[PATCH v4 2/4] ARM: meson: add watchdog driver
Carlo Caione
carlo at caione.org
Sat Sep 20 10:06:50 PDT 2014
This patch adds the watchdog driver for the Amlogic Meson SoCs used also
to reboot the device.
Reviewed-by: Guenter Roeck <linux at roeck-us.net>
Signed-off-by: Carlo Caione <carlo at caione.org>
---
drivers/watchdog/Kconfig | 10 ++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/meson_wdt.c | 236 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 247 insertions(+)
create mode 100644 drivers/watchdog/meson_wdt.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index f57312f..836cb00 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -443,6 +443,16 @@ config TEGRA_WATCHDOG
To compile this driver as a module, choose M here: the
module will be called tegra_wdt.
+config MESON_WATCHDOG
+ tristate "Amlogic Meson SoCs watchdog support"
+ depends on ARCH_MESON
+ select WATCHDOG_CORE
+ help
+ Say Y here to include support for the watchdog timer
+ in Amlogic Meson SoCs.
+ To compile this driver as a module, choose M here: the
+ module will be called meson_wdt.
+
# AVR32 Architecture
config AT32AP700X_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 468c320..e7a9259 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -59,6 +59,7 @@ obj-$(CONFIG_MOXART_WDT) += moxart_wdt.o
obj-$(CONFIG_SIRFSOC_WATCHDOG) += sirfsoc_wdt.o
obj-$(CONFIG_BCM_KONA_WDT) += bcm_kona_wdt.o
obj-$(CONFIG_TEGRA_WATCHDOG) += tegra_wdt.o
+obj-$(CONFIG_MESON_WATCHDOG) += meson_wdt.o
# AVR32 Architecture
obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/watchdog/meson_wdt.c b/drivers/watchdog/meson_wdt.c
new file mode 100644
index 0000000..37f9f5ec
--- /dev/null
+++ b/drivers/watchdog/meson_wdt.c
@@ -0,0 +1,236 @@
+/*
+ * Meson Watchdog Driver
+ *
+ * Copyright (c) 2014 Carlo Caione
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/notifier.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+
+#define DRV_NAME "meson_wdt"
+
+#define MESON_WDT_TC 0x00
+#define MESON_WDT_TC_EN BIT(22)
+#define MESON_WDT_TC_TM_MASK 0x3fffff
+#define MESON_WDT_DC_RESET (3 << 24)
+
+#define MESON_WDT_RESET 0x04
+
+#define MESON_WDT_TIMEOUT 30
+#define MESON_WDT_MIN_TIMEOUT 1
+#define MESON_WDT_MAX_TIMEOUT (MESON_WDT_TC_TM_MASK / 100000)
+
+#define MESON_SEC_TO_TC(s) ((s) * 100000)
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+static unsigned int timeout = MESON_WDT_TIMEOUT;
+
+struct meson_wdt_dev {
+ struct watchdog_device wdt_dev;
+ void __iomem *wdt_base;
+ struct notifier_block restart_handler;
+};
+
+static int meson_restart_handle(struct notifier_block *this, unsigned long mode,
+ void *cmd)
+{
+ u32 tc_reboot = MESON_WDT_DC_RESET | MESON_WDT_TC_EN | 100;
+ struct meson_wdt_dev *meson_wdt = container_of(this,
+ struct meson_wdt_dev,
+ restart_handler);
+
+ while (1) {
+ writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC);
+ mdelay(5);
+ }
+
+ return NOTIFY_DONE;
+}
+
+static int meson_wdt_ping(struct watchdog_device *wdt_dev)
+{
+ struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
+
+ writel(0, meson_wdt->wdt_base + MESON_WDT_RESET);
+
+ return 0;
+}
+
+static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev,
+ unsigned int timeout)
+{
+ struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
+ u32 reg;
+
+ reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
+ reg &= ~MESON_WDT_TC_TM_MASK;
+ reg |= MESON_SEC_TO_TC(timeout);
+ writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
+}
+
+static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev,
+ unsigned int timeout)
+{
+ wdt_dev->timeout = timeout;
+
+ meson_wdt_change_timeout(wdt_dev, timeout);
+ meson_wdt_ping(wdt_dev);
+
+ return 0;
+}
+
+static int meson_wdt_stop(struct watchdog_device *wdt_dev)
+{
+ struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
+ u32 reg;
+
+ reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
+ reg &= ~MESON_WDT_TC_EN;
+ writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
+
+ return 0;
+}
+
+static int meson_wdt_start(struct watchdog_device *wdt_dev)
+{
+ struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);
+ u32 reg;
+
+ meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout);
+ meson_wdt_ping(wdt_dev);
+
+ reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);
+ reg |= MESON_WDT_TC_EN;
+ writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);
+
+ return 0;
+}
+
+static const struct watchdog_info meson_wdt_info = {
+ .identity = DRV_NAME,
+ .options = WDIOF_SETTIMEOUT |
+ WDIOF_KEEPALIVEPING |
+ WDIOF_MAGICCLOSE,
+};
+
+static const struct watchdog_ops meson_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = meson_wdt_start,
+ .stop = meson_wdt_stop,
+ .ping = meson_wdt_ping,
+ .set_timeout = meson_wdt_set_timeout,
+};
+
+static int meson_wdt_probe(struct platform_device *pdev)
+{
+ struct resource *res;
+ struct meson_wdt_dev *meson_wdt;
+ int err;
+
+ meson_wdt = devm_kzalloc(&pdev->dev, sizeof(*meson_wdt), GFP_KERNEL);
+ if (!meson_wdt)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ meson_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(meson_wdt->wdt_base))
+ return PTR_ERR(meson_wdt->wdt_base);
+
+ meson_wdt->wdt_dev.parent = &pdev->dev;
+ meson_wdt->wdt_dev.info = &meson_wdt_info;
+ meson_wdt->wdt_dev.ops = &meson_wdt_ops;
+ meson_wdt->wdt_dev.timeout = MESON_WDT_TIMEOUT;
+ meson_wdt->wdt_dev.max_timeout = MESON_WDT_MAX_TIMEOUT;
+ meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT;
+
+ watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt);
+
+ watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, &pdev->dev);
+ watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout);
+
+ meson_wdt_stop(&meson_wdt->wdt_dev);
+
+ err = watchdog_register_device(&meson_wdt->wdt_dev);
+ if (err)
+ return err;
+
+ platform_set_drvdata(pdev, meson_wdt);
+
+ meson_wdt->restart_handler.notifier_call = meson_restart_handle;
+ meson_wdt->restart_handler.priority = 128;
+ err = register_restart_handler(&meson_wdt->restart_handler);
+ if (err)
+ dev_err(&pdev->dev,
+ "cannot register restart handler (err=%d)\n", err);
+
+ dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
+ meson_wdt->wdt_dev.timeout, nowayout);
+
+ return 0;
+}
+
+static int meson_wdt_remove(struct platform_device *pdev)
+{
+ struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev);
+
+ unregister_restart_handler(&meson_wdt->restart_handler);
+
+ watchdog_unregister_device(&meson_wdt->wdt_dev);
+
+ return 0;
+}
+
+static void meson_wdt_shutdown(struct platform_device *pdev)
+{
+ struct meson_wdt_dev *meson_wdt = platform_get_drvdata(pdev);
+
+ meson_wdt_stop(&meson_wdt->wdt_dev);
+}
+
+static const struct of_device_id meson_wdt_dt_ids[] = {
+ { .compatible = "amlogic,meson6-wdt" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids);
+
+static struct platform_driver meson_wdt_driver = {
+ .probe = meson_wdt_probe,
+ .remove = meson_wdt_remove,
+ .shutdown = meson_wdt_shutdown,
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = DRV_NAME,
+ .of_match_table = meson_wdt_dt_ids,
+ },
+};
+
+module_platform_driver(meson_wdt_driver);
+
+module_param(timeout, uint, 0);
+MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
+
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+ "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Carlo Caione <carlo at caione.org>");
+MODULE_DESCRIPTION("Meson Watchdog Timer Driver");
--
1.9.1
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