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c5b8e46446
Add the watchdog driver for Toshiba Visconti series. Signed-off-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp> Reviewed-by: Punit Agrawal <punit1.agrawal@toshiba.co.jp> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20201005023012.603026-3-nobuhiro1.iwamatsu@toshiba.co.jp Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
196 lines
4.9 KiB
C
196 lines
4.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2020 TOSHIBA CORPORATION
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* Copyright (c) 2020 Toshiba Electronic Devices & Storage Corporation
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* Copyright (c) 2020 Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>
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*/
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/watchdog.h>
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#define WDT_CNT 0x00
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#define WDT_MIN 0x04
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#define WDT_MAX 0x08
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#define WDT_CTL 0x0c
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#define WDT_CMD 0x10
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#define WDT_CMD_CLEAR 0x4352
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#define WDT_CMD_START_STOP 0x5354
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#define WDT_DIV 0x30
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#define VISCONTI_WDT_FREQ 2000000 /* 2MHz */
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#define WDT_DEFAULT_TIMEOUT 10U /* in seconds */
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static bool nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(
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nowayout,
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"Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT)")");
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struct visconti_wdt_priv {
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struct watchdog_device wdev;
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void __iomem *base;
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u32 div;
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};
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static int visconti_wdt_start(struct watchdog_device *wdev)
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{
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struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdev);
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u32 timeout = wdev->timeout * VISCONTI_WDT_FREQ;
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writel(priv->div, priv->base + WDT_DIV);
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writel(0, priv->base + WDT_MIN);
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writel(timeout, priv->base + WDT_MAX);
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writel(0, priv->base + WDT_CTL);
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writel(WDT_CMD_START_STOP, priv->base + WDT_CMD);
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return 0;
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}
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static int visconti_wdt_stop(struct watchdog_device *wdev)
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{
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struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdev);
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writel(1, priv->base + WDT_CTL);
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writel(WDT_CMD_START_STOP, priv->base + WDT_CMD);
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return 0;
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}
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static int visconti_wdt_ping(struct watchdog_device *wdd)
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{
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struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdd);
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writel(WDT_CMD_CLEAR, priv->base + WDT_CMD);
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return 0;
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}
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static unsigned int visconti_wdt_get_timeleft(struct watchdog_device *wdev)
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{
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struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdev);
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u32 timeout = wdev->timeout * VISCONTI_WDT_FREQ;
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u32 cnt = readl(priv->base + WDT_CNT);
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if (timeout <= cnt)
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return 0;
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timeout -= cnt;
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return timeout / VISCONTI_WDT_FREQ;
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}
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static int visconti_wdt_set_timeout(struct watchdog_device *wdev, unsigned int timeout)
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{
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u32 val;
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struct visconti_wdt_priv *priv = watchdog_get_drvdata(wdev);
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wdev->timeout = timeout;
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val = wdev->timeout * VISCONTI_WDT_FREQ;
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/* Clear counter before setting timeout because WDT expires */
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writel(WDT_CMD_CLEAR, priv->base + WDT_CMD);
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writel(val, priv->base + WDT_MAX);
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return 0;
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}
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static const struct watchdog_info visconti_wdt_info = {
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.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
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.identity = "Visconti Watchdog",
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};
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static const struct watchdog_ops visconti_wdt_ops = {
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.owner = THIS_MODULE,
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.start = visconti_wdt_start,
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.stop = visconti_wdt_stop,
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.ping = visconti_wdt_ping,
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.get_timeleft = visconti_wdt_get_timeleft,
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.set_timeout = visconti_wdt_set_timeout,
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};
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static void visconti_clk_disable_unprepare(void *data)
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{
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clk_disable_unprepare(data);
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}
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static int visconti_wdt_probe(struct platform_device *pdev)
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{
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struct watchdog_device *wdev;
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struct visconti_wdt_priv *priv;
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struct device *dev = &pdev->dev;
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struct clk *clk;
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int ret;
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unsigned long clk_freq;
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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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priv->base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(priv->base))
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return PTR_ERR(priv->base);
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clk = devm_clk_get(dev, NULL);
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if (IS_ERR(clk))
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return dev_err_probe(dev, PTR_ERR(clk), "Could not get clock\n");
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ret = clk_prepare_enable(clk);
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if (ret) {
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dev_err(dev, "Could not enable clock\n");
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return ret;
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}
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ret = devm_add_action_or_reset(dev, visconti_clk_disable_unprepare, clk);
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if (ret)
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return ret;
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clk_freq = clk_get_rate(clk);
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if (!clk_freq)
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return -EINVAL;
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priv->div = clk_freq / VISCONTI_WDT_FREQ;
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/* Initialize struct watchdog_device. */
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wdev = &priv->wdev;
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wdev->info = &visconti_wdt_info;
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wdev->ops = &visconti_wdt_ops;
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wdev->parent = dev;
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wdev->min_timeout = 1;
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wdev->max_timeout = 0xffffffff / VISCONTI_WDT_FREQ;
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wdev->timeout = min(wdev->max_timeout, WDT_DEFAULT_TIMEOUT);
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watchdog_set_drvdata(wdev, priv);
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watchdog_set_nowayout(wdev, nowayout);
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watchdog_stop_on_unregister(wdev);
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/* This overrides the default timeout only if DT configuration was found */
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ret = watchdog_init_timeout(wdev, 0, dev);
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if (ret)
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dev_warn(dev, "Specified timeout value invalid, using default\n");
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return devm_watchdog_register_device(dev, wdev);
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}
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static const struct of_device_id visconti_wdt_of_match[] = {
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{ .compatible = "toshiba,visconti-wdt", },
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{}
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};
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MODULE_DEVICE_TABLE(of, visconti_wdt_of_match);
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static struct platform_driver visconti_wdt_driver = {
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.driver = {
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.name = "visconti_wdt",
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.of_match_table = visconti_wdt_of_match,
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},
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.probe = visconti_wdt_probe,
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};
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module_platform_driver(visconti_wdt_driver);
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MODULE_DESCRIPTION("TOSHIBA Visconti Watchdog Driver");
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MODULE_AUTHOR("Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp");
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MODULE_LICENSE("GPL v2");
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