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195 lines
4.9 KiB
195 lines
4.9 KiB
// 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 <[email protected]> |
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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 <[email protected]"); |
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MODULE_LICENSE("GPL v2");
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