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- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * sunplus Watchdog Driver
- *
- * Copyright (C) 2021 Sunplus Technology Co., Ltd.
- *
- */
- #include <linux/clk.h>
- #include <linux/io.h>
- #include <linux/module.h>
- #include <linux/mod_devicetable.h>
- #include <linux/platform_device.h>
- #include <linux/reset.h>
- #include <linux/watchdog.h>
- #define WDT_CTRL 0x00
- #define WDT_CNT 0x04
- #define WDT_STOP 0x3877
- #define WDT_RESUME 0x4A4B
- #define WDT_CLRIRQ 0x7482
- #define WDT_UNLOCK 0xAB00
- #define WDT_LOCK 0xAB01
- #define WDT_CONMAX 0xDEAF
- /* TIMEOUT_MAX = ffff0/90kHz =11.65, so longer than 11 seconds will time out. */
- #define SP_WDT_MAX_TIMEOUT 11U
- #define SP_WDT_DEFAULT_TIMEOUT 10
- #define STC_CLK 90000
- #define DEVICE_NAME "sunplus-wdt"
- static unsigned int timeout;
- module_param(timeout, int, 0);
- MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
- static bool nowayout = WATCHDOG_NOWAYOUT;
- module_param(nowayout, bool, 0);
- MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
- __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
- struct sp_wdt_priv {
- struct watchdog_device wdev;
- void __iomem *base;
- struct clk *clk;
- struct reset_control *rstc;
- };
- static int sp_wdt_restart(struct watchdog_device *wdev,
- unsigned long action, void *data)
- {
- struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
- void __iomem *base = priv->base;
- writel(WDT_STOP, base + WDT_CTRL);
- writel(WDT_UNLOCK, base + WDT_CTRL);
- writel(0x0001, base + WDT_CNT);
- writel(WDT_LOCK, base + WDT_CTRL);
- writel(WDT_RESUME, base + WDT_CTRL);
- return 0;
- }
- static int sp_wdt_ping(struct watchdog_device *wdev)
- {
- struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
- void __iomem *base = priv->base;
- u32 count;
- if (wdev->timeout > SP_WDT_MAX_TIMEOUT) {
- /* WDT_CONMAX sets the count to the maximum (down-counting). */
- writel(WDT_CONMAX, base + WDT_CTRL);
- } else {
- writel(WDT_UNLOCK, base + WDT_CTRL);
- /*
- * Watchdog timer is a 20-bit down-counting based on STC_CLK.
- * This register bits[16:0] is from bit[19:4] of the watchdog
- * timer counter.
- */
- count = (wdev->timeout * STC_CLK) >> 4;
- writel(count, base + WDT_CNT);
- writel(WDT_LOCK, base + WDT_CTRL);
- }
- return 0;
- }
- static int sp_wdt_stop(struct watchdog_device *wdev)
- {
- struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
- void __iomem *base = priv->base;
- writel(WDT_STOP, base + WDT_CTRL);
- return 0;
- }
- static int sp_wdt_start(struct watchdog_device *wdev)
- {
- struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
- void __iomem *base = priv->base;
- writel(WDT_RESUME, base + WDT_CTRL);
- return 0;
- }
- static unsigned int sp_wdt_get_timeleft(struct watchdog_device *wdev)
- {
- struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
- void __iomem *base = priv->base;
- u32 val;
- val = readl(base + WDT_CNT);
- val &= 0xffff;
- val = val << 4;
- return val;
- }
- static const struct watchdog_info sp_wdt_info = {
- .identity = DEVICE_NAME,
- .options = WDIOF_SETTIMEOUT |
- WDIOF_MAGICCLOSE |
- WDIOF_KEEPALIVEPING,
- };
- static const struct watchdog_ops sp_wdt_ops = {
- .owner = THIS_MODULE,
- .start = sp_wdt_start,
- .stop = sp_wdt_stop,
- .ping = sp_wdt_ping,
- .get_timeleft = sp_wdt_get_timeleft,
- .restart = sp_wdt_restart,
- };
- static void sp_clk_disable_unprepare(void *data)
- {
- clk_disable_unprepare(data);
- }
- static void sp_reset_control_assert(void *data)
- {
- reset_control_assert(data);
- }
- static int sp_wdt_probe(struct platform_device *pdev)
- {
- struct device *dev = &pdev->dev;
- struct sp_wdt_priv *priv;
- int ret;
- priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
- if (!priv)
- return -ENOMEM;
- priv->clk = devm_clk_get(dev, NULL);
- if (IS_ERR(priv->clk))
- return dev_err_probe(dev, PTR_ERR(priv->clk), "Failed to get clock\n");
- ret = clk_prepare_enable(priv->clk);
- if (ret)
- return dev_err_probe(dev, ret, "Failed to enable clock\n");
- ret = devm_add_action_or_reset(dev, sp_clk_disable_unprepare, priv->clk);
- if (ret)
- return ret;
- /* The timer and watchdog shared the STC reset */
- priv->rstc = devm_reset_control_get_shared(dev, NULL);
- if (IS_ERR(priv->rstc))
- return dev_err_probe(dev, PTR_ERR(priv->rstc), "Failed to get reset\n");
- reset_control_deassert(priv->rstc);
- ret = devm_add_action_or_reset(dev, sp_reset_control_assert, priv->rstc);
- if (ret)
- return ret;
- priv->base = devm_platform_ioremap_resource(pdev, 0);
- if (IS_ERR(priv->base))
- return PTR_ERR(priv->base);
- priv->wdev.info = &sp_wdt_info;
- priv->wdev.ops = &sp_wdt_ops;
- priv->wdev.timeout = SP_WDT_DEFAULT_TIMEOUT;
- priv->wdev.max_hw_heartbeat_ms = SP_WDT_MAX_TIMEOUT * 1000;
- priv->wdev.min_timeout = 1;
- priv->wdev.parent = dev;
- watchdog_set_drvdata(&priv->wdev, priv);
- watchdog_init_timeout(&priv->wdev, timeout, dev);
- watchdog_set_nowayout(&priv->wdev, nowayout);
- watchdog_stop_on_reboot(&priv->wdev);
- watchdog_set_restart_priority(&priv->wdev, 128);
- return devm_watchdog_register_device(dev, &priv->wdev);
- }
- static const struct of_device_id sp_wdt_of_match[] = {
- {.compatible = "sunplus,sp7021-wdt", },
- { /* sentinel */ }
- };
- MODULE_DEVICE_TABLE(of, sp_wdt_of_match);
- static struct platform_driver sp_wdt_driver = {
- .probe = sp_wdt_probe,
- .driver = {
- .name = DEVICE_NAME,
- .of_match_table = sp_wdt_of_match,
- },
- };
- module_platform_driver(sp_wdt_driver);
- MODULE_AUTHOR("Xiantao Hu <[email protected]>");
- MODULE_DESCRIPTION("Sunplus Watchdog Timer Driver");
- MODULE_LICENSE("GPL");
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