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Fri, 30 Aug 2019 09:49:48 -0700 (PDT) Date: Fri, 30 Aug 2019 09:49:47 -0700 From: Guenter Roeck To: Anson Huang Subject: Re: [PATCH V4 2/4] watchdog: Add i.MX7ULP watchdog support Message-ID: <20190830164947.GE7911@roeck-us.net> References: <1566441463-11911-1-git-send-email-Anson.Huang@nxp.com> <1566441463-11911-2-git-send-email-Anson.Huang@nxp.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1566441463-11911-2-git-send-email-Anson.Huang@nxp.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190830_094949_577586_F7B839CC X-CRM114-Status: GOOD ( 28.56 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, devicetree@vger.kernel.org, leonard.crestez@nxp.com, schnitzeltony@gmail.com, linux-watchdog@vger.kernel.org, otavio@ossystems.com.br, festevam@gmail.com, s.hauer@pengutronix.de, jan.tuerk@emtrion.com, linux@armlinux.org.uk, linux-kernel@vger.kernel.org, robh+dt@kernel.org, Linux-imx@nxp.com, kernel@pengutronix.de, u.kleine-koenig@pengutronix.de, wim@linux-watchdog.org, shawnguo@kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Aug 21, 2019 at 10:37:41PM -0400, Anson Huang wrote: > The i.MX7ULP Watchdog Timer (WDOG) module is an independent timer > that is available for system use. > It provides a safety feature to ensure that software is executing > as planned and that the CPU is not stuck in an infinite loop or > executing unintended code. If the WDOG module is not serviced > (refreshed) within a certain period, it resets the MCU. > > Add driver support for i.MX7ULP watchdog. > > Signed-off-by: Anson Huang Reviewed-by: Guenter Roeck > --- > Changes since V3: > - pass clk directly for reset action to avoid dereference from structure; > - use constant instead of variable for wdog clock rate, as it is fixed as 1KHz. > --- > drivers/watchdog/Kconfig | 13 +++ > drivers/watchdog/Makefile | 1 + > drivers/watchdog/imx7ulp_wdt.c | 243 +++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 257 insertions(+) > create mode 100644 drivers/watchdog/imx7ulp_wdt.c > > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > index a8f5c81..d68e5b5 100644 > --- a/drivers/watchdog/Kconfig > +++ b/drivers/watchdog/Kconfig > @@ -724,6 +724,19 @@ config IMX_SC_WDT > To compile this driver as a module, choose M here: the > module will be called imx_sc_wdt. > > +config IMX7ULP_WDT > + tristate "IMX7ULP Watchdog" > + depends on ARCH_MXC || COMPILE_TEST > + select WATCHDOG_CORE > + help > + This is the driver for the hardware watchdog on the Freescale > + IMX7ULP and later processors. If you have one of these > + processors and wish to have watchdog support enabled, > + say Y, otherwise say N. > + > + To compile this driver as a module, choose M here: the > + module will be called imx7ulp_wdt. > + > config UX500_WATCHDOG > tristate "ST-Ericsson Ux500 watchdog" > depends on MFD_DB8500_PRCMU > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile > index b5a0aed..2ee352b 100644 > --- a/drivers/watchdog/Makefile > +++ b/drivers/watchdog/Makefile > @@ -67,6 +67,7 @@ obj-$(CONFIG_TS4800_WATCHDOG) += ts4800_wdt.o > obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o > obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o > obj-$(CONFIG_IMX_SC_WDT) += imx_sc_wdt.o > +obj-$(CONFIG_IMX7ULP_WDT) += imx7ulp_wdt.o > obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o > obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o > obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o > diff --git a/drivers/watchdog/imx7ulp_wdt.c b/drivers/watchdog/imx7ulp_wdt.c > new file mode 100644 > index 0000000..5ce5102 > --- /dev/null > +++ b/drivers/watchdog/imx7ulp_wdt.c > @@ -0,0 +1,243 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Copyright 2019 NXP. > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define WDOG_CS 0x0 > +#define WDOG_CS_CMD32EN BIT(13) > +#define WDOG_CS_ULK BIT(11) > +#define WDOG_CS_RCS BIT(10) > +#define WDOG_CS_EN BIT(7) > +#define WDOG_CS_UPDATE BIT(5) > + > +#define WDOG_CNT 0x4 > +#define WDOG_TOVAL 0x8 > + > +#define REFRESH_SEQ0 0xA602 > +#define REFRESH_SEQ1 0xB480 > +#define REFRESH ((REFRESH_SEQ1 << 16) | REFRESH_SEQ0) > + > +#define UNLOCK_SEQ0 0xC520 > +#define UNLOCK_SEQ1 0xD928 > +#define UNLOCK ((UNLOCK_SEQ1 << 16) | UNLOCK_SEQ0) > + > +#define DEFAULT_TIMEOUT 60 > +#define MAX_TIMEOUT 128 > +#define WDOG_CLOCK_RATE 1000 > + > +static bool nowayout = WATCHDOG_NOWAYOUT; > +module_param(nowayout, bool, 0000); > +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" > + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); > + > +struct imx7ulp_wdt_device { > + struct notifier_block restart_handler; > + struct watchdog_device wdd; > + void __iomem *base; > + struct clk *clk; > +}; > + > +static inline void imx7ulp_wdt_enable(void __iomem *base, bool enable) > +{ > + u32 val = readl(base + WDOG_CS); > + > + writel(UNLOCK, base + WDOG_CNT); > + if (enable) > + writel(val | WDOG_CS_EN, base + WDOG_CS); > + else > + writel(val & ~WDOG_CS_EN, base + WDOG_CS); > +} > + > +static inline bool imx7ulp_wdt_is_enabled(void __iomem *base) > +{ > + u32 val = readl(base + WDOG_CS); > + > + return val & WDOG_CS_EN; > +} > + > +static int imx7ulp_wdt_ping(struct watchdog_device *wdog) > +{ > + struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog); > + > + writel(REFRESH, wdt->base + WDOG_CNT); > + > + return 0; > +} > + > +static int imx7ulp_wdt_start(struct watchdog_device *wdog) > +{ > + struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog); > + > + imx7ulp_wdt_enable(wdt->base, true); > + > + return 0; > +} > + > +static int imx7ulp_wdt_stop(struct watchdog_device *wdog) > +{ > + struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog); > + > + imx7ulp_wdt_enable(wdt->base, false); > + > + return 0; > +} > + > +static int imx7ulp_wdt_set_timeout(struct watchdog_device *wdog, > + unsigned int timeout) > +{ > + struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog); > + u32 val = WDOG_CLOCK_RATE * timeout; > + > + writel(UNLOCK, wdt->base + WDOG_CNT); > + writel(val, wdt->base + WDOG_TOVAL); > + > + wdog->timeout = timeout; > + > + return 0; > +} > + > +static const struct watchdog_ops imx7ulp_wdt_ops = { > + .owner = THIS_MODULE, > + .start = imx7ulp_wdt_start, > + .stop = imx7ulp_wdt_stop, > + .ping = imx7ulp_wdt_ping, > + .set_timeout = imx7ulp_wdt_set_timeout, > +}; > + > +static const struct watchdog_info imx7ulp_wdt_info = { > + .identity = "i.MX7ULP watchdog timer", > + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | > + WDIOF_MAGICCLOSE, > +}; > + > +static inline void imx7ulp_wdt_init(void __iomem *base, unsigned int timeout) > +{ > + u32 val; > + > + /* unlock the wdog for reconfiguration */ > + writel_relaxed(UNLOCK_SEQ0, base + WDOG_CNT); > + writel_relaxed(UNLOCK_SEQ1, base + WDOG_CNT); > + > + /* set an initial timeout value in TOVAL */ > + writel(timeout, base + WDOG_TOVAL); > + /* enable 32bit command sequence and reconfigure */ > + val = BIT(13) | BIT(8) | BIT(5); > + writel(val, base + WDOG_CS); > +} > + > +static void imx7ulp_wdt_action(void *data) > +{ > + clk_disable_unprepare(data); > +} > + > +static int imx7ulp_wdt_probe(struct platform_device *pdev) > +{ > + struct imx7ulp_wdt_device *imx7ulp_wdt; > + struct device *dev = &pdev->dev; > + struct watchdog_device *wdog; > + int ret; > + > + imx7ulp_wdt = devm_kzalloc(dev, sizeof(*imx7ulp_wdt), GFP_KERNEL); > + if (!imx7ulp_wdt) > + return -ENOMEM; > + > + platform_set_drvdata(pdev, imx7ulp_wdt); > + > + imx7ulp_wdt->base = devm_platform_ioremap_resource(pdev, 0); > + if (IS_ERR(imx7ulp_wdt->base)) > + return PTR_ERR(imx7ulp_wdt->base); > + > + imx7ulp_wdt->clk = devm_clk_get(dev, NULL); > + if (IS_ERR(imx7ulp_wdt->clk)) { > + dev_err(dev, "Failed to get watchdog clock\n"); > + return PTR_ERR(imx7ulp_wdt->clk); > + } > + > + ret = clk_prepare_enable(imx7ulp_wdt->clk); > + if (ret) > + return ret; > + > + ret = devm_add_action_or_reset(dev, imx7ulp_wdt_action, imx7ulp_wdt->clk); > + if (ret) > + return ret; > + > + wdog = &imx7ulp_wdt->wdd; > + wdog->info = &imx7ulp_wdt_info; > + wdog->ops = &imx7ulp_wdt_ops; > + wdog->min_timeout = 1; > + wdog->max_timeout = MAX_TIMEOUT; > + wdog->parent = dev; > + wdog->timeout = DEFAULT_TIMEOUT; > + > + watchdog_init_timeout(wdog, 0, dev); > + watchdog_stop_on_reboot(wdog); > + watchdog_stop_on_unregister(wdog); > + watchdog_set_drvdata(wdog, imx7ulp_wdt); > + imx7ulp_wdt_init(imx7ulp_wdt->base, wdog->timeout * WDOG_CLOCK_RATE); > + > + return devm_watchdog_register_device(dev, wdog); > +} > + > +static int __maybe_unused imx7ulp_wdt_suspend(struct device *dev) > +{ > + struct imx7ulp_wdt_device *imx7ulp_wdt = dev_get_drvdata(dev); > + > + if (watchdog_active(&imx7ulp_wdt->wdd)) > + imx7ulp_wdt_stop(&imx7ulp_wdt->wdd); > + > + clk_disable_unprepare(imx7ulp_wdt->clk); > + > + return 0; > +} > + > +static int __maybe_unused imx7ulp_wdt_resume(struct device *dev) > +{ > + struct imx7ulp_wdt_device *imx7ulp_wdt = dev_get_drvdata(dev); > + u32 timeout = imx7ulp_wdt->wdd.timeout * WDOG_CLOCK_RATE; > + int ret; > + > + ret = clk_prepare_enable(imx7ulp_wdt->clk); > + if (ret) > + return ret; > + > + if (imx7ulp_wdt_is_enabled(imx7ulp_wdt->base)) > + imx7ulp_wdt_init(imx7ulp_wdt->base, timeout); > + > + if (watchdog_active(&imx7ulp_wdt->wdd)) > + imx7ulp_wdt_start(&imx7ulp_wdt->wdd); > + > + return 0; > +} > + > +static SIMPLE_DEV_PM_OPS(imx7ulp_wdt_pm_ops, imx7ulp_wdt_suspend, > + imx7ulp_wdt_resume); > + > +static const struct of_device_id imx7ulp_wdt_dt_ids[] = { > + { .compatible = "fsl,imx7ulp-wdt", }, > + { /* sentinel */ } > +}; > +MODULE_DEVICE_TABLE(of, imx7ulp_wdt_dt_ids); > + > +static struct platform_driver imx7ulp_wdt_driver = { > + .probe = imx7ulp_wdt_probe, > + .driver = { > + .name = "imx7ulp-wdt", > + .pm = &imx7ulp_wdt_pm_ops, > + .of_match_table = imx7ulp_wdt_dt_ids, > + }, > +}; > +module_platform_driver(imx7ulp_wdt_driver); > + > +MODULE_AUTHOR("Anson Huang "); > +MODULE_DESCRIPTION("Freescale i.MX7ULP watchdog driver"); > +MODULE_LICENSE("GPL v2"); > -- > 2.7.4 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel