[PATCH v2 1/2] watchdog: Add driver for Mediatek watchdog

Matthias Brugger
2014-12-12T14:51:12Z

This patch adds a driver for the Mediatek SoC integrated
watchdog. This driver supports watchdog and software reset
for mt65xx and mt81xx SoCs.

Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
---
drivers/watchdog/Kconfig | 10 ++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/mtk_wdt.c | 257 +++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 268 insertions(+)
create mode 100644 drivers/watchdog/mtk_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index d0107d4..fcbca1b 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -505,6 +505,16 @@ config MESON_WATCHDOG
To compile this driver as a module, choose M here: the
module will be called meson_wdt.

+config MEDIATEK_WATCHDOG
+ tristate "Mediatek SoCs watchdog support"
+ depends on ARCH_MEDIATEK
+ select WATCHDOG_CORE
+ help
+ Say Y here to include support for the watchdog timer
+ in Mediatek SoCs.
+ To compile this driver as a module, choose M here: the
+ module will be called mtk_wdt.
+
# AVR32 Architecture

config AT32AP700X_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index c569ec8..0d4821f 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -63,6 +63,7 @@ obj-$(CONFIG_QCOM_WDT) += qcom-wdt.o
obj-$(CONFIG_BCM_KONA_WDT) += bcm_kona_wdt.o
obj-$(CONFIG_TEGRA_WATCHDOG) += tegra_wdt.o
obj-$(CONFIG_MESON_WATCHDOG) += meson_wdt.o
+obj-$(CONFIG_MEDIATEK_WATCHDOG) += mtk_wdt.o

# AVR32 Architecture
obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
new file mode 100644
index 0000000..5f75442
--- /dev/null
+++ b/drivers/watchdog/mtk_wdt.c
@@ -0,0 +1,257 @@
+/*
+ * Mediatek Watchdog Driver
+ *
+ * Copyright (C) 2014 Matthias Brugger
+ *
+ * Matthias Brugger <matthias.bgg@gmail.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * Based on mtk_wdt.c
+ */
+
+#include <linux/clk.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/of.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/delay.h>
+
+#define WDT_MAX_TIMEOUT 31
+#define WDT_MIN_TIMEOUT 1
+#define WDT_LENGTH_TIMEOUT(n) ((n) << 5)
+
+#define WDT_LENGTH 0x04
+#define WDT_LENGTH_KEY 0x8
+
+#define WDT_RST 0x08
+#define WDT_RST_RELOAD 0x1971
+
+#define WDT_MODE 0x00
+#define WDT_MODE_EN (1 << 0)
+#define WDT_MODE_EXT_POL_LOW (0 << 1)
+#define WDT_MODE_EXT_POL_HIGH (1 << 1)
+#define WDT_MODE_EXRST_EN (1 << 2)
+#define WDT_MODE_IRQ_EN (1 << 3)
+#define WDT_MODE_AUTO_START (1 << 4)
+#define WDT_MODE_DUAL_EN (1 << 6)
+#define WDT_MODE_KEY 0x22000000
+
+#define WDT_SWRST 0x14
+#define WDT_SWRST_KEY 0x1209
+
+#define DRV_NAME "mtk-wdt"
+#define DRV_VERSION "1.0"
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+static unsigned int timeout = WDT_MAX_TIMEOUT;
+
+struct mtk_wdt_dev {
+ struct watchdog_device wdt_dev;
+ void __iomem *wdt_base;
+ struct notifier_block restart_handler;
+};
+
+static int mtk_reset_handler(struct notifier_block *this, unsigned long mode,
+ void *cmd)
+{
+ struct mtk_wdt_dev *mtk_wdt = container_of(this,
+ struct mtk_wdt_dev,
+ restart_handler);
+ void __iomem *wdt_base = mtk_wdt->wdt_base;
+ u32 reg;
+
+ /* Reset system */
+ writel(WDT_SWRST_KEY, wdt_base + WDT_SWRST);
+
+ while (1) {
+ mdelay(5);
+ writel(WDT_SWRST_KEY, wdt_base + WDT_SWRST);
+ }
+ return NOTIFY_DONE;
+
+}
+
+static int mtk_wdt_ping(struct watchdog_device *wdt_dev)
+{
+ struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
+ void __iomem *wdt_base = mtk_wdt->wdt_base;
+
+ iowrite32(WDT_RST_RELOAD, wdt_base + WDT_RST);
+
+ return 0;
+}
+
+static int mtk_wdt_set_timeout(struct watchdog_device *wdt_dev,
+ unsigned int timeout)
+{
+ struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
+ void __iomem *wdt_base = mtk_wdt->wdt_base;
+ u32 reg;
+
+ mtk_wdt->wdt_dev.timeout = timeout;
+
+ /* One bit is the value of 512 ticks
+ * The clock has 32 KHz
+ */
+ reg = WDT_LENGTH_TIMEOUT(timeout << 6) | WDT_LENGTH_KEY;
+ iowrite32(reg, wdt_base + WDT_LENGTH);
+
+ mtk_wdt_ping(wdt_dev);
+
+ return 0;
+}
+
+static int mtk_wdt_stop(struct watchdog_device *wdt_dev)
+{
+ struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
+ void __iomem *wdt_base = mtk_wdt->wdt_base;
+ u32 reg;
+
+ reg = readl(wdt_base + WDT_MODE);
+ reg &= ~(WDT_MODE_EN);
+ iowrite32(reg, wdt_base + WDT_MODE);
+
+ return 0;
+}
+
+static int mtk_wdt_start(struct watchdog_device *wdt_dev)
+{
+ u32 reg;
+ struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
+ void __iomem *wdt_base = mtk_wdt->wdt_base;
+ u32 ret;
+
+ ret = mtk_wdt_set_timeout(&mtk_wdt->wdt_dev,
+ mtk_wdt->wdt_dev.timeout);
+ if (ret < 0)
+ return ret;
+
+ reg = ioread32(wdt_base + WDT_MODE);
+ reg &= ~(WDT_MODE_IRQ_EN | WDT_MODE_DUAL_EN);
+ reg |= (WDT_MODE_EN | WDT_MODE_KEY);
+ iowrite32(reg, wdt_base + WDT_MODE);
+
+ return 0;
+}
+
+static const struct watchdog_info mtk_wdt_info = {
+ .identity = DRV_NAME,
+ .options = WDIOF_SETTIMEOUT |
+ WDIOF_KEEPALIVEPING |
+ WDIOF_MAGICCLOSE,
+};
+
+static const struct watchdog_ops mtk_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = mtk_wdt_start,
+ .stop = mtk_wdt_stop,
+ .ping = mtk_wdt_ping,
+ .set_timeout = mtk_wdt_set_timeout,
+};
+
+static int mtk_wdt_probe(struct platform_device *pdev)
+{
+ struct mtk_wdt_dev *mtk_wdt;
+ struct resource *res;
+ int err;
+
+ mtk_wdt = devm_kzalloc(&pdev->dev, sizeof(*mtk_wdt), GFP_KERNEL);
+ if (!mtk_wdt)
+ return -EINVAL;
+
+ platform_set_drvdata(pdev, mtk_wdt);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ mtk_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(mtk_wdt->wdt_base))
+ return PTR_ERR(mtk_wdt->wdt_base);
+
+ mtk_wdt->wdt_dev.info = &mtk_wdt_info;
+ mtk_wdt->wdt_dev.ops = &mtk_wdt_ops;
+ mtk_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
+ mtk_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
+ mtk_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
+ mtk_wdt->wdt_dev.parent = &pdev->dev;
+
+ watchdog_init_timeout(&mtk_wdt->wdt_dev, timeout, &pdev->dev);
+ watchdog_set_nowayout(&mtk_wdt->wdt_dev, nowayout);
+
+ watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt);
+
+ mtk_wdt_stop(&mtk_wdt->wdt_dev);
+
+ err = watchdog_register_device(&mtk_wdt->wdt_dev);
+ if (unlikely(err))
+ return err;
+
+ mtk_wdt->restart_handler.notifier_call = mtk_reset_handler;
+ mtk_wdt->restart_handler.priority = 128;
+ err = register_restart_handler(&mtk_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)",
+ mtk_wdt->wdt_dev.timeout, nowayout);
+
+ return 0;
+}
+
+static int mtk_wdt_remove(struct platform_device *pdev)
+{
+ struct mtk_wdt_dev *mtk_wdt = platform_get_drvdata(pdev);
+
+ unregister_restart_handler(&mtk_wdt->restart_handler);
+
+ watchdog_unregister_device(&mtk_wdt->wdt_dev);
+ watchdog_set_drvdata(&mtk_wdt->wdt_dev, NULL);
+
+ return 0;
+}
+
+static const struct of_device_id mtk_wdt_dt_ids[] = {
+ { .compatible = "mediatek,mt6589-wdt" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mtk_wdt_dt_ids);
+
+static struct platform_driver mtk_wdt_driver = {
+ .probe = mtk_wdt_probe,
+ .remove = mtk_wdt_remove,
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = DRV_NAME,
+ .of_match_table = mtk_wdt_dt_ids,
+ },
+};
+
+module_platform_driver(mtk_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("Matthias Brugger <matthias.bgg@gmail.com>");
+MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver");
+MODULE_VERSION(DRV_VERSION);
--
1.9.1