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@xxxxxxxxx>
---
Changes v2:
- Drop clock-frequency implementation
- Add missing bitfield.h header
- Attach BUS clock
drivers/watchdog/Kconfig | 8 ++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/airoha_wdt.c | 216 ++++++++++++++++++++++++++++++++++
3 files changed, 225 insertions(+)
create mode 100644 drivers/watchdog/airoha_wdt.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 85eea38dbdf4..be4616d18b29 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -394,6 +394,14 @@ 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 2d1117564f5b..32a0f689a9be 100644
--- 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
index 000000000000..dc8ca11c14d8
--- /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@xxxxxxxxxx>
+ * Christian Marangi <ansuelsmth@xxxxxxxxx>
+ *
+ */
+
+#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@xxxxxxxxxx>");
+MODULE_AUTHOR("Christian Marangi <ansuelsmth@xxxxxxxxx>");
+MODULE_DESCRIPTION("Airoha EN7581 Watchdog Driver");
+MODULE_LICENSE("GPL");
--
2.45.2
