On 11/11/21 12:52 AM, Biju Das wrote:
Add Watchdog Timer driver for RZ/G2L SoC.
WDT IP block supports normal watchdog timer function and reset
request function due to CPU parity error.
This driver currently supports normal watchdog timer function
and later will add support for reset request function due to
CPU parity error.
Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
---
RFC->V1
* Removed pclk_rate from priv.
* rzg2l_wdt_write() returns void and Removed tiemout related to register update
* rzg2l_wdt_init_timeout() returns void and removed delays.
* removed set_bit(WDOG_HW_RUNNING,..) as we can stop watchdog
* renamed reset_assert_clock_disable->reset_assert_pm_disable_put
* started using devm_reset_control_get_exclusive()
* removed platform_set_drvdata(pdev, priv) as there is no user
* removed watchdog_set_restart_priority(&priv->wdev, 0) as 0 is the default.
* removed remove callback as it is empty.
---
drivers/watchdog/Kconfig | 8 ++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/rzg2l_wdt.c | 262 +++++++++++++++++++++++++++++++++++
3 files changed, 271 insertions(+)
create mode 100644 drivers/watchdog/rzg2l_wdt.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index bf59faeb3de1..34da309a7afd 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -895,6 +895,14 @@ config RENESAS_RZAWDT
This driver adds watchdog support for the integrated watchdogs in the
Renesas RZ/A SoCs. These watchdogs can be used to reset a system.
+config RENESAS_RZG2LWDT
+ tristate "Renesas RZ/G2L WDT Watchdog"
+ depends on ARCH_RENESAS || COMPILE_TEST
+ select WATCHDOG_CORE
+ help
+ This driver adds watchdog support for the integrated watchdogs in the
+ Renesas RZ/G2L SoCs. These watchdogs can be used to reset a system.
+
config ASPEED_WATCHDOG
tristate "Aspeed BMC watchdog support"
depends on ARCH_ASPEED || COMPILE_TEST
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 1bd2d6f37c53..e7e8ce546814 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -85,6 +85,7 @@ obj-$(CONFIG_LPC18XX_WATCHDOG) += lpc18xx_wdt.o
obj-$(CONFIG_BCM7038_WDT) += bcm7038_wdt.o
obj-$(CONFIG_RENESAS_WDT) += renesas_wdt.o
obj-$(CONFIG_RENESAS_RZAWDT) += rza_wdt.o
+obj-$(CONFIG_RENESAS_RZG2LWDT) += rzg2l_wdt.o
obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o
obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o
obj-$(CONFIG_UNIPHIER_WATCHDOG) += uniphier_wdt.o
diff --git a/drivers/watchdog/rzg2l_wdt.c b/drivers/watchdog/rzg2l_wdt.c
new file mode 100644
index 000000000000..75102310796d
--- /dev/null
+++ b/drivers/watchdog/rzg2l_wdt.c
@@ -0,0 +1,262 @@
+// 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/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))
+#define WDT_CYCLE_MSEC(f, wdttime) ((1024 * 1024 * (((u64)wdttime) + 1)) / \
+ ((f) / 1000000))
+
+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 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 / 2 * 1000000) / WDT_CYCLE_MSEC(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 = devm_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);
+ if (!priv->osc_clk_rate)
+ return dev_err_probe(&pdev->dev, -EINVAL, "oscclk rate is 0");
+
+ devm_clk_put(&pdev->dev, wdt_clk);
+
If the clocks are not needed anymore at this time, you should not use
devm_ functions to get them. The intent for devm_ functions is automatic
release in the remove function. If that isn't used, clk_get/clk_put
is good enough, and the overhead of devm_ functions is not worth the
complexity.
Guenter
+ /* Get Peripheral clock */
+ wdt_clk = devm_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);
+ if (!pclk_rate)
+ return dev_err_probe(&pdev->dev, -EINVAL, "pclk rate is 0");
+
+ devm_clk_put(&pdev->dev, wdt_clk);
+ 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;
+ }
+
+ ret = devm_add_action_or_reset(&pdev->dev,
+ rzg2l_wdt_reset_assert_pm_disable_put,
+ &priv->wdev);
+ if (ret < 0)
+ goto out_reset;
_or_reset implies that the action is taken on failure, so there is not need
to do it again.
+
+ 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 = WDT_CYCLE_MSEC(priv->osc_clk_rate, 0xfff);
+ priv->wdev.timeout = WDT_DEFAULT_TIMEOUT;
+
+ watchdog_set_drvdata(&priv->wdev, priv);
+ 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");
+
+ ret = devm_watchdog_register_device(&pdev->dev, &priv->wdev);
+ if (ret < 0)
+ return ret;
+
+ return 0;
return ret;
is good enough, or even
return devm_watchdog_register_device(&pdev->dev, &priv->wdev);
+
+out_reset:
+ pm_runtime_put(dev);
+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@xxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
