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Date:	Sat, 13 Dec 2014 10:08:10 +0800
From:	Chen-Yu Tsai <wens@...e.org>
To:	Matthias Brugger <matthias.bgg@...il.com>
Cc:	Wim Van Sebroeck <wim@...ana.be>, Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Grant Likely <grant.likely@...aro.org>,
	Heiko Stübner <heiko@...ech.de>,
	yingjoe.chen@...il.com,
	linux-kernel <linux-kernel@...r.kernel.org>,
	ibanezchen@...il.com, greta.zhang@...iatek.com,
	eddie.huang@...iatek.com,
	linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
	linux-watchdog@...r.kernel.org
Subject: Re: [PATCH v2 1/2] watchdog: Add driver for Mediatek watchdog

Hi,

On Fri, Dec 12, 2014 at 10:50 PM, Matthias Brugger
<matthias.bgg@...il.com> wrote:
> 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@...il.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@...il.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

Did you base your code on itself from the future? :)

ChenYu

> + */
> +
> +#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@...il.com>");
> +MODULE_DESCRIPTION("Mediatek WatchDog Timer Driver");
> +MODULE_VERSION(DRV_VERSION);
> --
> 1.9.1
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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