// SPDX-License-Identifier: GPL-2.0+
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/*
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* Watchdog driver for TQMx86 PLD.
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*
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* The watchdog supports power of 2 timeouts from 1 to 4096sec.
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* Once started, it cannot be stopped.
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*
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* Based on the vendor code written by Vadim V.Vlasov
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* <vvlasov@dev.rtsoft.ru>
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*/
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#include <linux/io.h>
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#include <linux/log2.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/timer.h>
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#include <linux/watchdog.h>
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/* default timeout (secs) */
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#define WDT_TIMEOUT 32
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static unsigned int timeout;
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module_param(timeout, uint, 0);
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MODULE_PARM_DESC(timeout,
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"Watchdog timeout in seconds. (1<=timeout<=4096, default="
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__MODULE_STRING(WDT_TIMEOUT) ")");
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struct tqmx86_wdt {
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struct watchdog_device wdd;
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void __iomem *io_base;
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};
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#define TQMX86_WDCFG 0x00 /* Watchdog Configuration Register */
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#define TQMX86_WDCS 0x01 /* Watchdog Config/Status Register */
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static int tqmx86_wdt_start(struct watchdog_device *wdd)
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{
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struct tqmx86_wdt *priv = watchdog_get_drvdata(wdd);
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iowrite8(0x81, priv->io_base + TQMX86_WDCS);
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return 0;
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}
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static int tqmx86_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
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{
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struct tqmx86_wdt *priv = watchdog_get_drvdata(wdd);
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u8 val;
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t = roundup_pow_of_two(t);
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val = ilog2(t) | 0x90;
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val += 3; /* values 0,1,2 correspond to 0.125,0.25,0.5s timeouts */
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iowrite8(val, priv->io_base + TQMX86_WDCFG);
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wdd->timeout = t;
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return 0;
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}
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static const struct watchdog_info tqmx86_wdt_info = {
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.options = WDIOF_SETTIMEOUT |
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WDIOF_KEEPALIVEPING,
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.identity = "TQMx86 Watchdog",
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};
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static struct watchdog_ops tqmx86_wdt_ops = {
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.owner = THIS_MODULE,
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.start = tqmx86_wdt_start,
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.set_timeout = tqmx86_wdt_set_timeout,
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};
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static int tqmx86_wdt_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct tqmx86_wdt *priv;
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struct resource *res;
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int err;
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priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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res = platform_get_resource(pdev, IORESOURCE_IO, 0);
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if (!res)
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return -ENODEV;
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priv->io_base = devm_ioport_map(dev, res->start, resource_size(res));
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if (!priv->io_base)
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return -ENOMEM;
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watchdog_set_drvdata(&priv->wdd, priv);
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priv->wdd.parent = dev;
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priv->wdd.info = &tqmx86_wdt_info;
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priv->wdd.ops = &tqmx86_wdt_ops;
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priv->wdd.min_timeout = 1;
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priv->wdd.max_timeout = 4096;
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priv->wdd.max_hw_heartbeat_ms = 4096*1000;
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priv->wdd.timeout = WDT_TIMEOUT;
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watchdog_init_timeout(&priv->wdd, timeout, dev);
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watchdog_set_nowayout(&priv->wdd, WATCHDOG_NOWAYOUT);
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tqmx86_wdt_set_timeout(&priv->wdd, priv->wdd.timeout);
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err = devm_watchdog_register_device(dev, &priv->wdd);
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if (err)
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return err;
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dev_info(dev, "TQMx86 watchdog\n");
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return 0;
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}
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static struct platform_driver tqmx86_wdt_driver = {
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.driver = {
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.name = "tqmx86-wdt",
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},
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.probe = tqmx86_wdt_probe,
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};
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module_platform_driver(tqmx86_wdt_driver);
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MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
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MODULE_DESCRIPTION("TQMx86 Watchdog");
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MODULE_ALIAS("platform:tqmx86-wdt");
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MODULE_LICENSE("GPL");
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