt_dev->ops = &mid_wdt_ops;
132 wdt_dev->min_timeout = MID_WDT_TIMEOUT_MIN;
133 wdt_dev->max_timeout = MID_WDT_TIMEOUT_MAX;
134 wdt_dev->timeout = MID_WDT_DEFAULT_TIMEOUT;
135 wdt_dev->parent = dev;
137 watchdog_set_nowayout(wdt_dev, WATCHDOG_NOWAYOUT);
138 watchdog_set_drvdata(wdt_dev, dev);
140 ret = devm_request_irq(dev, pdata->irq, mid_wdt_irq,
141 IRQF_SHARED | IRQF_NO_SUSPEND, "watchdog",
144 dev_err(dev, "error requesting warning irq %d\n", pdata->irq);
149 * The firmware followed by U-Boot leaves the watchdog running
150 * with the default threshold which may vary. When we get here
151 * we should make a decision to prevent any side effects before
152 * user space daemon will take care of it. The best option,
153 * taking into consideration that there is no way to read values
154 * back from hardware, is to enforce watchdog being run with
155 * deterministic values.
157 ret = wdt_start(wdt_dev);
161 /* Make sure the watchdog is serviced */
162 set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
164 ret = devm_watchdog_register_device(dev, wdt_dev);
168 dev_info(dev, "Intel MID watchdog device probed\n");
173 static struct platform_driver mid_wdt_driver = {
174 .probe = mid_wdt_probe,
176 .name = "intel_mid_wdt",
180 module_platform_driver(mid_wdt_driver);
182 MODULE_AUTHOR("David Cohen <david.a.cohen@linux.intel.com>");
183 MODULE_DESCRIPTION("Watchdog Driver for Intel MID platform");
184 MODULE_LICENSE("GPL");