drivers/watchdog/tqmx86_wdt.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 /*
0003  * Watchdog driver for TQMx86 PLD.
0004  *
0005  * The watchdog supports power of 2 timeouts from 1 to 4096sec.
0006  * Once started, it cannot be stopped.
0007  *
0008  * Based on the vendor code written by Vadim V.Vlasov
0009  * <vvlasov@dev.rtsoft.ru>
0010  */
0011
0012 #include <linux/io.h>
0013 #include <linux/log2.h>
0014 #include <linux/module.h>
0015 #include <linux/platform_device.h>
0016 #include <linux/timer.h>
0017 #include <linux/watchdog.h>
0018
0019 /* default timeout (secs) */
0020 #define WDT_TIMEOUT 32
0021
0022 static unsigned int timeout;
0023 module_param(timeout, uint, 0);
0024 MODULE_PARM_DESC(timeout,
0025     "Watchdog timeout in seconds. (1<=timeout<=4096, default="
0026                 __MODULE_STRING(WDT_TIMEOUT) ")");
0027 struct tqmx86_wdt {
0028     struct watchdog_device wdd;
0029     void __iomem *io_base;
0030 };
0031
0032 #define TQMX86_WDCFG    0x00 /* Watchdog Configuration Register */
0033 #define TQMX86_WDCS 0x01 /* Watchdog Config/Status Register */
0034
0035 static int tqmx86_wdt_start(struct watchdog_device *wdd)
0036 {
0037     struct tqmx86_wdt *priv = watchdog_get_drvdata(wdd);
0038
0039     iowrite8(0x81, priv->io_base + TQMX86_WDCS);
0040
0041     return 0;
0042 }
0043
0044 static int tqmx86_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
0045 {
0046     struct tqmx86_wdt *priv = watchdog_get_drvdata(wdd);
0047     u8 val;
0048
0049     t = roundup_pow_of_two(t);
0050     val = ilog2(t) | 0x90;
0051     val += 3; /* values 0,1,2 correspond to 0.125,0.25,0.5s timeouts */
0052     iowrite8(val, priv->io_base + TQMX86_WDCFG);
0053
0054     wdd->timeout = t;
0055
0056     return 0;
0057 }
0058
0059 static const struct watchdog_info tqmx86_wdt_info = {
0060     .options    = WDIOF_SETTIMEOUT |
0061               WDIOF_KEEPALIVEPING,
0062     .identity   = "TQMx86 Watchdog",
0063 };
0064
0065 static const struct watchdog_ops tqmx86_wdt_ops = {
0066     .owner      = THIS_MODULE,
0067     .start      = tqmx86_wdt_start,
0068     .set_timeout    = tqmx86_wdt_set_timeout,
0069 };
0070
0071 static int tqmx86_wdt_probe(struct platform_device *pdev)
0072 {
0073     struct device *dev = &pdev->dev;
0074     struct tqmx86_wdt *priv;
0075     struct resource *res;
0076     int err;
0077
0078     priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
0079     if (!priv)
0080         return -ENOMEM;
0081
0082     res = platform_get_resource(pdev, IORESOURCE_IO, 0);
0083     if (!res)
0084         return -ENODEV;
0085
0086     priv->io_base = devm_ioport_map(dev, res->start, resource_size(res));
0087     if (!priv->io_base)
0088         return -ENOMEM;
0089
0090     watchdog_set_drvdata(&priv->wdd, priv);
0091
0092     priv->wdd.parent = dev;
0093     priv->wdd.info = &tqmx86_wdt_info;
0094     priv->wdd.ops = &tqmx86_wdt_ops;
0095     priv->wdd.min_timeout = 1;
0096     priv->wdd.max_timeout = 4096;
0097     priv->wdd.max_hw_heartbeat_ms = 4096*1000;
0098     priv->wdd.timeout = WDT_TIMEOUT;
0099
0100     watchdog_init_timeout(&priv->wdd, timeout, dev);
0101     watchdog_set_nowayout(&priv->wdd, WATCHDOG_NOWAYOUT);
0102
0103     tqmx86_wdt_set_timeout(&priv->wdd, priv->wdd.timeout);
0104
0105     err = devm_watchdog_register_device(dev, &priv->wdd);
0106     if (err)
0107         return err;
0108
0109     dev_info(dev, "TQMx86 watchdog\n");
0110
0111     return 0;
0112 }
0113
0114 static struct platform_driver tqmx86_wdt_driver = {
0115     .driver     = {
0116         .name   = "tqmx86-wdt",
0117     },
0118     .probe      = tqmx86_wdt_probe,
0119 };
0120
0121 module_platform_driver(tqmx86_wdt_driver);
0122
0123 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
0124 MODULE_DESCRIPTION("TQMx86 Watchdog");
0125 MODULE_ALIAS("platform:tqmx86-wdt");
0126 MODULE_LICENSE("GPL");