watchdog: Add support for Airoha EN7851 watchdog

Add support for Airoha EN7851 watchdog. This is a very basic watchdog
with no pretimeout support, max timeout is 28 seconds and it ticks based
on half the SoC BUS clock.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20241011104411.28659-2-ansuelsmth@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 684b9fe84fff5b08a35693aefa57db135196b909..6e0944cfb409ff2b2a89f10dee1d0237d75f77c9 100644 (file)
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -408,6 +408,14 @@ config SL28CPLD_WATCHDOG
 
 # ARM Architecture
 
+config AIROHA_WATCHDOG
+       tristate "Airoha EN7581 Watchdog"
+       depends on ARCH_AIROHA || COMPILE_TEST
+       select WATCHDOG_CORE
+       help
+         Watchdog timer embedded into Airoha SoC. This will reboot your
+         system when the timeout is reached.
+
 config ARM_SP805_WATCHDOG
        tristate "ARM SP805 Watchdog"
        depends on (ARM || ARM64 || COMPILE_TEST) && ARM_AMBA

diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index ab6f2b41e38e649f7929333b2284349106f913de..99eccefd6c335c96bce5db8fef931a0b284d9e75 100644 (file)
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -40,6 +40,7 @@ obj-$(CONFIG_USBPCWATCHDOG) += pcwd_usb.o
 obj-$(CONFIG_ARM_SP805_WATCHDOG) += sp805_wdt.o
 obj-$(CONFIG_ARM_SBSA_WATCHDOG) += sbsa_gwdt.o
 obj-$(CONFIG_ARMADA_37XX_WATCHDOG) += armada_37xx_wdt.o
+obj-$(CONFIG_AIROHA_WATCHDOG) += airoha_wdt.o
 obj-$(CONFIG_ASM9260_WATCHDOG) += asm9260_wdt.o
 obj-$(CONFIG_AT91RM9200_WATCHDOG) += at91rm9200_wdt.o
 obj-$(CONFIG_AT91SAM9X_WATCHDOG) += at91sam9_wdt.o

diff --git a/drivers/watchdog/airoha_wdt.c b/drivers/watchdog/airoha_wdt.c
new file mode 100644 (file)
index 0000000..dc8ca11
--- /dev/null
+++ b/drivers/watchdog/airoha_wdt.c
@@ -0,0 +1,216 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *     Airoha Watchdog Driver
+ *
+ *     Copyright (c) 2024, AIROHA  All rights reserved.
+ *
+ *     Mayur Kumar <mayur.kumar@airoha.com>
+ *     Christian Marangi <ansuelsmth@gmail.com>
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/math.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+/* Base address of timer and watchdog registers */
+#define TIMER_CTRL                     0x0
+#define   WDT_ENABLE                   BIT(25)
+#define   WDT_TIMER_INTERRUPT          BIT(21)
+/* Timer3 is used as Watchdog Timer */
+#define   WDT_TIMER_ENABLE             BIT(5)
+#define WDT_TIMER_LOAD_VALUE           0x2c
+#define WDT_TIMER_CUR_VALUE            0x30
+#define  WDT_TIMER_VAL                 GENMASK(31, 0)
+#define WDT_RELOAD                     0x38
+#define   WDT_RLD                      BIT(0)
+
+/* Airoha watchdog structure description */
+struct airoha_wdt_desc {
+       struct watchdog_device wdog_dev;
+       unsigned int wdt_freq;
+       void __iomem *base;
+};
+
+#define WDT_HEARTBEAT                  24
+static int heartbeat = WDT_HEARTBEAT;
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. (default="
+                __MODULE_STRING(WDT_HEARTBEAT) ")");
+
+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) ")");
+
+static int airoha_wdt_start(struct watchdog_device *wdog_dev)
+{
+       struct airoha_wdt_desc *airoha_wdt = watchdog_get_drvdata(wdog_dev);
+       u32 val;
+
+       val = readl(airoha_wdt->base + TIMER_CTRL);
+       val |= (WDT_TIMER_ENABLE | WDT_ENABLE | WDT_TIMER_INTERRUPT);
+       writel(val, airoha_wdt->base + TIMER_CTRL);
+       val = wdog_dev->timeout * airoha_wdt->wdt_freq;
+       writel(val, airoha_wdt->base + WDT_TIMER_LOAD_VALUE);
+
+       return 0;
+}
+
+static int airoha_wdt_stop(struct watchdog_device *wdog_dev)
+{
+       struct airoha_wdt_desc *airoha_wdt = watchdog_get_drvdata(wdog_dev);
+       u32 val;
+
+       val = readl(airoha_wdt->base + TIMER_CTRL);
+       val &= (~WDT_ENABLE & ~WDT_TIMER_ENABLE);
+       writel(val, airoha_wdt->base + TIMER_CTRL);
+
+       return 0;
+}
+
+static int airoha_wdt_ping(struct watchdog_device *wdog_dev)
+{
+       struct airoha_wdt_desc *airoha_wdt = watchdog_get_drvdata(wdog_dev);
+       u32 val;
+
+       val = readl(airoha_wdt->base + WDT_RELOAD);
+       val |= WDT_RLD;
+       writel(val, airoha_wdt->base + WDT_RELOAD);
+
+       return 0;
+}
+
+static int airoha_wdt_set_timeout(struct watchdog_device *wdog_dev, unsigned int timeout)
+{
+       wdog_dev->timeout = timeout;
+
+       if (watchdog_active(wdog_dev)) {
+               airoha_wdt_stop(wdog_dev);
+               return airoha_wdt_start(wdog_dev);
+       }
+
+       return 0;
+}
+
+static unsigned int airoha_wdt_get_timeleft(struct watchdog_device *wdog_dev)
+{
+       struct airoha_wdt_desc *airoha_wdt = watchdog_get_drvdata(wdog_dev);
+       u32 val;
+
+       val = readl(airoha_wdt->base + WDT_TIMER_CUR_VALUE);
+       return DIV_ROUND_UP(val, airoha_wdt->wdt_freq);
+}
+
+static const struct watchdog_info airoha_wdt_info = {
+       .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
+       .identity = "Airoha Watchdog",
+};
+
+static const struct watchdog_ops airoha_wdt_ops = {
+       .owner = THIS_MODULE,
+       .start = airoha_wdt_start,
+       .stop = airoha_wdt_stop,
+       .ping = airoha_wdt_ping,
+       .set_timeout = airoha_wdt_set_timeout,
+       .get_timeleft = airoha_wdt_get_timeleft,
+};
+
+static int airoha_wdt_probe(struct platform_device *pdev)
+{
+       struct airoha_wdt_desc *airoha_wdt;
+       struct watchdog_device *wdog_dev;
+       struct device *dev = &pdev->dev;
+       struct clk *bus_clk;
+       int ret;
+
+       airoha_wdt = devm_kzalloc(dev, sizeof(*airoha_wdt), GFP_KERNEL);
+       if (!airoha_wdt)
+               return -ENOMEM;
+
+       airoha_wdt->base = devm_platform_ioremap_resource(pdev, 0);
+       if (IS_ERR(airoha_wdt->base))
+               return PTR_ERR(airoha_wdt->base);
+
+       bus_clk = devm_clk_get_enabled(dev, "bus");
+       if (IS_ERR(bus_clk))
+               return dev_err_probe(dev, PTR_ERR(bus_clk),
+                                    "failed to enable bus clock\n");
+
+       /* Watchdog ticks at half the bus rate */
+       airoha_wdt->wdt_freq = clk_get_rate(bus_clk) / 2;
+
+       /* Initialize struct watchdog device */
+       wdog_dev = &airoha_wdt->wdog_dev;
+       wdog_dev->timeout = heartbeat;
+       wdog_dev->info = &airoha_wdt_info;
+       wdog_dev->ops = &airoha_wdt_ops;
+       /* Bus 300MHz, watchdog 150MHz, 28 seconds */
+       wdog_dev->max_timeout = FIELD_MAX(WDT_TIMER_VAL) / airoha_wdt->wdt_freq;
+       wdog_dev->parent = dev;
+
+       watchdog_set_drvdata(wdog_dev, airoha_wdt);
+       watchdog_set_nowayout(wdog_dev, nowayout);
+       watchdog_stop_on_unregister(wdog_dev);
+
+       ret = devm_watchdog_register_device(dev, wdog_dev);
+       if (ret)
+               return ret;
+
+       platform_set_drvdata(pdev, airoha_wdt);
+       return 0;
+}
+
+static int airoha_wdt_suspend(struct device *dev)
+{
+       struct airoha_wdt_desc *airoha_wdt = dev_get_drvdata(dev);
+
+       if (watchdog_active(&airoha_wdt->wdog_dev))
+               airoha_wdt_stop(&airoha_wdt->wdog_dev);
+
+       return 0;
+}
+
+static int airoha_wdt_resume(struct device *dev)
+{
+       struct airoha_wdt_desc *airoha_wdt = dev_get_drvdata(dev);
+
+       if (watchdog_active(&airoha_wdt->wdog_dev)) {
+               airoha_wdt_start(&airoha_wdt->wdog_dev);
+               airoha_wdt_ping(&airoha_wdt->wdog_dev);
+       }
+       return 0;
+}
+
+static const struct of_device_id airoha_wdt_of_match[] = {
+       { .compatible = "airoha,en7581-wdt", },
+       { },
+};
+
+MODULE_DEVICE_TABLE(of, airoha_wdt_of_match);
+
+static DEFINE_SIMPLE_DEV_PM_OPS(airoha_wdt_pm_ops, airoha_wdt_suspend, airoha_wdt_resume);
+
+static struct platform_driver airoha_wdt_driver = {
+       .probe = airoha_wdt_probe,
+       .driver = {
+               .name = "airoha-wdt",
+               .pm = pm_sleep_ptr(&airoha_wdt_pm_ops),
+               .of_match_table = airoha_wdt_of_match,
+       },
+};
+
+module_platform_driver(airoha_wdt_driver);
+
+MODULE_AUTHOR("Mayur Kumar <mayur.kumar@airoha.com>");
+MODULE_AUTHOR("Christian Marangi <ansuelsmth@gmail.com>");
+MODULE_DESCRIPTION("Airoha EN7581 Watchdog Driver");
+MODULE_LICENSE("GPL");