[PATCH v2 1/2] watchdog: Add driver for Mediatek watchdog
From: linux@roeck-us.net (Guenter Roeck)
Date: 2014-12-13 15:44:55
Also in:
linux-watchdog, lkml
On 12/12/2014 06:50 AM, Matthias Brugger wrote:
quoted hunk ↗ jump to hunk
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.cdiff --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_WDTdiff --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.odiff --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; +
Unnecessary empty line. See checkpatch --strict.
+}
+
+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)Continuation line alignment is off. See checkpatch --strict.
+{
+ 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 ticksPlease use standard multi-line comment style.
+ * 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;-ENOMEM
+ + 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,
dev_warn
+ "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);Unnecessary. mtk_wdt is about to be freed.
+
+ 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 [off-list ref]");
+MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver");
+MODULE_VERSION(DRV_VERSION);