--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Watchdog driver for Intel Keem Bay non-secure watchdog.
+ *
+ * Copyright (C) 2020 Intel Corporation
+ */
+
+#include <linux/arm-smccc.h>
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/limits.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/watchdog.h>
+
+/* Non-secure watchdog register offsets */
+#define TIM_WATCHDOG 0x0
+#define TIM_WATCHDOG_INT_THRES 0x4
+#define TIM_WDOG_EN 0x8
+#define TIM_SAFE 0xc
+
+#define WDT_ISR_MASK GENMASK(9, 8)
+#define WDT_ISR_CLEAR 0x8200ff18
+#define WDT_UNLOCK 0xf1d0dead
+#define WDT_LOAD_MAX U32_MAX
+#define WDT_LOAD_MIN 1
+#define WDT_TIMEOUT 5
+
+static unsigned int timeout = WDT_TIMEOUT;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout period in seconds (default = "
+ __MODULE_STRING(WDT_TIMEOUT) ")");
+
+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 keembay_wdt {
+ struct watchdog_device wdd;
+ struct clk *clk;
+ unsigned int rate;
+ int to_irq;
+ int th_irq;
+ void __iomem *base;
+};
+
+static inline u32 keembay_wdt_readl(struct keembay_wdt *wdt, u32 offset)
+{
+ return readl(wdt->base + offset);
+}
+
+static inline void keembay_wdt_writel(struct keembay_wdt *wdt, u32 offset, u32 val)
+{
+ writel(WDT_UNLOCK, wdt->base + TIM_SAFE);
+ writel(val, wdt->base + offset);
+}
+
+static void keembay_wdt_set_timeout_reg(struct watchdog_device *wdog)
+{
+ struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
+
+ keembay_wdt_writel(wdt, TIM_WATCHDOG, wdog->timeout * wdt->rate);
+}
+
+static void keembay_wdt_set_pretimeout_reg(struct watchdog_device *wdog)
+{
+ struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
+ u32 th_val = 0;
+
+ if (wdog->pretimeout)
+ th_val = wdog->timeout - wdog->pretimeout;
+
+ keembay_wdt_writel(wdt, TIM_WATCHDOG_INT_THRES, th_val * wdt->rate);
+}
+
+static int keembay_wdt_start(struct watchdog_device *wdog)
+{
+ struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
+
+ keembay_wdt_set_timeout_reg(wdog);
+ keembay_wdt_writel(wdt, TIM_WDOG_EN, 1);
+
+ return 0;
+}
+
+static int keembay_wdt_stop(struct watchdog_device *wdog)
+{
+ struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
+
+ keembay_wdt_writel(wdt, TIM_WDOG_EN, 0);
+
+ return 0;
+}
+
+static int keembay_wdt_ping(struct watchdog_device *wdog)
+{
+ keembay_wdt_set_timeout_reg(wdog);
+
+ return 0;
+}
+
+static int keembay_wdt_set_timeout(struct watchdog_device *wdog, u32 t)
+{
+ wdog->timeout = t;
+ keembay_wdt_set_timeout_reg(wdog);
+
+ return 0;
+}
+
+static int keembay_wdt_set_pretimeout(struct watchdog_device *wdog, u32 t)
+{
+ if (t > wdog->timeout)
+ return -EINVAL;
+
+ wdog->pretimeout = t;
+ keembay_wdt_set_pretimeout_reg(wdog);
+
+ return 0;
+}
+
+static unsigned int keembay_wdt_get_timeleft(struct watchdog_device *wdog)
+{
+ struct keembay_wdt *wdt = watchdog_get_drvdata(wdog);
+
+ return keembay_wdt_readl(wdt, TIM_WATCHDOG) / wdt->rate;
+}
+
+/*
+ * SMC call is used to clear the interrupt bits, because the TIM_GEN_CONFIG
+ * register is in the secure bank.
+ */
+static irqreturn_t keembay_wdt_to_isr(int irq, void *dev_id)
+{
+ struct keembay_wdt *wdt = dev_id;
+ struct arm_smccc_res res;
+
+ keembay_wdt_writel(wdt, TIM_WATCHDOG, 1);
+ arm_smccc_smc(WDT_ISR_CLEAR, WDT_ISR_MASK, 0, 0, 0, 0, 0, 0, &res);
+ dev_crit(wdt->wdd.parent, "Intel Keem Bay non-sec wdt timeout.\n");
+ emergency_restart();
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t keembay_wdt_th_isr(int irq, void *dev_id)
+{
+ struct keembay_wdt *wdt = dev_id;
+ struct arm_smccc_res res;
+
+ arm_smccc_smc(WDT_ISR_CLEAR, WDT_ISR_MASK, 0, 0, 0, 0, 0, 0, &res);
+ dev_crit(wdt->wdd.parent, "Intel Keem Bay non-sec wdt pre-timeout.\n");
+ watchdog_notify_pretimeout(&wdt->wdd);
+
+ return IRQ_HANDLED;
+}
+
+static const struct watchdog_info keembay_wdt_info = {
+ .identity = "Intel Keem Bay Watchdog Timer",
+ .options = WDIOF_SETTIMEOUT |
+ WDIOF_PRETIMEOUT |
+ WDIOF_MAGICCLOSE |
+ WDIOF_KEEPALIVEPING,
+};
+
+static const struct watchdog_ops keembay_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = keembay_wdt_start,
+ .stop = keembay_wdt_stop,
+ .ping = keembay_wdt_ping,
+ .set_timeout = keembay_wdt_set_timeout,
+ .set_pretimeout = keembay_wdt_set_pretimeout,
+ .get_timeleft = keembay_wdt_get_timeleft,
+};
+
+static int keembay_wdt_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct keembay_wdt *wdt;
+ int ret;
+
+ wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ wdt->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(wdt->base))
+ return PTR_ERR(wdt->base);
+
+ /* we do not need to enable the clock as it is enabled by default */
+ wdt->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(wdt->clk))
+ return dev_err_probe(dev, PTR_ERR(wdt->clk), "Failed to get clock\n");
+
+ wdt->rate = clk_get_rate(wdt->clk);
+ if (!wdt->rate)
+ return dev_err_probe(dev, -EINVAL, "Failed to get clock rate\n");
+
+ wdt->th_irq = platform_get_irq_byname(pdev, "threshold");
+ if (wdt->th_irq < 0)
+ return dev_err_probe(dev, wdt->th_irq, "Failed to get IRQ for threshold\n");
+
+ ret = devm_request_irq(dev, wdt->th_irq, keembay_wdt_th_isr, 0,
+ "keembay-wdt", wdt);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to request IRQ for threshold\n");
+
+ wdt->to_irq = platform_get_irq_byname(pdev, "timeout");
+ if (wdt->to_irq < 0)
+ return dev_err_probe(dev, wdt->to_irq, "Failed to get IRQ for timeout\n");
+
+ ret = devm_request_irq(dev, wdt->to_irq, keembay_wdt_to_isr, 0,
+ "keembay-wdt", wdt);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to request IRQ for timeout\n");
+
+ wdt->wdd.parent = dev;
+ wdt->wdd.info = &keembay_wdt_info;
+ wdt->wdd.ops = &keembay_wdt_ops;
+ wdt->wdd.min_timeout = WDT_LOAD_MIN;
+ wdt->wdd.max_timeout = WDT_LOAD_MAX / wdt->rate;
+ wdt->wdd.timeout = WDT_TIMEOUT;
+
+ watchdog_set_drvdata(&wdt->wdd, wdt);
+ watchdog_set_nowayout(&wdt->wdd, nowayout);
+ watchdog_init_timeout(&wdt->wdd, timeout, dev);
+ keembay_wdt_set_timeout(&wdt->wdd, wdt->wdd.timeout);
+
+ ret = devm_watchdog_register_device(dev, &wdt->wdd);
+ if (ret)
+ return dev_err_probe(dev, ret, "Failed to register watchdog device.\n");
+
+ platform_set_drvdata(pdev, wdt);
+ dev_info(dev, "Initial timeout %d sec%s.\n",
+ wdt->wdd.timeout, nowayout ? ", nowayout" : "");
+
+ return 0;
+}
+
+static int __maybe_unused keembay_wdt_suspend(struct device *dev)
+{
+ struct keembay_wdt *wdt = dev_get_drvdata(dev);
+
+ if (watchdog_active(&wdt->wdd))
+ return keembay_wdt_stop(&wdt->wdd);
+
+ return 0;
+}
+
+static int __maybe_unused keembay_wdt_resume(struct device *dev)
+{
+ struct keembay_wdt *wdt = dev_get_drvdata(dev);
+
+ if (watchdog_active(&wdt->wdd))
+ return keembay_wdt_start(&wdt->wdd);
+
+ return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(keembay_wdt_pm_ops, keembay_wdt_suspend,
+ keembay_wdt_resume);
+
+static const struct of_device_id keembay_wdt_match[] = {
+ { .compatible = "intel,keembay-wdt" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, keembay_wdt_match);
+
+static struct platform_driver keembay_wdt_driver = {
+ .probe = keembay_wdt_probe,
+ .driver = {
+ .name = "keembay_wdt",
+ .of_match_table = keembay_wdt_match,
+ .pm = &keembay_wdt_pm_ops,
+ },
+};
+
+module_platform_driver(keembay_wdt_driver);
+
+MODULE_DESCRIPTION("Intel Keem Bay SoC watchdog driver");
+MODULE_AUTHOR("Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com");
+MODULE_LICENSE("GPL v2");
projects / platform / kernel / linux-starfive.git / commitdiff