--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Renesas RZ/G2L WDT Watchdog Driver
+ *
+ * Copyright (C) 2021 Renesas Electronics Corporation
+ */
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset.h>
+#include <linux/units.h>
+#include <linux/watchdog.h>
+
+#define WDTCNT 0x00
+#define WDTSET 0x04
+#define WDTTIM 0x08
+#define WDTINT 0x0C
+#define WDTCNT_WDTEN BIT(0)
+#define WDTINT_INTDISP BIT(0)
+
+#define WDT_DEFAULT_TIMEOUT 60U
+
+/* Setting period time register only 12 bit set in WDTSET[31:20] */
+#define WDTSET_COUNTER_MASK (0xFFF00000)
+#define WDTSET_COUNTER_VAL(f) ((f) << 20)
+
+#define F2CYCLE_NSEC(f) (1000000000 / (f))
+
+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 rzg2l_wdt_priv {
+ void __iomem *base;
+ struct watchdog_device wdev;
+ struct reset_control *rstc;
+ unsigned long osc_clk_rate;
+ unsigned long delay;
+};
+
+static void rzg2l_wdt_wait_delay(struct rzg2l_wdt_priv *priv)
+{
+ /* delay timer when change the setting register */
+ ndelay(priv->delay);
+}
+
+static u32 rzg2l_wdt_get_cycle_usec(unsigned long cycle, u32 wdttime)
+{
+ u64 timer_cycle_us = 1024 * 1024 * (wdttime + 1) * MICRO;
+
+ return div64_ul(timer_cycle_us, cycle);
+}
+
+static void rzg2l_wdt_write(struct rzg2l_wdt_priv *priv, u32 val, unsigned int reg)
+{
+ if (reg == WDTSET)
+ val &= WDTSET_COUNTER_MASK;
+
+ writel_relaxed(val, priv->base + reg);
+ /* Registers other than the WDTINT is always synchronized with WDT_CLK */
+ if (reg != WDTINT)
+ rzg2l_wdt_wait_delay(priv);
+}
+
+static void rzg2l_wdt_init_timeout(struct watchdog_device *wdev)
+{
+ struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
+ u32 time_out;
+
+ /* Clear Lapsed Time Register and clear Interrupt */
+ rzg2l_wdt_write(priv, WDTINT_INTDISP, WDTINT);
+ /* 2 consecutive overflow cycle needed to trigger reset */
+ time_out = (wdev->timeout * (MICRO / 2)) /
+ rzg2l_wdt_get_cycle_usec(priv->osc_clk_rate, 0);
+ rzg2l_wdt_write(priv, WDTSET_COUNTER_VAL(time_out), WDTSET);
+}
+
+static int rzg2l_wdt_start(struct watchdog_device *wdev)
+{
+ struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
+
+ reset_control_deassert(priv->rstc);
+ pm_runtime_get_sync(wdev->parent);
+
+ /* Initialize time out */
+ rzg2l_wdt_init_timeout(wdev);
+
+ /* Initialize watchdog counter register */
+ rzg2l_wdt_write(priv, 0, WDTTIM);
+
+ /* Enable watchdog timer*/
+ rzg2l_wdt_write(priv, WDTCNT_WDTEN, WDTCNT);
+
+ return 0;
+}
+
+static int rzg2l_wdt_stop(struct watchdog_device *wdev)
+{
+ struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
+
+ pm_runtime_put(wdev->parent);
+ reset_control_assert(priv->rstc);
+
+ return 0;
+}
+
+static int rzg2l_wdt_restart(struct watchdog_device *wdev,
+ unsigned long action, void *data)
+{
+ struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
+
+ /* Reset the module before we modify any register */
+ reset_control_reset(priv->rstc);
+ pm_runtime_get_sync(wdev->parent);
+
+ /* smallest counter value to reboot soon */
+ rzg2l_wdt_write(priv, WDTSET_COUNTER_VAL(1), WDTSET);
+
+ /* Enable watchdog timer*/
+ rzg2l_wdt_write(priv, WDTCNT_WDTEN, WDTCNT);
+
+ return 0;
+}
+
+static const struct watchdog_info rzg2l_wdt_ident = {
+ .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
+ .identity = "Renesas RZ/G2L WDT Watchdog",
+};
+
+static int rzg2l_wdt_ping(struct watchdog_device *wdev)
+{
+ struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
+
+ rzg2l_wdt_write(priv, WDTINT_INTDISP, WDTINT);
+
+ return 0;
+}
+
+static const struct watchdog_ops rzg2l_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = rzg2l_wdt_start,
+ .stop = rzg2l_wdt_stop,
+ .ping = rzg2l_wdt_ping,
+ .restart = rzg2l_wdt_restart,
+};
+
+static void rzg2l_wdt_reset_assert_pm_disable_put(void *data)
+{
+ struct watchdog_device *wdev = data;
+ struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
+
+ pm_runtime_put(wdev->parent);
+ pm_runtime_disable(wdev->parent);
+ reset_control_assert(priv->rstc);
+}
+
+static int rzg2l_wdt_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct rzg2l_wdt_priv *priv;
+ unsigned long pclk_rate;
+ struct clk *wdt_clk;
+ int ret;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+
+ /* Get watchdog main clock */
+ wdt_clk = clk_get(&pdev->dev, "oscclk");
+ if (IS_ERR(wdt_clk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(wdt_clk), "no oscclk");
+
+ priv->osc_clk_rate = clk_get_rate(wdt_clk);
+ clk_put(wdt_clk);
+ if (!priv->osc_clk_rate)
+ return dev_err_probe(&pdev->dev, -EINVAL, "oscclk rate is 0");
+
+ /* Get Peripheral clock */
+ wdt_clk = clk_get(&pdev->dev, "pclk");
+ if (IS_ERR(wdt_clk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(wdt_clk), "no pclk");
+
+ pclk_rate = clk_get_rate(wdt_clk);
+ clk_put(wdt_clk);
+ if (!pclk_rate)
+ return dev_err_probe(&pdev->dev, -EINVAL, "pclk rate is 0");
+
+ priv->delay = F2CYCLE_NSEC(priv->osc_clk_rate) * 6 + F2CYCLE_NSEC(pclk_rate) * 9;
+
+ priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+ if (IS_ERR(priv->rstc))
+ return dev_err_probe(&pdev->dev, PTR_ERR(priv->rstc),
+ "failed to get cpg reset");
+
+ reset_control_deassert(priv->rstc);
+ pm_runtime_enable(&pdev->dev);
+ ret = pm_runtime_resume_and_get(&pdev->dev);
+ if (ret < 0) {
+ dev_err(dev, "pm_runtime_resume_and_get failed ret=%pe", ERR_PTR(ret));
+ goto out_pm_get;
+ }
+
+ priv->wdev.info = &rzg2l_wdt_ident;
+ priv->wdev.ops = &rzg2l_wdt_ops;
+ priv->wdev.parent = dev;
+ priv->wdev.min_timeout = 1;
+ priv->wdev.max_timeout = rzg2l_wdt_get_cycle_usec(priv->osc_clk_rate, 0xfff) /
+ USEC_PER_SEC;
+ priv->wdev.timeout = WDT_DEFAULT_TIMEOUT;
+
+ watchdog_set_drvdata(&priv->wdev, priv);
+ ret = devm_add_action_or_reset(&pdev->dev,
+ rzg2l_wdt_reset_assert_pm_disable_put,
+ &priv->wdev);
+ if (ret < 0)
+ return ret;
+
+ watchdog_set_nowayout(&priv->wdev, nowayout);
+ watchdog_stop_on_unregister(&priv->wdev);
+
+ ret = watchdog_init_timeout(&priv->wdev, 0, dev);
+ if (ret)
+ dev_warn(dev, "Specified timeout invalid, using default");
+
+ return devm_watchdog_register_device(&pdev->dev, &priv->wdev);
+
+out_pm_get:
+ pm_runtime_disable(dev);
+ reset_control_assert(priv->rstc);
+
+ return ret;
+}
+
+static const struct of_device_id rzg2l_wdt_ids[] = {
+ { .compatible = "renesas,rzg2l-wdt", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rzg2l_wdt_ids);
+
+static struct platform_driver rzg2l_wdt_driver = {
+ .driver = {
+ .name = "rzg2l_wdt",
+ .of_match_table = rzg2l_wdt_ids,
+ },
+ .probe = rzg2l_wdt_probe,
+};
+module_platform_driver(rzg2l_wdt_driver);
+
+MODULE_DESCRIPTION("Renesas RZ/G2L WDT Watchdog Driver");
+MODULE_AUTHOR("Biju Das <biju.das.jz@bp.renesas.com>");
+MODULE_LICENSE("GPL v2");
projects / linux-block.git / commitdiff