Re: [PATCH v2] ARM: sunxi: New watchdog driver for Allwinner A10/A13

[Maxime Ripard <maxime.ripard@free-electrons.com>]

Hi Carlo,

On Sat, May 18, 2013 at 09:05:56PM +0200, Carlo Caione wrote:
> This patch adds the driver for the watchdog found in the Allwinner A10 and
> A13 SoCs. It has DT-support and uses the new watchdog framework.
> 
> Signed-off-by: Carlo Caione <carlo.caione@gmail.com>
> ---
>  drivers/watchdog/Kconfig     |  10 ++
>  drivers/watchdog/Makefile    |   1 +
>  drivers/watchdog/sunxi_wdt.c | 226 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 237 insertions(+)
>  create mode 100644 drivers/watchdog/sunxi_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index e89fc31..8ad2238 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -299,6 +299,16 @@ config ORION_WATCHDOG
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called orion_wdt.
>  
> +config SUNXI_WATCHDOG
> +	tristate "Allwinner SoCs watchdog support"
> +	depends on ARCH_SUNXI
> +	select WATCHDOG_CORE
> +	help
> +	  Say Y here to include support for the watchdog timer
> +	  in Allwinner SoCs.
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called sunxi_wdt.
> +
>  config COH901327_WATCHDOG
>  	bool "ST-Ericsson COH 901 327 watchdog"
>  	depends on ARCH_U300
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index a300b94..5012d5f 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -47,6 +47,7 @@ obj-$(CONFIG_PNX4008_WATCHDOG) += pnx4008_wdt.o
>  obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
>  obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o
>  obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o
> +obj-$(CONFIG_SUNXI_WATCHDOG) += sunxi_wdt.o
>  obj-$(CONFIG_COH901327_WATCHDOG) += coh901327_wdt.o
>  obj-$(CONFIG_STMP3XXX_RTC_WATCHDOG) += stmp3xxx_rtc_wdt.o
>  obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
> diff --git a/drivers/watchdog/sunxi_wdt.c b/drivers/watchdog/sunxi_wdt.c
> new file mode 100644
> index 0000000..105b26a
> --- /dev/null
> +++ b/drivers/watchdog/sunxi_wdt.c
> @@ -0,0 +1,226 @@
> +/*
> + *      sunxi Watchdog Driver
> + *
> + *      Copyright (c) 2013 Carlo Caione
> + *                    2012 Henrik Nordstrom
> + *
> + *      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.
> + *
> + *      Based on xen_wdt.c
> + *      (c) Copyright 2010 Novell, Inc.
> + */
> +
> +#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/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/types.h>
> +#include <linux/watchdog.h>
> +
> +#define WDT_MAX_TIMEOUT         16
> +#define WDT_MIN_TIMEOUT         1
> +#define WDT_MODE_TIMEOUT(n)     ((n) << 3)
> +#define WDT_TIMEOUT_MASK        WDT_MODE_TIMEOUT(0x0F)
> +
> +#define WDT_CTRL                0x00
> +#define WDT_CTRL_RESTART        (1 << 0)
> +#define WDT_CTRL_RESERVED       (0x0a57 << 1)

You didn't replied to me on that part in the previous mail. It doesn't
seem to be needed, so why keeping it?

> +#define WDT_MODE                0x04
> +#define WDT_MODE_EN             (1 << 0)
> +#define WDT_MODE_RST_EN         (1 << 1)
> +
> +#define DRV_NAME		"sunxi-wdt"
> +#define DRV_VERSION		"1.0"
> +
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +static int heartbeat = WDT_MAX_TIMEOUT;
> +
> +/*
> + * wdt_timeout_map maps the watchdog timer interval value in seconds to
> + * the value of the register WDT_MODE bit 3:6
> + *
> + * [timeout seconds] = register value
> + *
> + */
> +
> +static const int wdt_timeout_map[] = {
> +	[1] = 0b0001,  /* 1s  */
> +	[2] = 0b0010,  /* 2s  */
> +	[3] = 0b0011,  /* 3s  */
> +	[4] = 0b0100,  /* 4s  */
> +	[5] = 0b0101,  /* 5s  */
> +	[6] = 0b0110,  /* 6s  */
> +	[8] = 0b0111,  /* 8s  */
> +	[10] = 0b1000, /* 10s */
> +	[12] = 0b1001, /* 12s */
> +	[14] = 0b1010, /* 14s */
> +	[16] = 0b1011, /* 16s */
> +};

Much better, thanks :)

> +
> +static int sunxi_wdt_ping(struct watchdog_device *sunxi_wdt_dev)
> +{
> +	u32 reg;
> +	void __iomem *wdt_base = watchdog_get_drvdata(sunxi_wdt_dev);
> +
> +	reg = ioread32(wdt_base + WDT_CTRL);
> +	reg |= (WDT_CTRL_RESTART | WDT_CTRL_RESERVED);
> +	iowrite32(reg, wdt_base + WDT_CTRL);
> +
> +	return 0;
> +}
> +
> +static int sunxi_wdt_set_timeout(struct watchdog_device *sunxi_wdt_dev,
> +		unsigned int timeout)
> +{
> +	u32 reg;
> +	void __iomem *wdt_base = watchdog_get_drvdata(sunxi_wdt_dev);
> +
> +	if ((timeout > WDT_MAX_TIMEOUT) || (0 == wdt_timeout_map[timeout]))
> +		return -EINVAL;
> +
> +	sunxi_wdt_dev->timeout = timeout;
> +
> +	reg = ioread32(wdt_base + WDT_MODE);
> +	reg &= ~(WDT_TIMEOUT_MASK);
> +	reg |= WDT_MODE_TIMEOUT(wdt_timeout_map[sunxi_wdt_dev->timeout]);
> +	iowrite32(reg, wdt_base + WDT_MODE);
> +
> +	sunxi_wdt_ping(sunxi_wdt_dev);
> +
> +	return 0;
> +}
> +
> +static int sunxi_wdt_stop(struct watchdog_device *sunxi_wdt_dev)
> +{
> +	u32 reg;
> +	void __iomem *wdt_base = watchdog_get_drvdata(sunxi_wdt_dev);
> +
> +	reg = ioread32(wdt_base + WDT_MODE);
> +	reg &= ~(WDT_MODE_RST_EN | WDT_MODE_EN);
> +	iowrite32(reg, wdt_base + WDT_MODE);
> +
> +	return 0;
> +}
> +
> +static int sunxi_wdt_start(struct watchdog_device *sunxi_wdt_dev)
> +{
> +	u32 reg;
> +	int ret;
> +	void __iomem *wdt_base = watchdog_get_drvdata(sunxi_wdt_dev);
> +
> +	ret = sunxi_wdt_set_timeout(sunxi_wdt_dev, sunxi_wdt_dev->timeout);
> +	if (ret < 0)
> +		return ret;
> +
> +	reg = ioread32(wdt_base + WDT_MODE);
> +	reg |= (WDT_MODE_RST_EN | WDT_MODE_EN);
> +	iowrite32(reg, wdt_base + WDT_MODE);
> +
> +	return 0;
> +}
> +
> +static const struct watchdog_info sunxi_wdt_info = {
> +	.identity	= DRV_NAME,
> +	.options	= WDIOF_SETTIMEOUT |
> +			  WDIOF_KEEPALIVEPING |
> +			  WDIOF_MAGICCLOSE,
> +};
> +
> +static const struct watchdog_ops sunxi_wdt_ops = {
> +	.owner		= THIS_MODULE,
> +	.start		= sunxi_wdt_start,
> +	.stop		= sunxi_wdt_stop,
> +	.ping		= sunxi_wdt_ping,
> +	.set_timeout	= sunxi_wdt_set_timeout,
> +};
> +
> +static struct watchdog_device sunxi_wdt_dev = {
> +	.info		= &sunxi_wdt_info,
> +	.ops		= &sunxi_wdt_ops,
> +	.timeout	= WDT_MAX_TIMEOUT,
> +	.max_timeout	= WDT_MAX_TIMEOUT,
> +	.min_timeout	= WDT_MIN_TIMEOUT,
> +};
> +
> +static int __init sunxi_wdt_probe(struct platform_device *pdev)
> +{
> +	int err;
> +	void __iomem *wdt_base;
> +
> +	wdt_base = of_iomap(pdev->dev.of_node, 0);
> +	if (unlikely(!wdt_base)) {
> +		err = -ENOMEM;
> +		goto error_mem_out;
> +	}
> +
> +	sunxi_wdt_dev.parent = &pdev->dev;
> +	watchdog_init_timeout(&sunxi_wdt_dev, heartbeat, &pdev->dev);
> +	watchdog_set_nowayout(&sunxi_wdt_dev, nowayout);
> +
> +	err = watchdog_register_device(&sunxi_wdt_dev);
> +	if (unlikely(err))
> +		goto error_wdt;
> +
> +	watchdog_set_drvdata(&sunxi_wdt_dev, wdt_base);
> +
> +	pr_info("Watchdog enabled (heartbeat=%d sec, nowayout=%d)",
> +			sunxi_wdt_dev.timeout, nowayout);
> +	return 0;
> +
> +error_wdt:
> +	iounmap(wdt_base);
> +error_mem_out:
> +	return err;
> +}
> +
> +static int __exit sunxi_wdt_remove(struct platform_device *pdev)
> +{
> +	void __iomem *wdt_base = watchdog_get_drvdata(&sunxi_wdt_dev);
> +
> +	sunxi_wdt_stop(&sunxi_wdt_dev);
> +	watchdog_unregister_device(&sunxi_wdt_dev);
> +	iounmap(wdt_base);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id sunxi_wdt_dt_ids[] = {
> +	{ .compatible = "allwinner,sun4i-wdt" },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
> +
> +static struct platform_driver sunxi_wdt_driver = {
> +	.probe		= sunxi_wdt_probe,
> +	.remove		= sunxi_wdt_remove,
> +	.driver		= {
> +		.owner		= THIS_MODULE,
> +		.name		= DRV_NAME,
> +		.of_match_table	= of_match_ptr(sunxi_wdt_dt_ids)
> +	},
> +};
> +
> +module_platform_driver(sunxi_wdt_driver);
> +
> +module_param(heartbeat, int, 0);
> +MODULE_PARM_DESC(heartbeat, "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("Carlo Caione <carlo.caione@gmail.com>");
> +MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>");
> +MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
> +MODULE_VERSION(DRV_VERSION);
> -- 
> 1.8.2.3
> 

I'm pretty happy with this driver, we only need to figure out this
reserved bits stuff, and we'll be fine.

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com