Re: [PATCH] watchdog: add Alphascale asm9260-wdt driver

[Guenter Roeck <linux@roeck-us.net>]

On Tue, Oct 20, 2015 at 09:49:10AM +0200, Oleksij Rempel wrote:
> Hallo all,
> 
> any feedback here? or it can be merged?
> 
>From my side just too much work and not enough time :-(

Guenter

> Am 18.09.2015 um 11:23 schrieb Oleksij Rempel:
> > Add WD support for Alphascale asm9260 SoC. This driver
> > provide support for different function modes:
> > - HW mode to trigger SoC reset on timeout
> > - SW mode do soft reset if needed
> > - DEBUG mode
> > 
> > Optional support for stopping watchdog. If reset binding are not provided
> > this driver will work in nowayout mode.
> > 
> > Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
> > ---
> >  .../bindings/watchdog/alphascale-asm9260.txt       |  38 ++
> >  drivers/watchdog/Kconfig                           |   9 +
> >  drivers/watchdog/Makefile                          |   1 +
> >  drivers/watchdog/asm9260_wdt.c                     | 405 +++++++++++++++++++++
> >  4 files changed, 453 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/watchdog/alphascale-asm9260.txt
> >  create mode 100644 drivers/watchdog/asm9260_wdt.c
> > 
> > diff --git a/Documentation/devicetree/bindings/watchdog/alphascale-asm9260.txt b/Documentation/devicetree/bindings/watchdog/alphascale-asm9260.txt
> > new file mode 100644
> > index 0000000..cbe388b
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/watchdog/alphascale-asm9260.txt
> > @@ -0,0 +1,38 @@
> > +Alphascale asm9260 Watchdog timer
> > +
> > +Required properties:
> > +
> > +- compatible : should be "alphascale,asm9260-wdt".
> > +- reg : Specifies base physical address and size of the registers.
> > +- clocks : the clock feeding the watchdog timer.
> > +	Needed if platform uses clocks. See clock-bindings.txt
> > +- clock-names : should be set to
> > +	"mod" - source for tick counter.
> > +	"ahb" - ahb gate.
> > +
> > +Optional properties:
> > +- resets : phandle pointing to the system reset controller with correct
> > +	reset line index for watchdog controller reset. This propertie is
> > +	required if you need to disable "nowayout" and it works only with
> > +	CONFIG_WATCHDOG_NOWAYOUT=n.
> > +- reset-names : should be set to "wdt_rst" if "resets" is used.
> > +- timeout-sec : shall contain the default watchdog timeout in seconds,
> > +	if unset, the default timeout is 30 seconds.
> > +- alphascale,mode : tree modes are supported
> > +	"hw" - hw reset (defaul).
> > +	"sw" - sw reset.
> > +	"debug" - no action is taken.
> > +
> > +Example:
> > +
> > +watchdog0: watchdog@80048000 {
> > +	compatible = "alphascale,asm9260-wdt";
> > +	reg = <0x80048000 0x10>;
> > +	clocks = <&acc CLKID_SYS_WDT>, <&acc CLKID_AHB_WDT>;
> > +	clock-names = "mod", "ahb";
> > +	interrupts = <55>;
> > +	resets = <&rst WDT_RESET>;
> > +	reset-names = "wdt_rst";
> > +	timeout-sec = <30>;
> > +	alphascale,mode = "hw"
> > +};
> > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> > index c68edc1..cc5f675 100644
> > --- a/drivers/watchdog/Kconfig
> > +++ b/drivers/watchdog/Kconfig
> > @@ -173,6 +173,15 @@ config ARM_SP805_WATCHDOG
> >  	  ARM Primecell SP805 Watchdog timer. This will reboot your system when
> >  	  the timeout is reached.
> >  
> > +config ASM9260_WATCHDOG
> > +	tristate "Alphascale ASM9260 watchdog"
> > +	depends on MACH_ASM9260
> > +	depends on OF
> > +	select WATCHDOG_CORE
> > +	help
> > +	  Watchdog timer embedded into Alphascale asm9260 chips. This will reboot your
> > +	  system when the timeout is reached.
> > +
> >  config AT91RM9200_WATCHDOG
> >  	tristate "AT91RM9200 watchdog"
> >  	depends on SOC_AT91RM9200 && MFD_SYSCON
> > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> > index 0c616e3..bd7b0cd 100644
> > --- a/drivers/watchdog/Makefile
> > +++ b/drivers/watchdog/Makefile
> > @@ -30,6 +30,7 @@ obj-$(CONFIG_USBPCWATCHDOG) += pcwd_usb.o
> >  
> >  # ARM Architecture
> >  obj-$(CONFIG_ARM_SP805_WATCHDOG) += sp805_wdt.o
> > +obj-$(CONFIG_ASM9260_WATCHDOG) += asm9260_wdt.o
> >  obj-$(CONFIG_AT91RM9200_WATCHDOG) += at91rm9200_wdt.o
> >  obj-$(CONFIG_AT91SAM9X_WATCHDOG) += at91sam9_wdt.o
> >  obj-$(CONFIG_CADENCE_WATCHDOG) += cadence_wdt.o
> > diff --git a/drivers/watchdog/asm9260_wdt.c b/drivers/watchdog/asm9260_wdt.c
> > new file mode 100644
> > index 0000000..e5f859b
> > --- /dev/null
> > +++ b/drivers/watchdog/asm9260_wdt.c
> > @@ -0,0 +1,405 @@
> > +/*
> > + * Watchdog driver for Alphascale ASM9260.
> > + *
> > + * Copyright (c) 2014 Oleksij Rempel <linux@rempel-privat.de>
> > + *
> > + * Licensed under GPLv2 or later.
> > + */
> > +
> > +#include <linux/delay.h>
> > +#include <linux/clk.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/moduleparam.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/reboot.h>
> > +#include <linux/reset.h>
> > +#include <linux/uaccess.h>
> > +#include <linux/watchdog.h>
> > +
> > +#define CLOCK_FREQ	1000000
> > +
> > +/* Watchdog Mode register */
> > +#define HW_WDMOD			0x00
> > +/* Wake interrupt. Set by HW, can't be cleared. */
> > +#define BM_MOD_WDINT			BIT(3)
> > +/* This bit set if timeout reached. Cleared by SW. */
> > +#define BM_MOD_WDTOF			BIT(2)
> > +/* HW Reset on timeout */
> > +#define BM_MOD_WDRESET			BIT(1)
> > +/* WD enable */
> > +#define BM_MOD_WDEN			BIT(0)
> > +
> > +/*
> > + * Watchdog Timer Constant register
> > + * Minimal value is 0xff, the meaning of this value
> > + * depends on used clock: T = WDCLK * (0xff + 1) * 4
> > + */
> > +#define HW_WDTC				0x04
> > +#define BM_WDTC_MAX(freq)		(0x7fffffff / (freq))
> > +
> > +/* Watchdog Feed register */
> > +#define HW_WDFEED			0x08
> > +
> > +/* Watchdog Timer Value register */
> > +#define HW_WDTV				0x0c
> > +
> > +#define ASM9260_WDT_DEFAULT_TIMEOUT	30
> > +
> > +enum asm9260_wdt_mode {
> > +	HW_RESET,
> > +	SW_RESET,
> > +	DEBUG,
> > +};
> > +
> > +struct asm9260_wdt_priv {
> > +	struct device		*dev;
> > +	struct watchdog_device	wdd;
> > +	struct clk		*clk;
> > +	struct clk		*clk_ahb;
> > +	struct reset_control	*rst;
> > +	struct notifier_block	restart_handler;
> > +
> > +	void __iomem		*iobase;
> > +	int			irq;
> > +	unsigned long		wdt_freq;
> > +	enum asm9260_wdt_mode	mode;
> > +};
> > +
> > +static int asm9260_wdt_feed(struct watchdog_device *wdd)
> > +{
> > +	struct asm9260_wdt_priv *priv = watchdog_get_drvdata(wdd);
> > +
> > +	iowrite32(0xaa, priv->iobase + HW_WDFEED);
> > +	iowrite32(0x55, priv->iobase + HW_WDFEED);
> > +
> > +	return 0;
> > +}
> > +
> > +static unsigned int asm9260_wdt_gettimeleft(struct watchdog_device *wdd)
> > +{
> > +	struct asm9260_wdt_priv *priv = watchdog_get_drvdata(wdd);
> > +	u32 counter;
> > +
> > +	counter = ioread32(priv->iobase + HW_WDTV);
> > +
> > +	return DIV_ROUND_CLOSEST(counter, priv->wdt_freq);
> > +}
> > +
> > +static int asm9260_wdt_updatetimeout(struct watchdog_device *wdd)
> > +{
> > +	struct asm9260_wdt_priv *priv = watchdog_get_drvdata(wdd);
> > +	u32 counter;
> > +
> > +	counter = wdd->timeout * priv->wdt_freq;
> > +
> > +	iowrite32(counter, priv->iobase + HW_WDTC);
> > +
> > +	return 0;
> > +}
> > +
> > +static int asm9260_wdt_enable(struct watchdog_device *wdd)
> > +{
> > +	struct asm9260_wdt_priv *priv = watchdog_get_drvdata(wdd);
> > +	u32 mode = 0;
> > +
> > +	if (priv->mode == HW_RESET)
> > +		mode = BM_MOD_WDRESET;
> > +
> > +	iowrite32(BM_MOD_WDEN | mode, priv->iobase + HW_WDMOD);
> > +
> > +	asm9260_wdt_updatetimeout(wdd);
> > +
> > +	asm9260_wdt_feed(wdd);
> > +
> > +	return 0;
> > +}
> > +
> > +static int asm9260_wdt_disable(struct watchdog_device *wdd)
> > +{
> > +	struct asm9260_wdt_priv *priv = watchdog_get_drvdata(wdd);
> > +
> > +	/* The only way to disable WD is to reset it. */
> > +	reset_control_assert(priv->rst);
> > +	reset_control_deassert(priv->rst);
> > +
> > +	return 0;
> > +}
> > +
> > +static int asm9260_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
> > +{
> > +	wdd->timeout = to;
> > +	asm9260_wdt_updatetimeout(wdd);
> > +
> > +	return 0;
> > +}
> > +
> > +static void asm9260_wdt_sys_reset(struct asm9260_wdt_priv *priv)
> > +{
> > +	/* init WD if it was not started */
> > +	priv->wdd.timeout = 1;
> > +
> > +	iowrite32(BM_MOD_WDEN | BM_MOD_WDRESET, priv->iobase + HW_WDMOD);
> > +
> > +	asm9260_wdt_updatetimeout(&priv->wdd);
> > +	/* first pass correct sequence */
> > +	asm9260_wdt_feed(&priv->wdd);
> > +	/*
> > +	 * Then write wrong pattern to the feed to trigger reset
> > +	 * ASAP.
> > +	 */
> > +	iowrite32(0xff, priv->iobase + HW_WDFEED);
> > +
> > +	mdelay(1000);
> > +}
> > +
> > +static irqreturn_t asm9260_wdt_irq(int irq, void *devid)
> > +{
> > +	struct asm9260_wdt_priv *priv = devid;
> > +	u32 stat;
> > +
> > +	stat = ioread32(priv->iobase + HW_WDMOD);
> > +	if (!(stat & BM_MOD_WDINT))
> > +		return IRQ_NONE;
> > +
> > +	/*
> > +	 * BM_MOD_WDINT flag can't be removed by SW. Only way is
> > +	 * to reset WD Controller.
> > +	 * TODO: add Controller reset if needed.
> > +	 */
> > +	if (priv->mode == DEBUG)
> > +		dev_info(priv->dev, "Watchdog Timeout. Do nothing.\n");
> > +	else {
> > +		dev_info(priv->dev, "Watchdog Timeout. Doing SW Reset.\n");
> > +		asm9260_wdt_sys_reset(priv);
> > +	}
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static int asm9260_restart_handler(struct notifier_block *this,
> > +				unsigned long mode, void *cmd)
> > +{
> > +	struct asm9260_wdt_priv *priv =
> > +		container_of(this, struct asm9260_wdt_priv, restart_handler);
> > +
> > +	asm9260_wdt_sys_reset(priv);
> > +
> > +	return NOTIFY_DONE;
> > +}
> > +
> > +static const struct watchdog_info asm9260_wdt_ident = {
> > +	.options          =     WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
> > +				| WDIOF_MAGICCLOSE,
> > +	.firmware_version =	0,
> > +	.identity         =	"Alphascale asm9260 Watchdog",
> > +};
> > +
> > +static struct watchdog_ops asm9260_wdt_ops = {
> > +	.owner		= THIS_MODULE,
> > +	.start		= asm9260_wdt_enable,
> > +	.stop		= asm9260_wdt_disable,
> > +	.get_timeleft	= asm9260_wdt_gettimeleft,
> > +	.ping		= asm9260_wdt_feed,
> > +	.set_timeout	= asm9260_wdt_settimeout,
> > +};
> > +
> > +static int __init asm9260_wdt_get_dt_clks(struct asm9260_wdt_priv *priv)
> > +{
> > +	int clk_idx = 0, err;
> > +
> > +	priv->clk = devm_clk_get(priv->dev, "mod");
> > +	if (IS_ERR(priv->clk))
> > +		goto out_err;
> > +
> > +	/* configure AHB clock */
> > +	clk_idx = 1;
> > +	priv->clk_ahb = devm_clk_get(priv->dev, "ahb");
> > +	if (IS_ERR(priv->clk_ahb))
> > +		goto out_err;
> > +
> > +	err = clk_prepare_enable(priv->clk_ahb);
> > +	if (err)
> > +		dev_err(priv->dev, "Failed to enable ahb_clk!\n");
> > +
> > +	err = clk_set_rate(priv->clk, CLOCK_FREQ);
> > +	if (err) {
> > +		clk_disable_unprepare(priv->clk_ahb);
> > +		dev_err(priv->dev, "Failed to set rate!\n");
> > +	}
> > +
> > +	err = clk_prepare_enable(priv->clk);
> > +	if (err) {
> > +		clk_disable_unprepare(priv->clk_ahb);
> > +		dev_err(priv->dev, "Failed to enable clk!\n");
> > +	}
> > +
> > +	/* wdt has internal divider */
> > +	priv->wdt_freq = clk_get_rate(priv->clk) / 2;
> > +
> > +	return 0;
> > +out_err:
> > +	dev_err(priv->dev, "%s: Failed to get clk (%i)\n", __func__, clk_idx);
> > +	return 1;
> > +}
> > +
> > +static void __init asm9260_wdt_get_dt_mode(struct asm9260_wdt_priv *priv)
> > +{
> > +	const char *tmp;
> > +	int ret;
> > +
> > +	/* default mode */
> > +	priv->mode = HW_RESET;
> > +
> > +	ret = of_property_read_string(priv->dev->of_node,
> > +			"alphascale,mode", &tmp);
> > +	if (ret)
> > +		return;
> > +
> > +	if (!strcmp(tmp, "hw"))
> > +		priv->mode = HW_RESET;
> > +	else if (!strcmp(tmp, "sw"))
> > +		priv->mode = SW_RESET;
> > +	else if (!strcmp(tmp, "debug"))
> > +		priv->mode = DEBUG;
> > +	else {
> > +		dev_warn(priv->dev, "unknown reset-type: %s. Using defaul \"hw\" mode.",
> > +			tmp);
> > +		return;
> > +	}
> > +
> > +	dev_info(priv->dev, "using \"%s\" mode.", tmp);
> > +}
> > +
> > +static int __init asm9260_wdt_probe(struct platform_device *pdev)
> > +{
> > +	struct asm9260_wdt_priv *priv;
> > +	struct watchdog_device *wdd;
> > +	struct resource *res;
> > +	bool nowayout = WATCHDOG_NOWAYOUT;
> > +	int ret;
> > +
> > +	priv = devm_kzalloc(&pdev->dev, sizeof(struct asm9260_wdt_priv),
> > +			GFP_KERNEL);
> > +	if (!priv)
> > +		return -ENOMEM;
> > +
> > +	priv->dev = &pdev->dev;
> > +
> > +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +	priv->iobase = devm_ioremap_resource(&pdev->dev, res);
> > +	if (IS_ERR(priv->iobase))
> > +		return PTR_ERR(priv->iobase);
> > +
> > +	ret = asm9260_wdt_get_dt_clks(priv);
> > +	if (ret)
> > +		return ret;
> > +
> > +	priv->rst = devm_reset_control_get(&pdev->dev, "wdt_rst");
> > +	if (IS_ERR(priv->rst)) {
> > +		dev_info(&pdev->dev, "No reset control found. Enabling \"nowayout\" mode\n");
> > +		nowayout = 1;
> > +		priv->rst = NULL;
> > +	}
> > +
> > +	wdd = &priv->wdd;
> > +	wdd->info = &asm9260_wdt_ident;
> > +	wdd->ops = &asm9260_wdt_ops;
> > +	wdd->min_timeout = 1;
> > +	wdd->max_timeout = BM_WDTC_MAX(priv->wdt_freq);
> > +	wdd->parent = &pdev->dev;
> > +
> > +	watchdog_set_drvdata(wdd, priv);
> > +
> > +	/*
> > +	 * If 'timeout-sec' unspecified in devicetree, assume a 30 second
> > +	 * default, unless the max timeout is less than 30 seconds, then use
> > +	 * the max instead.
> > +	 */
> > +	wdd->timeout = ASM9260_WDT_DEFAULT_TIMEOUT;
> > +	watchdog_init_timeout(wdd, 0, &pdev->dev);
> > +
> > +	watchdog_set_nowayout(wdd, nowayout);
> > +
> > +	asm9260_wdt_get_dt_mode(priv);
> > +
> > +	if (priv->mode != HW_RESET)
> > +		priv->irq = platform_get_irq(pdev, 0);
> > +
> > +	if (priv->irq > 0) {
> > +		/*
> > +		 * Not all supported platforms specify an interrupt for the
> > +		 * watchdog, so let's make it optional.
> > +		 */
> > +		ret = devm_request_irq(&pdev->dev, priv->irq,
> > +				asm9260_wdt_irq, IRQF_SHARED,
> > +				pdev->name, priv);
> > +		if (ret < 0)
> > +			dev_err(&pdev->dev, "failed to request IRQ\n");
> > +	}
> > +
> > +	ret = watchdog_register_device(wdd);
> > +	if (ret)
> > +		goto clk_off;
> > +
> > +	platform_set_drvdata(pdev, priv);
> > +
> > +	priv->restart_handler.notifier_call = asm9260_restart_handler;
> > +	priv->restart_handler.priority = 128;
> > +	ret = register_restart_handler(&priv->restart_handler);
> > +	if (ret)
> > +		dev_err(&pdev->dev, "cannot register restart handler\n");
> > +
> > +	dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
> > +		wdd->timeout, nowayout);
> > +	return 0;
> > +
> > +clk_off:
> > +	clk_disable_unprepare(priv->clk);
> > +	clk_disable_unprepare(priv->clk_ahb);
> > +	return ret;
> > +}
> > +
> > +static void asm9260_wdt_shutdown(struct platform_device *pdev)
> > +{
> > +	struct asm9260_wdt_priv *priv = platform_get_drvdata(pdev);
> > +
> > +	asm9260_wdt_disable(&priv->wdd);
> > +}
> > +
> > +static int __exit asm9260_wdt_remove(struct platform_device *pdev)
> > +{
> > +	struct asm9260_wdt_priv *priv = platform_get_drvdata(pdev);
> > +
> > +	asm9260_wdt_shutdown(pdev);
> > +
> > +	unregister_restart_handler(&priv->restart_handler);
> > +	clk_disable_unprepare(priv->clk);
> > +	clk_disable_unprepare(priv->clk_ahb);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct of_device_id asm9260_wdt_of_match[] = {
> > +	{ .compatible = "alphascale,asm9260-wdt"},
> > +	{},
> > +};
> > +MODULE_DEVICE_TABLE(of, asm9260_wdt_of_match);
> > +
> > +static struct platform_driver asm9260_wdt_driver = {
> > +	.driver = {
> > +		.name = "asm9260-wdt",
> > +		.owner = THIS_MODULE,
> > +		.of_match_table	= asm9260_wdt_of_match,
> > +	},
> > +	.probe = asm9260_wdt_probe,
> > +	.remove = asm9260_wdt_remove,
> > +	.shutdown = asm9260_wdt_shutdown,
> > +};
> > +module_platform_driver(asm9260_wdt_driver);
> > +
> > +MODULE_DESCRIPTION("asm9260 WatchDog Timer Driver");
> > +MODULE_AUTHOR("Oleksij Rempel <linux@rempel-privat.de>");
> > +MODULE_LICENSE("GPL");
> > 
> 
> 
> -- 
> Regards,
> Oleksij
>